Immunopathological Aspects

**3**

**Chapter 1**

**Abstract**

be emphasized.

**1. Introduction**

immune response.

these cells [2]. TCD4+

*Giovanna Rosa Degasperi*

response, T regulatory cells, toll-like receptors

in a process known as differentiation of TCD4+

Mucosal Immunology in the

Inflammatory Bowel Diseases

Inflammatory bowel disease (IBD) includes two major phenotypes, Crohn's disease and ulcerative colitis, which have different clinical characteristics and immune response profiles. Dysregulation of the intestinal immune response with elevated secretion of proinflammatory cytokines is a hallmark of IBD. In this chapter, we will characterize the cells of the innate and adaptive immunity involved in the pathogenesis of IBD. Innate lymphoid cells as well as dendritic cells, neutrophils, macrophages, B cells and T cells, including Th1 and Th2, Th9 and Th17 cells will be specifically characterized in this scenario. The cross talks and cytokine-mediated regulation of these cells with emphasis on cytokines IL-17, IL-22 and IL-23 will also

**Keywords:** inflammatory bowel disease, innate immune response, adaptive immune

Inflammatory bowel disease has become a worldwide health burden with increasing incidence and prevalence, contributing to the increased risk of colorectal cancer development [1]. IBD encompasses both Crohn's disease (CD) and ulcerative colitis (UC). Its etiopathology is still unknown, although it is believed that it may be a combination of genetic and environmental factors, as well as microbiota, diet and

Evidence suggests that abnormalities in both the innate and adaptive immune responses against intestinal microbiota, harmful antigens or extrinsic pathogens which may have crossed the intestinal barrier play an important role in the inflammatory process associated with the disease in genetically susceptible individuals. Several components of the mucosal immune system are implicated in the pathogenesis of IBD, including innate lymphoid cells, innate immune response (macrophages, neutrophils, and dendritic cells), and adaptive immune response (T and B cells) cells, as well as different cytokine and chemokine types which are secreted by

lymphocytes from the intestinal mucosa, through the production of

or Th0 cells, which results in the

pro-inflammatory cytokines, play a central role both in the induction and in the persistence of chronic inflammation which are characteristic of CD and UC. These cells are key components of the adaptive immune response able to secrete specific cytokines in response to the recognition of peptides in MHC Class II in antigenpresenting cells (ACP), several cytokines and the expression of transition factors,

#### **Chapter 1**

## Mucosal Immunology in the Inflammatory Bowel Diseases

*Giovanna Rosa Degasperi*

#### **Abstract**

Inflammatory bowel disease (IBD) includes two major phenotypes, Crohn's disease and ulcerative colitis, which have different clinical characteristics and immune response profiles. Dysregulation of the intestinal immune response with elevated secretion of proinflammatory cytokines is a hallmark of IBD. In this chapter, we will characterize the cells of the innate and adaptive immunity involved in the pathogenesis of IBD. Innate lymphoid cells as well as dendritic cells, neutrophils, macrophages, B cells and T cells, including Th1 and Th2, Th9 and Th17 cells will be specifically characterized in this scenario. The cross talks and cytokine-mediated regulation of these cells with emphasis on cytokines IL-17, IL-22 and IL-23 will also be emphasized.

**Keywords:** inflammatory bowel disease, innate immune response, adaptive immune response, T regulatory cells, toll-like receptors

#### **1. Introduction**

Inflammatory bowel disease has become a worldwide health burden with increasing incidence and prevalence, contributing to the increased risk of colorectal cancer development [1]. IBD encompasses both Crohn's disease (CD) and ulcerative colitis (UC). Its etiopathology is still unknown, although it is believed that it may be a combination of genetic and environmental factors, as well as microbiota, diet and immune response.

Evidence suggests that abnormalities in both the innate and adaptive immune responses against intestinal microbiota, harmful antigens or extrinsic pathogens which may have crossed the intestinal barrier play an important role in the inflammatory process associated with the disease in genetically susceptible individuals. Several components of the mucosal immune system are implicated in the pathogenesis of IBD, including innate lymphoid cells, innate immune response (macrophages, neutrophils, and dendritic cells), and adaptive immune response (T and B cells) cells, as well as different cytokine and chemokine types which are secreted by these cells [2].

TCD4+ lymphocytes from the intestinal mucosa, through the production of pro-inflammatory cytokines, play a central role both in the induction and in the persistence of chronic inflammation which are characteristic of CD and UC. These cells are key components of the adaptive immune response able to secrete specific cytokines in response to the recognition of peptides in MHC Class II in antigenpresenting cells (ACP), several cytokines and the expression of transition factors, in a process known as differentiation of TCD4+ or Th0 cells, which results in the

generation of T helper lymphocytes (Th) Th1, Th2, Th17, and Th9. These cells have the peculiarity of secreting specific cytokines. These subsets of differentiated T helper lymphocytes perform a number of functions. However, immune responses executed in a dysregulated manner by some of these subsets result in chronic inflammation and tissue damage [3].

In the intestinal mucosa, APCs such as dendritic cells can induce differentiation of *naïve* TCD4+ lymphocytes in one of the specific subsets of T helper which will be responsible for altering intestinal homeostasis, contributing to the setting in of chronic inflammation in the intestine which is a hallmark of IBD. While CD is mediated by Th1 cells, UC has been identified as a disease associated to Th2 cells. Studies indicate that, in CD, the Th1-related cytokines, such as the tumoral necrosis factor α (TNF-α), interferon-γ (IFN-γ), interleukin-12 (IL-12), as well as those associated to Th17 such as IL-17A, IL-21, and IL-23, are increased in the intestinal mucosa [4]. In UC, it has been demonstrated that there is an increase in the production of IL-5 and IL-13 which are Th2 identity cytokine [5].

In addition to Th17 cells, IL-9-secreting Th9 cells can also promote exacerbate inflammatory diseases such as IBD [6, 7]. Th9 cells are also known to be involved in immunity against helminth parasites [8]. Moreover, results from colitis animal models and studies in humans indicate a role for innate lymphoid cells (ILC) in the pathogenesis of chronic intestinal inflammation in IBD. The ILC are a population of lymphocytes present in regions of the mucosa, in which they perform the function of protecting against pathogens, including extracellular bacteria, helminths, and viruses. The ILCs are cells with a high degree of plasticity depending on the exposition to cytokines from the microenvironment in which they are present.

#### **2. General features of the colon mucosal: barriers of protection and intestinal immune system**

The intestinal epithelium has important functions, such as absorption, secretion and digestion. In the epithelium, in addition to enterocytes, some other epithelial cells, such as goblet cells, perform a protective function through the secretion of mucus. This protective action may be verified in experiments with animal models which show that MUC2-null mice developed spontaneous colitis [9]. In addition to goblet cells, Paneth cells also display protective action, since they produce defensins, which are antimicrobial peptides that modulate the composition of the intestinal microbiota [10].

The epithelium forms a mucous barrier with tight junctions between the enterocytes preventing the entrance of a myriad of substances. Defects in the epithelial integrity may contribute to the development of IBD, allowing the passage of microorganisms through the epithelial layer. In chronic inflammatory disorders, such as IBD, the microbial components of the microbiota are translocated through the damaged barrier of the mucosa and, through the interaction with cells of the immune system in the lamina propria, trigger an inflammatory response [11].

The intestinal epithelium is located between the lumen and the lamina propria. In the lamina propria there are cells of the immune system, and, in the lumen, the microbiota consists of commensal microorganisms, including bacteria, viruses and fungi. The most abundant cells in the epithelial compartment are absorptive cells, which not only provide a physical barrier against luminal antigens, but also mediate the crosstalk between the intestinal microbiome and the immune system of the host, particularly through the innate immune receptors, specifically, the pattern recognition receptors (PRR), known as Toll-like receptors (TLR), which are expressed throughout the intestinal tract. The healthy human small intestine

**5**

related to IBD.

*Mucosal Immunology in the Inflammatory Bowel Diseases*

patibility complex type II (MHC II). The TCD4+

expresses TLR-2 and TLR-4 [12]. Cells of the innate immune compartment which reside in the lamina propria are sentinels which detect invading pathogens through their TLR. These cells are part of the mononuclear phagocytic system, including macrophages and dendritic cells which encompass and process microbial antigens

which activate B cells into transforming into plasmocytes which selectively produce

The IgA is an abundant isotype in blood serum, in which it is normally present in concentrations of 1 to 3 mg/ml. In circulation, IgA is generally found as a monomer IgA [13, 14]. Dimeric IgA is the predominant antibody in secretions of the gastrointestinal tract. In this format, IgA is generated by the union of two molecules of monomeric IgA. Its production is mediated by the plasmocytes located in the lamina propria of the mucosa, and, despite being a protein, IgA present in the secretions of the lumen is quite resistant to proteolysis by the gastric and intestinal

The process of transport and secretion of this immunoglobulin of the plasmocytes located in the lamina propria from the mucosa to the intestinal lumen occurs through the connection to receptors for immunoglobulins which are expressed in the mucosal epithelial cells' basal layer. Once the connection is made, the complex formed is endocytosed by the epithelial cell and transported to the apical portion of the cell membrane, where it is then liberated in the lumen with the extracellular

In the lumen, these IgA have the capacity to connect to antigens from the mucosa surface, preventing their penetration and adherence to the epithelial layer of the mucosa. The formation of the antigen-sIgA complex favors the retention of pathogenic microorganisms to the mucus and stimulates its secretion, facilitating the enzymatic degradation and antigen elimination without having to activate the

In patients with IBD, the damage of the barrier function of the intestinal epithelial layer results in an influx of IgA-opsonized bacteria. Interestingly, it has been demonstrated that the presence of these immune IgA complexes in the lamina propria contributes to inflammation induced by FcαRI [13]. Recent findings have demonstrated that co-stimulation of FcαRI strongly affects pro-inflammatory cytokine production by some immune system cells such as phagocytes. FcαRI is also

Thus, there is ample evidence of defense against intestinal pathogens. The epithelial layer, mucus, antimicrobial peptides, immune system cells in the lamina propria, and IgA together help to establish a beneficial environment to tolerate the diverse community of bacteria of the microbiota and food antigens, as well as to

Throughout the gastrointestinal mucosa there are receptors which specialize in identifying pathogenic microorganisms. The process of recognition of pathogens is highly specific and occurs through the connection between pathogen-associated molecular patters (PAMP) and PRR. Known PRR are classified as: TLR, NOD-like receptors (NLR), RIG-1-like receptors (RLR), of which the TLR are the most cor-

In mammals, TLR comprise a family of 13 types of receptors, of which TLR 1**–**9 are more easily found in cells from the small and large intestines. In humans, only

expressed in immune cells such as eosinophils and dendritic cells [18].

elaborate a response against pathogenic microorganisms.

**3. TLRS: key immune sensors of microbiota in the gut**

fragment of the receptor, thus forming secretory IgA (sIgA) [16].

lymphocytes from Peyer's patches, through major histocom-

lymphocytes produce cytokines

*DOI: http://dx.doi.org/10.5772/intechopen.90037*

in the *naïve* TCD4+

enzymes [15].

immunoglobulin A (IgA).

inflammatory response [17].

*Biological Therapy for Inflammatory Bowel Disease*

inflammation and tissue damage [3].

**intestinal immune system**

intestinal microbiota [10].

of *naïve* TCD4+

generation of T helper lymphocytes (Th) Th1, Th2, Th17, and Th9. These cells have the peculiarity of secreting specific cytokines. These subsets of differentiated T helper lymphocytes perform a number of functions. However, immune responses executed in a dysregulated manner by some of these subsets result in chronic

In the intestinal mucosa, APCs such as dendritic cells can induce differentiation

In addition to Th17 cells, IL-9-secreting Th9 cells can also promote exacerbate inflammatory diseases such as IBD [6, 7]. Th9 cells are also known to be involved in immunity against helminth parasites [8]. Moreover, results from colitis animal models and studies in humans indicate a role for innate lymphoid cells (ILC) in the pathogenesis of chronic intestinal inflammation in IBD. The ILC are a population of lymphocytes present in regions of the mucosa, in which they perform the function of protecting against pathogens, including extracellular bacteria, helminths, and viruses. The ILCs are cells with a high degree of plasticity depending on the exposi-

tion to cytokines from the microenvironment in which they are present.

**2. General features of the colon mucosal: barriers of protection and** 

The intestinal epithelium has important functions, such as absorption, secretion and digestion. In the epithelium, in addition to enterocytes, some other epithelial cells, such as goblet cells, perform a protective function through the secretion of mucus. This protective action may be verified in experiments with animal models which show that MUC2-null mice developed spontaneous colitis [9]. In addition to goblet cells, Paneth cells also display protective action, since they produce defensins, which are antimicrobial peptides that modulate the composition of the

The epithelium forms a mucous barrier with tight junctions between the enterocytes preventing the entrance of a myriad of substances. Defects in the epithelial integrity may contribute to the development of IBD, allowing the passage of microorganisms through the epithelial layer. In chronic inflammatory disorders, such as IBD, the microbial components of the microbiota are translocated through the damaged barrier of the mucosa and, through the interaction with cells of the immune system in the lamina propria, trigger an inflammatory response [11].

The intestinal epithelium is located between the lumen and the lamina propria. In the lamina propria there are cells of the immune system, and, in the lumen, the microbiota consists of commensal microorganisms, including bacteria, viruses and fungi. The most abundant cells in the epithelial compartment are absorptive cells, which not only provide a physical barrier against luminal antigens, but also mediate the crosstalk between the intestinal microbiome and the immune system of the host, particularly through the innate immune receptors, specifically, the pattern recognition receptors (PRR), known as Toll-like receptors (TLR), which are expressed throughout the intestinal tract. The healthy human small intestine

be responsible for altering intestinal homeostasis, contributing to the setting in of chronic inflammation in the intestine which is a hallmark of IBD. While CD is mediated by Th1 cells, UC has been identified as a disease associated to Th2 cells. Studies indicate that, in CD, the Th1-related cytokines, such as the tumoral necrosis factor α (TNF-α), interferon-γ (IFN-γ), interleukin-12 (IL-12), as well as those associated to Th17 such as IL-17A, IL-21, and IL-23, are increased in the intestinal mucosa [4]. In UC, it has been demonstrated that there is an increase in the produc-

tion of IL-5 and IL-13 which are Th2 identity cytokine [5].

lymphocytes in one of the specific subsets of T helper which will

**4**

expresses TLR-2 and TLR-4 [12]. Cells of the innate immune compartment which reside in the lamina propria are sentinels which detect invading pathogens through their TLR. These cells are part of the mononuclear phagocytic system, including macrophages and dendritic cells which encompass and process microbial antigens in the *naïve* TCD4+ lymphocytes from Peyer's patches, through major histocompatibility complex type II (MHC II). The TCD4+ lymphocytes produce cytokines which activate B cells into transforming into plasmocytes which selectively produce immunoglobulin A (IgA).

The IgA is an abundant isotype in blood serum, in which it is normally present in concentrations of 1 to 3 mg/ml. In circulation, IgA is generally found as a monomer IgA [13, 14]. Dimeric IgA is the predominant antibody in secretions of the gastrointestinal tract. In this format, IgA is generated by the union of two molecules of monomeric IgA. Its production is mediated by the plasmocytes located in the lamina propria of the mucosa, and, despite being a protein, IgA present in the secretions of the lumen is quite resistant to proteolysis by the gastric and intestinal enzymes [15].

The process of transport and secretion of this immunoglobulin of the plasmocytes located in the lamina propria from the mucosa to the intestinal lumen occurs through the connection to receptors for immunoglobulins which are expressed in the mucosal epithelial cells' basal layer. Once the connection is made, the complex formed is endocytosed by the epithelial cell and transported to the apical portion of the cell membrane, where it is then liberated in the lumen with the extracellular fragment of the receptor, thus forming secretory IgA (sIgA) [16].

In the lumen, these IgA have the capacity to connect to antigens from the mucosa surface, preventing their penetration and adherence to the epithelial layer of the mucosa. The formation of the antigen-sIgA complex favors the retention of pathogenic microorganisms to the mucus and stimulates its secretion, facilitating the enzymatic degradation and antigen elimination without having to activate the inflammatory response [17].

In patients with IBD, the damage of the barrier function of the intestinal epithelial layer results in an influx of IgA-opsonized bacteria. Interestingly, it has been demonstrated that the presence of these immune IgA complexes in the lamina propria contributes to inflammation induced by FcαRI [13]. Recent findings have demonstrated that co-stimulation of FcαRI strongly affects pro-inflammatory cytokine production by some immune system cells such as phagocytes. FcαRI is also expressed in immune cells such as eosinophils and dendritic cells [18].

Thus, there is ample evidence of defense against intestinal pathogens. The epithelial layer, mucus, antimicrobial peptides, immune system cells in the lamina propria, and IgA together help to establish a beneficial environment to tolerate the diverse community of bacteria of the microbiota and food antigens, as well as to elaborate a response against pathogenic microorganisms.

#### **3. TLRS: key immune sensors of microbiota in the gut**

Throughout the gastrointestinal mucosa there are receptors which specialize in identifying pathogenic microorganisms. The process of recognition of pathogens is highly specific and occurs through the connection between pathogen-associated molecular patters (PAMP) and PRR. Known PRR are classified as: TLR, NOD-like receptors (NLR), RIG-1-like receptors (RLR), of which the TLR are the most correlated to IBD.

In mammals, TLR comprise a family of 13 types of receptors, of which TLR 1**–**9 are more easily found in cells from the small and large intestines. In humans, only

TLR 2, 3, 4, 5, and 9 have been consistently identified, highlighting that TLR-3 and TLR-5 are present in larger numbers in the enterocytes. The TLR are found in the plasma membrane or in the endosomal intracellular compartments. The activation of these receptors is made by PAMP which have relative specificity to distinct TLR. The TLR-2, for example, identifies peptidoglycans and lipoproteins; TLR-3 identifies viral RNA; TLR-4 recognizes lipopolysaccharide (LPS); TLR-5 recognizes flagellin, and TLR-9 connects to bacterial DNA. Despite the small number of receptors, this distribution reflects the elevated capacity for identifying molecular patters in a number of pathogens [19].

Once activated, TLR become dimerized and trigger the subsequent activation of downstream signaling cascades, e.g., the activation of NF-κB which leads to the induction of a variety of inflammatory cytokines. Except for TLR3, other TLR signaling pathways depend on MyD88 to activate NF-κB and produce pro-inflammatory cytokines. The TLR signaling pathway is quite similar to the interleukin (IL)-1R family, since TLR contains the domain Toll/Interleukin-1 (TIR). The TIR domain contains the TIRAP adaptor protein. When TLR-1, 2 or 6 are activated, the domain containing TIRAP lying downstream of these TLR and recruits the adaptor protein from the primary myeloid response 88 (MyD88) which leads to the activation of the kinase associated with the IL-1 receptor (IRAK). The activation of IRAK, in turn, induces the activation of serine and threonine kinases which are responsible for the degrading of IκB*α*, known as an inhibitor of the nuclear transcription factor κB or NF-κB. The degrading of IκB*α* allows for the migration of the NF-κB from cytoplasm to the nucleus. In the nucleus, this nuclear factor induces the production of pro-inflammatory cytokines and chemokines which will trigger the innate and, subsequently, the adaptive immune responses [20].

Furthermore, there is an alternate signaling pathway to MyD88 which involves TLR-3 and TLR-4. This alternate pathway is mediated by the activation of the TIRdomain-containing adapter-inducing Interferon-β (TRIF). Thus, signaling TLR is divided in two pathways: one dependent on MyD88 and the other independent of MyD88, but dependent on TRIF. Downstream of the TLR signaling pathways, activated NF-κB and interferon regulatory factor (IRF) to the production of proinflammatory cytokines [20].

Additionally, TLRs provides a connection between innate and adaptive immunity. Dendritic cells that is innate immune response cell, can sense microbes by these receptors in their surface. In this way, this cell controls microbial driven T lymphocyte polarization to Th1, Th2, Th9 or Th17 in lymphoid tissues. After interaction with microbial components, immature dendritic cell migrate to the draining lymphoid tissues to present microbial antigens to T lymphocytes [21]. It was hypothesized that an abnormal pattern of bacterial recognition by these cells through TLRs alter its activation and cytokine production which may underlie chronic inflammatory processes, such as IBD [22].

A number of studies have shown a correlation between TLR and IBD, be it enabling or inhibiting the disease. Interestingly, it has been demonstrated that TLR-2 must form heterodimers with TLR1 or TLR6 in order to trigger intracellular signaling pathways. The inhibition of TLR2/6 signaling has played a beneficial role by slowing down IBD progression. It was also reported that TLR6 was overexpressed in the intestines of IBD patients and might promote experimental colitis in mice [23]. In this case, it was proved that TLR-6 was important and activated the polarization of Th1 and Th17 of TCD4<sup>+</sup> lymphocytes. Also, considering that TLR4 gene expression was upregulated in the intestinal epithelia of patients with active UC, TLR4 might be a participant in UC disease development. Moreover, it was demonstrated that TLR8 is upregulated in patients with active UC and that the expression of the genes TLR2, 4, 8 and 9 is positively regulated in these patients.

**7**

CD103+

CD11b+

*Mucosal Immunology in the Inflammatory Bowel Diseases*

**the role of macrophages and dendritic cells**

means of the presentation of antigens to the *naïve* TCD4+

the inflammatory condition established by this disease [27].

microorganisms are presented to *naïve* TCD4+

the generation of responses by intestinal TCD4+

and CD103+

Contrary to the evidence presented above, which show TLR supporting IBD, studies show that the activation of TLR-9 prevented the development of inflammation of the mucosa, and fomented healing of wounds in models of colitis [24]. Still others presented data that TLR3, TLR7, or TLR9 agonists could induce type I IFN, which

**4. The link between innate and adaptive immune response in intestine:** 

The recognition of microorganisms for phagocytosis occurs by means of PRR. Macrophages also express PRR which recognize PAMP present on the surface of invading intestinal microorganisms. It is through this interaction that immune cells distinguish between commensal microorganisms and pathogens, thus designing an appropriate immune response program. Captured antigens from pathogenic

1998, it was described that intestinal macrophages in mice carrying colitis present low levels of MHC class II expression, which hinder adaptive immune response in

With relation to dendritic cells, they also have the function of transporting antigens to mesenteric lymph nodes and Peyer's patches, and, subsequently, inducing

gen. They act as sentinels, acquiring antigens in peripheral tissues before migrating to secondary lymphoid organs. Dendritic cells can recognize antigens through the emission of their extensions in the luminal region. Alternatively, this recognition may occur through M cells which are also considered as presenting antigens. The M cells can recognize antigens in the intestinal lumen, internalize them and present them to the dendritic cells located in the lamina propria of the mucosa [28, 29].

Dendritic cells and macrophages are characterized according to their expression of specific membrane markers [30]. The intestinal dendritic cells may be divided in

CD11b<sup>−</sup> in mice, or CD103<sup>+</sup>

Macrophages residing in the lamina may still be differentiated in two distinct phenotypes characterized as M1 and M2. Specific combinations of cytokines induce the polarization to one of these phenotypes. IFN-γ induces the appearance of the M1 phenotype, which has as its identity the secretion of TNF-α, IL-12, IL-6 and IL-23 pro-inflammatory cytokines. These cytokines are present in the context of inflammatory intestinal diseases. The M2 macrophages arise in microenvironments rich in IL-4 and produce large quantities of IL-10 [37]. It is known that mice deficient in IL-10 develop spontaneous colitis [38]. Moreover, mutations in genes which codify proteins in the IL10R subunit have been found in patients with early-onset enterocolitis [39]. Generally, while M1 macrophages cause tissue damage and hinder cell proliferation, M2 macrophages support proliferation and tissue repair [40]. It was shown that M1 macrophages which invade intestinal tissues contribute directly

humans [31]. Dendritic cells, both in mice and humans, stimulate the differentiation of Th1 and Th17 lymphocytes subtypes [32]. Regarding intestinal macrophages, they are identified by their expression of the F4/80, CD64, CD11b and CX3CR1 markers [33, 34]. In these macrophages, despite their ample phagocytic activity, the expression of co-stimulatory molecules CD40, CD80 and CD86 are decreased, as

well as innate immune response receptors such as LPS or CR3 [35, 36].

Macrophages and intestinal dendritic cells which reside in the lamina propria are APCs that act as sentinels to the maintenance of intestinal homeostasis. They are capable of establishing an interaction between the innate and adaptive immunity by

, via MHC II [26].

lymphocytes via MHC class II. In

lymphocytes specific to the anti-

and CD103+

Sirpα− in

Sirpα<sup>+</sup>

*DOI: http://dx.doi.org/10.5772/intechopen.90037*

can prevent experimental colitis [25].

*Mucosal Immunology in the Inflammatory Bowel Diseases DOI: http://dx.doi.org/10.5772/intechopen.90037*

*Biological Therapy for Inflammatory Bowel Disease*

in a number of pathogens [19].

inflammatory cytokines [20].

subsequently, the adaptive immune responses [20].

chronic inflammatory processes, such as IBD [22].

the polarization of Th1 and Th17 of TCD4<sup>+</sup>

TLR 2, 3, 4, 5, and 9 have been consistently identified, highlighting that TLR-3 and TLR-5 are present in larger numbers in the enterocytes. The TLR are found in the plasma membrane or in the endosomal intracellular compartments. The activation of these receptors is made by PAMP which have relative specificity to distinct TLR. The TLR-2, for example, identifies peptidoglycans and lipoproteins; TLR-3 identifies viral RNA; TLR-4 recognizes lipopolysaccharide (LPS); TLR-5 recognizes flagellin, and TLR-9 connects to bacterial DNA. Despite the small number of receptors, this distribution reflects the elevated capacity for identifying molecular patters

Once activated, TLR become dimerized and trigger the subsequent activation of downstream signaling cascades, e.g., the activation of NF-κB which leads to the induction of a variety of inflammatory cytokines. Except for TLR3, other TLR signaling pathways depend on MyD88 to activate NF-κB and produce pro-inflammatory cytokines. The TLR signaling pathway is quite similar to the interleukin (IL)-1R family, since TLR contains the domain Toll/Interleukin-1 (TIR). The TIR domain contains the TIRAP adaptor protein. When TLR-1, 2 or 6 are activated, the domain containing TIRAP lying downstream of these TLR and recruits the adaptor protein from the primary myeloid response 88 (MyD88) which leads to the activation of the kinase associated with the IL-1 receptor (IRAK). The activation of IRAK, in turn, induces the activation of serine and threonine kinases which are responsible for the degrading of IκB*α*, known as an inhibitor of the nuclear transcription factor κB or NF-κB. The degrading of IκB*α* allows for the migration of the NF-κB from cytoplasm to the nucleus. In the nucleus, this nuclear factor induces the production of pro-inflammatory cytokines and chemokines which will trigger the innate and,

Furthermore, there is an alternate signaling pathway to MyD88 which involves TLR-3 and TLR-4. This alternate pathway is mediated by the activation of the TIRdomain-containing adapter-inducing Interferon-β (TRIF). Thus, signaling TLR is divided in two pathways: one dependent on MyD88 and the other independent of MyD88, but dependent on TRIF. Downstream of the TLR signaling pathways, activated NF-κB and interferon regulatory factor (IRF) to the production of pro-

Additionally, TLRs provides a connection between innate and adaptive immunity. Dendritic cells that is innate immune response cell, can sense microbes by these receptors in their surface. In this way, this cell controls microbial driven T lymphocyte polarization to Th1, Th2, Th9 or Th17 in lymphoid tissues. After interaction with microbial components, immature dendritic cell migrate to the draining lymphoid tissues to present microbial antigens to T lymphocytes [21]. It was hypothesized that an abnormal pattern of bacterial recognition by these cells through TLRs alter its activation and cytokine production which may underlie

A number of studies have shown a correlation between TLR and IBD, be it enabling or inhibiting the disease. Interestingly, it has been demonstrated that TLR-2 must form heterodimers with TLR1 or TLR6 in order to trigger intracellular signaling pathways. The inhibition of TLR2/6 signaling has played a beneficial role by slowing down IBD progression. It was also reported that TLR6 was overexpressed in the intestines of IBD patients and might promote experimental colitis in mice [23]. In this case, it was proved that TLR-6 was important and activated

TLR4 gene expression was upregulated in the intestinal epithelia of patients with active UC, TLR4 might be a participant in UC disease development. Moreover, it was demonstrated that TLR8 is upregulated in patients with active UC and that the expression of the genes TLR2, 4, 8 and 9 is positively regulated in these patients.

lymphocytes. Also, considering that

**6**

Contrary to the evidence presented above, which show TLR supporting IBD, studies show that the activation of TLR-9 prevented the development of inflammation of the mucosa, and fomented healing of wounds in models of colitis [24]. Still others presented data that TLR3, TLR7, or TLR9 agonists could induce type I IFN, which can prevent experimental colitis [25].

#### **4. The link between innate and adaptive immune response in intestine: the role of macrophages and dendritic cells**

Macrophages and intestinal dendritic cells which reside in the lamina propria are APCs that act as sentinels to the maintenance of intestinal homeostasis. They are capable of establishing an interaction between the innate and adaptive immunity by means of the presentation of antigens to the *naïve* TCD4+ , via MHC II [26].

The recognition of microorganisms for phagocytosis occurs by means of PRR. Macrophages also express PRR which recognize PAMP present on the surface of invading intestinal microorganisms. It is through this interaction that immune cells distinguish between commensal microorganisms and pathogens, thus designing an appropriate immune response program. Captured antigens from pathogenic microorganisms are presented to *naïve* TCD4+ lymphocytes via MHC class II. In 1998, it was described that intestinal macrophages in mice carrying colitis present low levels of MHC class II expression, which hinder adaptive immune response in the inflammatory condition established by this disease [27].

With relation to dendritic cells, they also have the function of transporting antigens to mesenteric lymph nodes and Peyer's patches, and, subsequently, inducing the generation of responses by intestinal TCD4+ lymphocytes specific to the antigen. They act as sentinels, acquiring antigens in peripheral tissues before migrating to secondary lymphoid organs. Dendritic cells can recognize antigens through the emission of their extensions in the luminal region. Alternatively, this recognition may occur through M cells which are also considered as presenting antigens. The M cells can recognize antigens in the intestinal lumen, internalize them and present them to the dendritic cells located in the lamina propria of the mucosa [28, 29].

Dendritic cells and macrophages are characterized according to their expression of specific membrane markers [30]. The intestinal dendritic cells may be divided in CD103+ CD11b+ and CD103+ CD11b<sup>−</sup> in mice, or CD103<sup>+</sup> Sirpα<sup>+</sup> and CD103+ Sirpα− in humans [31]. Dendritic cells, both in mice and humans, stimulate the differentiation of Th1 and Th17 lymphocytes subtypes [32]. Regarding intestinal macrophages, they are identified by their expression of the F4/80, CD64, CD11b and CX3CR1 markers [33, 34]. In these macrophages, despite their ample phagocytic activity, the expression of co-stimulatory molecules CD40, CD80 and CD86 are decreased, as well as innate immune response receptors such as LPS or CR3 [35, 36].

Macrophages residing in the lamina may still be differentiated in two distinct phenotypes characterized as M1 and M2. Specific combinations of cytokines induce the polarization to one of these phenotypes. IFN-γ induces the appearance of the M1 phenotype, which has as its identity the secretion of TNF-α, IL-12, IL-6 and IL-23 pro-inflammatory cytokines. These cytokines are present in the context of inflammatory intestinal diseases. The M2 macrophages arise in microenvironments rich in IL-4 and produce large quantities of IL-10 [37]. It is known that mice deficient in IL-10 develop spontaneous colitis [38]. Moreover, mutations in genes which codify proteins in the IL10R subunit have been found in patients with early-onset enterocolitis [39]. Generally, while M1 macrophages cause tissue damage and hinder cell proliferation, M2 macrophages support proliferation and tissue repair [40]. It was shown that M1 macrophages which invade intestinal tissues contribute directly

to break the epithelial barrier by means of disruption of tight junction proteins and induction of apoptosis of epithelial cells, thus supporting intestinal inflammation which is characteristic of IBD [41].

While mononuclear phagocytes perform an important role in the induction of inflammation in several tissues by means of the production of pro-inflammatory cytokines, chemokines and oxygen-free radicals, residing macrophages as well as intestinal dendritic cells exhibit a tolerogenic phenotype mediating tolerance to commensal microorganisms [42, 43].

Thus, macrophages phagocyte intestinal pathogens efficiently, although they do not cause an exacerbated inflammatory response. This is a characteristic which distinguishes intestinal macrophages from those found in other compartments. When macrophages present disorders in the recognizing microorganisms in the intestine, an inflammatory reaction may be established. This condition has been observed in IBD. In such situations, these macrophages produce high, significant quantities of IL-1*β*, IL-6, TNF-*α* and IL-23 [44]. Among them, IL-23 can stimulate the production of IL-22 under several infectious conditions [45]. IL-22 is essential for preventing the integrity of the intestinal barrier and inducing the production of antimicrobial peptides and chemokines which recruit cells such as, e. g., neutrophils [46].

#### **5. Old and new lymphocyte players in inflammatory bowel disease**

#### **5.1 Revisiting TH1 and TH2 lymphocytes**

*Naïve* TCD4<sup>+</sup> lymphocytes have a high degree of plasticity and the capacity for differentiating into subsets of effector or regulatory T cells during the process of activation. For approximately two decades, it was believed that these lymphocytes could only divide into the subtypes Th1 or Th2 [47].

The effector T lymphocytes subtypes Th1/Th2 were the first to be described in scholarly literature, leading to the comprehension of how TCD4+ could shape the appropriate response to different pathogens. Subsequently, the identification of effector T lymphocytes Th17, T regulatory (Treg) and Th9 changed the Th1/Th2 historical paradigm.

These subtypes express distinct factors of transcription and secret different cytokines. In response to antigenic stimuli, TCD4+ lymphocytes express transcription factors which determine specific signaling pathways. These are responsible for the production of cytokines to each of these T cell patterns. The differentiation to a particular type of effector T lymphocytes is intimately related to interleukins which are available in the microenvironment in which a *naïve* TCD4+ lymphocytes is exposed. Th1 cells have as signature the production of IFN-γ, TNF-α and IL-12, which are responsible for cellular immunity and host defense against a number of pathogens, especially intracellular organisms. Interleukin-12 acting via the transcription factor STAT4, in concert with another transcription factor, T-bet, are critical for Th1 differentiation. On the contrary, the development of Th2 cells is initiated by the signaling of IL-4 with a participation of the STAT6 and GATA3 transcription factors. Classically, the Th2 lineage is specialized in the elimination of parasitic infections (such as helminths). IL-4, along with IL-5 and IL-13 produced by this lineage, are potent activators of B cells which, in this condition, produce IgE immunoglobulin and recruit eosinophils [48].

CD is a disease mediated by Th1, while it is believed that UC is mediated by Th2 response. A significant increase of Th1 cytokines has been demonstrated in inflamed mucosa of CD, whereas the in inflamed areas of UC as increased

**9**

*Mucosal Immunology in the Inflammatory Bowel Diseases*

cytokines were present in a Th2 profile [49]. Another study showed that the T cells in the mucosa of DC patients secret high amounts of IFN-γ and IL-2 than from T-lymphocytes from UC patients [50, 51]. Furthermore, it has been demonstrated that UC patients produce increased amounts of IL-5 [52]. Data from biopsies of both DC and UC patients showed high *ex vivo* levels of IFN-γ and lower levels of IL-13 have been found in UC as compared to DC patients [53]. In addition, it has been demonstrated that IL-5, IL-13, IL-15 and IL-33 mRNA levels in DC patients were significantly increased when compared to both DC and control [5]. Interestingly, it was shown that pediatric CD is characterized by Th1 in the terminal ileum and Th1/Th17 immune response in the colon [54]. However, currently it is considered that Th1 and Th2 immune responses do not represent the complexity of immune responses measured by intestinal T cells. In such a context, as will be discussed in the next section, more recent studies have demonstrated the involvement of the Th17 pathway in the physiopathological processes of IBD [55].

Studies suggest that Th17 cells perform an important role in the host's defense against extracellular pathogens which are not effectively countered by Th1 or Th2 cells. They are also known by their action in the physiopathology of autoimmune

Th17 cells require specific cytokines and transcription factors for their differentiation. They are dependent on IL-6 and TGF-β for their differentiation and are defined by expression of the transcription factor RORγt orphan nuclear receptor [56]. Interestingly, in the absence of IL-6, the cytokine TGF-β promotes the differentiation of FoxP3 innate regulatory T cells (iTreg). The expression of IL-23R is low in *naïve* T lymphocytes, although, in the presence of IL-6 and TGF-β, there is an increase in the expression of the IL-23 receptor. IL-23 is not necessary for the appearance of the Th17 phenotype, although it is important for its maintenance and expansion [57]. The signaling of TGF-β hinders IL-23R and antagonizes RORyt,

Signal transduction downstream of IL-6 and TGF-β, including JAK/STAT3 activation, induces expression of RORγt, which is the master transcription factor defining Th17 cells as a distinct lineage and promotes transcription of IL-17*.* The cytokines produced belong to the IL-17 family and are known as IL-17A (commonly known as IL-17), IL-17B, IL-17C, IL-17D, IL-17E (or IL-25) and IL-17F [57]. Cytokines are characterized as pro-inflammatory if they induce the recruitment of neutrophils. However, Th17 cells are also capable of secreting IL-21 and IL-22, which perform the important role of host defense on the mucosa surface as well as acting against extracellular pathogens, such as fungi and bacteria. In addition to Th17 cells, others have been characterized as secreting IL-17 and IL-22, such as innate lymphoid cells (ILCs), natural killer cells, NKT cells, mast cells, as well as

Some evidence show that interleukins IL-17 and IL-22 may perform a protective function by inducing the production of antimicrobial peptides, as well as acting in the recruitment of neutrophils to act in the defense against fungi and bacteria [60–62]. It is known that in intestinal epithelial cells IL-17 stimulates the expression of tight junction claudin proteins [63]. In an experimental animal model of dextran sulfate sodium (DSS)-induced colitis, it was demonstrated that IL-17 regulates the localization of the tight junction protein occludin and also reduces gut permeability following epithelial injury [64]. In the IBD scenario, Th17 cells appear as protagonists in the inflammatory process [65]. It was demonstrated that IL17R knockout

diseases and recently have been identified in the scenario of IBD.

contributing also to the appearance of iTreg [58].

phagocytes that are recruited to the site of infection [59].

*DOI: http://dx.doi.org/10.5772/intechopen.90037*

**5.2 TH17: friend and foe**

cytokines were present in a Th2 profile [49]. Another study showed that the T cells in the mucosa of DC patients secret high amounts of IFN-γ and IL-2 than from T-lymphocytes from UC patients [50, 51]. Furthermore, it has been demonstrated that UC patients produce increased amounts of IL-5 [52]. Data from biopsies of both DC and UC patients showed high *ex vivo* levels of IFN-γ and lower levels of IL-13 have been found in UC as compared to DC patients [53]. In addition, it has been demonstrated that IL-5, IL-13, IL-15 and IL-33 mRNA levels in DC patients were significantly increased when compared to both DC and control [5]. Interestingly, it was shown that pediatric CD is characterized by Th1 in the terminal ileum and Th1/Th17 immune response in the colon [54]. However, currently it is considered that Th1 and Th2 immune responses do not represent the complexity of immune responses measured by intestinal T cells. In such a context, as will be discussed in the next section, more recent studies have demonstrated the involvement of the Th17 pathway in the physiopathological processes of IBD [55].

#### **5.2 TH17: friend and foe**

*Biological Therapy for Inflammatory Bowel Disease*

which is characteristic of IBD [41].

commensal microorganisms [42, 43].

**5.1 Revisiting TH1 and TH2 lymphocytes**

could only divide into the subtypes Th1 or Th2 [47].

cytokines. In response to antigenic stimuli, TCD4+

immunoglobulin and recruit eosinophils [48].

scholarly literature, leading to the comprehension of how TCD4+

which are available in the microenvironment in which a *naïve* TCD4+

*Naïve* TCD4<sup>+</sup>

historical paradigm.

to break the epithelial barrier by means of disruption of tight junction proteins and induction of apoptosis of epithelial cells, thus supporting intestinal inflammation

While mononuclear phagocytes perform an important role in the induction of inflammation in several tissues by means of the production of pro-inflammatory cytokines, chemokines and oxygen-free radicals, residing macrophages as well as intestinal dendritic cells exhibit a tolerogenic phenotype mediating tolerance to

Thus, macrophages phagocyte intestinal pathogens efficiently, although they do not cause an exacerbated inflammatory response. This is a characteristic which distinguishes intestinal macrophages from those found in other compartments. When macrophages present disorders in the recognizing microorganisms in the intestine, an inflammatory reaction may be established. This condition has been observed in IBD. In such situations, these macrophages produce high, significant quantities of IL-1*β*, IL-6, TNF-*α* and IL-23 [44]. Among them, IL-23 can stimulate the production of IL-22 under several infectious conditions [45]. IL-22 is essential for preventing the integrity of the intestinal barrier and inducing the production of antimicrobial peptides and chemokines which recruit cells such as, e. g., neutrophils [46].

**5. Old and new lymphocyte players in inflammatory bowel disease**

differentiating into subsets of effector or regulatory T cells during the process of activation. For approximately two decades, it was believed that these lymphocytes

appropriate response to different pathogens. Subsequently, the identification of effector T lymphocytes Th17, T regulatory (Treg) and Th9 changed the Th1/Th2

These subtypes express distinct factors of transcription and secret different

tion factors which determine specific signaling pathways. These are responsible for the production of cytokines to each of these T cell patterns. The differentiation to a particular type of effector T lymphocytes is intimately related to interleukins

is exposed. Th1 cells have as signature the production of IFN-γ, TNF-α and IL-12, which are responsible for cellular immunity and host defense against a number of pathogens, especially intracellular organisms. Interleukin-12 acting via the transcription factor STAT4, in concert with another transcription factor, T-bet, are critical for Th1 differentiation. On the contrary, the development of Th2 cells is initiated by the signaling of IL-4 with a participation of the STAT6 and GATA3 transcription factors. Classically, the Th2 lineage is specialized in the elimination of parasitic infections (such as helminths). IL-4, along with IL-5 and IL-13 produced by this lineage, are potent activators of B cells which, in this condition, produce IgE

CD is a disease mediated by Th1, while it is believed that UC is mediated by Th2 response. A significant increase of Th1 cytokines has been demonstrated in inflamed mucosa of CD, whereas the in inflamed areas of UC as increased

The effector T lymphocytes subtypes Th1/Th2 were the first to be described in

lymphocytes have a high degree of plasticity and the capacity for

could shape the

lymphocytes

lymphocytes express transcrip-

**8**

Studies suggest that Th17 cells perform an important role in the host's defense against extracellular pathogens which are not effectively countered by Th1 or Th2 cells. They are also known by their action in the physiopathology of autoimmune diseases and recently have been identified in the scenario of IBD.

Th17 cells require specific cytokines and transcription factors for their differentiation. They are dependent on IL-6 and TGF-β for their differentiation and are defined by expression of the transcription factor RORγt orphan nuclear receptor [56]. Interestingly, in the absence of IL-6, the cytokine TGF-β promotes the differentiation of FoxP3 innate regulatory T cells (iTreg). The expression of IL-23R is low in *naïve* T lymphocytes, although, in the presence of IL-6 and TGF-β, there is an increase in the expression of the IL-23 receptor. IL-23 is not necessary for the appearance of the Th17 phenotype, although it is important for its maintenance and expansion [57]. The signaling of TGF-β hinders IL-23R and antagonizes RORyt, contributing also to the appearance of iTreg [58].

Signal transduction downstream of IL-6 and TGF-β, including JAK/STAT3 activation, induces expression of RORγt, which is the master transcription factor defining Th17 cells as a distinct lineage and promotes transcription of IL-17*.* The cytokines produced belong to the IL-17 family and are known as IL-17A (commonly known as IL-17), IL-17B, IL-17C, IL-17D, IL-17E (or IL-25) and IL-17F [57]. Cytokines are characterized as pro-inflammatory if they induce the recruitment of neutrophils. However, Th17 cells are also capable of secreting IL-21 and IL-22, which perform the important role of host defense on the mucosa surface as well as acting against extracellular pathogens, such as fungi and bacteria. In addition to Th17 cells, others have been characterized as secreting IL-17 and IL-22, such as innate lymphoid cells (ILCs), natural killer cells, NKT cells, mast cells, as well as phagocytes that are recruited to the site of infection [59].

Some evidence show that interleukins IL-17 and IL-22 may perform a protective function by inducing the production of antimicrobial peptides, as well as acting in the recruitment of neutrophils to act in the defense against fungi and bacteria [60–62]. It is known that in intestinal epithelial cells IL-17 stimulates the expression of tight junction claudin proteins [63]. In an experimental animal model of dextran sulfate sodium (DSS)-induced colitis, it was demonstrated that IL-17 regulates the localization of the tight junction protein occludin and also reduces gut permeability following epithelial injury [64]. In the IBD scenario, Th17 cells appear as protagonists in the inflammatory process [65]. It was demonstrated that IL17R knockout

mice were protected against the induction of colitis by trinitrobenzenesulfonic acid (TNBS). In another study, a high expression of IL-17A was reported in blood serum and in the colon of IBD patients [66]. Other groups indicated a positive correlation between the severity of the disease and the levels of IL-17 in ulcerative colitis patients, or even that lymphocytes which produce IL-17 and IL-23 were increased in colitis and DC patients [67].

Thus, this protector role contradicts the pro-inflammatory role of Th17 cells in IBD and the distinguishing factor between beneficent and pathogenic Th17 is still unclear. Additional studies are required to clarify if Th17 lymphocytes at any moment lose this protecting role in the course of IBD or if the inflammatory role in these diseases is due to a Th17 pro-inflammatory cell response which is boosted by recently activated *naïve* TCD4+ lymphocytes.

#### **5.3 T regulatory cells in maintaining homeostasis at the intestinal lamina propria**

Two types of Tregs cells are well characterized in the literature such as natural Tregs (nTregs) cells which are generated in the thymus through IL-2 signaling and as induced or adaptive Tregs (iTregs) arising in peripheral tissues [68, 69]. The key cytokine for the induction of Treg cells, especially the iTregs, is the TGF-β and the FOXP3 transcription factor is considered as an identity and the main regulator for the differentiation and function of these cells [69]. Treg cells produce IL-10 and themselves also produce large amounts of TGF-β.

These cells play a role in maintaining peripheral tolerance to their own antigens [70]. In the intestinal lamina propria they are important for the maintenance of tissue homeostasis through the negative regulation of T effector cells (Teff cells). This regulation occurs through the production of the immunosuppressive cytokine IL-10 and the expression of CTLA-4, which is able to deplete CD80/CD86 [71]. The CD80 and CD86 expressed by APCs provide essential co-stimulatory signals to T lymphocytes through ligation of CD28 in addition to T cell receptor (TCR) signaling [72]. CTLA-4 also appears to play a particularly important immunoregulatory role in the human intestine. It has been shown that treatment with anti-CTLA-4 Ipilimumab for cancer, increases the immune response against the disease by decreasing Treg cell function. However, data shows that this treatment can result in potentially lethal colitis in a number of patients [73, 74].

Abnormalities in the functions as well as the presence of these cells in the intestine contribute to the establishment of IBD [75, 76]. The inhibitory molecule CTLA-4 is highly expressed on the surface of Treg cells and plays a critical role in the inhibitory function both *in vitro* and *in vivo* of Treg cells by limiting availability of CD80 and CD86 (Slavik et al., 1996). CD80 and CD86 expressed by APCs supply essential co-stimulatory signals to T cells via ligation of CD28 in addition to TCR signaling [77].

Inflammation in IBD may occur as a function of an imbalance between Th17 cells and Treg cells. It is known that both Th17 and iTregs are from TCD4+ lymphocytes in the presence of TGF-β. However, when IL-6 cytokine levels are elevated in the gut, TGF-β and TCR signaling result in upregulation of RORγt and therefore in the appearance of Th17 cells with pro-inflammatory profile. As discussed above, the role of lymphocytes in IBD is unclear. Several studies have shown them to be either pathogenic or protective [78].

A decrease in Treg and increase in Th17 cells was observed in the peripheral blood of IBD patients [79]. Additionally, the ability of Treg cells to suppress autologous T-cell proliferation was reduced in IBD patients [80].

**11**

*Mucosal Immunology in the Inflammatory Bowel Diseases*

In addition to the previously discussed T lymphocyte subtypes Th1, Th2 and Th17, studies have confirmed the existence of a new one denominated Th9, which are characterized by the expression of high amounts of IL-9. Initially, it was believed that IL-9 was produced by the Th2 subtype; however, it has been discovered that Th9 lymphocytes do not express the GATA-3 transcription factor in comparable levels to the Th2 lymphocyte, and not even other transcription factor, such as T-bet, RORγt and FOXP-3, characteristic of Th1, Th17 and Treg, respectively. *Naïve* T cells differentiate into Th9 if they are exposed simultaneously to IL-4 and TGF-β. The transcription factor STAT6 protein, activated by IL-4, stimulates an increase of IL-9 in Th9 cells [81]. Interestingly, it was shown that IL-4 and STAT6 are responsible for downregulating Treg cells by the inhibition of FOXP3 expression,

Still, a complicated network of transcription factors, such as Interferon 4 (IRF4) regulating factor and Smads are essential to adequate induction of this phenotype. Additionally, PU.1 transcription factor is critically involved in the signaling mediated by TGF-β. TGF-β is also important to the signaling pathways which culminate in the activation of Smad2, Smad3 and Smad4 transcription factors, which are

Several experimental pieces of evidence suggest that Th9 cells are involved in the pathogenesis of IBD. It has been demonstrated that mice which received *in vitro* cultivated T cells with TGF-β and IL-4 developed severe colitis [84]. Nalleweg et al. investigated the expression of IL-9 and IL-9R in peripheral blood, biopsies and surgical samples from patients with ulcerative colitis. Among other results, they showed that mRNA expression was significantly increased in inflamed samples from these patients. Additionally, it was shown that IL-9R was overexpressed on gut epithelial cells and IL-9 induced STAT5 activation in these cells. Considering the results, it was suggested that targeting IL-9 might become a therapeutic option for patients with ulcerative colitis also suggest that Th9 cells represent a likely target for the treatment of chronic intestinal inflammation [85]. The authors found that in patients with ulcerative colitis are more T cells expressing the transcription factor PU.1 and interleukin 9 (IL-9). In this study, the mice whose T cells were deficient in PU.1 were protected from colitis, which was even suppressed when these animals

Additionally, a study which analyzed IL-9 in venous blood samples de CD and UC patients, it became evident that there was a significant correlation between

Th9 cells also regulate the intestinal mucosa's barrier function. The exacerbated intestinal IL-9 production breaks the intestinal epithelial barrier and compromises tolerance to certain commensal microorganisms, which enables the occurrence of inflammation. In an animal experimental model of TNBS-induced colitis, the expression of tight junction molecules was investigated in the inflamed colon. It was observed that some of these molecules were up regulated in the colon of TNBS-

disease severity and IL-9 in the CD patients, but not in the UC [86].

**6. Innate lymphoid cells (ILCS): innate counterparts of T-helper** 

A decade after their discovery, ILCs are currently recognized as performing a regulator function of intestinal homeostasis, and alterations in these cells'

*DOI: http://dx.doi.org/10.5772/intechopen.90037*

**5.4 TH9: new lymphocyte players in IBD**

which results IL-9 production [82].

were treated with antibody to IL-9.

treated IL-9 KO mice [87].

**lymphocytes**

necessary to appearance of the Th9 phenotype [83].

#### **5.4 TH9: new lymphocyte players in IBD**

*Biological Therapy for Inflammatory Bowel Disease*

colitis and DC patients [67].

recently activated *naïve* TCD4+

**lamina propria**

mice were protected against the induction of colitis by trinitrobenzenesulfonic acid (TNBS). In another study, a high expression of IL-17A was reported in blood serum and in the colon of IBD patients [66]. Other groups indicated a positive correlation between the severity of the disease and the levels of IL-17 in ulcerative colitis patients, or even that lymphocytes which produce IL-17 and IL-23 were increased in

Thus, this protector role contradicts the pro-inflammatory role of Th17 cells in IBD and the distinguishing factor between beneficent and pathogenic Th17 is still unclear. Additional studies are required to clarify if Th17 lymphocytes at any moment lose this protecting role in the course of IBD or if the inflammatory role in these diseases is due to a Th17 pro-inflammatory cell response which is boosted by

Two types of Tregs cells are well characterized in the literature such as natural Tregs (nTregs) cells which are generated in the thymus through IL-2 signaling and as induced or adaptive Tregs (iTregs) arising in peripheral tissues [68, 69]. The key cytokine for the induction of Treg cells, especially the iTregs, is the TGF-β and the FOXP3 transcription factor is considered as an identity and the main regulator for the differentiation and function of these cells [69]. Treg cells produce IL-10 and

These cells play a role in maintaining peripheral tolerance to their own antigens [70]. In the intestinal lamina propria they are important for the maintenance of tissue homeostasis through the negative regulation of T effector cells (Teff cells). This regulation occurs through the production of the immunosuppressive cytokine IL-10 and the expression of CTLA-4, which is able to deplete CD80/CD86 [71]. The CD80 and CD86 expressed by APCs provide essential co-stimulatory signals to T lymphocytes through ligation of CD28 in addition to T cell receptor (TCR) signaling [72]. CTLA-4 also appears to play a particularly important immunoregulatory role in the human intestine. It has been shown that treatment with anti-CTLA-4 Ipilimumab for cancer, increases the immune response against the disease by decreasing Treg cell function. However, data shows that this treatment can result in potentially lethal

Abnormalities in the functions as well as the presence of these cells in the intestine contribute to the establishment of IBD [75, 76]. The inhibitory molecule CTLA-4 is highly expressed on the surface of Treg cells and plays a critical role in the inhibitory function both *in vitro* and *in vivo* of Treg cells by limiting availability of CD80 and CD86 (Slavik et al., 1996). CD80 and CD86 expressed by APCs supply essential co-stimulatory signals to T cells via ligation of CD28 in addition to TCR

Inflammation in IBD may occur as a function of an imbalance between Th17

cytes in the presence of TGF-β. However, when IL-6 cytokine levels are elevated in the gut, TGF-β and TCR signaling result in upregulation of RORγt and therefore in the appearance of Th17 cells with pro-inflammatory profile. As discussed above, the role of lymphocytes in IBD is unclear. Several studies have shown them to be either

A decrease in Treg and increase in Th17 cells was observed in the peripheral blood

of IBD patients [79]. Additionally, the ability of Treg cells to suppress autologous

lympho-

cells and Treg cells. It is known that both Th17 and iTregs are from TCD4+

lymphocytes.

**5.3 T regulatory cells in maintaining homeostasis at the intestinal** 

themselves also produce large amounts of TGF-β.

colitis in a number of patients [73, 74].

**10**

signaling [77].

pathogenic or protective [78].

T-cell proliferation was reduced in IBD patients [80].

In addition to the previously discussed T lymphocyte subtypes Th1, Th2 and Th17, studies have confirmed the existence of a new one denominated Th9, which are characterized by the expression of high amounts of IL-9. Initially, it was believed that IL-9 was produced by the Th2 subtype; however, it has been discovered that Th9 lymphocytes do not express the GATA-3 transcription factor in comparable levels to the Th2 lymphocyte, and not even other transcription factor, such as T-bet, RORγt and FOXP-3, characteristic of Th1, Th17 and Treg, respectively.

*Naïve* T cells differentiate into Th9 if they are exposed simultaneously to IL-4 and TGF-β. The transcription factor STAT6 protein, activated by IL-4, stimulates an increase of IL-9 in Th9 cells [81]. Interestingly, it was shown that IL-4 and STAT6 are responsible for downregulating Treg cells by the inhibition of FOXP3 expression, which results IL-9 production [82].

Still, a complicated network of transcription factors, such as Interferon 4 (IRF4) regulating factor and Smads are essential to adequate induction of this phenotype. Additionally, PU.1 transcription factor is critically involved in the signaling mediated by TGF-β. TGF-β is also important to the signaling pathways which culminate in the activation of Smad2, Smad3 and Smad4 transcription factors, which are necessary to appearance of the Th9 phenotype [83].

Several experimental pieces of evidence suggest that Th9 cells are involved in the pathogenesis of IBD. It has been demonstrated that mice which received *in vitro* cultivated T cells with TGF-β and IL-4 developed severe colitis [84]. Nalleweg et al. investigated the expression of IL-9 and IL-9R in peripheral blood, biopsies and surgical samples from patients with ulcerative colitis. Among other results, they showed that mRNA expression was significantly increased in inflamed samples from these patients. Additionally, it was shown that IL-9R was overexpressed on gut epithelial cells and IL-9 induced STAT5 activation in these cells. Considering the results, it was suggested that targeting IL-9 might become a therapeutic option for patients with ulcerative colitis also suggest that Th9 cells represent a likely target for the treatment of chronic intestinal inflammation [85]. The authors found that in patients with ulcerative colitis are more T cells expressing the transcription factor PU.1 and interleukin 9 (IL-9). In this study, the mice whose T cells were deficient in PU.1 were protected from colitis, which was even suppressed when these animals were treated with antibody to IL-9.

Additionally, a study which analyzed IL-9 in venous blood samples de CD and UC patients, it became evident that there was a significant correlation between disease severity and IL-9 in the CD patients, but not in the UC [86].

Th9 cells also regulate the intestinal mucosa's barrier function. The exacerbated intestinal IL-9 production breaks the intestinal epithelial barrier and compromises tolerance to certain commensal microorganisms, which enables the occurrence of inflammation. In an animal experimental model of TNBS-induced colitis, the expression of tight junction molecules was investigated in the inflamed colon. It was observed that some of these molecules were up regulated in the colon of TNBStreated IL-9 KO mice [87].

#### **6. Innate lymphoid cells (ILCS): innate counterparts of T-helper lymphocytes**

A decade after their discovery, ILCs are currently recognized as performing a regulator function of intestinal homeostasis, and alterations in these cells' responses are related to IBD [88]. They represent a family of immune system cells which derive from a progenitor known as Id2 and process the morphologic characteristics of lymphocytes, although they do not have rearrangements at the antigen receptors. The cells of these groups are able to produce cytokines which correspond to the profile of those produced by the TCD4<sup>+</sup> subtypes [89]. ILC are categorized in three groups, detailed bellow.

Group 1 ILC are comprised of ILC1 and natural killer cells. The Tbet transcription factor and the IL-12, IL-15 and IL-18 cytokines are responsible for the generation of these cells which have as a characteristic the production of Th1 cytokines, particularly IFN-γ [90]. The cells in the Group 02 are characterized as ILC-2 and are dependent on GATA and RORyt transcription factor, as well as the stimulus of IL-25 and IL-33 cytokines. These cells produce Th2 cytokines, such as IL-5 and IL-13 [91]. In Group 3, ILC3 and lymphoid tissue inducer (LTi) cells are RORyt dependent, and, similarly to Th17, have the ability of secreting IL-17 and IL-22 through the same stimulus with IL-1β and IL-23 [92]. ILC3 are the most abundant in the gastrointestinal tract [93, 94].

The ILC3, in the intestine, in addition to interacting directly with the microbiota, act together with other cells to ensure and maintain local homeostasis. Studies have revealed that ILC of this group express MHC II and can process and present antigens. However, when in contact with TCD4+ lymphocytes by MHC II, instead of inducing the proliferation of these cells, the ILC act by limiting the response theses lymphocytes to commensal bacteria. It has been demonstrated that, in the

#### **Figure 1.**

*During intestinal inflammation, such as IBD, barrier permeability is impaired, allowing the passage of luminal antigens into the lamina propria. These antigens can be recognize by TLR or captured by M cells. The exposure of immune cells to the luminal content induces TCD4+ activation, differentiation and inflammatory cytokine release as well as neutrophil recruitment. IgA-opsonized bacteria contributes to the inflammation induced by FcαRI. Several environmental factors (diet, genetics, lifestyle) can modulate the microbiota composition and the activation of immune cells in the gut. UC, Ulcerative Colitis; DC, Crohn's Disease; ILCs, Innate Lymphoid Cells, Th, T helper cells; Targ, T Regulatory Cells, IgA, Immunoglobulin A; sIgA, Secretory IgA, TLR, Toll Like Receptor; FcαRI, FcαReceptor I.*

**13**

*Mucosal Immunology in the Inflammatory Bowel Diseases*

absence of MHC II, the ILC of murines induce deregulated responses in TCD4+

for commensal bacteria, causing, thus, spontaneous intestinal inflammation [95]. In addition, it has been proved that pediatric Crohn's disease patients have reduced

The ILC3 have also been described as key effector cells in immunity against pathogens [97]. This protector effect occurs mainly through the secretion of IL-22 and IL-17, which induce epithelial cells and produce antimicrobial peptides against pathogens. The lack of ILC3 in the intestine leads to a decrease of IL-22 and hinders

However, ILC3 seems to act as a double-edged sword. It was demonstrated that inappropriate activation of ILC3 causes intestinal damage through the excessive production of IL-22. This may induce epithelial cells and generate chemokines which attract neutrophils, which leads to the accumulation of these cells and to the tissue destruction [98]. Additionally, it was shown that colonic ILC3 from UC and CD patients showed higher expression of IL-22 when compared to healthy individu-

Although ILC3 are smaller in number in the gastrointestinal tract, studies on ILC1 accumulate in inflamed mucosal tissues. It was shown that the frequency of the ILC1 subset was higher in inflamed intestine of CD patients, which indicates a role for these IFN-γ-producing ILC1 in the pathogenesis of gut mucosal inflammation [100, 101]. Forkel et al., also identified an increase in the ILC1 subset frequency

In conclusion, recently, a new population of ILC has been discovered and identified as ILCreg. During the intestinal inflammatory process, these cells may be induced to suppress the activation of ILC1 and ILC3, through IL-10, resulting in

TIRAP toll-interleukin 1 receptor (TIR) domain-containing adapter

cells

*DOI: http://dx.doi.org/10.5772/intechopen.90037*

ILC3 [96].

the production of antimicrobial peptides [88].

in DC patients when diagnosed with the disease.

APC antigen presenting cells

TIR toll-interleukin 1 receptor

protein IBD inflammatory bowel disease

DC Crohn's disease

UC ulcerative colitis DSS dextran sulfate sodium FcαRI FC alpha receptor I FOXP3 forkhead box P3

IFN interferon

ILCS innate lymphoid cells

NOD NOD-like receptors

NK CELL natural killer cell

CTLA-4 cytotoxic T lymphocyte antigen 4

IRAK IL-1 receptor-associated kinase IΚBα transcription factor inhibitor κB

IRF-4 interferon regulatory factor 4 LTI lymphoid tissue inducer IRF interferon regulatory factor

MYD88 myeloid differentiation protein

NF-KB transcription nuclear factor

MHC CLASS II major histocompatibility complex type II

protection against the inflammatory process **Figure 1** [102].

levels of MHC II<sup>+</sup>

als [99].

**Abbreviations**

*Mucosal Immunology in the Inflammatory Bowel Diseases DOI: http://dx.doi.org/10.5772/intechopen.90037*

*Biological Therapy for Inflammatory Bowel Disease*

to the profile of those produced by the TCD4<sup>+</sup>

antigens. However, when in contact with TCD4+

three groups, detailed bellow.

intestinal tract [93, 94].

responses are related to IBD [88]. They represent a family of immune system cells which derive from a progenitor known as Id2 and process the morphologic characteristics of lymphocytes, although they do not have rearrangements at the antigen receptors. The cells of these groups are able to produce cytokines which correspond

Group 1 ILC are comprised of ILC1 and natural killer cells. The Tbet transcription factor and the IL-12, IL-15 and IL-18 cytokines are responsible for the generation of these cells which have as a characteristic the production of Th1 cytokines, particularly IFN-γ [90]. The cells in the Group 02 are characterized as ILC-2 and are dependent on GATA and RORyt transcription factor, as well as the stimulus of IL-25 and IL-33 cytokines. These cells produce Th2 cytokines, such as IL-5 and IL-13 [91]. In Group 3, ILC3 and lymphoid tissue inducer (LTi) cells are RORyt dependent, and, similarly to Th17, have the ability of secreting IL-17 and IL-22 through the same stimulus with IL-1β and IL-23 [92]. ILC3 are the most abundant in the gastro-

The ILC3, in the intestine, in addition to interacting directly with the microbiota, act together with other cells to ensure and maintain local homeostasis. Studies have revealed that ILC of this group express MHC II and can process and present

of inducing the proliferation of these cells, the ILC act by limiting the response theses lymphocytes to commensal bacteria. It has been demonstrated that, in the

*During intestinal inflammation, such as IBD, barrier permeability is impaired, allowing the passage of luminal antigens into the lamina propria. These antigens can be recognize by TLR or captured by M cells. The* 

*cytokine release as well as neutrophil recruitment. IgA-opsonized bacteria contributes to the inflammation induced by FcαRI. Several environmental factors (diet, genetics, lifestyle) can modulate the microbiota composition and the activation of immune cells in the gut. UC, Ulcerative Colitis; DC, Crohn's Disease; ILCs, Innate Lymphoid Cells, Th, T helper cells; Targ, T Regulatory Cells, IgA, Immunoglobulin A; sIgA, Secretory* 

*exposure of immune cells to the luminal content induces TCD4+*

*IgA, TLR, Toll Like Receptor; FcαRI, FcαReceptor I.*

subtypes [89]. ILC are categorized in

lymphocytes by MHC II, instead

 *activation, differentiation and inflammatory* 

**12**

**Figure 1.**

absence of MHC II, the ILC of murines induce deregulated responses in TCD4+ cells for commensal bacteria, causing, thus, spontaneous intestinal inflammation [95]. In addition, it has been proved that pediatric Crohn's disease patients have reduced levels of MHC II<sup>+</sup> ILC3 [96].

The ILC3 have also been described as key effector cells in immunity against pathogens [97]. This protector effect occurs mainly through the secretion of IL-22 and IL-17, which induce epithelial cells and produce antimicrobial peptides against pathogens. The lack of ILC3 in the intestine leads to a decrease of IL-22 and hinders the production of antimicrobial peptides [88].

However, ILC3 seems to act as a double-edged sword. It was demonstrated that inappropriate activation of ILC3 causes intestinal damage through the excessive production of IL-22. This may induce epithelial cells and generate chemokines which attract neutrophils, which leads to the accumulation of these cells and to the tissue destruction [98]. Additionally, it was shown that colonic ILC3 from UC and CD patients showed higher expression of IL-22 when compared to healthy individuals [99].

Although ILC3 are smaller in number in the gastrointestinal tract, studies on ILC1 accumulate in inflamed mucosal tissues. It was shown that the frequency of the ILC1 subset was higher in inflamed intestine of CD patients, which indicates a role for these IFN-γ-producing ILC1 in the pathogenesis of gut mucosal inflammation [100, 101]. Forkel et al., also identified an increase in the ILC1 subset frequency in DC patients when diagnosed with the disease.

In conclusion, recently, a new population of ILC has been discovered and identified as ILCreg. During the intestinal inflammatory process, these cells may be induced to suppress the activation of ILC1 and ILC3, through IL-10, resulting in protection against the inflammatory process **Figure 1** [102].


#### **Abbreviations**

#### *Biological Therapy for Inflammatory Bowel Disease*


#### **Author details**

Giovanna Rosa Degasperi Pontifical Catholic University of Campinas, São Paulo, Brazil

\*Address all correspondence to: giovannadegasperi@puc-campinas.edu.br

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**15**

*Mucosal Immunology in the Inflammatory Bowel Diseases*

[9] Van der Sluis M, De Koning BA, De Bruijn AC, Velcich A, Meijerink JP, Van Goudoever JB, et al. Muc2-deficient mice spontaneously develop colitis, indicating that MUC2 is critical for colonic protection. Gastroenterology.

[10] Sankaran-Walters S, Hart R, Dills C. Guardians of the gut: Enteric defensins. Frontiers in Microbiology.

[11] Vancamelbeke M, Vermeire S. The intestinal barrier: A fundamental role in health and disease. Expert Review of Gastroenterology & Hepatology. 2017;**11**:821-834. DOI: 10.1080/17474124.2017.1343143

[12] Moossavi S, Rezaei N. Toll-like receptor signalling and their therapeutic

International Immunopharmacology. 2013;**16**:199-209. DOI: 10.1016/j.

[14] Breedveld A, van Egmond M. IgA and FcαRI: Pathological roles and therapeutic opportunities. Frontiers in Immunology. 2019;**10**:553. DOI: 10.3389/

[15] Brandtzaeg P, Bjerke K, Kett K, Kvale D, Rognum TO, Scott H, et al. Production and secretion of immunoglobulins in the gastrointestinal tract. Annals of Allergy. 1987;**59**:21-39

[16] Bunker JJ, Erickson SA, Flynn TM, Henry C, Koval JC, Meisel M, et al. Natural polyreactive IgA antibodies coat the intestinal microbiota. Science. 2017;**358**(6361):eaan6619. DOI: 10.1126/

targeting in colorectal cancer.

[13] Hansen IS, Baeten DLP, den Dunnen J. The inflammatory function of human IgA. Cellular and Molecular Life Sciences. 2019;**76**(6):1041-1055. DOI: 10.1007/s00018-018-2976-8

intimp.2013.03.017

fimmu.2019.00553

science.aan6619

2017;**8**:647. DOI: 10.3389/

2006;**131**:117-129

fmicb.2017.00647

*DOI: http://dx.doi.org/10.5772/intechopen.90037*

[1] Molodecky NA, Soon IS, Rabi DM, Ghali WA, Ferris M, Chernoff G, et al. Increasing incidence and prevalence of the inflammatory bowel diseases with time, based on systematic review. Gastroenterology. 2012;**142**:46-54. DOI:

[2] Wallace KL, Zheng LB, Kanazawa Y,

subsets in inflammatory bowel diseases. Frontiers in Immunology. 2018;**9**:1212. DOI: 10.3389/fimmu.2018.01212

Monteleone G. Interleukin-23 and Th17 cells in the control of gut inflammation.

10.1053/j.gastro.2011.10.001

Shih DQ. Immunopathology of inflammatory bowel disease. World Journal of Gastroenterology. 2014;**20**: 6-21. DOI: 10.3748/wjg.v20.i1.6

[3] Imam T, Park S, Kaplan MH, Olson MR. Effector T helper cell

[4] Monteleone I, Pallone F,

Mediators of Inflammation. 2009;**2009**:297645. DOI: 10.1155/2009/297645

[5] Nemeth ZH, Bogdanovski DA, Barratt-Stopper P, Paglinco SR, Antonioli L, Rolandelli RH. Crohn's disease and ulcerative colitis show unique cytokine profiles. Cureus. 2017;**9**:e1177. DOI: 10.7759/cureus.1177

[6] Vyas SP, Goswami R. A decade of Th9 cells: Role of Th9 cells in inflammatory bowel disease. Frontiers in Immunology. 2018;**9**:1139. DOI:

[7] Weigmann B, Neurath MF. Th9 cells in inflammatory bowel diseases. Seminars in Immunopathology. 2017;**39**:89-95. DOI: 10.1007/

[8] Licona-Limón P, Arias-Rojas A, Olguín-Martínez E. IL-9 and Th9 in parasite immunity. Seminars in

10.1007/s00281-016-0606-9.

Immunopathology. 2017;**39**:29-38. DOI:

10.3389/fimmu.2018.01139

s00281-016-0603-z

**References**

*Mucosal Immunology in the Inflammatory Bowel Diseases DOI: http://dx.doi.org/10.5772/intechopen.90037*

#### **References**

*Biological Therapy for Inflammatory Bowel Disease*

PRR pattern recognition receptors

TNB 2,4,6 trinitrobenzenesulfonic acid TGF-β transforming growth factor beta

RLR RIG-1-like receptors

Teff T effector cells Th T helper cells TCR T cell receptor TLR toll-like receptors Treg regulatory T cells

PAMP pathogen-associated molecular pattern

RORγT transcription factor orphan nuclear receptor

TIR domain containing adapter-inducing beta interferon

**14**

**Author details**

Giovanna Rosa Degasperi

provided the original work is properly cited.

Pontifical Catholic University of Campinas, São Paulo, Brazil

\*Address all correspondence to: giovannadegasperi@puc-campinas.edu.br

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

[1] Molodecky NA, Soon IS, Rabi DM, Ghali WA, Ferris M, Chernoff G, et al. Increasing incidence and prevalence of the inflammatory bowel diseases with time, based on systematic review. Gastroenterology. 2012;**142**:46-54. DOI: 10.1053/j.gastro.2011.10.001

[2] Wallace KL, Zheng LB, Kanazawa Y, Shih DQ. Immunopathology of inflammatory bowel disease. World Journal of Gastroenterology. 2014;**20**: 6-21. DOI: 10.3748/wjg.v20.i1.6

[3] Imam T, Park S, Kaplan MH, Olson MR. Effector T helper cell subsets in inflammatory bowel diseases. Frontiers in Immunology. 2018;**9**:1212. DOI: 10.3389/fimmu.2018.01212

[4] Monteleone I, Pallone F, Monteleone G. Interleukin-23 and Th17 cells in the control of gut inflammation. Mediators of Inflammation. 2009;**2009**:297645. DOI: 10.1155/2009/297645

[5] Nemeth ZH, Bogdanovski DA, Barratt-Stopper P, Paglinco SR, Antonioli L, Rolandelli RH. Crohn's disease and ulcerative colitis show unique cytokine profiles. Cureus. 2017;**9**:e1177. DOI: 10.7759/cureus.1177

[6] Vyas SP, Goswami R. A decade of Th9 cells: Role of Th9 cells in inflammatory bowel disease. Frontiers in Immunology. 2018;**9**:1139. DOI: 10.3389/fimmu.2018.01139

[7] Weigmann B, Neurath MF. Th9 cells in inflammatory bowel diseases. Seminars in Immunopathology. 2017;**39**:89-95. DOI: 10.1007/ s00281-016-0603-z

[8] Licona-Limón P, Arias-Rojas A, Olguín-Martínez E. IL-9 and Th9 in parasite immunity. Seminars in Immunopathology. 2017;**39**:29-38. DOI: 10.1007/s00281-016-0606-9.

[9] Van der Sluis M, De Koning BA, De Bruijn AC, Velcich A, Meijerink JP, Van Goudoever JB, et al. Muc2-deficient mice spontaneously develop colitis, indicating that MUC2 is critical for colonic protection. Gastroenterology. 2006;**131**:117-129

[10] Sankaran-Walters S, Hart R, Dills C. Guardians of the gut: Enteric defensins. Frontiers in Microbiology. 2017;**8**:647. DOI: 10.3389/ fmicb.2017.00647

[11] Vancamelbeke M, Vermeire S. The intestinal barrier: A fundamental role in health and disease. Expert Review of Gastroenterology & Hepatology. 2017;**11**:821-834. DOI: 10.1080/17474124.2017.1343143

[12] Moossavi S, Rezaei N. Toll-like receptor signalling and their therapeutic targeting in colorectal cancer. International Immunopharmacology. 2013;**16**:199-209. DOI: 10.1016/j. intimp.2013.03.017

[13] Hansen IS, Baeten DLP, den Dunnen J. The inflammatory function of human IgA. Cellular and Molecular Life Sciences. 2019;**76**(6):1041-1055. DOI: 10.1007/s00018-018-2976-8

[14] Breedveld A, van Egmond M. IgA and FcαRI: Pathological roles and therapeutic opportunities. Frontiers in Immunology. 2019;**10**:553. DOI: 10.3389/ fimmu.2019.00553

[15] Brandtzaeg P, Bjerke K, Kett K, Kvale D, Rognum TO, Scott H, et al. Production and secretion of immunoglobulins in the gastrointestinal tract. Annals of Allergy. 1987;**59**:21-39

[16] Bunker JJ, Erickson SA, Flynn TM, Henry C, Koval JC, Meisel M, et al. Natural polyreactive IgA antibodies coat the intestinal microbiota. Science. 2017;**358**(6361):eaan6619. DOI: 10.1126/ science.aan6619

[17] Corthésy B. Role of secretory IgA in infection and maintenance of homeostasis. Autoimmunity Reviews. 2013;**12**:661-665. DOI: 10.1016/j. autrev.2012.10.012

[18] Monteiro RC, Van De Winkel JG. IgA Fc receptors. Annual Review of Immunology. 2003;**21**:177-204

[19] Kordjazy N, Haj-Mirzaian A, Haj-Mirzaian A, Rohani MM, Gelfand EW, Rezaei N, et al. Role of toll-like receptors in inflammatory bowel disease. Pharmacological Research. 2018;**129**:204-215. DOI: 10.1016/j.phrs.2017.11.017

[20] Takeda K, Akira S. Toll-like receptors. Current Protocols in Immunology. 2015;**109**:1-10. DOI: 10.1002/0471142735.im1412s109 25

[21] Banchereau J, Steinman RM. Dendritic cells and the control of immunity. Nature. 1998;**392**:245-252

[22] Hart AL, Al-Hassi HO, Rigby RJ, Bell SJ, Emmanuel AV, Knight SC, et al. Characteristics of intestinal dendritic cells in inflammatory bowel diseases. Gastroenterology. 2005;**129**:50-65. DOI: 10.1053/j.gastro.2005.05.013

[23] Morgan ME, Koelink PJ, Zheng B, den Brok MH, van de Kant HJ, Verspaget HW, et al. Toll-like receptor 6 stimulation promotes T-helper 1 and 17 responses in gastrointestinal-associated lymphoid tissue and mod-ulates murine experimental colitis. Mucosal Immunology. 2014;**7**:1266-1277. DOI: 10.1038/mi.2014.16

[24] Atreya R, Bloom S, Scaldaferri F, Gerardi V, Admyre C, Karlsson A, et al. Clinical effects of a topically applied toll-like receptor 9 agonist in active moderate-to-severe ulcerative colitis. Journal of Crohn's & Colitis. 2016;**10**:1294-1302

[25] Sainathan SK, Bishnupuri KS, Aden K, Luo Q, Houchen CW,

Anant S, et al. Toll-like receptor-7 ligand imiquimod induces type I interferon and antimi-crobial peptides to ameliorate dextran sodium sulfateinduced acute colitis. Inflammatory Bowel Diseases. 2012;**18**:955-967. DOI: 10.1002/ibd.21867

[26] Mann ER, Li X. Intestinal antigenpresenting cells in mucosal immune homeostasis: Crosstalk between dendritic cells, macrophages and B-cells. World Journal of Gastroenterology. 2014;**20**:9653-9664. DOI: 10.3748/wjg. v20.i29.9653

[27] Rogler G, Hausmann M, Vogl D, Aschenbrenner E, Andus T, Falk W, et al. Isolation and phenotypic characterization of colonic macrophages. Clinical and Experimental Immunology. 1998;**112**:205-215

[28] Kucharzik T, Lügering N, Rautenberg K, Lügering A, Schmidt MA, Stoll R, et al. Role of M cells in intestinal barrier function. Annals of the New York Academy of Sciences. 2000;**915**:171-183

[29] Bernardo D. Human intestinal dendritic cells as controllers of mucosal immunity. Revista Española de Enfermedades Digestivas. 2013;**105**:279-290

[30] Cerovic V, Bain CC, Mowat AM, Milling SW. Intestinal macrophages and dendritic cells: What's the difference? Trends in Immunology. 2014;**35**(6):270- 277. DOI: 10.1016/j.it.2014.04.003

[31] Schiavi E, Smolinska S, O'Mahony L. Intestinal dendritic cells. Current Opinion in Gastroenterology. 2015;**31**:98-103. DOI: 10.1097/ MOG.0000000000000155

[32] Persson EK, Uronen-Hansson H, Semmrich M, Rivollier A, Hägerbrand K, Marsal J, et al. IRF4 transcriptionfactor-dependent CD103(+)CD11b(+) dendritic cells drive mucosal T helper

**17**

*Mucosal Immunology in the Inflammatory Bowel Diseases*

Inflammatory bowel disease and mutations affecting the interleukin-10 receptor. The New England Journal of Medicine. 2009;**361**:2033-2045. DOI:

10.1056/NEJMoa0907206

2014;**291**:41-48

[40] Bain CC, Mowat AM. The monocyte-macrophage axis in the intestine. Cellular Immunology.

[42] Smith PD, Smythies LE,

DOI: 10.1038/mi.2010.66

10.1155/2016/1958650

Shen R, Greenwell-Wild T, Gliozzi M, Wahl SM. Intestinal macrophages and response to microbial encroachment. Mucosal Immunology. 2011;**4**:31-42.

[43] Steimle A, Frick JS. Molecular mechanisms of induction of tolerant and tolerogenic intestinal dendritic cells in mice. Journal of Immunology Research. 2016;**2016**:1958650. DOI:

[44] Bain CC, Schridde A. Origin, differentiation, and function of intestinal macrophages. Frontiers in Immunology. 2018;**9**:2733. DOI:

et al. Epithelial IL-23R signaling licenses protective IL-22 responses in intestinal inflammation. Cell Reports. 2016;**16**:2208-2218. DOI: 10.1016/j.

[45] Aden K, Rehman A, Falk-Paulsen M,

[46] Mizoguchi A, Yano A, Himuro H, Ezaki Y, Sadanaga T, Mizoguchi E. Clinical importance of IL-22 cascade in IBD. Journal of Gastroenterology. 2018;**53**(4):465-474. DOI: 10.1007/

10.3389/fimmu.2018.02733

celrep.2016.07.054

s00535-017-1401-7

[41] Lissner D, Schumann M, Batra A, Kredel LI, Kühl AA, Erben U, et al. Monocyte and M1 macrophageinduced barrier defect contributes to chronic intestinal inflammation in IBD. Inflammatory Bowel Diseases. 2015;**21**:1297-1305. DOI: 10.1097/ MIB.0000000000000384

*DOI: http://dx.doi.org/10.5772/intechopen.90037*

Lelouard H, de Bovis B, de Haar C, van der Woude CJ, et al. CD64 distinguishes macrophages from dendritic cells in the gut and reveals the Th1-inducing role of mesenteric lymph node macrophages during colitis. European Journal of Immunology. 2012;**42**:3150-3166. DOI:

[34] Regoli M, Bertelli E, Gulisano M,

Brandtzaeg P. Differential distribution of B7.1 (CD80) and B7.2 (CD86) costimulatory molecules on mucosal macrophage subsets in human inflammatory bowel disease (IBD). Clinical and Experimental Immunology.

Nicoletti C. The multifaceted personality of intestinal CX3CR1+ macrophages. Trends in Immunology. 2017;**38**(12):879-887. DOI: 10.1016/j.

[35] Rugtveit J, Bakka A,

1997;**110**(1):104-113

[36] Smythies LE, Sellers M,

Clements RH, Mosteller-Barnum M, Meng G, Benjamin WH, et al. Human intestinal macrophages display

profound inflammatory anergy despite avid phagocytic and bacteriocidal activity. The Journal of Clinical Investigation. 2005;**115**:66-75

[37] Shrivastava R, Shukla N. Attributes

2019;**1**(224):222-231. DOI: 10.1016/j.

[38] Keubler LM, Buettner M, Häger C, Bleich A. A multihit model: Colitis lessons from the interleukin-10 deficient mouse. Inflammatory Bowel Diseases. 2015;**21**:1967-1975. DOI: 10.1097/MIB.0000000000000468

[39] Glocker EO, Kotlarz D, Boztug K, Gertz EM, Schäffer AA, Noyan F, et al.

of alternatively activated (M2) macrophages. Life Sciences.

lfs.2019.03.062

17 cell differentiation. Immunity.

[33] Tamoutounour S, Henri S,

2013;**38**:958-969

10.1002/eji.201242847

it.2017.07.009

*Mucosal Immunology in the Inflammatory Bowel Diseases DOI: http://dx.doi.org/10.5772/intechopen.90037*

17 cell differentiation. Immunity. 2013;**38**:958-969

*Biological Therapy for Inflammatory Bowel Disease*

Anant S, et al. Toll-like receptor-7 ligand imiquimod induces type I interferon and antimi-crobial peptides to ameliorate dextran sodium sulfateinduced acute colitis. Inflammatory Bowel Diseases. 2012;**18**:955-967. DOI:

[26] Mann ER, Li X. Intestinal antigenpresenting cells in mucosal immune homeostasis: Crosstalk between

dendritic cells, macrophages and B-cells. World Journal of Gastroenterology. 2014;**20**:9653-9664. DOI: 10.3748/wjg.

[27] Rogler G, Hausmann M, Vogl D,

Falk W, et al. Isolation and phenotypic

macrophages. Clinical and Experimental

Rautenberg K, Lügering A, Schmidt MA,

Aschenbrenner E, Andus T,

characterization of colonic

Immunology. 1998;**112**:205-215

[28] Kucharzik T, Lügering N,

Stoll R, et al. Role of M cells in intestinal barrier function. Annals of the New York Academy of Sciences.

[29] Bernardo D. Human intestinal dendritic cells as controllers of mucosal immunity. Revista Española

[30] Cerovic V, Bain CC, Mowat AM, Milling SW. Intestinal macrophages and dendritic cells: What's the difference? Trends in Immunology. 2014;**35**(6):270- 277. DOI: 10.1016/j.it.2014.04.003

O'Mahony L. Intestinal dendritic cells. Current Opinion in Gastroenterology.

[32] Persson EK, Uronen-Hansson H, Semmrich M, Rivollier A, Hägerbrand K, Marsal J, et al. IRF4 transcriptionfactor-dependent CD103(+)CD11b(+) dendritic cells drive mucosal T helper

de Enfermedades Digestivas.

[31] Schiavi E, Smolinska S,

2015;**31**:98-103. DOI: 10.1097/ MOG.0000000000000155

2000;**915**:171-183

2013;**105**:279-290

10.1002/ibd.21867

v20.i29.9653

[18] Monteiro RC, Van De Winkel JG. IgA

[17] Corthésy B. Role of secretory IgA in infection and maintenance of homeostasis. Autoimmunity Reviews. 2013;**12**:661-665. DOI: 10.1016/j.

Fc receptors. Annual Review of Immunology. 2003;**21**:177-204

[19] Kordjazy N, Haj-Mirzaian A, Haj-Mirzaian A, Rohani MM, Gelfand EW, Rezaei N, et al. Role of toll-like receptors in inflammatory bowel disease. Pharmacological Research. 2018;**129**:204-215. DOI:

10.1016/j.phrs.2017.11.017

[20] Takeda K, Akira S. Toll-like receptors. Current Protocols in Immunology. 2015;**109**:1-10. DOI: 10.1002/0471142735.im1412s109 25

[21] Banchereau J, Steinman RM. Dendritic cells and the control of immunity. Nature. 1998;**392**:245-252

[22] Hart AL, Al-Hassi HO, Rigby RJ, Bell SJ, Emmanuel AV, Knight SC, et al. Characteristics of intestinal dendritic cells in inflammatory bowel diseases. Gastroenterology. 2005;**129**:50-65. DOI:

Zheng B, den Brok MH, van de Kant HJ, Verspaget HW, et al. Toll-like receptor 6 stimulation promotes T-helper 1 and 17 responses in gastrointestinal-associated

10.1053/j.gastro.2005.05.013

[23] Morgan ME, Koelink PJ,

lymphoid tissue and mod-ulates murine experimental colitis. Mucosal Immunology. 2014;**7**:1266-1277. DOI:

[24] Atreya R, Bloom S, Scaldaferri F, Gerardi V, Admyre C, Karlsson A, et al. Clinical effects of a topically applied toll-like receptor 9 agonist in active moderate-to-severe ulcerative colitis. Journal of Crohn's & Colitis.

[25] Sainathan SK, Bishnupuri KS, Aden K, Luo Q, Houchen CW,

10.1038/mi.2014.16

2016;**10**:1294-1302

autrev.2012.10.012

**16**

[33] Tamoutounour S, Henri S, Lelouard H, de Bovis B, de Haar C, van der Woude CJ, et al. CD64 distinguishes macrophages from dendritic cells in the gut and reveals the Th1-inducing role of mesenteric lymph node macrophages during colitis. European Journal of Immunology. 2012;**42**:3150-3166. DOI: 10.1002/eji.201242847

[34] Regoli M, Bertelli E, Gulisano M, Nicoletti C. The multifaceted personality of intestinal CX3CR1+ macrophages. Trends in Immunology. 2017;**38**(12):879-887. DOI: 10.1016/j. it.2017.07.009

[35] Rugtveit J, Bakka A, Brandtzaeg P. Differential distribution of B7.1 (CD80) and B7.2 (CD86) costimulatory molecules on mucosal macrophage subsets in human inflammatory bowel disease (IBD). Clinical and Experimental Immunology. 1997;**110**(1):104-113

[36] Smythies LE, Sellers M, Clements RH, Mosteller-Barnum M, Meng G, Benjamin WH, et al. Human intestinal macrophages display profound inflammatory anergy despite avid phagocytic and bacteriocidal activity. The Journal of Clinical Investigation. 2005;**115**:66-75

[37] Shrivastava R, Shukla N. Attributes of alternatively activated (M2) macrophages. Life Sciences. 2019;**1**(224):222-231. DOI: 10.1016/j. lfs.2019.03.062

[38] Keubler LM, Buettner M, Häger C, Bleich A. A multihit model: Colitis lessons from the interleukin-10 deficient mouse. Inflammatory Bowel Diseases. 2015;**21**:1967-1975. DOI: 10.1097/MIB.0000000000000468

[39] Glocker EO, Kotlarz D, Boztug K, Gertz EM, Schäffer AA, Noyan F, et al. Inflammatory bowel disease and mutations affecting the interleukin-10 receptor. The New England Journal of Medicine. 2009;**361**:2033-2045. DOI: 10.1056/NEJMoa0907206

[40] Bain CC, Mowat AM. The monocyte-macrophage axis in the intestine. Cellular Immunology. 2014;**291**:41-48

[41] Lissner D, Schumann M, Batra A, Kredel LI, Kühl AA, Erben U, et al. Monocyte and M1 macrophageinduced barrier defect contributes to chronic intestinal inflammation in IBD. Inflammatory Bowel Diseases. 2015;**21**:1297-1305. DOI: 10.1097/ MIB.0000000000000384

[42] Smith PD, Smythies LE, Shen R, Greenwell-Wild T, Gliozzi M, Wahl SM. Intestinal macrophages and response to microbial encroachment. Mucosal Immunology. 2011;**4**:31-42. DOI: 10.1038/mi.2010.66

[43] Steimle A, Frick JS. Molecular mechanisms of induction of tolerant and tolerogenic intestinal dendritic cells in mice. Journal of Immunology Research. 2016;**2016**:1958650. DOI: 10.1155/2016/1958650

[44] Bain CC, Schridde A. Origin, differentiation, and function of intestinal macrophages. Frontiers in Immunology. 2018;**9**:2733. DOI: 10.3389/fimmu.2018.02733

[45] Aden K, Rehman A, Falk-Paulsen M, et al. Epithelial IL-23R signaling licenses protective IL-22 responses in intestinal inflammation. Cell Reports. 2016;**16**:2208-2218. DOI: 10.1016/j. celrep.2016.07.054

[46] Mizoguchi A, Yano A, Himuro H, Ezaki Y, Sadanaga T, Mizoguchi E. Clinical importance of IL-22 cascade in IBD. Journal of Gastroenterology. 2018;**53**(4):465-474. DOI: 10.1007/ s00535-017-1401-7

[47] Muraille E, Leo O. Revisiting the Th1/Th2 paradigm. Scandinavian Journal of Immunology. 1998;**47**(1):1-9

[48] Zhang Y, Zhang Y, Gu W, Sun B. TH1/TH2 cell differentiation and molecular signals. Advances in Experimental Medicine and Biology. 2014;**841**:15-44. DOI: 10.1007/978-94-017-9487-9\_2

[49] Shih DQ, Targan SR, McGovern D. Recent advances in IBD pathogenesis: Genetics and immunobiology. Current Gastroenterology Reports. 2008;**10**:568-575

[50] Breese E, Braegger CP, Corrigan CJ, Walker-Smith JA, MacDonald TT. Interleukin-2- and interferon-gammasecreting T cells in normal and diseased human intestinal mucosa. Immunology. 1993;**78**:127-131

[51] Monteleone G, Biancone L, Marasco R, Morrone G, Marasco O, Luzza F, et al. Interleukin 12 is expressed and actively released by Crohn's disease intestinal lamina propria mononuclear cells. Gastroenterology. 1997;**112**:1169-1178

[52] Fuss IJ, Neurath M, Boirivant M, Klein JS, de la Motte C, Strong SA, et al. Disparate CD4+ lamina propria (LP) lymphokine secretion profiles in inflammatory bowel disease. Crohn's disease LP cells manifest increased secretion of IFN-gamma, whereas ulcerative colitis LP cells manifest increased secretion of IL-5. Journal of Immunology. 1996;**157**:1261-1270

[53] Bakema JE, van Egmond M. The human immunoglobulin a fc receptor FcalphaRI: A multifaceted regulator of mucosal immunity. Mucosal Immunology. 2011;**4**:612-624

[54] Savić Mlakar A, Hojsak I, Jergović M, Čimić S, Bendelja K. Pediatric Crohn disease is characterized by Th1 in the terminal ileum and Th1/Th17 immune response in the colon. European Journal of Pediatrics. 2018;**177**:611-616. DOI: 10.1007/ s00431-017-3076-8

[55] Monteleone I, Pallone F, Monteleone G. Th17-related cytokines: New players in the control of chronic intestinal inflammation. BMC Medicine. 2011;**9**:122. DOI: 10.1186/1741-7015-9-122

[56] Ivanov II, McKenzie BS, Zhou L, Tadokoro CE, Lepelley A, Lafaille JJ, et al. The orphan nuclear receptor RORgammat directs the differentiation program of proinflammatory IL-17+ T helper cells. Cell. 2006;**126**:1121-1133

[57] McGeachy MJ, Cua DJ, Gaffen SL. The IL-17 family of cytokines in health and disease. Immunity. 2019;**50**:892-906. DOI: 10.1016/j. immuni.2019.03.021

[58] Zhou L, Lopes JE, Chong MM, Ivanov II, Min R, Victora GD, et al. TGF-beta-induced Foxp3 inhibits T(H)17 cell differentiation by antagonizing RORgammat function. Nature. 2008;**453**(7192):236-240. DOI: 10.1038/nature06878

[59] Valeri M, Raffatellu M, et al. Cytokines IL-17 and IL-22 in the host response to infection. Pathogens and Disease. 2016;**74**(9):ftw111

[60] Liang SC, Tan XY, Luxenberg DP, Karim R, Dunussi-Joannopoulos K, Collins M, et al. Interleukin (IL)-22 and IL- 17 are coexpressed by Th17 cells and cooperatively enhance expression of antimicrobial peptides. The Journal of Experimental Medicine. 2006;**203**:2271-2229

[61] Isailovic N, Daigo K, Mantovani A, Selmi C. Interleukin-17 and innate immunity in infections and

**19**

*Mucosal Immunology in the Inflammatory Bowel Diseases*

[70] Yang SH, Gao CY, Li L, Chang C, Leung PSC, Gershwin ME, et al. The molecular basis of immune regulation in autoimmunity. Clinical Science (London, England). 2018;**132**:43-67.

[71] Soukou S, Brockmann L, Bedke T, Gagliani N, Flavell RA, Huber S. Role of IL-10 receptor signaling in the function of CD4+ T-regulatory type 1 cells: T-cell therapy in patients with inflammatory bowel disease. Critical Reviews in Immunology. 2018;**38**:415-431. DOI: 10.1615/ CritRevImmunol.2018026850

[72] Wing K, Onishi Y, Prieto-Martin P, et al. CTLA-4 control over Foxp3+ regulatory T cell function. Science.

DOI: 10.1042/CS20171154

2008;**322**:271-275

2009;**157**:9-19

1999;**19**:1-24

[73] Peggs KS, Quezada SA,

Allison JP. Cancer immunotherapy: Co-stimulatory agonists and co-inhibitory antagonists. Clinical and Experimental Immunology.

[74] Plevy SE, Targan SR. Future therapeutic approaches for inflammatory bowel diseases.

Immunity. 2009;**31**:401-411

[77] Lenschow DJ, Walunas TL, Bluestone JA. CD28/B7 system of T cell costimulation. Annual Review of Immunology. 1996;**14**:233-258

Nature. 2008;**453**:236-240

[78] Zhou L, Lopes JE, Chong MMW, et al. TGF-beta-induced Foxp3 inhibits T(H)17 celldifferentiation by antagonizing RORgammat function.

Gastroenterology. 2011;**140**:1838-1846

[75] Barnes MJ, Powrie F. Regulatory T cells reinforce intestinal homeostasis.

[76] Barnes MJ, Powrie F. Regulatory T cells reinforce intestinal homeostasis. Immunity. Immunologic Research.

*DOI: http://dx.doi.org/10.5772/intechopen.90037*

chronic inflammation. Journal of Autoimmunity. 2015;**60**:1-11. DOI:

[62] Chen K, Kolls JK. Interluekin-17A (IL17A). Gene. 2017;**614**:8-14. DOI:

[63] Kinugasa T, Sakaguchi T, Gu X, Reinecker HC. Claudins regulate the intestinal barrier in response to immune mediators. Gastroenterology.

[64] Lee JS, Tato CM, Joyce-Shaikh B, Gulen MF, Cayatte C, Chen Y, et al. Interleukin-23-independent IL-17 production regulates intestinal epithelial permeability. Immunity. 2015;**43**:727- 738. DOI: 10.1016/j.immuni.2015.09.003

[65] Zhang Z, Zheng M, Bindas J, Schwarzenberger P, Kolls JK. Critical role of IL-17 receptor signaling in acute TNBS-induced colitis. Inflammatory Bowel Diseases. 2006;**12**:382-388

[66] Liu QL, Huang L, Zhao QJ, Li Q, He Z. Relationship between serum interleukin-17 level and inflammatory bowel disease. Journal of Biological Regulators and Homeostatic Agents.

[67] Gálvez J. Role of Th17 cells in the pathogenesis of human IBD. ISRN Inflammation. 2014;**2014**:928461. DOI:

[68] Bieńkowska A, Kiernozek E, Kozlowska E, Zarzycki M, Drela N. Thymus-deriving natural regulatory T cell generation in vitro: Role of the source of activation signals.

DOI: 10.1016/j.imlet.2014.10.024

[69] Kanamori M, Nakatsukasa H, Okada M, Lu Q, Yoshimura A. Induced regulatory T cells: Their development, stability, and applications. Trends in Immunology. 2016;**37**:803-811. DOI:

10.1016/j.it.2016.08.012

Immunology Letters. 2014;**162**:199-209.

10.1016/j.jaut.2015.04.006

10.1016/j.gene.2017.01.016

2000;**118**:1001-1011

2016;**30**:181-188

10.1155/2014/928461

*Mucosal Immunology in the Inflammatory Bowel Diseases DOI: http://dx.doi.org/10.5772/intechopen.90037*

chronic inflammation. Journal of Autoimmunity. 2015;**60**:1-11. DOI: 10.1016/j.jaut.2015.04.006

*Biological Therapy for Inflammatory Bowel Disease*

by Th1 in the terminal ileum and Th1/Th17 immune response in the colon. European Journal of Pediatrics. 2018;**177**:611-616. DOI: 10.1007/

[55] Monteleone I, Pallone F,

New players in the control of chronic intestinal inflammation. BMC Medicine. 2011;**9**:122. DOI:

10.1186/1741-7015-9-122

Cell. 2006;**126**:1121-1133

immuni.2019.03.021

10.1038/nature06878

2006;**203**:2271-2229

Selmi C. Interleukin-17 and innate immunity in infections and

[57] McGeachy MJ, Cua DJ,

in health and disease. Immunity. 2019;**50**:892-906. DOI: 10.1016/j.

[58] Zhou L, Lopes JE, Chong MM, Ivanov II, Min R, Victora GD, et al. TGF-beta-induced Foxp3 inhibits T(H)17 cell differentiation by antagonizing RORgammat function. Nature. 2008;**453**(7192):236-240. DOI:

[59] Valeri M, Raffatellu M, et al. Cytokines IL-17 and IL-22 in the host response to infection. Pathogens and

[60] Liang SC, Tan XY, Luxenberg DP, Karim R, Dunussi-Joannopoulos K, Collins M, et al. Interleukin (IL)-22 and IL- 17 are coexpressed by Th17 cells and cooperatively enhance expression of antimicrobial peptides. The Journal of Experimental Medicine.

[61] Isailovic N, Daigo K, Mantovani A,

Disease. 2016;**74**(9):ftw111

[56] Ivanov II, McKenzie BS, Zhou L, Tadokoro CE, Lepelley A, Lafaille JJ, et al. The orphan nuclear receptor RORgammat directs the differentiation program of

Monteleone G. Th17-related cytokines:

proinflammatory IL-17+ T helper cells.

Gaffen SL. The IL-17 family of cytokines

s00431-017-3076-8

[47] Muraille E, Leo O. Revisiting the Th1/Th2 paradigm. Scandinavian Journal of Immunology. 1998;**47**(1):1-9

[49] Shih DQ, Targan SR, McGovern D. Recent advances in IBD pathogenesis: Genetics and immunobiology. Current Gastroenterology Reports.

[50] Breese E, Braegger CP, Corrigan CJ, Walker-Smith JA, MacDonald TT. Interleukin-2- and interferon-gammasecreting T cells in normal and diseased human intestinal mucosa. Immunology.

[51] Monteleone G, Biancone L,

Marasco O, Luzza F, et al. Interleukin 12 is expressed and actively released by Crohn's disease intestinal lamina propria mononuclear cells. Gastroenterology.

[52] Fuss IJ, Neurath M, Boirivant M, Klein JS, de la Motte C, Strong SA, et al. Disparate CD4+ lamina propria (LP) lymphokine secretion profiles in inflammatory bowel disease. Crohn's disease LP cells manifest increased secretion of IFN-gamma, whereas ulcerative colitis LP cells manifest increased secretion of IL-5. Journal of Immunology. 1996;**157**:1261-1270

[53] Bakema JE, van Egmond M. The human immunoglobulin a fc receptor FcalphaRI: A multifaceted regulator of mucosal immunity. Mucosal Immunology. 2011;**4**:612-624

Pediatric Crohn disease is characterized

[54] Savić Mlakar A, Hojsak I, Jergović M, Čimić S, Bendelja K.

Marasco R, Morrone G,

1997;**112**:1169-1178

[48] Zhang Y, Zhang Y, Gu W, Sun B. TH1/TH2 cell differentiation and molecular signals. Advances in Experimental Medicine and Biology. 2014;**841**:15-44. DOI: 10.1007/978-94-017-9487-9\_2

2008;**10**:568-575

1993;**78**:127-131

**18**

[62] Chen K, Kolls JK. Interluekin-17A (IL17A). Gene. 2017;**614**:8-14. DOI: 10.1016/j.gene.2017.01.016

[63] Kinugasa T, Sakaguchi T, Gu X, Reinecker HC. Claudins regulate the intestinal barrier in response to immune mediators. Gastroenterology. 2000;**118**:1001-1011

[64] Lee JS, Tato CM, Joyce-Shaikh B, Gulen MF, Cayatte C, Chen Y, et al. Interleukin-23-independent IL-17 production regulates intestinal epithelial permeability. Immunity. 2015;**43**:727- 738. DOI: 10.1016/j.immuni.2015.09.003

[65] Zhang Z, Zheng M, Bindas J, Schwarzenberger P, Kolls JK. Critical role of IL-17 receptor signaling in acute TNBS-induced colitis. Inflammatory Bowel Diseases. 2006;**12**:382-388

[66] Liu QL, Huang L, Zhao QJ, Li Q, He Z. Relationship between serum interleukin-17 level and inflammatory bowel disease. Journal of Biological Regulators and Homeostatic Agents. 2016;**30**:181-188

[67] Gálvez J. Role of Th17 cells in the pathogenesis of human IBD. ISRN Inflammation. 2014;**2014**:928461. DOI: 10.1155/2014/928461

[68] Bieńkowska A, Kiernozek E, Kozlowska E, Zarzycki M, Drela N. Thymus-deriving natural regulatory T cell generation in vitro: Role of the source of activation signals. Immunology Letters. 2014;**162**:199-209. DOI: 10.1016/j.imlet.2014.10.024

[69] Kanamori M, Nakatsukasa H, Okada M, Lu Q, Yoshimura A. Induced regulatory T cells: Their development, stability, and applications. Trends in Immunology. 2016;**37**:803-811. DOI: 10.1016/j.it.2016.08.012

[70] Yang SH, Gao CY, Li L, Chang C, Leung PSC, Gershwin ME, et al. The molecular basis of immune regulation in autoimmunity. Clinical Science (London, England). 2018;**132**:43-67. DOI: 10.1042/CS20171154

[71] Soukou S, Brockmann L, Bedke T, Gagliani N, Flavell RA, Huber S. Role of IL-10 receptor signaling in the function of CD4+ T-regulatory type 1 cells: T-cell therapy in patients with inflammatory bowel disease. Critical Reviews in Immunology. 2018;**38**:415-431. DOI: 10.1615/ CritRevImmunol.2018026850

[72] Wing K, Onishi Y, Prieto-Martin P, et al. CTLA-4 control over Foxp3+ regulatory T cell function. Science. 2008;**322**:271-275

[73] Peggs KS, Quezada SA, Allison JP. Cancer immunotherapy: Co-stimulatory agonists and co-inhibitory antagonists. Clinical and Experimental Immunology. 2009;**157**:9-19

[74] Plevy SE, Targan SR. Future therapeutic approaches for inflammatory bowel diseases. Gastroenterology. 2011;**140**:1838-1846

[75] Barnes MJ, Powrie F. Regulatory T cells reinforce intestinal homeostasis. Immunity. 2009;**31**:401-411

[76] Barnes MJ, Powrie F. Regulatory T cells reinforce intestinal homeostasis. Immunity. Immunologic Research. 1999;**19**:1-24

[77] Lenschow DJ, Walunas TL, Bluestone JA. CD28/B7 system of T cell costimulation. Annual Review of Immunology. 1996;**14**:233-258

[78] Zhou L, Lopes JE, Chong MMW, et al. TGF-beta-induced Foxp3 inhibits T(H)17 celldifferentiation by antagonizing RORgammat function. Nature. 2008;**453**:236-240

[79] Eastaff-Leung N, Mabarrack N, Barbour A, Cummins A, Barry S. Foxp3+ regulatory T cells, Th17 effector cells, and cytokine environment in inflammatory bowel disease. Journal of Clinical Immunology. 2010;**30**:80-89. DOI: 10.1007/s10875-009-9345-1

[80] Ueno A, Jijon H, Chan R, Ford K, Hirota C, Kaplan GG, et al. Increased prevalence of circulating novel IL-17 secreting Foxp3 expressing CD4+ T cells and defective suppressive function of circulating Foxp3+ regulatory cells support plasticity between Th17 and regulatory T cells in inflammatory bowel disease patients. Inflammatory Bowel Diseases. 2013;**19**:2522-2534. DOI: 10.1097/ MIB.0b013e3182a85709

[81] Goswami R, Jabeen R, Yagi R, Pham D, Zhu J, Goenka S, et al. STAT6 dependent regulation of Th9 development. Journal of Immunology. 2012;**188**(3):968-975. DOI: 10.4049/ jimmunol.1102840

[82] Dardalhon V, Awasthi A, Kwon H, Galileos G, Gao W, Sobel RA, et al. IL-4 inhibits TGF-beta-induced Foxp3+ T cells and, together with TGFbeta, generates IL-9+ IL-10+ Foxp3(−) effector T cells. Nature Immunology. 2008;**9**:1347-1355. DOI: 10.1038/ ni.1677

[83] Chang HC, Sehra S, Goswami R, Yao W, Yu Q, Stritesky GL, et al. The transcription factor PU.1 is required for the development of IL-9-producing T cells and allergic inflammation. Nature Immunology. 2010;**11**:527-534. DOI: 10.1038/ni.1867

[84] Shohan M, Elahi S, Shirzad H, Rafieian-Kopaei M, Bagheri N, Soltani E. Th9 cells: Probable players in ulcerative colitis pathogenesis. International Reviews of Immunology. 2018;**37**:192-205. DOI: 10.1080/08830185.2018.1457659

[85] Gerlach K, Hwang Y, Nikolaev A, Atreya R, Dornhoff H, Steiner S, et al. Th9 cells that express the transcription factor PU.1 drive T cell-mediated colitis via IL-9 receptor signaling in intestinal epithelial cells. Nature Immunology. 2014;**15**:676-686. DOI: 10.1038/ni.2920

[86] Defendenti C, Sarzi-Puttini P, Saibeni S, Bollani S, Bruno S, Almasio PL, et al. Significance of serum Il-9 levels in inflammatory bowel disease. International Journal of Immunopathology and Pharmacology. 2015;**28**(4):569-575. DOI: 10.1177/0394632015600535

[87] Gerlach K, McKenzie AN, Neurath MF, Weigmann B. IL-9 regulates intestinal barrier function in experimental T cell-mediated colitis. Tissue Barriers. 2015;**3**(1-2):e983777. DOI: 10.4161/21688370.2014.983777

[88] Sonnenberg GF, Artis D. Innate lymphoid cell interactions with microbiota: Implications for intestinal health and disease. Immunity. 2012;**37**:601-610

[89] Spits H, Cupedo T. Innate lymphoid cells: Emerging insights in development, lineage relationships, and function. Annual Review of Immunology. 2012;**30**:647-675

[90] Klose CSN, Flach M, Möhle L, Rogell L, Hoyler T, Ebert K, et al. Differentiation oftype 1 ILCs from a common progenitor to all helper-like innate lymphoid celllineages. Cell. 2014;**157**:340-356

[91] Brestoff JR, Kim BS, Saenz SA, Stine RR, Monticelli LA, Sonnenberg GF, et al. Group2 innate lymphoid cells promote beiging of white adipose tissue and limit obesity. Nature. 2015;**519**:242-246

[92] Pantazi E, Powell N. Group 3 ILCs: Peacekeepers or troublemakers? What's your gut telling you?! Frontiers

**21**

10.1038/mi.2013.33

*Mucosal Immunology in the Inflammatory Bowel Diseases*

[99] Longman RS, Diehl GE, Victorio DA, Huh JR, Galan C, Miraldi ER, et al. CX3CR1+

10.1084/jem.20140678

s11882-016-0652-3

[100] Bernink JH, Peters CP,

phagocytes support colitis-associated innate lymphoid cell production of IL-22. The Journal of Experimental Medicine. 2014;**211**:1571-1583. DOI:

Munneke M, te Velde AA, Meijer SL, Weijer K, et al. Human type 1 innate lymphoid cells accumulate in inflamed mucosal tissues. Nature Immunology. 2013;**14**:221-229. DOI: 10.1038/ni.2534

[101] Forkel M, Mjösberg J. Dysregulation of group 3 innate lymphoid cells in the pathogenesis of inflammatory bowel disease. Current Allergy and Asthma Reports. 2016;**16**(10):73. DOI: 10.1007/

[102] Wang S, Xia P, Chen Y, Qu Y, Xiong Z, Ye B, et al. Regulatory innate lymphoid cells control innate intestinal inflammation. Cell. 2017;**171**:201-216. e18. DOI: 10.1016/j.cell.2017.07.027

mononuclear

*DOI: http://dx.doi.org/10.5772/intechopen.90037*

in Immunology. 2019;**10**:676. DOI: 10.3389/fimmu.2019.00676

[93] Forkel M, van Tol S, Höög C, Michaëlsson J, Almer S, Mjösberg J. Distinct alterations in the composition of mucosal innate lymphoid cells in newly diagnosed and established Crohn's disease and ulcerative colitis. Journal of Crohn's & Colitis. 2019;**13**:67-

78. DOI: 10.1093/ecco-jcc/jjy119

Schwarze-Zander C, et al. Compartmentspecific distribution of human intestinal innate lymphoid cells is altered in HIV patients under effective therapy. PLoS Pathogens. 2017;**13**(5):e1006373. DOI:

[94] Krämer B, Goeser F, Lutz P, Glässner A, Boesecke C,

10.1371/journal.ppat.1006373

[96] Hepworth MR, Fung TC,

bacteria-specific CD4<sup>+</sup>

science.aaa4812

Masur SH, Kelsen JR, McConnell FM, Dubrot J, et al. Immune tolerance. Group 3 innate lymphoid cells mediate intestinal selection of commensal

2015;**348**:1031-1035. DOI: 10.1126/

[97] Guo X, Qiu J, Tu T, Yang X, Deng L, Anders RA, et al. Induction of innate lymphoid cell-derived interleukin-22 by the transcription factor STAT3 mediates protection against intestinal infection. Immunity. 2014;**40**:25-39. DOI: 10.1016/j.immuni.2013.10.021

[98] Eken A, Singh AK, Treuting PM, Oukka M. IL-23R+ innate lymphoid cells induce colitis via interleukin-22-dependent mechanism. Mucosal Immunology. 2014;**7**:143-154. DOI:

T cells. Science.

nature12240

[95] Hepworth MR, Monticelli LA, Fung TC, Ziegler CG, Grunberg S, Sinha R, et al. Innate lymphoid cells regulate CD4+ T-cell responses to intestinal commensal bacteria. Nature. 2013;**498**:113-117. DOI: 10.1038/

*Mucosal Immunology in the Inflammatory Bowel Diseases DOI: http://dx.doi.org/10.5772/intechopen.90037*

in Immunology. 2019;**10**:676. DOI: 10.3389/fimmu.2019.00676

*Biological Therapy for Inflammatory Bowel Disease*

[85] Gerlach K, Hwang Y, Nikolaev A, Atreya R, Dornhoff H, Steiner S, et al. Th9 cells that express the transcription factor PU.1 drive T cell-mediated colitis via IL-9 receptor signaling in intestinal epithelial cells. Nature Immunology. 2014;**15**:676-686. DOI: 10.1038/ni.2920

[86] Defendenti C, Sarzi-Puttini P, Saibeni S, Bollani S, Bruno S,

2015;**28**(4):569-575. DOI: 10.1177/0394632015600535

[87] Gerlach K, McKenzie AN,

intestinal barrier function in

Almasio PL, et al. Significance of serum Il-9 levels in inflammatory bowel disease. International Journal of Immunopathology and Pharmacology.

Neurath MF, Weigmann B. IL-9 regulates

experimental T cell-mediated colitis. Tissue Barriers. 2015;**3**(1-2):e983777. DOI: 10.4161/21688370.2014.983777

[88] Sonnenberg GF, Artis D. Innate lymphoid cell interactions with microbiota: Implications for intestinal

[89] Spits H, Cupedo T. Innate lymphoid cells: Emerging insights in development, lineage relationships, and function. Annual Review of Immunology.

[90] Klose CSN, Flach M, Möhle L, Rogell L, Hoyler T, Ebert K, et al. Differentiation oftype 1 ILCs from a common progenitor to all helper-like innate lymphoid celllineages. Cell.

Saenz SA, Stine RR, Monticelli LA, Sonnenberg GF, et al. Group2 innate lymphoid cells promote beiging of white adipose tissue and limit obesity. Nature.

[92] Pantazi E, Powell N. Group 3 ILCs: Peacekeepers or troublemakers? What's your gut telling you?! Frontiers

health and disease. Immunity.

2012;**37**:601-610

2012;**30**:647-675

2014;**157**:340-356

2015;**519**:242-246

[91] Brestoff JR, Kim BS,

[79] Eastaff-Leung N, Mabarrack N, Barbour A, Cummins A, Barry S. Foxp3+ regulatory T cells, Th17 effector cells, and cytokine environment in inflammatory bowel disease. Journal of Clinical Immunology. 2010;**30**:80-89. DOI: 10.1007/s10875-009-9345-1

[80] Ueno A, Jijon H, Chan R, Ford K, Hirota C, Kaplan GG, et al. Increased prevalence of circulating novel IL-17 secreting Foxp3 expressing CD4+ T cells and defective suppressive function of circulating Foxp3+ regulatory cells support plasticity between Th17 and regulatory T cells in inflammatory bowel disease patients. Inflammatory Bowel Diseases. 2013;**19**:2522-2534. DOI: 10.1097/

MIB.0b013e3182a85709

jimmunol.1102840

ni.1677

10.1038/ni.1867

[84] Shohan M, Elahi S,

Shirzad H, Rafieian-Kopaei M, Bagheri N, Soltani E. Th9 cells: Probable players in ulcerative colitis pathogenesis. International Reviews of Immunology. 2018;**37**:192-205. DOI:

10.1080/08830185.2018.1457659

[81] Goswami R, Jabeen R, Yagi R, Pham D, Zhu J, Goenka S, et al. STAT6-

development. Journal of Immunology. 2012;**188**(3):968-975. DOI: 10.4049/

[82] Dardalhon V, Awasthi A, Kwon H, Galileos G, Gao W, Sobel RA, et al. IL-4 inhibits TGF-beta-induced Foxp3+ T cells and, together with TGFbeta, generates IL-9+ IL-10+ Foxp3(−) effector T cells. Nature Immunology. 2008;**9**:1347-1355. DOI: 10.1038/

[83] Chang HC, Sehra S, Goswami R, Yao W, Yu Q, Stritesky GL, et al. The transcription factor PU.1 is required for the development of IL-9-producing T cells and allergic inflammation. Nature Immunology. 2010;**11**:527-534. DOI:

dependent regulation of Th9

**20**

[93] Forkel M, van Tol S, Höög C, Michaëlsson J, Almer S, Mjösberg J. Distinct alterations in the composition of mucosal innate lymphoid cells in newly diagnosed and established Crohn's disease and ulcerative colitis. Journal of Crohn's & Colitis. 2019;**13**:67- 78. DOI: 10.1093/ecco-jcc/jjy119

[94] Krämer B, Goeser F, Lutz P, Glässner A, Boesecke C, Schwarze-Zander C, et al. Compartmentspecific distribution of human intestinal innate lymphoid cells is altered in HIV patients under effective therapy. PLoS Pathogens. 2017;**13**(5):e1006373. DOI: 10.1371/journal.ppat.1006373

[95] Hepworth MR, Monticelli LA, Fung TC, Ziegler CG, Grunberg S, Sinha R, et al. Innate lymphoid cells regulate CD4+ T-cell responses to intestinal commensal bacteria. Nature. 2013;**498**:113-117. DOI: 10.1038/ nature12240

[96] Hepworth MR, Fung TC, Masur SH, Kelsen JR, McConnell FM, Dubrot J, et al. Immune tolerance. Group 3 innate lymphoid cells mediate intestinal selection of commensal bacteria-specific CD4<sup>+</sup> T cells. Science. 2015;**348**:1031-1035. DOI: 10.1126/ science.aaa4812

[97] Guo X, Qiu J, Tu T, Yang X, Deng L, Anders RA, et al. Induction of innate lymphoid cell-derived interleukin-22 by the transcription factor STAT3 mediates protection against intestinal infection. Immunity. 2014;**40**:25-39. DOI: 10.1016/j.immuni.2013.10.021

[98] Eken A, Singh AK, Treuting PM, Oukka M. IL-23R+ innate lymphoid cells induce colitis via interleukin-22-dependent mechanism. Mucosal Immunology. 2014;**7**:143-154. DOI: 10.1038/mi.2013.33

[99] Longman RS, Diehl GE, Victorio DA, Huh JR, Galan C, Miraldi ER, et al. CX3CR1+ mononuclear phagocytes support colitis-associated innate lymphoid cell production of IL-22. The Journal of Experimental Medicine. 2014;**211**:1571-1583. DOI: 10.1084/jem.20140678

[100] Bernink JH, Peters CP, Munneke M, te Velde AA, Meijer SL, Weijer K, et al. Human type 1 innate lymphoid cells accumulate in inflamed mucosal tissues. Nature Immunology. 2013;**14**:221-229. DOI: 10.1038/ni.2534

[101] Forkel M, Mjösberg J. Dysregulation of group 3 innate lymphoid cells in the pathogenesis of inflammatory bowel disease. Current Allergy and Asthma Reports. 2016;**16**(10):73. DOI: 10.1007/ s11882-016-0652-3

[102] Wang S, Xia P, Chen Y, Qu Y, Xiong Z, Ye B, et al. Regulatory innate lymphoid cells control innate intestinal inflammation. Cell. 2017;**171**:201-216. e18. DOI: 10.1016/j.cell.2017.07.027

**23**

**Chapter 2**

**Abstract**

treatment of IBD.

**1. Introduction**

The Role of TNF in the

Bowel Disease

*Martina Perše and Ana Unkovič*

Pathogenesis of Inflammatory

Tumor necrosis factor (TNF) is a pleotropic cytokine involved in a wide range of pathological processes, including inflammatory bowel disease (IBD). In the past, TNF was recognized as a pro-inflammatory cytokine with deleterious effects. This has led to the development of anti-TNF drugs, which revolutionized the treatment of inflammatory disorders such as Crohn's disease. However, in the past 20 years, clinical studies have shown that anti-TNF drugs are not always effective. Moreover, in some rare cases, anti-TNF drugs can even cause an aggravation of the disease. Nowadays, there is increasing evidence that TNF is not only detrimental but can also play an important role in health and the maintenance of homeostasis. The aim of this chapter is to briefly summarize the literature demonstrating the complex dichotomous role of TNF in IBD and discuss the role of anti-TNF drugs in the

**Keywords:** tumor necrosis factor, inflammatory bowel disease, side effects,

Inflammatory bowel disease (IBD) is a chronic, relapsing inflammatory condition of gastrointestinal tract with high incidence and prevalence in Western countries (North America, Europe, the highest in Scandinavia, and the United Kingdom) [1]. It is estimated that IBD affects 2.5–3 million people in Europe [2]. IBD consist primarily of Crohn's disease (CD) and ulcerative colitis (UC), which are distinguished by the location and the nature of the inflammation [3]. Patients with IBD experience many symptoms, such as abdominal pain, fever, vomiting, diarrhea, rectal bleeding, anemia, and weight loss, which have significant impact on their quality of life. Symptoms vary depending on the location and severity of inflammation and can be very painful and disruptive and in some cases even life-

IBD affects a young population, in the second and third decades of life or even in late adolescence [4]. The majority of patients with IBD progress to relapsing and chronic disease and need lifelong treatment and care. The health economic burden and permanent work disability in IBD are high in Europe with a total yearly direct healthcare cost of 4.6–5.6 billion Euros [2]. In recent years, the management of IBD has improved, due to the fact that the new treatments with anti-TNF drugs induce

TNF inhibitors, paradoxical side effects, homeostasis

threatening (CD patients have 40% risk of mortality) [3].

#### **Chapter 2**

## The Role of TNF in the Pathogenesis of Inflammatory Bowel Disease

*Martina Perše and Ana Unkovič*

#### **Abstract**

Tumor necrosis factor (TNF) is a pleotropic cytokine involved in a wide range of pathological processes, including inflammatory bowel disease (IBD). In the past, TNF was recognized as a pro-inflammatory cytokine with deleterious effects. This has led to the development of anti-TNF drugs, which revolutionized the treatment of inflammatory disorders such as Crohn's disease. However, in the past 20 years, clinical studies have shown that anti-TNF drugs are not always effective. Moreover, in some rare cases, anti-TNF drugs can even cause an aggravation of the disease. Nowadays, there is increasing evidence that TNF is not only detrimental but can also play an important role in health and the maintenance of homeostasis. The aim of this chapter is to briefly summarize the literature demonstrating the complex dichotomous role of TNF in IBD and discuss the role of anti-TNF drugs in the treatment of IBD.

**Keywords:** tumor necrosis factor, inflammatory bowel disease, side effects, TNF inhibitors, paradoxical side effects, homeostasis

#### **1. Introduction**

Inflammatory bowel disease (IBD) is a chronic, relapsing inflammatory condition of gastrointestinal tract with high incidence and prevalence in Western countries (North America, Europe, the highest in Scandinavia, and the United Kingdom) [1]. It is estimated that IBD affects 2.5–3 million people in Europe [2].

IBD consist primarily of Crohn's disease (CD) and ulcerative colitis (UC), which are distinguished by the location and the nature of the inflammation [3]. Patients with IBD experience many symptoms, such as abdominal pain, fever, vomiting, diarrhea, rectal bleeding, anemia, and weight loss, which have significant impact on their quality of life. Symptoms vary depending on the location and severity of inflammation and can be very painful and disruptive and in some cases even lifethreatening (CD patients have 40% risk of mortality) [3].

IBD affects a young population, in the second and third decades of life or even in late adolescence [4]. The majority of patients with IBD progress to relapsing and chronic disease and need lifelong treatment and care. The health economic burden and permanent work disability in IBD are high in Europe with a total yearly direct healthcare cost of 4.6–5.6 billion Euros [2]. In recent years, the management of IBD has improved, due to the fact that the new treatments with anti-TNF drugs induce

not only clinical remission but also a significant endoscopic improvement or even disappearance of the intestinal lesions [5, 6].

However, in the past two decades, clinical studies have shown that anti-TNF drugs are not always effective. Moreover, in some rare cases, anti-TNF drugs can even cause an aggravation of the disease. Therefore, this chapter aims to briefly summarize the detrimental role of TNF in the pathogenesis of IBD and to highlight the beneficial role of TNF, which is too often overlooked in the health and the disease.

#### **2. Dual identification of TNF (cachectin)**

Tumor necrosis factor (TNF, also known as TNFa, cachectin, or cachexin) was identified/named in 1975 by Carswell et al. who demonstrated that the serum of endotoxin-treated mice, rat, and rabbits, previously infected with *Mycobacterium bovis* strain Bacillus Calmette-Guerin caused hemorrhagic necrosis of various tumors in mice. They found that hemorrhagic necrosis of tumors in vivo was caused by so-called tumor necrosis factor (TNF) released from host cells, very likely macrophages, in response to injected endotoxin. They showed that both, a TNF-positive serum and endotoxin, were effective in causing necrosis of similar spectrum of transplanted tumors and at a similar phase of their growth. Moreover, a TNF-positive serum had cytotoxic effects on mouse and human tumor cells in vitro as well [7].

In 1985, human TNF was purified, characterized, and cloned, which enabled production of large quantities of a highly purified TNF protein for extensive investigations [8, 9]. Since recombinant TNF has shown antitumor activity in both transplantable murine tumors and human tumor xenografts, TNF was quickly launched into clinical trials as a potential anticancer agent. Recombinant human TNF has been tested in several phase I and phase II clinical trials in the 1980s and 1990s. However, the initial enthusiasm for the use of TNF as a systemic treatment has waned in the face of significant toxicities and a lack of evidence for therapeutic benefit. Systemic TNF treatment was found to cause dose-dependent toxicities such as fever, hypotension, and tachycardia [10–12].

Independently, other groups of researchers investigated metabolic basis for cachexia and endotoxin-induced septicemia and septic shock syndrome. Hypertriglyceridemia in animals injected with endotoxin was found to result from defective triglyceride clearance due to systemic suppression of the enzyme lipoprotein lipase. Finally, the substance responsible for specific suppression of lipoprotein lipase activity was identified and named cachectin [13, 14]. Interestingly, soon after the characterization of human TNF in 1985, it was recognized that the TNF and cachectin are the same single protein with the complex dual role [8, 9, 15].

Nevertheless, direct evidence that cachectin is a mediator of the pathology/ septicemia induced by endotoxin was demonstrated by Beutler and colleagues [16, 17]. They showed that passive immunization with rabbit antiserum or purified Ig against murine TNF protected the mice from the lethal effect of the endotoxin lipopolysaccharide [16]. The same group then showed that injection of recombinant human TNF into rats in quantities similar to those produced endogenously in response to endotoxin caused hypotension, metabolic acidosis, hemoconcentration, and death of animals within minutes to hours. Thus, effects similar to those are induced by injection of endotoxin [17]. These observations led to the speculation that neutralization of TNF may be beneficial in life-threatening septicemia. Despite increased interest in the use of anti-TNF drugs for the treatment of sepsis, numerous clinical trials have showed only a small survival benefit (3.6%) [18]. The likely

**25**

and even death [31].

tissues.

*The Role of TNF in the Pathogenesis of Inflammatory Bowel Disease*

reason for the failure of anti-TNF drugs in sepsis can be found in the original animal study, where it was clearly demonstrated that neutralization of TNF was efficient in preventing death in mice only when administered before a very short time after the

Nevertheless, the effort invested in the development of anti-TNF drugs, originally intended for the treatment of sepsis, enabled the use of anti-TNF therapy in the chronic inflammatory diseases, including IBD. However, the investigations and hopes regarding the use of anti-TNF drugs in sepsis and the use of TNF as an

The first evidence showing a link between TNF and IBD were publications reporting that patients with IBD have increased levels of TNF in serum, stool, or mucosal biopsy specimens [20–23]. However, the initial hopes for the use of TNF as a marker of IBD have waned when it was recognized that TNF can be increased also during infectious colitis [24] or TNF may even not be increased in patients with IBD [25] or TNF can be reduced in response to certain medication such as cyclosporine A [22, 26]. Nevertheless, a published reports about successful treatment of CD patients with TNF chimeric monoclonal antibodies (cA2 or infliximab) [27] established clear association of TNF involvement in the pathogenesis of IBD and caused extensive investigation of TNF role in IBD and production of various genetic models, including transgenic mice with persistent TNF overproduction in various

It was clearly demonstrated that persistent systemic overproduction of TNF (TNF<sup>∆</sup>ARE/∆ARE mice) can cause severe systemic health problems in mice, such as severe chronic polyarthritis, profound inflammatory changes in the terminal ileum and occasionally in the proximal colon, hypoplastic thymus with atrophied and disorganized cortical and medullary areas, and occasional mild inflammation in the liver and lung. These alterations were first detected in homozygous mice between 1 and 4 weeks of their age. Heterozygous mice developed the same health problems but later in their life inflammatory arthritis at 6–8 weeks of age and severe inflammatory bowel disease extending into muscular layers of the bowel wall at 4–7 months of their age. Homozygous mice never exceeded the body weight of 3-week-old mice and died between 5 and 12 weeks of their age [28]. It was also demonstrated that chronic intestinal inflammation can be triggered by persistent local TNF overproduction. Mice homozygous for persistent overproduction of TNF in the intestinal epithelium (TNFi∆ARE/i∆ARE mice) developed chronic ileitis by the age of 16–20 weeks and had increased mucosal and systemic protein levels of TNF. No inflammation in other tissues was found. No histological signs of joint injury were observed. Heterozygous mice (TNFi∆ARE/+) develop only mild villous blunting with scarce inflammation (not significant) [29]. In addition, mice with persistent myeloid cell-specific TNF overproduction also developed symptoms of weight loss and ileitis by the age of 5 months (homo and heterozygous) but with more severe symptoms in the homozygous mice. Interestingly, mice with persistent T lymphocyte-specific TNF overproduction developed mild symptoms of IBD but only on homozygous background. On the other hand, mice with persistent B lymphocyte-specific TNF overproduction did not show any signs of IBD by the age of 15 months [30]. Results of numerous animal studies gave tacit confirmation that persistent systemic or local TNF overproduction is detrimental and responsible for intestinal inflammation, serious health problems,

*DOI: http://dx.doi.org/10.5772/intechopen.84375*

anticancer agent are still in progress [10, 19].

**3. A link between TNF and IBD**

injection of endotoxin [16].

*The Role of TNF in the Pathogenesis of Inflammatory Bowel Disease DOI: http://dx.doi.org/10.5772/intechopen.84375*

reason for the failure of anti-TNF drugs in sepsis can be found in the original animal study, where it was clearly demonstrated that neutralization of TNF was efficient in preventing death in mice only when administered before a very short time after the injection of endotoxin [16].

Nevertheless, the effort invested in the development of anti-TNF drugs, originally intended for the treatment of sepsis, enabled the use of anti-TNF therapy in the chronic inflammatory diseases, including IBD. However, the investigations and hopes regarding the use of anti-TNF drugs in sepsis and the use of TNF as an anticancer agent are still in progress [10, 19].

#### **3. A link between TNF and IBD**

*Biological Therapy for Inflammatory Bowel Disease*

disappearance of the intestinal lesions [5, 6].

**2. Dual identification of TNF (cachectin)**

as fever, hypotension, and tachycardia [10–12].

disease.

as well [7].

not only clinical remission but also a significant endoscopic improvement or even

However, in the past two decades, clinical studies have shown that anti-TNF drugs are not always effective. Moreover, in some rare cases, anti-TNF drugs can even cause an aggravation of the disease. Therefore, this chapter aims to briefly summarize the detrimental role of TNF in the pathogenesis of IBD and to highlight the beneficial role of TNF, which is too often overlooked in the health and the

Tumor necrosis factor (TNF, also known as TNFa, cachectin, or cachexin) was identified/named in 1975 by Carswell et al. who demonstrated that the serum of endotoxin-treated mice, rat, and rabbits, previously infected with *Mycobacterium bovis* strain Bacillus Calmette-Guerin caused hemorrhagic necrosis of various tumors in mice. They found that hemorrhagic necrosis of tumors in vivo was caused by so-called tumor necrosis factor (TNF) released from host cells, very likely macrophages, in response to injected endotoxin. They showed that both, a TNF-positive serum and endotoxin, were effective in causing necrosis of similar spectrum of transplanted tumors and at a similar phase of their growth. Moreover, a TNF-positive serum had cytotoxic effects on mouse and human tumor cells in vitro

In 1985, human TNF was purified, characterized, and cloned, which enabled production of large quantities of a highly purified TNF protein for extensive investigations [8, 9]. Since recombinant TNF has shown antitumor activity in both transplantable murine tumors and human tumor xenografts, TNF was quickly launched into clinical trials as a potential anticancer agent. Recombinant human TNF has been tested in several phase I and phase II clinical trials in the 1980s and 1990s. However, the initial enthusiasm for the use of TNF as a systemic treatment has waned in the face of significant toxicities and a lack of evidence for therapeutic benefit. Systemic TNF treatment was found to cause dose-dependent toxicities such

Independently, other groups of researchers investigated metabolic basis for cachexia and endotoxin-induced septicemia and septic shock syndrome. Hypertriglyceridemia in animals injected with endotoxin was found to result from defective triglyceride clearance due to systemic suppression of the enzyme lipoprotein lipase. Finally, the substance responsible for specific suppression of lipoprotein lipase activity was identified and named cachectin [13, 14]. Interestingly, soon after the characterization of human TNF in 1985, it was recognized that the TNF and cachectin are the same single protein with the complex dual role [8, 9, 15].

Nevertheless, direct evidence that cachectin is a mediator of the pathology/ septicemia induced by endotoxin was demonstrated by Beutler and colleagues [16, 17]. They showed that passive immunization with rabbit antiserum or purified Ig against murine TNF protected the mice from the lethal effect of the endotoxin lipopolysaccharide [16]. The same group then showed that injection of recombinant human TNF into rats in quantities similar to those produced endogenously in response to endotoxin caused hypotension, metabolic acidosis, hemoconcentration, and death of animals within minutes to hours. Thus, effects similar to those are induced by injection of endotoxin [17]. These observations led to the speculation that neutralization of TNF may be beneficial in life-threatening septicemia. Despite increased interest in the use of anti-TNF drugs for the treatment of sepsis, numerous clinical trials have showed only a small survival benefit (3.6%) [18]. The likely

**24**

The first evidence showing a link between TNF and IBD were publications reporting that patients with IBD have increased levels of TNF in serum, stool, or mucosal biopsy specimens [20–23]. However, the initial hopes for the use of TNF as a marker of IBD have waned when it was recognized that TNF can be increased also during infectious colitis [24] or TNF may even not be increased in patients with IBD [25] or TNF can be reduced in response to certain medication such as cyclosporine A [22, 26]. Nevertheless, a published reports about successful treatment of CD patients with TNF chimeric monoclonal antibodies (cA2 or infliximab) [27] established clear association of TNF involvement in the pathogenesis of IBD and caused extensive investigation of TNF role in IBD and production of various genetic models, including transgenic mice with persistent TNF overproduction in various tissues.

It was clearly demonstrated that persistent systemic overproduction of TNF (TNF<sup>∆</sup>ARE/∆ARE mice) can cause severe systemic health problems in mice, such as severe chronic polyarthritis, profound inflammatory changes in the terminal ileum and occasionally in the proximal colon, hypoplastic thymus with atrophied and disorganized cortical and medullary areas, and occasional mild inflammation in the liver and lung. These alterations were first detected in homozygous mice between 1 and 4 weeks of their age. Heterozygous mice developed the same health problems but later in their life inflammatory arthritis at 6–8 weeks of age and severe inflammatory bowel disease extending into muscular layers of the bowel wall at 4–7 months of their age. Homozygous mice never exceeded the body weight of 3-week-old mice and died between 5 and 12 weeks of their age [28]. It was also demonstrated that chronic intestinal inflammation can be triggered by persistent local TNF overproduction. Mice homozygous for persistent overproduction of TNF in the intestinal epithelium (TNFi∆ARE/i∆ARE mice) developed chronic ileitis by the age of 16–20 weeks and had increased mucosal and systemic protein levels of TNF. No inflammation in other tissues was found. No histological signs of joint injury were observed. Heterozygous mice (TNFi∆ARE/+) develop only mild villous blunting with scarce inflammation (not significant) [29]. In addition, mice with persistent myeloid cell-specific TNF overproduction also developed symptoms of weight loss and ileitis by the age of 5 months (homo and heterozygous) but with more severe symptoms in the homozygous mice. Interestingly, mice with persistent T lymphocyte-specific TNF overproduction developed mild symptoms of IBD but only on homozygous background. On the other hand, mice with persistent B lymphocyte-specific TNF overproduction did not show any signs of IBD by the age of 15 months [30]. Results of numerous animal studies gave tacit confirmation that persistent systemic or local TNF overproduction is detrimental and responsible for intestinal inflammation, serious health problems, and even death [31].

The introduction of anti-TNF therapies in the 1998 affected the treatment of many chronic inflammatory disorders, including rheumatoid arthritis, ankylosing spondylitis, and IBD. Five therapeutic agents have been licensed in the USA and most other parts of the world. Randomized controlled trials demonstrated the efficacy and safety of induction and maintenance therapy for moderate-to-severe IBD. Subsequent studies have demonstrated that infliximab treatment results in a positive clinical response as well as in a significant endoscopic improvement, confirmed also by histological examination as a complete reduction in the inflammation infiltrate. The breakthrough in the treatment of patients with IBD with anti-TNF therapy has firmly established the dogma that TNF is a major cytokine in this disease [32, 33]. Anti-TNF drugs such as infliximab, adalimumab, and etanercept are nowadays commonly used in the treatment of a variety of inflammatory and autoimmune diseases (IBD, rheumatoid arthritis, psoriasis, psoriasiform arthritis, and ankylosing spondylitis). Nevertheless, with the increasing use and longer follow-up periods, more information about effectiveness and side effects of anti-TNF therapy in IBD has been published.

#### **4. Side effects of anti-TNF drugs**

First reported/known adverse events of anti-TNF drugs were mainly immunogenicity leading to acute and delayed infusion reactions and loss of response, infectious complication, and concerns about tumor induction or progression [34, 35].

Today, after two decades of clinical experience with anti-TNF drugs and 2 million treated patients, it is widely known that around 30% of patients do not respond to anti-TNF therapy (primary nonresponders) and almost half of patients with initial response develop secondary loss of response within the first year. Among nonresponders, some may have low serum drug levels which could be explained by under-dosing or high drug clearance. Development of immunogenicity against the anti-TNF drugs is also associated with loss of response. In such cases, consideration of switch in anti-TNF drugs or dose escalation following loss of response may be an effective strategy [32]. However, some patients on anti-TNF drugs experience primary or secondary nonresponse despite adequate serum drug levels and the absence of neutralizing antibodies. Recently, it was proposed that such nonresponders may have upregulated other alternative inflammatory pathways independent of TNF [36]. Nevertheless, despite all complications and high costs of anti-TNF drugs, economic evaluation studies have shown that the benefit of anti-TNF drugs is still higher than the costs [37].

#### **4.1 Anti-TNF drugs and risk of infection and malignancy**

Susceptibility to infection and risk of malignancy has been a significant concern from the beginning of anti-TNF drug use. In the past, it was widely reported that anti-TNF therapy was associated with increased susceptibility to infections, particularly tuberculosis and hepatitis B. However, when it was recognized that anti-TNF drugs trigger the reactivation of latent infections [38], screening for tuberculosis and hepatitis B in clinical settings was implemented. Soon, reports about tuberculosis or hepatitis infections associated with anti-TNF therapy diminished [34]. Interestingly, recent publications report that anti-TNF therapy alone does not increase the risk of serious infection in IBD patients [39, 40]. Moreover, a systematic review (5528 patients) reported that the rate of serious infection was significantly lower among pediatric patients with IBD treated with anti-TNF than those treated with steroids or adults with IBD who received anti-TNF therapy [39].

**27**

the treatment.

*The Role of TNF in the Pathogenesis of Inflammatory Bowel Disease*

tion and opportunistic infection increases [34, 41].

**4.2 Anti-TNF drugs and paradoxical side effects**

In contrast, increasing number of reports about other untypical opportunistic infectious diseases, such as cytomegalovirus infection, histoplasmosis, aspergillosis appeared [34, 40]. Importantly, recent population-based study (190,694 patients with IBD) found that anti-TNF monotherapy was associated with increased risk of serious infection, mycobacterial infection, and bacterial infection but with decreased risk of opportunistic viral infection when compared with thiopurine monotherapy. However, when anti-TNF drugs are part of combination therapy with other immunosuppressive drugs, particularly thiopurines, the risk of serious infec-

Anti-TNF drugs have been associated with the increased risk for malignancy [34]. In the past, few studies reported T-cell non-Hodgkin's lymphoma or hepatosplenic T-cell lymphoma in IBD patients using anti-TNF drugs [42], while more recent studies found no association between anti-TNF drugs and hematologic malignancies. It was reported that the risk of lymphoma was no greater among children with IBD who received anti-TNF drugs than those treated with other IBD therapies or adults treated with anti-TNF drugs [39]. REFURBISH study found that the risk of T-cell non-Hodgkin's lymphoma in IBD patients is increased with the use of combination anti-TNF and thiopurine therapy but not with the use of anti-TNF monotherapy [43]. However, recent cohort study of 189,289 patients with IBD reported that the use of thiopurine monotherapy or anti-TNF monotherapy in patients with IBD was associated with a small but statistically significant increased risk of lymphoma, and this risk was higher

with combination therapy than with each of these treatments used alone [44].

Knowledge about immune diseases secondary to TNF target therapy is relatively new. Until 2007, altogether 233 cases of immune diseases secondary to TNF targeted therapy were reported [45]. Nowadays, increasing number of various paradoxical reactions is published such as psoriasiform skin lesions, uveitis, ileitis or colitis, joint manifestations, vasculitis and autoimmune disease (lupus and myositis), and sarcoidosis-like lesions. There are currently no predictors of their occurrence, and the optimal clinical management is still a matter of debate. Mostly paradoxical reactions are poorly described, and their prevalence and pathogenesis are not known. Therefore, it is important to be aware of all possible side effects of TNF therapy to properly inform the patient about potential side effects of anti-TNF therapy before

Psoriasis or psoriasiform skin lesions are one of the most frequently reported paradoxical reactions. Until November 2008, altogether 120 cases of psoriasis in patients treated with anti-TNF drugs were published. Among them 18 cases were found in patients with IBD (15%) [46]. Nowadays, increasing number of studies has shown that psoriasis can develop in IBD patients (adults or children) without any history of psoriasis and independent of the type of anti-TNF drugs [46–48]. However, in IBD patients with a history of psoriasis, anti-TNF treatment may trigger reappearance (3/21) [47] or exacerbation of the psoriasis (2/18) [46, 48]. Retrospective cohort (917) reported that 29% patients undergoing anti-TNF therapy (infliximab) developed skin lesions such as psoriasiform eczema, xerosis cutis, palmoplantar pustulosis, and psoriasis. The average time from the start of TNF therapy to the onset of skin lesions varied from 14.3 weeks [46] to 2 years [46–48]. In most patients psoriatic lesions were effectively treated with topical steroids, and in patients with severe psoriasis or patients without response to topical therapy, anti-TNF therapy was discontinued [47]. In another study in almost half of patients changed their initial anti-TNF agent despite conventional skin-directed therapies, and one-third of patients discontinued all anti-TNF therapy [48].

*DOI: http://dx.doi.org/10.5772/intechopen.84375*

#### *The Role of TNF in the Pathogenesis of Inflammatory Bowel Disease DOI: http://dx.doi.org/10.5772/intechopen.84375*

*Biological Therapy for Inflammatory Bowel Disease*

anti-TNF therapy in IBD has been published.

**4. Side effects of anti-TNF drugs**

higher than the costs [37].

**4.1 Anti-TNF drugs and risk of infection and malignancy**

Susceptibility to infection and risk of malignancy has been a significant concern from the beginning of anti-TNF drug use. In the past, it was widely reported that anti-TNF therapy was associated with increased susceptibility to infections, particularly tuberculosis and hepatitis B. However, when it was recognized that anti-TNF drugs trigger the reactivation of latent infections [38], screening for tuberculosis and hepatitis B in clinical settings was implemented. Soon, reports about tuberculosis or hepatitis infections associated with anti-TNF therapy diminished [34]. Interestingly, recent publications report that anti-TNF therapy alone does not increase the risk of serious infection in IBD patients [39, 40]. Moreover, a systematic review (5528 patients) reported that the rate of serious infection was significantly lower among pediatric patients with IBD treated with anti-TNF than those treated with steroids or adults with IBD who received anti-TNF therapy [39].

The introduction of anti-TNF therapies in the 1998 affected the treatment of many chronic inflammatory disorders, including rheumatoid arthritis, ankylosing spondylitis, and IBD. Five therapeutic agents have been licensed in the USA and most other parts of the world. Randomized controlled trials demonstrated the efficacy and safety of induction and maintenance therapy for moderate-to-severe IBD. Subsequent studies have demonstrated that infliximab treatment results in a positive clinical response as well as in a significant endoscopic improvement, confirmed also by histological examination as a complete reduction in the inflammation infiltrate. The breakthrough in the treatment of patients with IBD with anti-TNF therapy has firmly established the dogma that TNF is a major cytokine in this disease [32, 33]. Anti-TNF drugs such as infliximab, adalimumab, and etanercept are nowadays commonly used in the treatment of a variety of inflammatory and autoimmune diseases (IBD, rheumatoid arthritis, psoriasis, psoriasiform arthritis, and ankylosing spondylitis). Nevertheless, with the increasing use and longer follow-up periods, more information about effectiveness and side effects of

First reported/known adverse events of anti-TNF drugs were mainly immunogenicity leading to acute and delayed infusion reactions and loss of response, infectious complication, and concerns about tumor induction or progression [34, 35]. Today, after two decades of clinical experience with anti-TNF drugs and 2 million treated patients, it is widely known that around 30% of patients do not respond to anti-TNF therapy (primary nonresponders) and almost half of patients with initial response develop secondary loss of response within the first year. Among nonresponders, some may have low serum drug levels which could be explained by under-dosing or high drug clearance. Development of immunogenicity against the anti-TNF drugs is also associated with loss of response. In such cases, consideration of switch in anti-TNF drugs or dose escalation following loss of response may be an effective strategy [32]. However, some patients on anti-TNF drugs experience primary or secondary nonresponse despite adequate serum drug levels and the absence of neutralizing antibodies. Recently, it was proposed that such nonresponders may have upregulated other alternative inflammatory pathways independent of TNF [36]. Nevertheless, despite all complications and high costs of anti-TNF drugs, economic evaluation studies have shown that the benefit of anti-TNF drugs is still

**26**

In contrast, increasing number of reports about other untypical opportunistic infectious diseases, such as cytomegalovirus infection, histoplasmosis, aspergillosis appeared [34, 40]. Importantly, recent population-based study (190,694 patients with IBD) found that anti-TNF monotherapy was associated with increased risk of serious infection, mycobacterial infection, and bacterial infection but with decreased risk of opportunistic viral infection when compared with thiopurine monotherapy. However, when anti-TNF drugs are part of combination therapy with other immunosuppressive drugs, particularly thiopurines, the risk of serious infection and opportunistic infection increases [34, 41].

Anti-TNF drugs have been associated with the increased risk for malignancy [34]. In the past, few studies reported T-cell non-Hodgkin's lymphoma or hepatosplenic T-cell lymphoma in IBD patients using anti-TNF drugs [42], while more recent studies found no association between anti-TNF drugs and hematologic malignancies. It was reported that the risk of lymphoma was no greater among children with IBD who received anti-TNF drugs than those treated with other IBD therapies or adults treated with anti-TNF drugs [39]. REFURBISH study found that the risk of T-cell non-Hodgkin's lymphoma in IBD patients is increased with the use of combination anti-TNF and thiopurine therapy but not with the use of anti-TNF monotherapy [43]. However, recent cohort study of 189,289 patients with IBD reported that the use of thiopurine monotherapy or anti-TNF monotherapy in patients with IBD was associated with a small but statistically significant increased risk of lymphoma, and this risk was higher with combination therapy than with each of these treatments used alone [44].

#### **4.2 Anti-TNF drugs and paradoxical side effects**

Knowledge about immune diseases secondary to TNF target therapy is relatively new. Until 2007, altogether 233 cases of immune diseases secondary to TNF targeted therapy were reported [45]. Nowadays, increasing number of various paradoxical reactions is published such as psoriasiform skin lesions, uveitis, ileitis or colitis, joint manifestations, vasculitis and autoimmune disease (lupus and myositis), and sarcoidosis-like lesions. There are currently no predictors of their occurrence, and the optimal clinical management is still a matter of debate. Mostly paradoxical reactions are poorly described, and their prevalence and pathogenesis are not known. Therefore, it is important to be aware of all possible side effects of TNF therapy to properly inform the patient about potential side effects of anti-TNF therapy before the treatment.

Psoriasis or psoriasiform skin lesions are one of the most frequently reported paradoxical reactions. Until November 2008, altogether 120 cases of psoriasis in patients treated with anti-TNF drugs were published. Among them 18 cases were found in patients with IBD (15%) [46]. Nowadays, increasing number of studies has shown that psoriasis can develop in IBD patients (adults or children) without any history of psoriasis and independent of the type of anti-TNF drugs [46–48]. However, in IBD patients with a history of psoriasis, anti-TNF treatment may trigger reappearance (3/21) [47] or exacerbation of the psoriasis (2/18) [46, 48].

Retrospective cohort (917) reported that 29% patients undergoing anti-TNF therapy (infliximab) developed skin lesions such as psoriasiform eczema, xerosis cutis, palmoplantar pustulosis, and psoriasis. The average time from the start of TNF therapy to the onset of skin lesions varied from 14.3 weeks [46] to 2 years [46–48]. In most patients psoriatic lesions were effectively treated with topical steroids, and in patients with severe psoriasis or patients without response to topical therapy, anti-TNF therapy was discontinued [47]. In another study in almost half of patients changed their initial anti-TNF agent despite conventional skin-directed therapies, and one-third of patients discontinued all anti-TNF therapy [48].

Lichenoid drug reaction in association with anti-TNF therapy was also reported. Until 2015, only seven cases were reported in association with anti-TNF drugs. Oral lichen planus occurred between 8 weeks and 6 months after anti-TNF therapy. Outcome was mainly favorable with improvement or recovery with or without cessation of the TNF blocker. Authors recommend a careful monitoring for oral manifestations in IBD patients treated with TNF inhibitors. OLP is thought to be mediated by dendritic cells and T cells [49].

Patients treated with anti-TNF therapy (i.e., etanercept, adalimumab, and infliximab) can develop sarcoidosis-like lesions. Until 2017, altogether 90 cases were reported, 6 cases in IBD patients. Median duration between initiation of anti-TNF therapy and diagnosis was 22.5 months (range 1–84 months). Most frequently affected organs were lungs, skin, and eyes [50].

Patients with IBD developed new onset arthritis or synovitis after 2.5 ± 1.6 years of successful anti-TNF treatment. The onset of paradoxical arthritis appeared when IBD patients were in clinical and endoscopic remission but with signs of histologically diagnosed subclinical inflammation. The inhibition of inflammatory pathways alternative to TNF (IL12/1L23) may be an effective therapeutic option for severe paradoxical articular manifestations [51].

The lupus-like syndrome can be observed in 0.5–1% of patients treated with anti-TNF drugs and appears independent of the type of anti-TNF drugs. Most patients develop fatigue or fever, musculoskeletal or skin symptoms, or serositis, a rarely major organ disease. The symptoms resolve after discontinuation of TNF therapy [52, 53].

#### **5. The beneficial role of TNF**

Soon after the identification of TNF and production of recombinant TNF, it was recognized that the biological effects of TNF may be both injurious and beneficial. TNF can have a direct cytostatic and cytotoxic effect on human tumor cells, as well as a variety of immunomodulatory effects on various immune effector cells, including neutrophils, macrophages, and T cells. It can have a number of anti-infective and metabolic effects [54].

Today, in the era of anti-TNF drugs, the beneficial role of TNF is often in the shadow and is highlighted only after the appearance of a new adverse effect of anti-TNF drugs in clinical use.

Experimental studies have shown that TNF has important role in maintaining intestinal integrity [55]. If infection or injury occurs, TNF is rapidly released to promote the acute-phase inflammatory response (i.e., IL1, IL6-production of pro-inflammatory cytokine cascade) and to trigger the localized accumulation of leukocytes. Endothelial cells respond to TNF by releasing chemokines (IL-8, MCP-1, IP-10) and adhesion molecules (E-selectin, ICAM-1, VCAM-1). Collectively, these solubles and cell surface molecules lead to the recruitment of distinct populations of leukocytes to sites of infection/injury to eliminate the initial cause of cell injury, clear out necrotic cells and tissues damaged from the original insult and the inflammatory process, and initiate tissue repair. Indirectly, TNF also contribute to increased local blood flow and vascular permeability and regulation of coagulation. TNF increases mediators such as prostaglandins and platelet-activating factor [56].

However, in case of chronic TNF deprivation, intestinal barrier is more sensitive to infection and injury. Mice with TNF deprivation (caused by anti-TNF drugs or target mutations) failed to resist *L. monocytogenes* infections and died few days after the infection [57]. Mice deficient in TNF or TNFR1 are highly susceptible to *Mycobacterium* and *Staphylococcus* infection as well [54, 59]. It was found that TNF

**29**

of T cells [61].

**6. Conclusions**

*The Role of TNF in the Pathogenesis of Inflammatory Bowel Disease*

deprivation caused delayed elimination of bacterium from the spleens and livers. However the effect was dose and time dependent. The worst results were observed

TNF has also important role in maintaining and protecting epithelial cells from toxic injury. For instance, DSS, a toxic agent that damages the intestinal epithelia, induce development of an acute inflammation in mice, which usually resolves in a few weeks. However, when mice have blocked production of TNF (induced by deletion of TNF gene or anti-TNF drugs), the inflammation in the intestine becomes

All these studies demonstrate that homeostatic concentrations of TNF have important protective role against intestinal injury. However, homeostatic concentrations of TNF are also important for effective innate and adaptive immune responses. It was found that mice genetically deficient in TNF completely lack splenic primary B-cell follicles and cannot form organized follicular dendritic cell networks and germinal centers [59]. Thus, chronic TNF deprivation may cause disturbances in innate and adaptive immunity. TNF is an important regulator of macrophage function required to control infection and can also contribute to containment of the disease by promoting migration of immune cells and granuloma formation at sites of infection. In case of tuberculosis, an intracellular pathogen, formation of granulomas and walling off the bacteria by macrophages

CD27+

It is interesting that increased susceptibility to infection and a slightly increased risk for malignancy have been expected side effects of anti-TNF drugs and have been confirmed in clinical practice. However, the observation that anti-TNF drug could lead to aggravation of preexisiting autoimmune diseases or onset of a new inflammatory diseases was not expected. Although numerous experimental studies have shown complex role of TNF in the innate and adaptive immunity [60], only paradoxical side effects of anti-TNF drugs clearly demonstrated that the maintenance of homeostatic TNF concentrations is important for normal function of organism. Recently, it was confirmed that paradoxical psoriasis is caused due to the TNF deprivation. Namely, in normal condition a production of type I IFN by plasmacytoid dendritic cells (pDC) is downregulated by TNF. In case of TNF deprivation (caused by anti-TNF drugs), production of IFN by pDC is not regulated anymore. The resulting type I interferon overexpression is responsible for the skin phenotype of paradoxical psoriasis, which, unlike classical psoriasis, is independent

Although our understanding of TNF has increased considerably over the past

two decades, novel finding is well in line with what had been predicted from previous mouse studies. However, the observation that anti-TNF drugs could lead to aggravation of preexisiting diseases or onset of a new inflammatory diseases was not expected. Nevertheless, paradoxical reaction appears independently of the underlying disease or the type of anti-TNF drugs used and regresses upon discontinuation of therapy, which suggests that paradoxical reactions really are a side effect of TNF blockade and not de novo disease. Thus, paradoxical reactions can

(CCR7<sup>−</sup>CD27<sup>−</sup>)), is thus one of the protective mechanisms to control tuberculosis infection. In latency, infection is contained in a nondividing state within macrophages. However, anti-TNF therapy disturbs the physiological TNF-mediated immunoinflammatory responses and causes disease reactivation or dissemination

) and effector memory T cells

when anti-TNF drug was given between days 0 and 2 of infection [57].

*DOI: http://dx.doi.org/10.5772/intechopen.84375*

devastating and life-threatening [58].

and T cell (central memory T cells (CCR7+

seen in patients receiving TNF blockade [38].

#### *The Role of TNF in the Pathogenesis of Inflammatory Bowel Disease DOI: http://dx.doi.org/10.5772/intechopen.84375*

*Biological Therapy for Inflammatory Bowel Disease*

mediated by dendritic cells and T cells [49].

affected organs were lungs, skin, and eyes [50].

paradoxical articular manifestations [51].

**5. The beneficial role of TNF**

and metabolic effects [54].

TNF drugs in clinical use.

therapy [52, 53].

Lichenoid drug reaction in association with anti-TNF therapy was also reported. Until 2015, only seven cases were reported in association with anti-TNF drugs. Oral lichen planus occurred between 8 weeks and 6 months after anti-TNF therapy. Outcome was mainly favorable with improvement or recovery with or without cessation of the TNF blocker. Authors recommend a careful monitoring for oral manifestations in IBD patients treated with TNF inhibitors. OLP is thought to be

Patients treated with anti-TNF therapy (i.e., etanercept, adalimumab, and infliximab) can develop sarcoidosis-like lesions. Until 2017, altogether 90 cases were reported, 6 cases in IBD patients. Median duration between initiation of anti-TNF therapy and diagnosis was 22.5 months (range 1–84 months). Most frequently

Patients with IBD developed new onset arthritis or synovitis after 2.5 ± 1.6 years of successful anti-TNF treatment. The onset of paradoxical arthritis appeared when IBD patients were in clinical and endoscopic remission but with signs of histologically diagnosed subclinical inflammation. The inhibition of inflammatory pathways alternative to TNF (IL12/1L23) may be an effective therapeutic option for severe

The lupus-like syndrome can be observed in 0.5–1% of patients treated with anti-TNF drugs and appears independent of the type of anti-TNF drugs. Most patients develop fatigue or fever, musculoskeletal or skin symptoms, or serositis, a rarely major organ disease. The symptoms resolve after discontinuation of TNF

Soon after the identification of TNF and production of recombinant TNF, it was recognized that the biological effects of TNF may be both injurious and beneficial. TNF can have a direct cytostatic and cytotoxic effect on human tumor cells, as well as a variety of immunomodulatory effects on various immune effector cells, including neutrophils, macrophages, and T cells. It can have a number of anti-infective

Today, in the era of anti-TNF drugs, the beneficial role of TNF is often in the shadow and is highlighted only after the appearance of a new adverse effect of anti-

Experimental studies have shown that TNF has important role in maintaining intestinal integrity [55]. If infection or injury occurs, TNF is rapidly released to promote the acute-phase inflammatory response (i.e., IL1, IL6-production of pro-inflammatory cytokine cascade) and to trigger the localized accumulation of leukocytes. Endothelial cells respond to TNF by releasing chemokines (IL-8, MCP-1, IP-10) and adhesion molecules (E-selectin, ICAM-1, VCAM-1). Collectively, these solubles and cell surface molecules lead to the recruitment of distinct populations of leukocytes to sites of infection/injury to eliminate the initial cause of cell injury, clear out necrotic cells and tissues damaged from the original insult and the inflammatory process, and initiate tissue repair. Indirectly, TNF also contribute to increased local blood flow and vascular permeability and regulation of coagulation. TNF increases mediators such as prostaglandins and platelet-activating factor [56]. However, in case of chronic TNF deprivation, intestinal barrier is more sensitive to infection and injury. Mice with TNF deprivation (caused by anti-TNF drugs or target mutations) failed to resist *L. monocytogenes* infections and died few days after the infection [57]. Mice deficient in TNF or TNFR1 are highly susceptible to *Mycobacterium* and *Staphylococcus* infection as well [54, 59]. It was found that TNF

**28**

deprivation caused delayed elimination of bacterium from the spleens and livers. However the effect was dose and time dependent. The worst results were observed when anti-TNF drug was given between days 0 and 2 of infection [57].

TNF has also important role in maintaining and protecting epithelial cells from toxic injury. For instance, DSS, a toxic agent that damages the intestinal epithelia, induce development of an acute inflammation in mice, which usually resolves in a few weeks. However, when mice have blocked production of TNF (induced by deletion of TNF gene or anti-TNF drugs), the inflammation in the intestine becomes devastating and life-threatening [58].

All these studies demonstrate that homeostatic concentrations of TNF have important protective role against intestinal injury. However, homeostatic concentrations of TNF are also important for effective innate and adaptive immune responses. It was found that mice genetically deficient in TNF completely lack splenic primary B-cell follicles and cannot form organized follicular dendritic cell networks and germinal centers [59]. Thus, chronic TNF deprivation may cause disturbances in innate and adaptive immunity. TNF is an important regulator of macrophage function required to control infection and can also contribute to containment of the disease by promoting migration of immune cells and granuloma formation at sites of infection. In case of tuberculosis, an intracellular pathogen, formation of granulomas and walling off the bacteria by macrophages and T cell (central memory T cells (CCR7+ CD27+ ) and effector memory T cells (CCR7<sup>−</sup>CD27<sup>−</sup>)), is thus one of the protective mechanisms to control tuberculosis infection. In latency, infection is contained in a nondividing state within macrophages. However, anti-TNF therapy disturbs the physiological TNF-mediated immunoinflammatory responses and causes disease reactivation or dissemination seen in patients receiving TNF blockade [38].

It is interesting that increased susceptibility to infection and a slightly increased risk for malignancy have been expected side effects of anti-TNF drugs and have been confirmed in clinical practice. However, the observation that anti-TNF drug could lead to aggravation of preexisiting autoimmune diseases or onset of a new inflammatory diseases was not expected. Although numerous experimental studies have shown complex role of TNF in the innate and adaptive immunity [60], only paradoxical side effects of anti-TNF drugs clearly demonstrated that the maintenance of homeostatic TNF concentrations is important for normal function of organism. Recently, it was confirmed that paradoxical psoriasis is caused due to the TNF deprivation. Namely, in normal condition a production of type I IFN by plasmacytoid dendritic cells (pDC) is downregulated by TNF. In case of TNF deprivation (caused by anti-TNF drugs), production of IFN by pDC is not regulated anymore. The resulting type I interferon overexpression is responsible for the skin phenotype of paradoxical psoriasis, which, unlike classical psoriasis, is independent of T cells [61].

#### **6. Conclusions**

Although our understanding of TNF has increased considerably over the past two decades, novel finding is well in line with what had been predicted from previous mouse studies. However, the observation that anti-TNF drugs could lead to aggravation of preexisiting diseases or onset of a new inflammatory diseases was not expected. Nevertheless, paradoxical reaction appears independently of the underlying disease or the type of anti-TNF drugs used and regresses upon discontinuation of therapy, which suggests that paradoxical reactions really are a side effect of TNF blockade and not de novo disease. Thus, paradoxical reactions can

once again remind us that TNF physiologically possess various beneficial roles, and thus the maintenance of homeostatic TNF concentrations is important for normal function of an organism.

### **Acknowledgements**

This work was in part supported by ARRS (Slovenian Research Agency, P3-054).

### **Conflict of interest**

Authors declare that no financial interest or conflict of interests exists.

### **Author details**

Martina Perše\* and Ana Unkovič Medical Experimental Centre, Institute of Pathology, Faculty of Medicine University of Ljubljana, Ljubljana, Slovenia

\*Address all correspondence to: martina.perse@mf.uni-lj.si

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**31**

*The Role of TNF in the Pathogenesis of Inflammatory Bowel Disease*

[8] Aggarwal BB, Kohr WJ. Human tumor necrosis factor. Methods in Enzymology. 1985;**116**:448-456

[10] Roberts NJ, Zhou S, Diaz LA, Holdhoff M. Systemic use of tumor necrosis factor alpha as an anticancer agent. Oncotarget. 2011;**2**(10):739-751

[11] Feinberg B, Kurzrock R, Talpaz M, Blick M, Saks S, Gutterman JU. A phase I trial of intravenously-administered recombinant tumor necrosis factoralpha in cancer patients. Journal of Clinical Oncology. 1988;**6**(8):1328-1334

[12] Creaven PJ, Plager JE, Dupere S, Huben RP, Takita H, Mittelman A, et al. Phase I clinical trial of recombinant human tumor necrosis factor. Cancer Chemotherapy and Pharmacology.

[13] Kawakami M, Cerami A. Studies of endotoxin-induced decrease in lipoprotein lipase activity. The Journal of Experimental Medicine.

[14] Pekala PH, Kawakami M, Angus CW, Lane MD, Cerami A. Selective inhibition of synthesis of enzymes for de novo fatty acid biosynthesis by an endotoxin-induced mediator from exudate cells. Proceedings of the National Academy of Sciences of the United States of America.

[15] Beutler B, Greenwald D, Hulmes JD,

Chang M, Pan YC, Mathison J, et al. Identity of tumour necrosis factor and the macrophage-secreted

1987;**20**(2):137-144

1981;**154**(3):631-639

1983;**80**(9):2743-2747

[9] Pennica D, Hayflick JS, Bringman TS, Palladino MA, Goeddel DV. Cloning and expression in *Escherichia coli* of the cDNA for murine tumor necrosis factor. Proceedings of the National Academy of Sciences of the United States of America. 1985;**82**(18):6060-6064

*DOI: http://dx.doi.org/10.5772/intechopen.84375*

Underwood FE, Tang W, Benchimol EI,

systematic review of population-based studies. Lancet. 2018;**390**(10114):

[1] Ng SC, Shi HY, Hamidi N,

et al. Worldwide incidence and prevalence of inflammatory bowel disease in the 21st century: A

[2] Burisch J, Jess T, Martinato M, Lakatos PL, -EpiCom E. The burden of inflammatory bowel disease in Europe. Journal of Crohn's & Colitis.

[3] Domènech E, Mañosa M, Cabré E. An overview of the natural history of inflammatory bowel diseases. Digestive

differences in presentation and course of inflammatory bowel disease: An update on the population-based literature. Journal of Crohn's & Colitis.

Diseases. 2014;**32**(4):320-327

2014;**8**(11):1351-1361

2013;**45**(12):969-977

2014;**8**(12):1582-1597

1975;**72**(9):3666-3670

[4] Duricova D, Burisch J, Jess T, Gower-Rousseau C, Lakatos PL, ECCO-EpiCom. Age-related

[5] Mazzuoli S, Guglielmi FW, Antonelli E, Salemme M, Bassotti G, Villanacci V. Definition and evaluation

of mucosal healing in clinical

[6] Bryant RV, Winer S, Travis SP, Riddell RH. Systematic review:

[7] Carswell EA, Old LJ, Kassel RL, Green S, Fiore N, Williamson B. An endotoxin-induced serum factor that causes necrosis of tumors. Proceedings of the National Academy of Sciences of the United States of America.

practice. Digestive and Liver Disease.

Histological remission in inflammatory bowel disease. Is 'complete' remission the new treatment paradigm? An IOIBD initiative. Journal of Crohn's & Colitis.

2769-2778

**References**

2013;**7**(4):322-337

*The Role of TNF in the Pathogenesis of Inflammatory Bowel Disease DOI: http://dx.doi.org/10.5772/intechopen.84375*

#### **References**

*Biological Therapy for Inflammatory Bowel Disease*

function of an organism.

**Acknowledgements**

**Conflict of interest**

once again remind us that TNF physiologically possess various beneficial roles, and thus the maintenance of homeostatic TNF concentrations is important for normal

This work was in part supported by ARRS (Slovenian Research Agency, P3-054).

Authors declare that no financial interest or conflict of interests exists.

**30**

**Author details**

Martina Perše\* and Ana Unkovič

provided the original work is properly cited.

University of Ljubljana, Ljubljana, Slovenia

\*Address all correspondence to: martina.perse@mf.uni-lj.si

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Medical Experimental Centre, Institute of Pathology, Faculty of Medicine

[1] Ng SC, Shi HY, Hamidi N, Underwood FE, Tang W, Benchimol EI, et al. Worldwide incidence and prevalence of inflammatory bowel disease in the 21st century: A systematic review of population-based studies. Lancet. 2018;**390**(10114): 2769-2778

[2] Burisch J, Jess T, Martinato M, Lakatos PL, -EpiCom E. The burden of inflammatory bowel disease in Europe. Journal of Crohn's & Colitis. 2013;**7**(4):322-337

[3] Domènech E, Mañosa M, Cabré E. An overview of the natural history of inflammatory bowel diseases. Digestive Diseases. 2014;**32**(4):320-327

[4] Duricova D, Burisch J, Jess T, Gower-Rousseau C, Lakatos PL, ECCO-EpiCom. Age-related differences in presentation and course of inflammatory bowel disease: An update on the population-based literature. Journal of Crohn's & Colitis. 2014;**8**(11):1351-1361

[5] Mazzuoli S, Guglielmi FW, Antonelli E, Salemme M, Bassotti G, Villanacci V. Definition and evaluation of mucosal healing in clinical practice. Digestive and Liver Disease. 2013;**45**(12):969-977

[6] Bryant RV, Winer S, Travis SP, Riddell RH. Systematic review: Histological remission in inflammatory bowel disease. Is 'complete' remission the new treatment paradigm? An IOIBD initiative. Journal of Crohn's & Colitis. 2014;**8**(12):1582-1597

[7] Carswell EA, Old LJ, Kassel RL, Green S, Fiore N, Williamson B. An endotoxin-induced serum factor that causes necrosis of tumors. Proceedings of the National Academy of Sciences of the United States of America. 1975;**72**(9):3666-3670

[8] Aggarwal BB, Kohr WJ. Human tumor necrosis factor. Methods in Enzymology. 1985;**116**:448-456

[9] Pennica D, Hayflick JS, Bringman TS, Palladino MA, Goeddel DV. Cloning and expression in *Escherichia coli* of the cDNA for murine tumor necrosis factor. Proceedings of the National Academy of Sciences of the United States of America. 1985;**82**(18):6060-6064

[10] Roberts NJ, Zhou S, Diaz LA, Holdhoff M. Systemic use of tumor necrosis factor alpha as an anticancer agent. Oncotarget. 2011;**2**(10):739-751

[11] Feinberg B, Kurzrock R, Talpaz M, Blick M, Saks S, Gutterman JU. A phase I trial of intravenously-administered recombinant tumor necrosis factoralpha in cancer patients. Journal of Clinical Oncology. 1988;**6**(8):1328-1334

[12] Creaven PJ, Plager JE, Dupere S, Huben RP, Takita H, Mittelman A, et al. Phase I clinical trial of recombinant human tumor necrosis factor. Cancer Chemotherapy and Pharmacology. 1987;**20**(2):137-144

[13] Kawakami M, Cerami A. Studies of endotoxin-induced decrease in lipoprotein lipase activity. The Journal of Experimental Medicine. 1981;**154**(3):631-639

[14] Pekala PH, Kawakami M, Angus CW, Lane MD, Cerami A. Selective inhibition of synthesis of enzymes for de novo fatty acid biosynthesis by an endotoxin-induced mediator from exudate cells. Proceedings of the National Academy of Sciences of the United States of America. 1983;**80**(9):2743-2747

[15] Beutler B, Greenwald D, Hulmes JD, Chang M, Pan YC, Mathison J, et al. Identity of tumour necrosis factor and the macrophage-secreted

factor cachectin. Nature. 1985;**316**(6028):552-554

[16] Beutler B, Milsark IW, Cerami AC. Passive immunization against cachectin/ tumor necrosis factor protects mice from lethal effect of endotoxin. Science. 1985;**229**(4716):869-871

[17] Tracey KJ, Beutler B, Lowry SF, Merryweather J, Wolpe S, Milsark IW, et al. Shock and tissue injury induced by recombinant human cachectin. Science. 1986;**234**(4775):470-474

[18] Reinhart K, Karzai W. Anti-tumor necrosis factor therapy in sepsis: Update on clinical trials and lessons learned. Critical Care Medicine. 2001;**29** (7 Suppl):S121-S125

[19] Qiu P, Cui X, Sun J, Welsh J, Natanson C, Eichacker PQ. Antitumor necrosis factor therapy is associated with improved survival in clinical sepsis trials: A meta-analysis. Critical Care Medicine. 2013;**41**(10):2419-2429

[20] Murch SH, Lamkin VA, Savage MO, Walker-Smith JA, MacDonald TT. Serum concentrations of tumour necrosis factor alpha in childhood chronic inflammatory bowel disease. Gut. 1991;**32**(8):913-917

[21] Braegger CP, Nicholls S, Murch SH, Stephens S, MacDonald TT. Tumour necrosis factor alpha in stool as a marker of intestinal inflammation. Lancet. 1992;**339**(8785):89-91

[22] Breese EJ, Michie CA, Nicholls SW, Murch SH, Williams CB, Domizio P, et al. Tumor necrosis factor alphaproducing cells in the intestinal mucosa of children with inflammatory bowel disease. Gastroenterology. 1994;**106**(6):1455-1466

[23] Maeda M, Watanabe N, Neda H, Yamauchi N, Okamoto T, Sasaki H, et al. Serum tumor necrosis factor activity in inflammatory bowel

disease. Immunopharmacology and Immunotoxicology. 1992;**14**(3):451-461

[24] de Silva DG, Mendis LN, Sheron N, Alexander GJ, Candy DC, Chart H, et al. TNF alpha in stool as marker of intestinal inflammation. Lancet. 1992;**340**(8815):372

[25] Hyams JS, Treem WR, Eddy E, Wyzga N, Moore RE. Tumor necrosis factor-alpha is not elevated in children with inflammatory bowel disease. Journal of Pediatric Gastroenterology and Nutrition. 1991;**12**(2):233-236

[26] Nielsen OH, Vainer B, Madsen SM, Seidelin JB, Heegaard NH. Established and emerging biological activity markers of inflammatory bowel disease. The American Journal of Gastroenterology. 2000;**95**(2):359-367

[27] Derkx B, Taminiau J, Radema S, Stronkhorst A, Wortel C, Tytgat G, et al. Tumour-necrosis-factor antibody treatment in Crohn's disease. Lancet. 1993;**342**(8864):173-174

[28] Kontoyiannis D, Pasparakis M, Pizarro TT, Cominelli F, Kollias G. Impaired on/off regulation of TNF biosynthesis in mice lacking TNF AU-rich elements: Implications for joint and gut-associated immunopathologies. Immunity. 1999;**10**(3):387-398

[29] Bamias G, Corridoni D, Pizarro TT, Cominelli F. New insights into the dichotomous role of innate cytokines in gut homeostasis and inflammation. Cytokine. 2012;**59**(3):451-459

[30] Kontoyiannis D, Boulougouris G, Manoloukos M, Armaka M, Apostolaki M, Pizarro T, et al. Genetic dissection of the cellular pathways and signaling mechanisms in modeled tumor necrosis factor-induced Crohn's-like inflammatory bowel disease. The Journal of Experimental Medicine. 2002;**196**(12):1563-1574

**33**

*The Role of TNF in the Pathogenesis of Inflammatory Bowel Disease*

Immunology, and Infection.

[39] Dulai PS, Thompson KD, Blunt HB, Dubinsky MC, Siegel CA. Risks of serious infection or lymphoma with anti-tumor necrosis factor therapy for pediatric inflammatory bowel disease: A systematic review. Clinical Gastroenterology and Hepatology. 2014;**12**(9):1443-1451 quiz e88-9

[40] Peyrin-Biroulet L. Anti-TNF therapy in inflammatory bowel diseases: A huge review. Minerva Gastroenterologica e Dietologica.

[41] Kirchgesner J, Lemaitre M, Carrat F, Zureik M, Carbonnel F, Dray-Spira R. Risk of serious and opportunistic infections associated with treatment of inflammatory

bowel diseases. Gastroenterology.

[42] Mackey AC, Green L, Liang LC, Dinndorf P, Avigan M. Hepatosplenic T cell lymphoma associated with infliximab use in young patients treated for inflammatory bowel disease. Journal of Pediatric Gastroenterology and Nutrition. 2007;**44**(2):265-267

[43] Deepak P, Sifuentes H, Sherid M, Stobaugh D, Sadozai Y, Ehrenpreis ED. T-cell non-Hodgkin's lymphomas reported to the FDA AERS with tumor necrosis factor-alpha (TNF-α) inhibitors: Results of the REFURBISH study. The American Journal of Gastroenterology. 2013;**108**(1):99-105

[44] Lemaitre M, Kirchgesner J, Rudnichi A, Carrat F, Zureik M, Carbonnel F, et al. Association between use of thiopurines or tumor necrosis factor antagonists alone or in combination and risk of lymphoma in patients with inflammatory bowel disease. JAMA. 2017;**318**(17):1679-1686

[45] Ramos-Casals M, Brito-Zerón P, Muñoz S, Soria N, Galiana D,

2018;**155**(2):337-346.e10

2014;**47**(4):268-274

2010;**56**(2):233-243

*DOI: http://dx.doi.org/10.5772/intechopen.84375*

[31] Kollias G, Douni E, Kassiotis G, Kontoyiannis D. The function of tumour necrosis factor and receptors in models of multi-organ inflammation, rheumatoid arthritis, multiple sclerosis and inflammatory bowel disease. Annals of the Rheumatic Diseases.

1999;**58**(Suppl 1):I32-I39

Sciences. 2018;**2244**:1-21

Sciences. 2018;**1442**:1-55

2013;**31**(3-4):374-378

2004;**126**(6):1593-1610

2019;**53**(3):210-215

2011;**15**(6):1-244

[34] Fellermann K. Adverse events of tumor necrosis factor inhibitors. Digestive Diseases.

[35] Rutgeerts P, Van Assche G, Vermeire S. Optimizing anti-TNF treatment in inflammatory bowel disease. Gastroenterology.

[36] Yarur AJ, Jain A, Quintero MA, Czul F, Deshpande AR, Kerman DH, et al. Inflammatory cytokine profile in Crohn's disease nonresponders to optimal antitumor necrosis factor therapy. Journal of Clinical Gastroenterology. Mar

[37] Dretzke J, Edlin R, Round J, Connock M, Hulme C, Czeczot J, et al. A systematic review and economic evaluation of the use of tumour necrosis

factor-alpha (TNF-α) inhibitors, adalimumab and infliximab, for Crohn's disease. Health Technology Assessment.

[38] Xie X, Li F, Chen JW, Wang J. Risk of tuberculosis infection in anti-TNF-α biological therapy: From bench to bedside. Journal of Microbiology,

[33] Steeland S, Libert C, Vandenbroucke RE. A new venue of TNF targeting. International Journal of Molecular

[32] Adegbola SO, Sahnan K, Warusavitarne J, Hart A, Tozer P. Anti-TNF therapy in Crohn's disease. International Journal of Molecular

*The Role of TNF in the Pathogenesis of Inflammatory Bowel Disease DOI: http://dx.doi.org/10.5772/intechopen.84375*

[31] Kollias G, Douni E, Kassiotis G, Kontoyiannis D. The function of tumour necrosis factor and receptors in models of multi-organ inflammation, rheumatoid arthritis, multiple sclerosis and inflammatory bowel disease. Annals of the Rheumatic Diseases. 1999;**58**(Suppl 1):I32-I39

*Biological Therapy for Inflammatory Bowel Disease*

disease. Immunopharmacology

[24] de Silva DG, Mendis LN, Sheron N, Alexander GJ, Candy DC, Chart H, et al. TNF alpha in stool as marker of intestinal inflammation. Lancet.

[25] Hyams JS, Treem WR, Eddy E, Wyzga N, Moore RE. Tumor necrosis factor-alpha is not elevated in children with inflammatory bowel disease. Journal of Pediatric Gastroenterology and Nutrition. 1991;**12**(2):233-236

[26] Nielsen OH, Vainer B, Madsen SM, Seidelin JB, Heegaard NH. Established and emerging biological activity markers of inflammatory bowel disease. The American Journal of Gastroenterology. 2000;**95**(2):359-367

[27] Derkx B, Taminiau J, Radema S, Stronkhorst A, Wortel C, Tytgat G, et al. Tumour-necrosis-factor antibody treatment in Crohn's disease. Lancet.

[28] Kontoyiannis D, Pasparakis M, Pizarro TT, Cominelli F, Kollias G. Impaired on/off regulation of TNF biosynthesis in mice lacking TNF AU-rich elements: Implications for joint and gut-associated immunopathologies.

Immunity. 1999;**10**(3):387-398

Cytokine. 2012;**59**(3):451-459

2002;**196**(12):1563-1574

[29] Bamias G, Corridoni D, Pizarro TT, Cominelli F. New insights into the dichotomous role of innate cytokines in gut homeostasis and inflammation.

[30] Kontoyiannis D, Boulougouris G, Manoloukos M, Armaka M, Apostolaki M, Pizarro T, et al. Genetic dissection of the cellular pathways and signaling mechanisms in modeled tumor necrosis factor-induced Crohn's-like inflammatory bowel disease. The Journal of Experimental Medicine.

1993;**342**(8864):173-174

and Immunotoxicology. 1992;**14**(3):451-461

1992;**340**(8815):372

[16] Beutler B, Milsark IW, Cerami AC. Passive immunization against cachectin/ tumor necrosis factor protects mice from lethal effect of endotoxin. Science.

[17] Tracey KJ, Beutler B, Lowry SF, Merryweather J, Wolpe S, Milsark IW, et al. Shock and tissue injury induced by recombinant human cachectin. Science.

[18] Reinhart K, Karzai W. Anti-tumor necrosis factor therapy in sepsis: Update on clinical trials and lessons learned. Critical Care Medicine. 2001;**29**

[19] Qiu P, Cui X, Sun J, Welsh J, Natanson C, Eichacker PQ. Antitumor necrosis factor therapy is associated with improved survival in clinical sepsis trials: A meta-analysis. Critical Care Medicine. 2013;**41**(10):2419-2429

[20] Murch SH, Lamkin VA, Savage MO, Walker-Smith JA, MacDonald TT. Serum concentrations of tumour necrosis factor alpha in childhood chronic inflammatory bowel disease.

[21] Braegger CP, Nicholls S, Murch SH, Stephens S, MacDonald TT. Tumour necrosis factor alpha in stool as a marker of intestinal inflammation. Lancet.

[22] Breese EJ, Michie CA, Nicholls SW, Murch SH, Williams CB, Domizio P, et al. Tumor necrosis factor alphaproducing cells in the intestinal mucosa of children with inflammatory bowel disease. Gastroenterology.

[23] Maeda M, Watanabe N, Neda H, Yamauchi N, Okamoto T, Sasaki H, et al. Serum tumor necrosis factor activity in inflammatory bowel

factor cachectin. Nature. 1985;**316**(6028):552-554

1985;**229**(4716):869-871

1986;**234**(4775):470-474

(7 Suppl):S121-S125

Gut. 1991;**32**(8):913-917

1992;**339**(8785):89-91

1994;**106**(6):1455-1466

**32**

[32] Adegbola SO, Sahnan K, Warusavitarne J, Hart A, Tozer P. Anti-TNF therapy in Crohn's disease. International Journal of Molecular Sciences. 2018;**2244**:1-21

[33] Steeland S, Libert C, Vandenbroucke RE. A new venue of TNF targeting. International Journal of Molecular Sciences. 2018;**1442**:1-55

[34] Fellermann K. Adverse events of tumor necrosis factor inhibitors. Digestive Diseases. 2013;**31**(3-4):374-378

[35] Rutgeerts P, Van Assche G, Vermeire S. Optimizing anti-TNF treatment in inflammatory bowel disease. Gastroenterology. 2004;**126**(6):1593-1610

[36] Yarur AJ, Jain A, Quintero MA, Czul F, Deshpande AR, Kerman DH, et al. Inflammatory cytokine profile in Crohn's disease nonresponders to optimal antitumor necrosis factor therapy. Journal of Clinical Gastroenterology. Mar 2019;**53**(3):210-215

[37] Dretzke J, Edlin R, Round J, Connock M, Hulme C, Czeczot J, et al. A systematic review and economic evaluation of the use of tumour necrosis factor-alpha (TNF-α) inhibitors, adalimumab and infliximab, for Crohn's disease. Health Technology Assessment. 2011;**15**(6):1-244

[38] Xie X, Li F, Chen JW, Wang J. Risk of tuberculosis infection in anti-TNF-α biological therapy: From bench to bedside. Journal of Microbiology,

Immunology, and Infection. 2014;**47**(4):268-274

[39] Dulai PS, Thompson KD, Blunt HB, Dubinsky MC, Siegel CA. Risks of serious infection or lymphoma with anti-tumor necrosis factor therapy for pediatric inflammatory bowel disease: A systematic review. Clinical Gastroenterology and Hepatology. 2014;**12**(9):1443-1451 quiz e88-9

[40] Peyrin-Biroulet L. Anti-TNF therapy in inflammatory bowel diseases: A huge review. Minerva Gastroenterologica e Dietologica. 2010;**56**(2):233-243

[41] Kirchgesner J, Lemaitre M, Carrat F, Zureik M, Carbonnel F, Dray-Spira R. Risk of serious and opportunistic infections associated with treatment of inflammatory bowel diseases. Gastroenterology. 2018;**155**(2):337-346.e10

[42] Mackey AC, Green L, Liang LC, Dinndorf P, Avigan M. Hepatosplenic T cell lymphoma associated with infliximab use in young patients treated for inflammatory bowel disease. Journal of Pediatric Gastroenterology and Nutrition. 2007;**44**(2):265-267

[43] Deepak P, Sifuentes H, Sherid M, Stobaugh D, Sadozai Y, Ehrenpreis ED. T-cell non-Hodgkin's lymphomas reported to the FDA AERS with tumor necrosis factor-alpha (TNF-α) inhibitors: Results of the REFURBISH study. The American Journal of Gastroenterology. 2013;**108**(1):99-105

[44] Lemaitre M, Kirchgesner J, Rudnichi A, Carrat F, Zureik M, Carbonnel F, et al. Association between use of thiopurines or tumor necrosis factor antagonists alone or in combination and risk of lymphoma in patients with inflammatory bowel disease. JAMA. 2017;**318**(17):1679-1686

[45] Ramos-Casals M, Brito-Zerón P, Muñoz S, Soria N, Galiana D,

Bertolaccini L, et al. Autoimmune diseases induced by TNFtargeted therapies: Analysis of 233 cases. Medicine (Baltimore). 2007;**86**(4):242-251

[46] Fiorino G, Allez M, Malesci A, Danese S. Review article: Anti TNF-alpha induced psoriasis in patients with inflammatory bowel disease. Alimentary Pharmacology & Therapeutics. 2009;**29**(9):921-927

[47] Guerra I, Algaba A, Pérez-Calle JL, Chaparro M, Marín-Jiménez I, García-Castellanos R, et al. Induction of psoriasis with anti-TNF agents in patients with inflammatory bowel disease: A report of 21 cases. Journal of Crohn's & Colitis. 2012;**6**(5):518-523

[48] Eickstaedt JB, Killpack L, Tung J, Davis D, Hand JL, Tollefson MM. Psoriasis and psoriasiform eruptions in pediatric patients with inflammatory bowel disease treated with anti-tumor necrosis factor alpha agents. Pediatric Dermatology. 2017;**34**(3):253-260

[49] Andrade P, Lopes S, Albuquerque A, Osório F, Pardal J, Macedo G. Oral lichen planus in IBD patients: A paradoxical adverse effect of anti-TNF-α therapy. Digestive Diseases and Sciences. 2015;**60**(9):2746-2749

[50] Decock A, Van Assche G, Vermeire S, Wuyts W, Ferrante M. Sarcoidosis-like lesions: Another paradoxical reaction to anti-TNF therapy? Journal of Crohn's & Colitis. 2017;**11**(3):378-383

[51] Alivernini S, Pugliese D, Tolusso B, Bui L, Petricca L, Guidi L, et al. Paradoxical arthritis occurring during anti-TNF in patients with inflammatory bowel disease: Histological and immunological features of a complex synovitis. RMD Open. 2018;**4**(1):e000667

[52] Aringer M, Smolen JS. The role of tumor necrosis factor-alpha in systemic lupus erythematosus. Arthritis Research & Therapy. 2008;**10**(1):202

[53] Shovman O, Tamar S, Amital H, Watad A, Shoenfeld Y. Diverse patterns of anti-TNF-α-induced lupus: Case series and review of the literature. Clinical Rheumatology. 2018;**37**(2):563-568

[54] Tracey D, Klareskog L, Sasso EH, Salfeld JG, Tak PP. Tumor necrosis factor antagonist mechanisms of action: A comprehensive review. Pharmacology & Therapeutics. 2008;**117**(2):244-279

[55] Roulis M, Armaka M, Manoloukos M, Apostolaki M, Kollias G. Intestinal epithelial cells as producers but not targets of chronic TNF suffice to cause murine Crohn-like pathology. Proceedings of the National Academy of Sciences of the United States of America. 2011;**108**(13):5396-5401

[56] Waters JP, Pober JS, Bradley JR. Tumour necrosis factor in infectious disease. The Journal of Pathology. 2013;**230**(2):132-147

[57] Nakane A, Minagawa T, Kato K. Endogenous tumor necrosis factor (cachectin) is essential to host resistance against Listeria monocytogenes infection. Infection and Immunity. 1988;**56**(10):2563-2569

[58] Perše M, Cerar A. Dextran sodium sulphate colitis mouse model: Traps and tricks. Journal of Biomedicine and Biotechnology. 2012;**2012**:718617. DOI: 10.1155/2012/718617. Epub 14 May 2012

[59] Pasparakis M, Alexopoulou L, Episkopou V, Kollias G. Immune and inflammatory responses in TNF alphadeficient mice: A critical requirement for TNF alpha in the formation of primary B cell follicles, follicular dendritic cell networks and germinal

**35**

*The Role of TNF in the Pathogenesis of Inflammatory Bowel Disease*

*DOI: http://dx.doi.org/10.5772/intechopen.84375*

[60] Kollias G, Kontoyiannis D, Douni E, Kassiotis G. The role of TNF/TNFR in organ-specific and systemic autoimmunity: Implications for the design of optimized 'anti-TNF' therapies. Current Directions in Autoimmunity. 2002;**5**:30-50

[61] Conrad C, Di Domizio J, Mylonas A, Belkhodja C, Demaria O, Navarini AA,

dysregulated type I interferon response without autoimmunity in paradoxical psoriasis. Nature Communications.

et al. TNF blockade induces a

2018;**9**(1):25

centers, and in the maturation of the humoral immune response. The Journal of Experimental Medicine.

1996;**184**(4):1397-1411

*The Role of TNF in the Pathogenesis of Inflammatory Bowel Disease DOI: http://dx.doi.org/10.5772/intechopen.84375*

centers, and in the maturation of the humoral immune response. The Journal of Experimental Medicine. 1996;**184**(4):1397-1411

*Biological Therapy for Inflammatory Bowel Disease*

[52] Aringer M, Smolen JS. The role of tumor necrosis factor-alpha in systemic lupus erythematosus. Arthritis Research

& Therapy. 2008;**10**(1):202

2018;**37**(2):563-568

[53] Shovman O, Tamar S, Amital H, Watad A, Shoenfeld Y. Diverse patterns of anti-TNF-α-induced lupus: Case series and review of the literature. Clinical Rheumatology.

[54] Tracey D, Klareskog L, Sasso EH, Salfeld JG, Tak PP. Tumor necrosis factor antagonist mechanisms of action: A comprehensive review. Pharmacology & Therapeutics. 2008;**117**(2):244-279

[55] Roulis M, Armaka M, Manoloukos M, Apostolaki M, Kollias G. Intestinal epithelial cells as producers but not targets of chronic TNF suffice to cause murine Crohn-like pathology. Proceedings of the National Academy of Sciences of the United States of America. 2011;**108**(13):5396-5401

[56] Waters JP, Pober JS, Bradley JR. Tumour necrosis factor in infectious disease. The Journal of Pathology.

[57] Nakane A, Minagawa T, Kato K. Endogenous tumor necrosis factor (cachectin) is essential to host resistance

[58] Perše M, Cerar A. Dextran sodium sulphate colitis mouse model: Traps and tricks. Journal of Biomedicine and Biotechnology. 2012;**2012**:718617. DOI: 10.1155/2012/718617. Epub 14 May 2012

[59] Pasparakis M, Alexopoulou L, Episkopou V, Kollias G. Immune and inflammatory responses in TNF alphadeficient mice: A critical requirement for TNF alpha in the formation of primary B cell follicles, follicular dendritic cell networks and germinal

against Listeria monocytogenes infection. Infection and Immunity.

2013;**230**(2):132-147

1988;**56**(10):2563-2569

Bertolaccini L, et al. Autoimmune

[46] Fiorino G, Allez M, Malesci A, Danese S. Review article: Anti TNF-alpha induced psoriasis in patients with inflammatory bowel disease. Alimentary Pharmacology & Therapeutics. 2009;**29**(9):921-927

[47] Guerra I, Algaba A, Pérez-Calle JL,

[48] Eickstaedt JB, Killpack L, Tung J, Davis D, Hand JL, Tollefson MM. Psoriasis and psoriasiform eruptions in pediatric patients with inflammatory bowel disease treated with anti-tumor necrosis factor alpha agents. Pediatric Dermatology. 2017;**34**(3):253-260

[49] Andrade P, Lopes S, Albuquerque A, Osório F, Pardal J, Macedo G. Oral lichen planus in IBD patients: A paradoxical adverse effect of anti-TNF-α therapy. Digestive Diseases and

Sciences. 2015;**60**(9):2746-2749

[50] Decock A, Van Assche G, Vermeire S, Wuyts W, Ferrante M. Sarcoidosis-like lesions: Another paradoxical reaction to anti-TNF therapy? Journal of Crohn's & Colitis.

[51] Alivernini S, Pugliese D, Tolusso B, Bui L, Petricca L, Guidi L, et al. Paradoxical arthritis occurring during anti-TNF in patients with inflammatory bowel disease:

Histological and immunological features of a complex synovitis. RMD Open.

2017;**11**(3):378-383

2018;**4**(1):e000667

Chaparro M, Marín-Jiménez I, García-Castellanos R, et al. Induction of psoriasis with anti-TNF agents in patients with inflammatory bowel disease: A report of 21 cases. Journal of Crohn's & Colitis. 2012;**6**(5):518-523

diseases induced by TNFtargeted therapies: Analysis of 233 cases. Medicine (Baltimore).

2007;**86**(4):242-251

**34**

[60] Kollias G, Kontoyiannis D, Douni E, Kassiotis G. The role of TNF/TNFR in organ-specific and systemic autoimmunity: Implications for the design of optimized 'anti-TNF' therapies. Current Directions in Autoimmunity. 2002;**5**:30-50

[61] Conrad C, Di Domizio J, Mylonas A, Belkhodja C, Demaria O, Navarini AA, et al. TNF blockade induces a dysregulated type I interferon response without autoimmunity in paradoxical psoriasis. Nature Communications. 2018;**9**(1):25

**37**

Section 2

Immunosuppressor and

Corticosteroid Therapy

### Section 2

## Immunosuppressor and Corticosteroid Therapy

**39**

**Chapter 3**

**Abstract**

**1. Introduction**

Traditional Drugs: Mechanisms

of Immunosuppressor and

*Cristina Ribeiro de Barros Cardoso,* 

*and Murillo Duarte-Silva*

Corticosteroid Therapies for

Inflammatory Bowel Diseases

*Amanda de Castro Habka, Camila Figueiredo Pinzan,* 

*Camilla Narjara Simão Oliveira, Jefferson Luiz da Silva* 

The inflammatory bowel diseases (IBD) such as Crohn's disease and ulcerative colitis are immunological dysfunctions of the gastrointestinal tract that develop because of multifactorial processes, including genetic predisposition, gut dysbiosis, and excessive inflammation in susceptible subjects. These pathologies affect millions of people worldwide, with substantial impact on healthcare systems and patients' quality of life. Considering the chronic inflammation that underlies the IBD presentation, the main treatment options are related to the control of patients' inflammatory response, through immunosuppressor and modulatory therapies. Therefore, in this chapter we reviewed the main mechanisms associated with the treatments that are aimed at suppressing mucosal immunity and the effects of

corticosteroid therapies in Crohn's disease and ulcerative colitis.

immunosuppressor, corticosteroid, therapy

**Keywords:** inflammatory bowel disease, Crohn's disease, ulcerative colitis,

The treatment of Crohn's disease and ulcerative colitis has central purposes such as to induce and maintain the patients' remission, while restraining the

disease's secondary effects and improving the quality of life of the affected subjects. Pharmacological therapy against these pathologies converges on controlling the exacerbation of immune response, either with systemic agents, such as corticosteroids, azathioprine (AZA), aminosalicylates, and methotrexate, or topical antiinflammatory drugs. Traditionally, the treatment for CD and UC follows a "step-up" approach. However, in the last years, a "top-down" strategy was implemented in IBD therapy, beginning to treat patients with biological agents, especially for more aggressive diseases [1]. After the main control of the inflammation, biologicals can be withdrawn, and weaker immunosuppressor medicines can be used, such as AZA,

### **Chapter 3**

## Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies for Inflammatory Bowel Diseases

*Cristina Ribeiro de Barros Cardoso, Amanda de Castro Habka, Camila Figueiredo Pinzan, Camilla Narjara Simão Oliveira, Jefferson Luiz da Silva and Murillo Duarte-Silva*

### **Abstract**

The inflammatory bowel diseases (IBD) such as Crohn's disease and ulcerative colitis are immunological dysfunctions of the gastrointestinal tract that develop because of multifactorial processes, including genetic predisposition, gut dysbiosis, and excessive inflammation in susceptible subjects. These pathologies affect millions of people worldwide, with substantial impact on healthcare systems and patients' quality of life. Considering the chronic inflammation that underlies the IBD presentation, the main treatment options are related to the control of patients' inflammatory response, through immunosuppressor and modulatory therapies. Therefore, in this chapter we reviewed the main mechanisms associated with the treatments that are aimed at suppressing mucosal immunity and the effects of corticosteroid therapies in Crohn's disease and ulcerative colitis.

**Keywords:** inflammatory bowel disease, Crohn's disease, ulcerative colitis, immunosuppressor, corticosteroid, therapy

### **1. Introduction**

The treatment of Crohn's disease and ulcerative colitis has central purposes such as to induce and maintain the patients' remission, while restraining the disease's secondary effects and improving the quality of life of the affected subjects. Pharmacological therapy against these pathologies converges on controlling the exacerbation of immune response, either with systemic agents, such as corticosteroids, azathioprine (AZA), aminosalicylates, and methotrexate, or topical antiinflammatory drugs. Traditionally, the treatment for CD and UC follows a "step-up" approach. However, in the last years, a "top-down" strategy was implemented in IBD therapy, beginning to treat patients with biological agents, especially for more aggressive diseases [1]. After the main control of the inflammation, biologicals can be withdrawn, and weaker immunosuppressor medicines can be used, such as AZA, aminosalicylates, or other drug alternatives for maintenance of disease remission [2], with different mechanisms of action, as discussed in the following section.

#### **2. Mechanisms of action of IBD's therapies: from corticosteroids to immunosuppressor drugs**

#### **2.1 Glucocorticoids**

Corticosteroids, a type of steroid hormones, are lipophilic molecules derived from cholesterol. Glucocorticoids, whose major representative is cortisol, play a role in the metabolism of lipids and carbohydrates and in the immune response, through immunosuppressive mechanisms. These hormones are synthesized by the adrenal glands in response to psychological or physiological stressful stimuli, such as excessive inflammation. The synthesis of glucocorticoids occurs after hypothalamic production of corticotropin-releasing hormone (CRH), which activates the pituitary secretion of corticotropin (ACTH) that, in turn, leads to adrenal release of cortisol, in a fine-tuned circadian rhythm [3].

Many of the immunosuppressive and anti-inflammatory functions of glucocorticoids occur after the binding of this hormone to the glucocorticoid receptor (GR). This molecule was described in the 1970s [4] and presents two isoforms of GR, GRα and GRβ, which differ in the C-terminal domain, being that the α forms the most prevalent in many human cells [5].

Glucocorticoids may exert their effects by non-genomic and mainly by the genomic signaling pathways [6]. One of the first evidences on the formation of a glucocorticoid-GR complex dated from 1972 in a study, which showed that free glucocorticoids penetrate hepatoma cells and bind to a cytoplasmic receptor, forming a complex which migrates to the nucleus shortly thereafter [7]. In the nucleus, the glucocorticoid/receptor complex binds to specific DNA sequences, named *glucocorticoid responsive elements* (GRE) [8]. Such binding to GREs may lead to repression and downregulation of target genes, especially those related to inflammatory response such as IFN-γ [9], TNF [10], and adhesion molecules [11], but may also lead to transcriptional activation of genes such as IL-10 [12], which plays an important anti-inflammatory activity. Another mechanism for gene transcription regulation by the glucocorticoid/receptor complex is the interference with other transcription factors, such as NF-κB, NFAT, and AP-1 [13], which also results in the inhibition of inflammatory responses.

Cortisol was first synthesized around 1937/1938 by Tadeusz Reichstein, who won the Nobel Prize about 10 years later for his work [14]. The first use of corticosteroids as an immunosuppressive and anti-inflammatory treatment occurred in the 1940s for rheumatoid arthritis in a study by Hench et al., who showed a decrease in symptoms when patients were treated with these hormones, besides disease relapse when treatment was stopped [15]. Since then, corticosteroids have been effective in treating other diseases, including intestinal inflammation [16].

Today, corticosteroid therapy is one of the most widely used and most effective drugs in the treatment of IBD, especially in acute inflammation, to induce disease remission [17]. However, there are important limitations regarding their long-term use, because of the drug's side effects. In line with that, despite the anti-inflammatory role in experimental colitis, budesonide worsens the general status of the mice, leading to endotoxemia and impaired epithelial repair in the gut, which are findings that could partially explain the fails in long-term glucocorticoid therapy for intestinal inflammation [18]. In contrast, mice exposed to dextran sodium sulfate for colitis development and treated for short term with the glucocorticoid

**41**

infections [30].

**2.2 Aminosalicylates**

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies…*

dexamethasone had decreased intestinal inflammation, with reduced expression of pro-inflammatory cytokines such as IFN-γ and IL-1, diminishment of

cytokine-producing cells such as IL-10. Moreover, the increase in the frequency of regulatory markers such as GITR, CTLA-4, PD-1, CD73, and FoxP3 in treated mice pointed to a relevant role for this short-term therapy in the induction of immune regulation [19], despite the long-term adverse effects of these drugs. These findings corroborate the relevance of this hormone in the regulation of mucosal immunity. In fact, regulatory T cells deficient for glucocorticoid receptor fail to control intestinal inflammatory diseases, in vivo. In addition, these knockout regulatory T cells acquire Th1 phenotype and secrete IFN-γ, with a consequent failure to inhibit

important to inflammation control, but the glucocorticoid receptor is critical for

Regarding the pivotal role of microbiota in the development of gut inflammation [21], it is known that the commensal intestinal bacteria may be involved in the mechanisms of action of glucocorticoid and mediate the anti-inflammatory effects of dexamethasone in the colon [22]. Indeed, the evaluation of mucosa transcriptomics of ulcerative colitis patients pointed to a corticosteroid-response gene signature that could predict response to this therapy, together with notable changes in gut microbiota [23]. In Crohn's disease or ulcerative colitis, the bacteria translocation in the gut is originally restrained by local phagocytic cells such as neutrophils, which in turn may contribute to tissue damage due to their excessive inflammation triggered in an attempt to control microbial invasion. Then, the mechanisms and efficacy of corticosteroids in IBD also involve the reduction in the chemokines responsible for the recruitment of neutrophils, besides natural killer cells and activated T lymphocytes to the gut, during ulcerative colitis [24]. There is also a decrease in adhesion and chemotaxis of these cells to the intestinal mucosa [25]. Although the efficacy of corticosteroid for the treatment of autoimmune and inflammatory diseases has been demonstrated, prolonged utilization of these drugs is associated with an increased risk of developing eye diseases such as glaucoma or cataract, hyperglycemia or insulin resistance, dermatological affections, and purpura [26]. Moreover, there is an increased risk of gastrointestinal problems such as peptic ulcer with perforations, bleeding, and acute pancreatitis [27]. The use of corticosteroids can also cause psychiatric and cognitive disorders [28], psychosis, and also sleep-related disorders [29]. Moreover, because of its immunosuppressive and anti-inflammatory effects, many patients who use corticosteroids may suffer from reduced effectiveness of the immune system and are at risk for opportunistic

The aminosalicylates (5-aminosalicylic acid, 5-ASA, or mesalazine) are one of the most used therapeutic choices to control mild to moderate inflammatory bowel diseases (IBD). Sulfasalazine (SASP), balsalazide, and olsalazine are prodrugs in which an azo bond is added to the structure to connect the 5-ASA moiety to carrier molecules. Sulfasalazine was the first aminosalicylate used for IBD and provided the basis for this class of medications. It was developed in the late 1930s, by the Swedish physician Nanna Svartz for the treatment of patients with rheumatic polyarthritis. Interestingly, some of the patients who were treated with SASP had ulcerative colitis too, and, surprisingly, their condition became more stable [31]. Therefore, SASP was soon being chosen as a treatment option for patients with IBD. Later, metabolic studies revealed that when this drug reaches the colon, the azo bond is cleaved by

T cells and augmented frequency of anti-inflammatory

T cells. Then, not only the synthetic glucocorticoid is

*DOI: http://dx.doi.org/10.5772/intechopen.90009*

IFN- γ-producing CD4<sup>+</sup>

the proliferation of CD4<sup>+</sup>

regulatory T cell functions neither [20].

#### *Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies… DOI: http://dx.doi.org/10.5772/intechopen.90009*

dexamethasone had decreased intestinal inflammation, with reduced expression of pro-inflammatory cytokines such as IFN-γ and IL-1, diminishment of IFN- γ-producing CD4<sup>+</sup> T cells and augmented frequency of anti-inflammatory cytokine-producing cells such as IL-10. Moreover, the increase in the frequency of regulatory markers such as GITR, CTLA-4, PD-1, CD73, and FoxP3 in treated mice pointed to a relevant role for this short-term therapy in the induction of immune regulation [19], despite the long-term adverse effects of these drugs. These findings corroborate the relevance of this hormone in the regulation of mucosal immunity. In fact, regulatory T cells deficient for glucocorticoid receptor fail to control intestinal inflammatory diseases, in vivo. In addition, these knockout regulatory T cells acquire Th1 phenotype and secrete IFN-γ, with a consequent failure to inhibit the proliferation of CD4<sup>+</sup> T cells. Then, not only the synthetic glucocorticoid is important to inflammation control, but the glucocorticoid receptor is critical for regulatory T cell functions neither [20].

Regarding the pivotal role of microbiota in the development of gut inflammation [21], it is known that the commensal intestinal bacteria may be involved in the mechanisms of action of glucocorticoid and mediate the anti-inflammatory effects of dexamethasone in the colon [22]. Indeed, the evaluation of mucosa transcriptomics of ulcerative colitis patients pointed to a corticosteroid-response gene signature that could predict response to this therapy, together with notable changes in gut microbiota [23]. In Crohn's disease or ulcerative colitis, the bacteria translocation in the gut is originally restrained by local phagocytic cells such as neutrophils, which in turn may contribute to tissue damage due to their excessive inflammation triggered in an attempt to control microbial invasion. Then, the mechanisms and efficacy of corticosteroids in IBD also involve the reduction in the chemokines responsible for the recruitment of neutrophils, besides natural killer cells and activated T lymphocytes to the gut, during ulcerative colitis [24]. There is also a decrease in adhesion and chemotaxis of these cells to the intestinal mucosa [25].

Although the efficacy of corticosteroid for the treatment of autoimmune and inflammatory diseases has been demonstrated, prolonged utilization of these drugs is associated with an increased risk of developing eye diseases such as glaucoma or cataract, hyperglycemia or insulin resistance, dermatological affections, and purpura [26]. Moreover, there is an increased risk of gastrointestinal problems such as peptic ulcer with perforations, bleeding, and acute pancreatitis [27]. The use of corticosteroids can also cause psychiatric and cognitive disorders [28], psychosis, and also sleep-related disorders [29]. Moreover, because of its immunosuppressive and anti-inflammatory effects, many patients who use corticosteroids may suffer from reduced effectiveness of the immune system and are at risk for opportunistic infections [30].

#### **2.2 Aminosalicylates**

The aminosalicylates (5-aminosalicylic acid, 5-ASA, or mesalazine) are one of the most used therapeutic choices to control mild to moderate inflammatory bowel diseases (IBD). Sulfasalazine (SASP), balsalazide, and olsalazine are prodrugs in which an azo bond is added to the structure to connect the 5-ASA moiety to carrier molecules. Sulfasalazine was the first aminosalicylate used for IBD and provided the basis for this class of medications. It was developed in the late 1930s, by the Swedish physician Nanna Svartz for the treatment of patients with rheumatic polyarthritis. Interestingly, some of the patients who were treated with SASP had ulcerative colitis too, and, surprisingly, their condition became more stable [31]. Therefore, SASP was soon being chosen as a treatment option for patients with IBD. Later, metabolic studies revealed that when this drug reaches the colon, the azo bond is cleaved by

*Biological Therapy for Inflammatory Bowel Disease*

**immunosuppressor drugs**

cortisol, in a fine-tuned circadian rhythm [3].

prevalent in many human cells [5].

inhibition of inflammatory responses.

**2.1 Glucocorticoids**

aminosalicylates, or other drug alternatives for maintenance of disease remission [2], with different mechanisms of action, as discussed in the following section.

**2. Mechanisms of action of IBD's therapies: from corticosteroids to** 

Corticosteroids, a type of steroid hormones, are lipophilic molecules derived from cholesterol. Glucocorticoids, whose major representative is cortisol, play a role in the metabolism of lipids and carbohydrates and in the immune response, through immunosuppressive mechanisms. These hormones are synthesized by the adrenal glands in response to psychological or physiological stressful stimuli, such as excessive inflammation. The synthesis of glucocorticoids occurs after hypothalamic production of corticotropin-releasing hormone (CRH), which activates the pituitary secretion of corticotropin (ACTH) that, in turn, leads to adrenal release of

Many of the immunosuppressive and anti-inflammatory functions of glucocorticoids occur after the binding of this hormone to the glucocorticoid receptor (GR). This molecule was described in the 1970s [4] and presents two isoforms of GR, GRα and GRβ, which differ in the C-terminal domain, being that the α forms the most

Glucocorticoids may exert their effects by non-genomic and mainly by the genomic signaling pathways [6]. One of the first evidences on the formation of a glucocorticoid-GR complex dated from 1972 in a study, which showed that free glucocorticoids penetrate hepatoma cells and bind to a cytoplasmic receptor, forming a complex which migrates to the nucleus shortly thereafter [7]. In the nucleus, the glucocorticoid/receptor complex binds to specific DNA sequences, named *glucocorticoid responsive elements* (GRE) [8]. Such binding to GREs may lead to repression and downregulation of target genes, especially those related to inflammatory response such as IFN-γ [9], TNF [10], and adhesion molecules [11], but may also lead to transcriptional activation of genes such as IL-10 [12], which plays an important anti-inflammatory activity. Another mechanism for gene transcription regulation by the glucocorticoid/receptor complex is the interference with other transcription factors, such as NF-κB, NFAT, and AP-1 [13], which also results in the

Cortisol was first synthesized around 1937/1938 by Tadeusz Reichstein, who won the Nobel Prize about 10 years later for his work [14]. The first use of corticosteroids as an immunosuppressive and anti-inflammatory treatment occurred in the 1940s for rheumatoid arthritis in a study by Hench et al., who showed a decrease in symptoms when patients were treated with these hormones, besides disease relapse when treatment was stopped [15]. Since then, corticosteroids have been effective in

Today, corticosteroid therapy is one of the most widely used and most effective drugs in the treatment of IBD, especially in acute inflammation, to induce disease remission [17]. However, there are important limitations regarding their long-term use, because of the drug's side effects. In line with that, despite the anti-inflammatory role in experimental colitis, budesonide worsens the general status of the mice, leading to endotoxemia and impaired epithelial repair in the gut, which are findings that could partially explain the fails in long-term glucocorticoid therapy for intestinal inflammation [18]. In contrast, mice exposed to dextran sodium sulfate for colitis development and treated for short term with the glucocorticoid

treating other diseases, including intestinal inflammation [16].

**40**

bacterial azoreductase, liberating 5-ASA and sulfapyridine, which is responsible for most of the usual adverse effects related to sulfasalazine [32]. In fact, in earlier elegant studies from the 70–80 decades, 5-ASA was shown to be the therapeutically active compound in sulfasalazine, while sulfapyridine plays a role as a carrier molecule, not required for clinical efficacy of the drug. These works were very important to drive the development of pure 5-ASA preparations useful for the treatment of IBD. Therefore, since aminosalicylates are among the most common therapeutic agents for these diseases, many studies have been performed in an attempt to discover the mechanisms of action of these drugs in the gut inflammation.

When the initial triggers break the mucosal tolerance in IBD, there is a vast infiltration of leukocytes in the intestine, with consequent production of soluble mediators of inflammation such as cytokines, chemokines, and eicosanoids. Some of these mediators are significantly elevated in the inflamed mucosa of IBD individuals, corroborating the pathogenesis of the disease, due to their pro-inflammatory impacts upon the bowel. In fact, the increased levels of seven eicosanoids, including prostaglandin (PG)E2, PGD2, thromboxane (TBX)B2, 5-HETE, 11-HETE, 12-HETE, and 15-HETE are found on mucosal biopsies from patients with ulcerative colitis, being correlated with the severity of inflammation [33]. Similarly, prostacyclin I2, PGE2, and TBXA2 are increased in cultured gut biopsies of active colitis patients, and, notably, the levels of these inflammatory mediators are reduced in the presence of 5-ASA. In fact, the activated leucocytes in patients' mucosa release toxic reactive oxygen metabolites and harmful eicosanoids such as LTB4, which seems to be an essential chemotactic agent in these diseases [34]. Therefore, considering the therapy mechanisms, sulfasalazine can effectively repress LTB4 and 5-HETE production by human polymorphonuclear leukocytes [35], while sulfasalazine, 5-ASA, and olsalazine (a 5-ASA dimer) potently inhibit colonic macrophage chemotaxis toward LTB4 [36]. These data suggested that one of the mechanisms of action of these drugs could be the inhibition of eicosanoids and then it is plausible to infer that the therapeutic inhibition of LOX or COX pathways could be useful in both ulcerative colitis and Crohn's disease.

Platelet-activating factor (PAF) is another phospholipid mediator released early in inflammation by a diversity of cell types, playing important roles in inflammatory conditions, including IBD. In active Crohn's disease, PAF levels are significantly higher and more elevated in inflamed than in noninflamed areas [37]. In parallel, PAF is increased in the colon and ileum from Crohn's disease patients [38], while biopsies of inflamed areas taken from ulcerative colitis subjects produce PAF spontaneously [39]. In this context, sulfasalazine and 5-ASA greatly reduce the synthesis of this mediator when incubated with mucosal biopsy specimens, indicating that these drugs exert beneficial effects in the inhibition of inflammation induced by PAF [40].

Chronic gut inflammation is also related to enhanced production of reactive metabolites of oxygen and nitrogen, since both reactive oxygen species (ROS) and nitric oxide (NO) deeply modulate the inflammatory responses. The generation of these reactive species can be attenuated by sulfasalazine, as it inhibits the binding of N-formyl-methionyl-leucyl-phenyl-alanine (fMLP) to its receptor on neutrophils [41] and also the superoxide production [42]. Interestingly, olsalazine and sulfasalazine are both potent inhibitors of superoxide production and degranulation of human neutrophils stimulated with fMLP, in contrast to 5-ASA and sulfapyridine, which do not have this ability [43]. On the other hand, 5-ASA can be converted to the oxidation products salicylate and gentisate, when the drug is incubated with activated human mononuclear cells and neutrophils, indicating that 5-ASA may scavenge toxic oxygen and nitrogen metabolites [44]. Similarly, evidences from an

**43**

outcome.

nal inflammation.

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies…*

in vivo study pointed once more to a scavenge role of sulfasalazine as a mechanism of action, thus reducing experimental intestinal inflammation induced by acetic acid [45]. In humans, 5-ASA oxidation products can be found in the stools of IBD patients using sulfasalazine, suggesting that this drug indeed plays a role as scaven-

A series of studies have demonstrated that sulfasalazine and its metabolites, at clinically relevant concentrations, also inhibit the release of cytokines produced by multiple cell types, including T cell mediators such as interleukin (IL)-2 [47] and those produced by monocytes or macrophages, like IL-12 [48], IL-1β, and tumor necrosis factor (TNF) [49]. Precisely, how sulfasalazine represses the release of cytokines has not been fully elucidated yet, but some studies have shown, for example, that sulfasalazine inhibits TNF expression in macrophages by inducing apoptosis [49] or inhibiting nuclear factor kappa B (NF-KB), a transcription factor crucial to the production of inflammatory mediators [50]. In the last years, the effects of sulfasalazine have been extensively studied in experimental models of intestinal inflammation. The chemically treated animals develop inflammation signs similar to those of human IBD, such as severe bloody diarrhea, body weight loss, colon length shortening, and gut pathological changes. In general, sulfasalazine treatment is able to reduce these signs and the colitis severity. Moreover, the drug significantly decreases the levels of inflammatory markers such as ROS [51], NF-KB, COX-2 [52], IL-6, TNF, IL-1 [53], NO [53], inducible nitric oxide synthase (iNOS) [52], myeloperoxidase (MPO) [54], monocyte chemoattractant protein-1 (MCP-1) [51], intercellular adhesion molecule-1 (ICAM-1) [51], and LTB4 [55], which are frequently overexpressed in IBD and widely known to be involved in chronic inflammatory disorders. Taken together, these experimental findings pointed to different mechanisms of action of sulfasalazine in the control of innate inflammatory reactions in gut mucosa, with outstanding relevance to the disease

Regarding adaptive and regulatory responses, it is known that a close relationship exists between colonic inflammation and T helper 1 (Th1) or Th17 immune reactions, which are related to the severity of inflammation in both human and experimental IBD [56]. In accordance, in a colitis model, mesalazine is able to inhibit Th1 and Th17 responses in contrast to an induction of regulatory immune profile, as observed by the disease amelioration, reduced expression neutrophil activity, IL-1β, TNF, IL-12, IFNγ, IL-17, IL-6, and RORγt, along with an augment in the suppressive cytokines IL-10 and TGF-β and in the transcription factor Foxp3 [57]. These data indicate that another mechanism of action of aminosalicylate drugs could be by decreasing pathogenic while increasing regulatory responses in intesti-

The peroxisome proliferator-activated receptor ligand-γ (PPARγ) plays a significant role in the immune control through its capacity to repress the expression of inflammatory cytokines and induce the differentiation of leukocytes toward anti-inflammatory phenotypes. Importantly, by using experimental approaches with epithelial colon cell lines and human biopsies, Rousseaux et al. showed that 5-ASA activates PPARγ, pointing to the receptor as an important drug's target for the control of intestinal inflammation [58]. In line with that, regulatory T cells (Tregs) play an indispensable role in suppressing exacerbated inflammatory immune responses that can be harmful to the host, such as in IBD [59]. Recently, Oh-Oka et al. proposed a new anti-inflammatory mechanism for mesalamine (5-ASA) in colitis, involving colonic Tregs. The oral treatment with this drug leads to the accumulation of Tregs in the colon lamina propria associated with increased levels of the active form of the anti-inflammatory cytokine TGF-β. These alterations attributed to mesalamine are dependent on the activation of aryl hydrocarbon

*DOI: http://dx.doi.org/10.5772/intechopen.90009*

ger for ROS and NO in these diseases [46].

#### *Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies… DOI: http://dx.doi.org/10.5772/intechopen.90009*

in vivo study pointed once more to a scavenge role of sulfasalazine as a mechanism of action, thus reducing experimental intestinal inflammation induced by acetic acid [45]. In humans, 5-ASA oxidation products can be found in the stools of IBD patients using sulfasalazine, suggesting that this drug indeed plays a role as scavenger for ROS and NO in these diseases [46].

A series of studies have demonstrated that sulfasalazine and its metabolites, at clinically relevant concentrations, also inhibit the release of cytokines produced by multiple cell types, including T cell mediators such as interleukin (IL)-2 [47] and those produced by monocytes or macrophages, like IL-12 [48], IL-1β, and tumor necrosis factor (TNF) [49]. Precisely, how sulfasalazine represses the release of cytokines has not been fully elucidated yet, but some studies have shown, for example, that sulfasalazine inhibits TNF expression in macrophages by inducing apoptosis [49] or inhibiting nuclear factor kappa B (NF-KB), a transcription factor crucial to the production of inflammatory mediators [50]. In the last years, the effects of sulfasalazine have been extensively studied in experimental models of intestinal inflammation. The chemically treated animals develop inflammation signs similar to those of human IBD, such as severe bloody diarrhea, body weight loss, colon length shortening, and gut pathological changes. In general, sulfasalazine treatment is able to reduce these signs and the colitis severity. Moreover, the drug significantly decreases the levels of inflammatory markers such as ROS [51], NF-KB, COX-2 [52], IL-6, TNF, IL-1 [53], NO [53], inducible nitric oxide synthase (iNOS) [52], myeloperoxidase (MPO) [54], monocyte chemoattractant protein-1 (MCP-1) [51], intercellular adhesion molecule-1 (ICAM-1) [51], and LTB4 [55], which are frequently overexpressed in IBD and widely known to be involved in chronic inflammatory disorders. Taken together, these experimental findings pointed to different mechanisms of action of sulfasalazine in the control of innate inflammatory reactions in gut mucosa, with outstanding relevance to the disease outcome.

Regarding adaptive and regulatory responses, it is known that a close relationship exists between colonic inflammation and T helper 1 (Th1) or Th17 immune reactions, which are related to the severity of inflammation in both human and experimental IBD [56]. In accordance, in a colitis model, mesalazine is able to inhibit Th1 and Th17 responses in contrast to an induction of regulatory immune profile, as observed by the disease amelioration, reduced expression neutrophil activity, IL-1β, TNF, IL-12, IFNγ, IL-17, IL-6, and RORγt, along with an augment in the suppressive cytokines IL-10 and TGF-β and in the transcription factor Foxp3 [57]. These data indicate that another mechanism of action of aminosalicylate drugs could be by decreasing pathogenic while increasing regulatory responses in intestinal inflammation.

The peroxisome proliferator-activated receptor ligand-γ (PPARγ) plays a significant role in the immune control through its capacity to repress the expression of inflammatory cytokines and induce the differentiation of leukocytes toward anti-inflammatory phenotypes. Importantly, by using experimental approaches with epithelial colon cell lines and human biopsies, Rousseaux et al. showed that 5-ASA activates PPARγ, pointing to the receptor as an important drug's target for the control of intestinal inflammation [58]. In line with that, regulatory T cells (Tregs) play an indispensable role in suppressing exacerbated inflammatory immune responses that can be harmful to the host, such as in IBD [59]. Recently, Oh-Oka et al. proposed a new anti-inflammatory mechanism for mesalamine (5-ASA) in colitis, involving colonic Tregs. The oral treatment with this drug leads to the accumulation of Tregs in the colon lamina propria associated with increased levels of the active form of the anti-inflammatory cytokine TGF-β. These alterations attributed to mesalamine are dependent on the activation of aryl hydrocarbon

*Biological Therapy for Inflammatory Bowel Disease*

ative colitis and Crohn's disease.

bacterial azoreductase, liberating 5-ASA and sulfapyridine, which is responsible for most of the usual adverse effects related to sulfasalazine [32]. In fact, in earlier elegant studies from the 70–80 decades, 5-ASA was shown to be the therapeutically active compound in sulfasalazine, while sulfapyridine plays a role as a carrier molecule, not required for clinical efficacy of the drug. These works were very important to drive the development of pure 5-ASA preparations useful for the treatment of IBD. Therefore, since aminosalicylates are among the most common therapeutic agents for these diseases, many studies have been performed in an attempt to discover the mechanisms of action of these drugs in the gut inflammation.

When the initial triggers break the mucosal tolerance in IBD, there is a vast infiltration of leukocytes in the intestine, with consequent production of soluble mediators of inflammation such as cytokines, chemokines, and eicosanoids. Some of these mediators are significantly elevated in the inflamed mucosa of IBD individuals, corroborating the pathogenesis of the disease, due to their pro-inflammatory impacts upon the bowel. In fact, the increased levels of seven eicosanoids, including prostaglandin (PG)E2, PGD2, thromboxane (TBX)B2, 5-HETE, 11-HETE, 12-HETE, and 15-HETE are found on mucosal biopsies from patients with ulcerative colitis, being correlated with the severity of inflammation [33]. Similarly, prostacyclin I2, PGE2, and TBXA2 are increased in cultured gut biopsies of active colitis patients, and, notably, the levels of these inflammatory mediators are reduced in the presence of 5-ASA. In fact, the activated leucocytes in patients' mucosa release toxic reactive oxygen metabolites and harmful eicosanoids such as LTB4, which seems to be an essential chemotactic agent in these diseases [34]. Therefore, considering the therapy mechanisms, sulfasalazine can effectively repress LTB4 and 5-HETE production by human polymorphonuclear leukocytes [35], while sulfasalazine, 5-ASA, and olsalazine (a 5-ASA dimer) potently inhibit colonic macrophage chemotaxis toward LTB4 [36]. These data suggested that one of the mechanisms of action of these drugs could be the inhibition of eicosanoids and then it is plausible to infer that the therapeutic inhibition of LOX or COX pathways could be useful in both ulcer-

Platelet-activating factor (PAF) is another phospholipid mediator released early in inflammation by a diversity of cell types, playing important roles in inflammatory conditions, including IBD. In active Crohn's disease, PAF levels are significantly higher and more elevated in inflamed than in noninflamed areas [37]. In parallel, PAF is increased in the colon and ileum from Crohn's disease patients [38], while biopsies of inflamed areas taken from ulcerative colitis subjects produce PAF spontaneously [39]. In this context, sulfasalazine and 5-ASA greatly reduce the synthesis of this mediator when incubated with mucosal biopsy specimens, indicating that these drugs exert beneficial effects in the inhibition of inflammation induced by

Chronic gut inflammation is also related to enhanced production of reactive metabolites of oxygen and nitrogen, since both reactive oxygen species (ROS) and nitric oxide (NO) deeply modulate the inflammatory responses. The generation of these reactive species can be attenuated by sulfasalazine, as it inhibits the binding of N-formyl-methionyl-leucyl-phenyl-alanine (fMLP) to its receptor on neutrophils [41] and also the superoxide production [42]. Interestingly, olsalazine and sulfasalazine are both potent inhibitors of superoxide production and degranulation of human neutrophils stimulated with fMLP, in contrast to 5-ASA and sulfapyridine, which do not have this ability [43]. On the other hand, 5-ASA can be converted to the oxidation products salicylate and gentisate, when the drug is incubated with activated human mononuclear cells and neutrophils, indicating that 5-ASA may scavenge toxic oxygen and nitrogen metabolites [44]. Similarly, evidences from an

**42**

PAF [40].

receptor (AhR), a transcription factor that regulates several immune processes, including Treg activation and differentiation [60].

Altogether, these studies show that aminosalicylates play an important role in the regulation of IBD responses.

#### **2.3 Thiopurines**

One of the most prescribed strategies for IBD therapy is the use of thiopurines, mainly azathioprine (AZA) and 6-mercaptopurine (6-MP). AZA is a prodrug that is metabolized by nonenzymatic mechanisms to be converted to 6-MP and other metabolites. Therefore, patients could be treated with AZA or directly with 6-MP, but the final metabolites produced from the thiopurines are the same. Also, both drugs generate endogenously active products able to interfere on DNA and RNA synthesis [61].

The discovery of AZA and 6-MP yielded a Nobel Prize in Medicine in 1988 for Gertrude B. Elion and George Hitchings. At first, the thiopurines were used in cancer therapy, in order to stop cell proliferation. Nonetheless, the immunosuppressive effect of thiopurines was evident as well as their efficiency in prolonging renal allograft transplant survival [62]. Thereafter, AZA and 6-MP began to be used in the clinics for inflammatory and rheumatic diseases. Since then, many mechanisms of action of thiopurines were proposed, mainly involving immunological axis in an attempt to unravel their immunosuppressive effects.

Some thiopurine metabolites, such as deoxyguanosine triphosphate (dGTP) and 6-thioguanine (6-TG), can be incorporated to DNA, replacing the natural purines adenine (A) and guanine (G). Then, during the DNA replication, a high level of substitution 6-TG could be particularly cytotoxic [63]. These DNA modifications are not restricted to cancer cells, and lymphocytes can be affected by the purine analogue 6-TG as well [64]. Besides that, some evidences point to the inhibition of de novo synthesis, which produce purines, by the thiopurine therapy. Then, the lack of abundant nitrogenous bases impairs the lymphocyte replication either, which contributes to the immunosuppression [65].

The thiopurines have the capacity to downregulate the expression of inflammatory genes in activated T lymphocytes [66]. One of these genes is the TNF-related apoptosis-inducing ligand (TRAIL), which is important to induce apoptosis and is upregulated in activated T lymphocytes. Despite being apparently contradictory, TRAIL could increase T cell proliferation and IFN-γ production [67], a phenomenon that is pathogenic for Crohn's disease patients. It is important to state that IFN-γ is a cytokine that accompanies the Th1 response, which increases gut inflammation. Also, CD27, which is a member of TNF superfamily, is downregulated by AZA [66]. This receptor is required to T cell maintenance and for B cell activation. Consequently, a low expression of CD27 could facilitate the lymphocyte death [68]. Besides, CD27 is involved in the NF-κB activation and IFN-γ production [69]. In fact, the 6-TG incorporation into T cell DNA is correlated to the decreased IFN-γ production in CD patients [70]. Lastly, the thiopurines could reduce the expression of the α4-integrin as well [66]. This integrin is mandatory to the lymphocyte accumulation in the gut and the chronic inflammation [71].

It is clear that the accumulation of T lymphocytes in the gut mucosa is one of the main hallmarks for the exacerbated inflammation and disease worsening. Accordingly, thiopurines also reduce T cell proliferation and the consequent excessive inflammatory mediators produced by this population. Indeed, 6-MP that impairs the A and T purine integration into the replicant DNA and replaces them for mimetic purines compromises the cell cycle and T cell proliferation. 6-MP interferes in the G1 to S phase transition and progression through S phase in cell cycle, with

**45**

CCR5+

IBD patients [75].

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies…*

drugs, besides the incorporation of mimetic purines, as described above.

consequent increase in lymphocyte death [72]. Thereby, it is unquestionable that the thiopurine metabolites incorporate into the genetic material and negatively influence the DNA integrity or stability, which causes cellular death. In the last decade, the first conclusive and detailed studies about the thiopurines' molecular mechanism of action in T lymphocytes explained better the delayed effects of these

The Ras-related C3 botulinum toxin substrate 1 (Rac1) is a GTPase protein that activates MEKK/IκB/NF-κB (mitogen-activated protein kinase kinase/IKK/ nuclear factor kappa-light-chain-enhancer of activated B cells) and signal transducer and activator of transcripition-3 (STAT-3) pathways, both of which lead to the accumulation of B-cell lymphoma-extra large (Bcl-xL) in the mitochondria. The enhancement of this protein results in an anti-apoptotic effect to cell survival. However, AZA and the 6-MP metabolite 6-thioguanine triphosphate (6-Thio-GTP) bind to Rac1, which impairs MEKK and STAT-3 phosphorylation, and consequently the anti-apoptotic effect by Bcl-xL is lost. Instead of that, there is an enhancement of Caspase-9, an apoptotic pathway of human cells involving mitochondria [73]. Interestingly, these mechanisms require the co-stimulation by CD28 in T cells.

The bind of CD28 by costimulatory molecules leads to lymphocyte's lamellipodia formations, which are projections of the cytoskeletal protein actin, necessary for T cell movement and membrane readjustment to make contact with antigen-presenting cells (APC). GTPase Rac1 also mediates this process [74]. Later, it was observed that thiopurines also bind to and block Rac2 activation, while the treatment with these drugs impairs the lamellipodia formation. Additionally, upon binding to Rac proteins, AZA and its metabolites reduce ezrin-radixin-moesin protein (ERM) desphosphorylation and subsequently the formation of APC-T cell conjugates, necessary for an effective immune adaptive response. Likewise, that was dependent on CD28 activation too [74]. Taken together, these results suggested that AZA and its metabolites binding Rac1 promote T cell apoptosis, by decreasing Bcl-xL and increasing caspase-9, but also interfere in T cell function or activation. Recently, a Bcl-2 inhibitor was suggested as a novel therapy to patients refractory to AZA treatment, despite Bcl-2, as a biomarker, cannot predict AZA treatment response in

In 2009 a study confirmed that 6-MP and 6-TG decrease the lymphoproliferative capacity of T cells, but in a physiological concentration (5 μM) [76]. The thiopurine therapy causes, in vivo, specifically depletion of T CD4 memory cells, thus reducing the capacity of response to a recurrent antigen. Considering that in IBD there is continuous microbial translocation and antigen presentation [77], this should explain, at least in part, the delayed onset of the drug's effect on the disease.

Thiopurine metabolites are also capable to inhibit the inflammatory response of macrophages and epithelial cells. These drugs significantly reduce the activity of c-Jun N-terminal kinase (JNK) and STAT3, as well IL-6, IL-8, CCL2, and CCL5 and inducible nitric oxide synthase (iNOS) expression. However, only iNOS in macrophages and IL-8 in epithelial cells are decreased dependent on Rac1 [78]. In fact, AZA restores the paracellular permeability after TNF-induced apoptosis. The treatment improves the expression of tight junctions and adherens junctions, such as occludin and E-cadherin [79]. Thus, the reduction of Rac1 is proposed as a biomarker for effectiveness of thiopurine treatment in patients with IBD [80]. It seems that the use of thiopurines can modulate the frequency of diverse immune cell populations, even by an indirect pathway. For example, patients treated with AZA have increased CCR5 expression in circulating monocytes. These

cells are considered to have an anti-inflammatory profile, with increased

CD163 and diminished TLR4-induced TNF and IL-6 secretion, probably in an attempt to achieve immunoregulation under AZA treatment [81]. Moreover,

*DOI: http://dx.doi.org/10.5772/intechopen.90009*

#### *Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies… DOI: http://dx.doi.org/10.5772/intechopen.90009*

consequent increase in lymphocyte death [72]. Thereby, it is unquestionable that the thiopurine metabolites incorporate into the genetic material and negatively influence the DNA integrity or stability, which causes cellular death. In the last decade, the first conclusive and detailed studies about the thiopurines' molecular mechanism of action in T lymphocytes explained better the delayed effects of these drugs, besides the incorporation of mimetic purines, as described above.

The Ras-related C3 botulinum toxin substrate 1 (Rac1) is a GTPase protein that activates MEKK/IκB/NF-κB (mitogen-activated protein kinase kinase/IKK/ nuclear factor kappa-light-chain-enhancer of activated B cells) and signal transducer and activator of transcripition-3 (STAT-3) pathways, both of which lead to the accumulation of B-cell lymphoma-extra large (Bcl-xL) in the mitochondria. The enhancement of this protein results in an anti-apoptotic effect to cell survival. However, AZA and the 6-MP metabolite 6-thioguanine triphosphate (6-Thio-GTP) bind to Rac1, which impairs MEKK and STAT-3 phosphorylation, and consequently the anti-apoptotic effect by Bcl-xL is lost. Instead of that, there is an enhancement of Caspase-9, an apoptotic pathway of human cells involving mitochondria [73]. Interestingly, these mechanisms require the co-stimulation by CD28 in T cells.

The bind of CD28 by costimulatory molecules leads to lymphocyte's lamellipodia formations, which are projections of the cytoskeletal protein actin, necessary for T cell movement and membrane readjustment to make contact with antigen-presenting cells (APC). GTPase Rac1 also mediates this process [74]. Later, it was observed that thiopurines also bind to and block Rac2 activation, while the treatment with these drugs impairs the lamellipodia formation. Additionally, upon binding to Rac proteins, AZA and its metabolites reduce ezrin-radixin-moesin protein (ERM) desphosphorylation and subsequently the formation of APC-T cell conjugates, necessary for an effective immune adaptive response. Likewise, that was dependent on CD28 activation too [74]. Taken together, these results suggested that AZA and its metabolites binding Rac1 promote T cell apoptosis, by decreasing Bcl-xL and increasing caspase-9, but also interfere in T cell function or activation. Recently, a Bcl-2 inhibitor was suggested as a novel therapy to patients refractory to AZA treatment, despite Bcl-2, as a biomarker, cannot predict AZA treatment response in IBD patients [75].

In 2009 a study confirmed that 6-MP and 6-TG decrease the lymphoproliferative capacity of T cells, but in a physiological concentration (5 μM) [76]. The thiopurine therapy causes, in vivo, specifically depletion of T CD4 memory cells, thus reducing the capacity of response to a recurrent antigen. Considering that in IBD there is continuous microbial translocation and antigen presentation [77], this should explain, at least in part, the delayed onset of the drug's effect on the disease.

Thiopurine metabolites are also capable to inhibit the inflammatory response of macrophages and epithelial cells. These drugs significantly reduce the activity of c-Jun N-terminal kinase (JNK) and STAT3, as well IL-6, IL-8, CCL2, and CCL5 and inducible nitric oxide synthase (iNOS) expression. However, only iNOS in macrophages and IL-8 in epithelial cells are decreased dependent on Rac1 [78]. In fact, AZA restores the paracellular permeability after TNF-induced apoptosis. The treatment improves the expression of tight junctions and adherens junctions, such as occludin and E-cadherin [79]. Thus, the reduction of Rac1 is proposed as a biomarker for effectiveness of thiopurine treatment in patients with IBD [80].

It seems that the use of thiopurines can modulate the frequency of diverse immune cell populations, even by an indirect pathway. For example, patients treated with AZA have increased CCR5 expression in circulating monocytes. These CCR5+ cells are considered to have an anti-inflammatory profile, with increased CD163 and diminished TLR4-induced TNF and IL-6 secretion, probably in an attempt to achieve immunoregulation under AZA treatment [81]. Moreover,

*Biological Therapy for Inflammatory Bowel Disease*

the regulation of IBD responses.

**2.3 Thiopurines**

synthesis [61].

including Treg activation and differentiation [60].

attempt to unravel their immunosuppressive effects.

contributes to the immunosuppression [65].

accumulation in the gut and the chronic inflammation [71].

receptor (AhR), a transcription factor that regulates several immune processes,

Altogether, these studies show that aminosalicylates play an important role in

One of the most prescribed strategies for IBD therapy is the use of thiopurines, mainly azathioprine (AZA) and 6-mercaptopurine (6-MP). AZA is a prodrug that is metabolized by nonenzymatic mechanisms to be converted to 6-MP and other metabolites. Therefore, patients could be treated with AZA or directly with 6-MP, but the final metabolites produced from the thiopurines are the same. Also, both drugs generate endogenously active products able to interfere on DNA and RNA

The discovery of AZA and 6-MP yielded a Nobel Prize in Medicine in 1988 for Gertrude B. Elion and George Hitchings. At first, the thiopurines were used in cancer therapy, in order to stop cell proliferation. Nonetheless, the immunosuppressive effect of thiopurines was evident as well as their efficiency in prolonging renal allograft transplant survival [62]. Thereafter, AZA and 6-MP began to be used in the clinics for inflammatory and rheumatic diseases. Since then, many mechanisms of action of thiopurines were proposed, mainly involving immunological axis in an

Some thiopurine metabolites, such as deoxyguanosine triphosphate (dGTP) and 6-thioguanine (6-TG), can be incorporated to DNA, replacing the natural purines adenine (A) and guanine (G). Then, during the DNA replication, a high level of substitution 6-TG could be particularly cytotoxic [63]. These DNA modifications are not restricted to cancer cells, and lymphocytes can be affected by the purine analogue 6-TG as well [64]. Besides that, some evidences point to the inhibition of de novo synthesis, which produce purines, by the thiopurine therapy. Then, the lack of abundant nitrogenous bases impairs the lymphocyte replication either, which

The thiopurines have the capacity to downregulate the expression of inflammatory genes in activated T lymphocytes [66]. One of these genes is the TNF-related apoptosis-inducing ligand (TRAIL), which is important to induce apoptosis and is upregulated in activated T lymphocytes. Despite being apparently contradictory, TRAIL could increase T cell proliferation and IFN-γ production [67], a phenomenon that is pathogenic for Crohn's disease patients. It is important to state that IFN-γ is a cytokine that accompanies the Th1 response, which increases gut inflammation. Also, CD27, which is a member of TNF superfamily, is downregulated by AZA [66]. This receptor is required to T cell maintenance and for B cell activation. Consequently, a low expression of CD27 could facilitate the lymphocyte death [68]. Besides, CD27 is involved in the NF-κB activation and IFN-γ production [69]. In fact, the 6-TG incorporation into T cell DNA is correlated to the decreased IFN-γ production in CD patients [70]. Lastly, the thiopurines could reduce the expression of the α4-integrin as well [66]. This integrin is mandatory to the lymphocyte

It is clear that the accumulation of T lymphocytes in the gut mucosa is one of the main hallmarks for the exacerbated inflammation and disease worsening. Accordingly, thiopurines also reduce T cell proliferation and the consequent excessive inflammatory mediators produced by this population. Indeed, 6-MP that impairs the A and T purine integration into the replicant DNA and replaces them for mimetic purines compromises the cell cycle and T cell proliferation. 6-MP interferes in the G1 to S phase transition and progression through S phase in cell cycle, with

**44**

thiopurine therapy decreases CD160 expression [82], as well as natural killer (NK) cells and the population of B lymphocytes in the peripheral blood of IBD patients [83]. Indeed, the reduction in B cells is one of the reasons for using combo therapy with AZA plus infliximab (IFX), instead of IFX alone. AZA diminishes the antibody formation against IFX and then improves the patients' responsiveness to the biological treatment [84].

The presence of variant Tγδ cells, specifically the TCR Vδ2, in the gut mucosa of Crohn's disease patients is associated with worse clinical prognosis and inflammation [85]. However, AZA is able to ablate this population in the blood and mucosa of patients treated with this drug, suggesting other potential mechanisms of action of AZA in the control of intestinal inflammation [86].

Besides the cellular changes, thiopurines are also capable of modulating soluble mediators, by decreasing IL-1β, TNF, and IFN-γ or increasing IL-10 *production* in vivo [87]. Likewise, the higher expression of inflammatory cytokines in detrimental to anti-inflammatory mediators may dictate the augmented production of matrix metalloproteinases (MMPs) in contrast to inhibitors of metalloproteinases (TIMPs), which are correlated to the control of the disease and improvement of intestinal barrier [88]. In line with that, the treatment with thiopurines reduced the pro-inflammatory effects, with decreased neutrophil MMP-9 and MMP-26 production, besides increased TIMP-3 expression by enterocytes [89].

Finally, a last mechanism of immune regulation was recently described involving AZA's use. This drug can induce autophagy, which is a natural mechanism to recycle cellular components and to promote cell survival, depending on PERK sensor and mTORC1 in lymphocytes. Hence, modulation of autophagy could represent an additional mechanism of inflammation control through AZA treatment in IBD [90].

#### **2.4 Methotrexate**

Methotrexate (MTX), originally known as amethopterin, is a folate antagonist. Its history and clinical use refers to Faber and Diamond [91], who reported the utilization of aminopterin, the first folic acid antagonist, as a treatment for acute leukemia in children. MTX, which is a derivative of aminopterin and is distinguished by having an additional methyl in its structure, subsequently replaced aminopterin after a study reported its lower toxicity in an experimental model of acute leukemia in rats [92]. The idea behind the use of antifolates for the treatment of neoplasias was based on the knowledge that folates function as cofactors for DNA biosynthesis. Subsequently, the ability of MTX to interfere in DNA synthesis was proven experimentally [93], and years later lower doses of MTX also began to be studied for other conditions such as psoriasis [94] and rheumatoid arthritis [95].

For IBD, Kozarek et al. [96] were the first to report the ability of this drug to induce clinical and histological remission in patients with Crohn's disease, but it was only after two randomized controlled trials (RCTs) of the North American Crohn's Study Group (NACSG) that MTX was formally established as a possible therapy for this disease [97]. On the other hand, there is no strong scientific basis for recommending the use of MTX as a monotherapy for UC. Nevertheless, the utilization of high or low doses of MTX in combination with anti-TNF has been shown to be effective in disease control at the same extent in both Crohn's disease and ulcerative colitis patients [98]. In summary, because of these and other results, MTX is usually recommended in specific conditions, especially depending on disease outcome and response to other therapies [99].

MTX acts as an antineoplastic drug when used at high doses and as immunosuppressive at low doses [100]. This led to the investigation of other possible

**47**

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies…*

of MTX as an immunomodulatory therapy, especially for Crohn's disease.

corticoids, because of its strong immune regulatory effects [107].

considered one of the main effects of this immunosuppressor drug [113].

Upon in vitro treatment of peripheral blood mononuclear cells (PBMCs), from ulcerative colitis or Crohn's disease patients with CsA, there is reduction of TNF, IL-17, and IL-10 in samples from all donors, besides an exclusive significant IL-13 decrease in subjects with UC. Also, CsA stimulates the cellular apoptosis of PBMC from patients with UC, though not by the mitochondrial route [114]. In an experimental colitis model, the treatment with CsA reduces the clinical activity of the disease and mRNA expression of several inflammatory cytokines such as IL-1β,

Hence, though the therapy with CsA has shown to be beneficial, the systemic treatment can be limited due to its side effects such as nephrotoxicity, hypertension, seizures, production of ROS or hydrogen peroxide, and opportunistic infections

Tacrolimus (Tac) was isolated in 1984 from the fungus strain *Streptomyces tsukubaensis*. It was initially used in the treatment of transplants and later in therapies for inflammatory or autoimmune diseases [117]. This drug is a substrate for cytochrome P450 isoenzymes (CYP3A), and the expression or activity of these enzymes in liver and intestinal cells may vary between individuals, thus contribut-

The Tac, compared to CsA, has a more potent inhibitory action against T cell activation, leading to immunosuppression. It binds to FKBP-12, with further inhibition of the calmodulin-dependent phosphatase activity of calcineurin [119]. Thus, it inhibits the action of activated nuclear T cell factor (NFAT), reducing the production of IL-2. In line with that, Tac can also decrease the activity of NF-κB [120]. Therefore, besides IL-2, Tac is a calcineurin inhibitor that leads to reduced

ing to different pharmacokinetic profile of Tac therapy [118].

The cyclosporine A (CsA) is an immunosuppressor drug initially used for organ transplantation on the late 70 and 80 decades [106]. Some years later, it was utilized as an alternative treatment for ulcerative colitis (UC) patients refractory to gluco-

CsA is a lipophilic cyclic peptide that is metabolized by hepatic enzymes of cytochrome P450 pathway [108]. Its immunosuppressor activity depends on the intracellular binding to cyclophilins with further inhibition of the calcium-calcineurin pathway and the resulting blockage of the nuclear activated T cell factor (NFAT) translocation to the nucleus [109], thus avoiding cellular activation. Consequently, there is reduction in the transcription of genes related to cytokine production such as IL-2, IL-4, and IFN-γ [110], inhibition of CD4 expression, cell proliferation [111], and activation of CD8 lymphocytes [112]. Therefore, the blockage of NFAT is

mechanisms capable of inducing immunosuppression, in addition to interfering in cell proliferation. In line with that, there is a lack of specific investigation unraveling the exact mechanisms of action of MTX in IBD, but this drug is capable of inducing apoptosis in activated T cells [101], inhibiting IL-8 production by peripheral blood mononuclear cells [102], and increasing extracellular adenosine levels. This metabolite has potent anti-inflammatory properties [103] in patients with rheumatoid arthritis [104] and potentially in IBD [105]. Clearly, more experimental studies are needed to better understand the action of MTX in IBD, but those mentioned above represent possible mechanisms that could explain the relative success

*DOI: http://dx.doi.org/10.5772/intechopen.90009*

**2.5 Cyclosporine**

IL-6, and TNF [115].

**2.6 Tacrolimus**

[116].

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies… DOI: http://dx.doi.org/10.5772/intechopen.90009*

mechanisms capable of inducing immunosuppression, in addition to interfering in cell proliferation. In line with that, there is a lack of specific investigation unraveling the exact mechanisms of action of MTX in IBD, but this drug is capable of inducing apoptosis in activated T cells [101], inhibiting IL-8 production by peripheral blood mononuclear cells [102], and increasing extracellular adenosine levels. This metabolite has potent anti-inflammatory properties [103] in patients with rheumatoid arthritis [104] and potentially in IBD [105]. Clearly, more experimental studies are needed to better understand the action of MTX in IBD, but those mentioned above represent possible mechanisms that could explain the relative success of MTX as an immunomodulatory therapy, especially for Crohn's disease.

#### **2.5 Cyclosporine**

*Biological Therapy for Inflammatory Bowel Disease*

AZA in the control of intestinal inflammation [86].

tion, besides increased TIMP-3 expression by enterocytes [89].

biological treatment [84].

ment in IBD [90].

**2.4 Methotrexate**

thiopurine therapy decreases CD160 expression [82], as well as natural killer (NK) cells and the population of B lymphocytes in the peripheral blood of IBD patients [83]. Indeed, the reduction in B cells is one of the reasons for using combo therapy with AZA plus infliximab (IFX), instead of IFX alone. AZA diminishes the antibody formation against IFX and then improves the patients' responsiveness to the

The presence of variant Tγδ cells, specifically the TCR Vδ2, in the gut mucosa of Crohn's disease patients is associated with worse clinical prognosis and inflammation [85]. However, AZA is able to ablate this population in the blood and mucosa of patients treated with this drug, suggesting other potential mechanisms of action of

Besides the cellular changes, thiopurines are also capable of modulating soluble

Finally, a last mechanism of immune regulation was recently described involving AZA's use. This drug can induce autophagy, which is a natural mechanism to recycle cellular components and to promote cell survival, depending on PERK sensor and mTORC1 in lymphocytes. Hence, modulation of autophagy could represent an additional mechanism of inflammation control through AZA treat-

Methotrexate (MTX), originally known as amethopterin, is a folate antagonist. Its history and clinical use refers to Faber and Diamond [91], who reported the utilization of aminopterin, the first folic acid antagonist, as a treatment for acute leukemia in children. MTX, which is a derivative of aminopterin and is distinguished by having an additional methyl in its structure, subsequently replaced aminopterin after a study reported its lower toxicity in an experimental model of acute leukemia in rats [92]. The idea behind the use of antifolates for the treatment of neoplasias was based on the knowledge that folates function as cofactors for DNA biosynthesis. Subsequently, the ability of MTX to interfere in DNA synthesis was proven experimentally [93], and years later lower doses of MTX also began to be studied for other conditions such as psoriasis [94] and rheumatoid arthritis [95]. For IBD, Kozarek et al. [96] were the first to report the ability of this drug to induce clinical and histological remission in patients with Crohn's disease, but it was only after two randomized controlled trials (RCTs) of the North American Crohn's Study Group (NACSG) that MTX was formally established as a possible therapy for this disease [97]. On the other hand, there is no strong scientific basis for recommending the use of MTX as a monotherapy for UC. Nevertheless, the utilization of high or low doses of MTX in combination with anti-TNF has been shown to be effective in disease control at the same extent in both Crohn's disease and ulcerative colitis patients [98]. In summary, because of these and other results, MTX is usually recommended in specific conditions, especially depending on disease outcome and

MTX acts as an antineoplastic drug when used at high doses and as immunosuppressive at low doses [100]. This led to the investigation of other possible

mediators, by decreasing IL-1β, TNF, and IFN-γ or increasing IL-10 *production* in vivo [87]. Likewise, the higher expression of inflammatory cytokines in detrimental to anti-inflammatory mediators may dictate the augmented production of matrix metalloproteinases (MMPs) in contrast to inhibitors of metalloproteinases (TIMPs), which are correlated to the control of the disease and improvement of intestinal barrier [88]. In line with that, the treatment with thiopurines reduced the pro-inflammatory effects, with decreased neutrophil MMP-9 and MMP-26 produc-

**46**

response to other therapies [99].

The cyclosporine A (CsA) is an immunosuppressor drug initially used for organ transplantation on the late 70 and 80 decades [106]. Some years later, it was utilized as an alternative treatment for ulcerative colitis (UC) patients refractory to glucocorticoids, because of its strong immune regulatory effects [107].

CsA is a lipophilic cyclic peptide that is metabolized by hepatic enzymes of cytochrome P450 pathway [108]. Its immunosuppressor activity depends on the intracellular binding to cyclophilins with further inhibition of the calcium-calcineurin pathway and the resulting blockage of the nuclear activated T cell factor (NFAT) translocation to the nucleus [109], thus avoiding cellular activation. Consequently, there is reduction in the transcription of genes related to cytokine production such as IL-2, IL-4, and IFN-γ [110], inhibition of CD4 expression, cell proliferation [111], and activation of CD8 lymphocytes [112]. Therefore, the blockage of NFAT is considered one of the main effects of this immunosuppressor drug [113].

Upon in vitro treatment of peripheral blood mononuclear cells (PBMCs), from ulcerative colitis or Crohn's disease patients with CsA, there is reduction of TNF, IL-17, and IL-10 in samples from all donors, besides an exclusive significant IL-13 decrease in subjects with UC. Also, CsA stimulates the cellular apoptosis of PBMC from patients with UC, though not by the mitochondrial route [114]. In an experimental colitis model, the treatment with CsA reduces the clinical activity of the disease and mRNA expression of several inflammatory cytokines such as IL-1β, IL-6, and TNF [115].

Hence, though the therapy with CsA has shown to be beneficial, the systemic treatment can be limited due to its side effects such as nephrotoxicity, hypertension, seizures, production of ROS or hydrogen peroxide, and opportunistic infections [116].

#### **2.6 Tacrolimus**

Tacrolimus (Tac) was isolated in 1984 from the fungus strain *Streptomyces tsukubaensis*. It was initially used in the treatment of transplants and later in therapies for inflammatory or autoimmune diseases [117]. This drug is a substrate for cytochrome P450 isoenzymes (CYP3A), and the expression or activity of these enzymes in liver and intestinal cells may vary between individuals, thus contributing to different pharmacokinetic profile of Tac therapy [118].

The Tac, compared to CsA, has a more potent inhibitory action against T cell activation, leading to immunosuppression. It binds to FKBP-12, with further inhibition of the calmodulin-dependent phosphatase activity of calcineurin [119]. Thus, it inhibits the action of activated nuclear T cell factor (NFAT), reducing the production of IL-2. In line with that, Tac can also decrease the activity of NF-κB [120]. Therefore, besides IL-2, Tac is a calcineurin inhibitor that leads to reduced

production of IL-3, TNF, IFN-γ, and IL-17, as well as the release of histamine from mast cells and proliferation of CD4+ or CD8+ T cells in a variety of inflammatory processes [121]. Tac treatment in bone marrow-derived macrophages also leads to reduced IL-12p40, IL-12p70, and IL-23 during LPS stimuli [122].

As described, in vitro treatment with Tac inhibits the activity of leukocytes such as T lymphocytes, NKT, and antigen-presenting cells, usually present on colon tissue. Moreover, the administration of Tac in trinitrobenzene sulfonic acid (TNBS) colitis results in the reduction of neutrophil infiltrate in the intestinal mucosa associated with inhibition of T cell activation, as well as decreased expression of CXCL1 and CXCL2 chemokines [123]. Most interestingly, Tac is able to inhibit the expression of IL-17 and TNF [124], suggesting that this drug could assume therapeutic effect on diseases mediated by Th17 responses, such as IBD. Furthermore, the rectal treatment in mice leads to better results than oral administration of the drug [125].

In experimental granulomatous colitis, treatment with Tac results in the reduction of intestinal permeability, neutrophil activity, as well as extra-intestinal manifestations of the disease, such as hepatic and splenic granulomas, caused by the colitis-inducing agent [126]. On the other scenario, myofibroblasts isolated from normal gut tissues and stimulated in vitro with TNF show increased phosphorylation of the p38 subunit of MAP kinase, leading to augmented CCL2 and CXCL10 expression. However, in vitro treatment with Tac suppresses the expression of CCL2 and CXCL10 mRNA by inhibiting phosphorylation of MAP kinase, indicating that these effects could be one of the mechanisms of therapeutic action of Tac on intestinal inflammation [127].

Hence, although this therapy may result in satisfactory IBD outcome, research has pointed that after mucosal healing, it is desirable to change this therapeutic intervention to other immunosuppressor drugs, in order to reduce the long-term adverse effects caused by Tac, such as nephrotoxicity [128].

#### **3. Conclusions**

The introduction of pharmacological therapies for IBD is of high importance to achieve remission and maintenance of quiescent disease in affected patients. Nonetheless, although these drugs act by diverse mechanisms, all of them are relevant in constraining the activation and perpetuation of the exacerbated immuneinflammatory responses that underline the gut inflammation in Crohn's disease and ulcerative colitis. Then, the balance between adequate control of inflammatory responses and drugs' adverse effects dictates the efficiency of corticosteroid and suppressor treatments in IBD.

#### **Acknowledgements**

The authors would like to thank Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), for the financial support 2017/08651.1 and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), 310174/2016-3.

**49**

Brazil

**Author details**

Cristina Ribeiro de Barros Cardoso1

Jefferson Luiz da Silva1,2 and Murillo Duarte-Silva2

\*Address all correspondence to: cristina@fcfrp.usp.br

provided the original work is properly cited.

Camila Figueiredo Pinzan1

Ribeirão Preto, Brazil

\*, Amanda de Castro Habka2

, Camilla Narjara Simão Oliveira2

1 School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo,

2 School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto,

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

,

,

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies…*

*DOI: http://dx.doi.org/10.5772/intechopen.90009*

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies… DOI: http://dx.doi.org/10.5772/intechopen.90009*

#### **Author details**

*Biological Therapy for Inflammatory Bowel Disease*

mast cells and proliferation of CD4+

intestinal inflammation [127].

suppressor treatments in IBD.

**Acknowledgements**

**3. Conclusions**

production of IL-3, TNF, IFN-γ, and IL-17, as well as the release of histamine from

T cells in a variety of inflammatory

or CD8+

reduced IL-12p40, IL-12p70, and IL-23 during LPS stimuli [122].

processes [121]. Tac treatment in bone marrow-derived macrophages also leads to

As described, in vitro treatment with Tac inhibits the activity of leukocytes such as T lymphocytes, NKT, and antigen-presenting cells, usually present on colon tissue. Moreover, the administration of Tac in trinitrobenzene sulfonic acid (TNBS) colitis results in the reduction of neutrophil infiltrate in the intestinal mucosa associated with inhibition of T cell activation, as well as decreased expression of CXCL1 and CXCL2 chemokines [123]. Most interestingly, Tac is able to inhibit the expression of IL-17 and TNF [124], suggesting that this drug could assume therapeutic effect on diseases mediated by Th17 responses, such as IBD. Furthermore, the rectal treatment in mice leads to better results than oral administration of the drug [125]. In experimental granulomatous colitis, treatment with Tac results in the reduc-

tion of intestinal permeability, neutrophil activity, as well as extra-intestinal

manifestations of the disease, such as hepatic and splenic granulomas, caused by the colitis-inducing agent [126]. On the other scenario, myofibroblasts isolated from normal gut tissues and stimulated in vitro with TNF show increased phosphorylation of the p38 subunit of MAP kinase, leading to augmented CCL2 and CXCL10 expression. However, in vitro treatment with Tac suppresses the expression of CCL2 and CXCL10 mRNA by inhibiting phosphorylation of MAP kinase, indicating that these effects could be one of the mechanisms of therapeutic action of Tac on

Hence, although this therapy may result in satisfactory IBD outcome, research has pointed that after mucosal healing, it is desirable to change this therapeutic intervention to other immunosuppressor drugs, in order to reduce the long-term

The introduction of pharmacological therapies for IBD is of high importance to achieve remission and maintenance of quiescent disease in affected patients. Nonetheless, although these drugs act by diverse mechanisms, all of them are relevant in constraining the activation and perpetuation of the exacerbated immuneinflammatory responses that underline the gut inflammation in Crohn's disease and ulcerative colitis. Then, the balance between adequate control of inflammatory responses and drugs' adverse effects dictates the efficiency of corticosteroid and

The authors would like to thank Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), for the financial support 2017/08651.1 and Conselho Nacional

de Desenvolvimento Científico e Tecnológico (CNPq), 310174/2016-3.

adverse effects caused by Tac, such as nephrotoxicity [128].

**48**

Cristina Ribeiro de Barros Cardoso1 \*, Amanda de Castro Habka2 , Camila Figueiredo Pinzan1 , Camilla Narjara Simão Oliveira2 , Jefferson Luiz da Silva1,2 and Murillo Duarte-Silva2

1 School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil

2 School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil

\*Address all correspondence to: cristina@fcfrp.usp.br

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

### **References**

[1] Khanna R, Bressler B, Levesque BG, Zou G, Stitt LW, Greenberg GR, et al. Early combined immunosuppression for the management of Crohn's disease (REACT): A cluster randomised controlled trial. Lancet. 2015;**386**(10006):1825-1834

[2] Casanova MJ, Chaparro M, Garcia-Sanchez V, Nantes O, Leo E, Rojas-Feria M, et al. Evolution after anti-TNF discontinuation in patients with inflammatory bowel disease: A multicenter long-term follow-up study. The American Journal of Gastroenterology. 2017;**112**(1):120-131

[3] Ramamoorthy S, Cidlowski JA. Corticosteroids: Mechanisms of action in health and disease. Rheumatic Diseases Clinics of North America. 2016;**42**(1):15-31. vii

[4] Wira C, Munck A. Specific glucocorticoid receptors in thymus cells. Localization in the nucleus and extraction of the cortisol-receptor complex. The Journal of Biological Chemistry. 1970;**245**(13):3436-3438

[5] Hollenberg SM, Weinberger C, Ong ES, Cerelli G, Oro A, Lebo R, et al. Primary structure and expression of a functional human glucocorticoid receptor cDNA. Nature. 1985;**318**(6047):635-641

[6] Panettieri RA, Schaafsma D, Amrani Y, Koziol-White C, Ostrom R, Tliba O. Non-genomic effects of glucocorticoids: An updated view. Trends in Pharmacological Sciences. 2019;**40**(1):38-49

[7] Baxter JD, Rousseau GG, Benson MC, Garcea RL, Ito J, Tomkins GM. Role of DNA and specific cytoplasmic receptors in glucocorticoid action. Proceedings of the National Academy of Sciences of the United States of America. 1972;**69**(7):1892-1896

[8] Dostert A, Heinzel T. Negative glucocorticoid receptor response elements and their role in glucocorticoid action. Current Pharmaceutical Design. 2004;**10**(23):2807-2816

[9] Curtin NM, Boyle NT, Mills KH, Connor TJ. Psychological stress suppresses innate IFN-gamma production via glucocorticoid receptor activation: Reversal by the anxiolytic chlordiazepoxide. Brain, Behavior, and Immunity. 2009;**23**(4):535-547

[10] Ballegeer M, Van Looveren K, Timmermans S, Eggermont M, Vandevyver S, Thery F, et al. Glucocorticoid receptor dimers control intestinal STAT1 and TNFinduced inflammation in mice. The Journal of Clinical Investigation. 2018;**128**(8):3265-3279

[11] Cronstein BN, Kimmel SC, Levin RI, Martiniuk F, Weissmann G. A mechanism for the antiinflammatory effects of corticosteroids: The glucocorticoid receptor regulates leukocyte adhesion to endothelial cells and expression of endothelial-leukocyte adhesion molecule 1 and intercellular adhesion molecule 1. Proceedings of the National Academy of Sciences of the United States of America. 1992;**89**(21):9991-9995

[12] Gayo A, Mozo L, Suarez A, Tunon A, Lahoz C, Gutierrez C. Glucocorticoids increase IL-10 expression in multiple sclerosis patients with acute relapse. Journal of Neuroimmunology. 1998;**85**(2):122-130

[13] Paliogianni F, Raptis A, Ahuja SS, Najjar SM, Boumpas DT. Negative transcriptional regulation of human interleukin 2 (IL-2) gene by glucocorticoids through interference with nuclear transcription factors AP-1 and NF-AT. The Journal of Clinical Investigation. 1993;**91**(4):1481-1489

**51**

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies…*

control experimental inflammatory bowel disease. Frontiers in Immunology.

[21] Yilmaz B, Juillerat P, Oyas O, Ramon C, Bravo FD, Franc Y, et al. Microbial network disturbances in relapsing refractory Crohn's disease. Nature Medicine. 2019;**25**(2):323-336

[22] Huang EY, Inoue T, Leone VA, Dalal S, Touw K, Wang Y, et al. Using corticosteroids to reshape the gut microbiome: Implications for inflammatory bowel diseases. Inflammatory Bowel Diseases.

2015;**21**(5):963-972

[23] Haberman Y, Karns R,

Dexheimer PJ, Schirmer M, Somekh J, Jurickova I, et al. Ulcerative colitis mucosal transcriptomes reveal mitochondriopathy and personalized mechanisms underlying disease

severity and treatment response. Nature

Communications. 2019;**10**(1):38

[24] Egesten A, Eliasson M, Olin AI, Erjefalt JS, Bjartell A, Sangfelt P, et al. The proinflammatory CXC-chemokines GRO-alpha/CXCL1 and MIG/CXCL9 are concomitantly expressed in ulcerative colitis and decrease during treatment with topical corticosteroids. International Journal of Colorectal Disease. 2007;**22**(12):1421-1427

[25] Wendt E, White GE, Ferry H, Huhn M, Greaves DR, Keshav S. Glucocorticoids suppress CCR9 mediated chemotaxis, calcium flux, and adhesion to MAdCAM-1 in human T cells. Journal of Immunology.

[26] Hengge UR, Ruzicka T, Schwartz RA, Cork MJ. Adverse effects of topical glucocorticosteroids. Journal of the American Academy of Dermatology.

2016;**196**(9):3910-3919

2006;**54**(1):1-15. quiz 16-18

[27] Sadr-Azodi O, Mattsson F, Bexlius TS, Lindblad M, Lagergren J,

2019;**10**:472

*DOI: http://dx.doi.org/10.5772/intechopen.90009*

Hommes DW, Buttgereit F. Molecular mechanisms of glucocorticoid action and selective glucocorticoid receptor agonists. Molecular and Cellular Endocrinology. 2007;**275**(1-2):71-78

[15] Hench PS, Kendall EC, et al. The effect of a hormone of the adrenal cortex (17-hydroxy-11-dehydrocorticosterone;

[16] Li J, Wang F, Zhang HJ, Sheng JQ, Yan WF, Ma MX, et al. Corticosteroid therapy in ulcerative colitis: Clinical response and predictors. World Journal of Gastroenterology. 2015;**21**(10):3005-3015

[17] Sales-Campos H, Basso PJ, Alves VB,

Fonseca MT, Bonfa G, Nardini V, et al. Classical and recent advances in the treatment of inflammatory bowel diseases. Brazilian Journal of Medical and Biological Research.

[18] Ocon B, Aranda CJ, Gamez-Belmonte R, Suarez MD, Zarzuelo A, Martinez-Augustin O, et al. The glucocorticoid budesonide has protective and deleterious effects in experimental colitis in mice. Biochemical Pharmacology.

[19] Sales-Campos H, de Souza PR, Basso PJ, Nardini V, Silva A, Banquieri F, et al. Amelioration of experimental colitis after short-term therapy with glucocorticoid and its relationship to the induction of different regulatory markers. Immunology.

[20] Rocamora-Reverte L, Tuzlak S, von Raffay L, Tisch M, Fiegl H, Drach M, et al. Glucocorticoid receptor-deficient Foxp3(+) regulatory T cells fail to

compound E) and of pituitary adrenocorticotropic hormone on rheumatoid arthritis. Proceedings of the Staff Meetings. Mayo Clinic.

1949;**24**(8):181-197

2015;**48**(2):96-107

2016;**116**:73-88

2017;**150**(1):115-126

[14] Stahn C, Lowenberg M,

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies… DOI: http://dx.doi.org/10.5772/intechopen.90009*

[14] Stahn C, Lowenberg M, Hommes DW, Buttgereit F. Molecular mechanisms of glucocorticoid action and selective glucocorticoid receptor agonists. Molecular and Cellular Endocrinology. 2007;**275**(1-2):71-78

[15] Hench PS, Kendall EC, et al. The effect of a hormone of the adrenal cortex (17-hydroxy-11-dehydrocorticosterone; compound E) and of pituitary adrenocorticotropic hormone on rheumatoid arthritis. Proceedings of the Staff Meetings. Mayo Clinic. 1949;**24**(8):181-197

[16] Li J, Wang F, Zhang HJ, Sheng JQ, Yan WF, Ma MX, et al. Corticosteroid therapy in ulcerative colitis: Clinical response and predictors. World Journal of Gastroenterology. 2015;**21**(10):3005-3015

[17] Sales-Campos H, Basso PJ, Alves VB, Fonseca MT, Bonfa G, Nardini V, et al. Classical and recent advances in the treatment of inflammatory bowel diseases. Brazilian Journal of Medical and Biological Research. 2015;**48**(2):96-107

[18] Ocon B, Aranda CJ, Gamez-Belmonte R, Suarez MD, Zarzuelo A, Martinez-Augustin O, et al. The glucocorticoid budesonide has protective and deleterious effects in experimental colitis in mice. Biochemical Pharmacology. 2016;**116**:73-88

[19] Sales-Campos H, de Souza PR, Basso PJ, Nardini V, Silva A, Banquieri F, et al. Amelioration of experimental colitis after short-term therapy with glucocorticoid and its relationship to the induction of different regulatory markers. Immunology. 2017;**150**(1):115-126

[20] Rocamora-Reverte L, Tuzlak S, von Raffay L, Tisch M, Fiegl H, Drach M, et al. Glucocorticoid receptor-deficient Foxp3(+) regulatory T cells fail to

control experimental inflammatory bowel disease. Frontiers in Immunology. 2019;**10**:472

[21] Yilmaz B, Juillerat P, Oyas O, Ramon C, Bravo FD, Franc Y, et al. Microbial network disturbances in relapsing refractory Crohn's disease. Nature Medicine. 2019;**25**(2):323-336

[22] Huang EY, Inoue T, Leone VA, Dalal S, Touw K, Wang Y, et al. Using corticosteroids to reshape the gut microbiome: Implications for inflammatory bowel diseases. Inflammatory Bowel Diseases. 2015;**21**(5):963-972

[23] Haberman Y, Karns R, Dexheimer PJ, Schirmer M, Somekh J, Jurickova I, et al. Ulcerative colitis mucosal transcriptomes reveal mitochondriopathy and personalized mechanisms underlying disease severity and treatment response. Nature Communications. 2019;**10**(1):38

[24] Egesten A, Eliasson M, Olin AI, Erjefalt JS, Bjartell A, Sangfelt P, et al. The proinflammatory CXC-chemokines GRO-alpha/CXCL1 and MIG/CXCL9 are concomitantly expressed in ulcerative colitis and decrease during treatment with topical corticosteroids. International Journal of Colorectal Disease. 2007;**22**(12):1421-1427

[25] Wendt E, White GE, Ferry H, Huhn M, Greaves DR, Keshav S. Glucocorticoids suppress CCR9 mediated chemotaxis, calcium flux, and adhesion to MAdCAM-1 in human T cells. Journal of Immunology. 2016;**196**(9):3910-3919

[26] Hengge UR, Ruzicka T, Schwartz RA, Cork MJ. Adverse effects of topical glucocorticosteroids. Journal of the American Academy of Dermatology. 2006;**54**(1):1-15. quiz 16-18

[27] Sadr-Azodi O, Mattsson F, Bexlius TS, Lindblad M, Lagergren J,

**50**

*Biological Therapy for Inflammatory Bowel Disease*

[1] Khanna R, Bressler B, Levesque BG, Zou G, Stitt LW, Greenberg GR, et al. Early combined immunosuppression for the management of Crohn's disease (REACT): A cluster

[8] Dostert A, Heinzel T. Negative glucocorticoid receptor response

[9] Curtin NM, Boyle NT, Mills KH, Connor TJ. Psychological stress suppresses innate IFN-gamma

production via glucocorticoid receptor activation: Reversal by the anxiolytic chlordiazepoxide. Brain, Behavior, and

Immunity. 2009;**23**(4):535-547

2018;**128**(8):3265-3279

1992;**89**(21):9991-9995

[12] Gayo A, Mozo L, Suarez A, Tunon A, Lahoz C, Gutierrez C. Glucocorticoids increase IL-10 expression in multiple sclerosis patients with acute relapse. Journal of Neuroimmunology. 1998;**85**(2):122-130

[13] Paliogianni F, Raptis A, Ahuja SS, Najjar SM, Boumpas DT. Negative transcriptional regulation of human interleukin 2 (IL-2) gene by glucocorticoids through interference with nuclear transcription factors AP-1 and NF-AT. The Journal of Clinical Investigation. 1993;**91**(4):1481-1489

[11] Cronstein BN, Kimmel SC,

Levin RI, Martiniuk F, Weissmann G. A mechanism for the antiinflammatory effects of corticosteroids: The glucocorticoid receptor regulates leukocyte adhesion to endothelial cells and expression of endothelial-leukocyte adhesion molecule 1 and intercellular adhesion molecule 1. Proceedings of the National Academy of Sciences of the United States of America.

[10] Ballegeer M, Van Looveren K, Timmermans S, Eggermont M, Vandevyver S, Thery F, et al. Glucocorticoid receptor dimers control intestinal STAT1 and TNFinduced inflammation in mice. The Journal of Clinical Investigation.

2004;**10**(23):2807-2816

elements and their role in glucocorticoid action. Current Pharmaceutical Design.

randomised controlled trial. Lancet.

2015;**386**(10006):1825-1834

**References**

[2] Casanova MJ, Chaparro M, Garcia-Sanchez V, Nantes O, Leo E, Rojas-Feria M, et al. Evolution after anti-TNF discontinuation in patients with inflammatory bowel disease: A multicenter long-term follow-up study. The American Journal of Gastroenterology. 2017;**112**(1):120-131

[3] Ramamoorthy S, Cidlowski JA. Corticosteroids: Mechanisms of action in health and disease. Rheumatic Diseases Clinics of North America.

[4] Wira C, Munck A. Specific glucocorticoid receptors in thymus cells. Localization in the nucleus and extraction of the cortisol-receptor complex. The Journal of Biological Chemistry. 1970;**245**(13):3436-3438

[5] Hollenberg SM, Weinberger C, Ong ES, Cerelli G, Oro A, Lebo R, et al. Primary structure and expression of a functional human glucocorticoid

[6] Panettieri RA, Schaafsma D, Amrani Y, Koziol-White C, Ostrom R, Tliba O. Non-genomic effects of glucocorticoids: An updated view. Trends in Pharmacological Sciences.

[7] Baxter JD, Rousseau GG, Benson MC, Garcea RL, Ito J, Tomkins GM. Role of DNA and specific cytoplasmic receptors in glucocorticoid action. Proceedings of the National Academy of Sciences of the United States of America.

receptor cDNA. Nature. 1985;**318**(6047):635-641

2019;**40**(1):38-49

1972;**69**(7):1892-1896

2016;**42**(1):15-31. vii

Ljung R. Association of oral glucocorticoid use with an increased risk of acute pancreatitis: A populationbased nested case-control study. JAMA Internal Medicine. 2013;**173**(6):444-449

[28] Kajiyama Y, Iijima Y, Chiba S, Furuta M, Ninomiya M, Izumi A, et al. Prednisolone causes anxiety- and depression-like behaviors and altered expression of apoptotic genes in mice hippocampus. Progress in Neuro-Psychopharmacology & Biological Psychiatry. 2010;**34**(1):159-165

[29] Wang ZJ, Zhang XQ, Cui XY, Cui SY, Yu B, Sheng ZF, et al. Glucocorticoid receptors in the locus coeruleus mediate sleep disorders caused by repeated corticosterone treatment. Scientific Reports. 2015;**5**:9442

[30] Stuck AE, Minder CE, Frey FJ. Risk of infectious complications in patients taking glucocorticosteroids. Reviews of Infectious Diseases. 1989;**11**(6):954-963

[31] Wollheim FA. Nanna Svartz (1890-1986): The first female professor of medicine in Sweden. Zeitschrift für Rheumatologie. 2017;**76**(9):813-819

[32] Klotz U. Clinical pharmacokinetics of sulphasalazine, its metabolites and other prodrugs of 5-aminosalicylic acid. Clinical Pharmacokinetics. 1985;**10**(4):285-302

[33] Masoodi M, Pearl DS, Eiden M, Shute JK, Brown JF, Calder PC, et al. Altered colonic mucosal polyunsaturated fatty acid (PUFA) derived lipid mediators in ulcerative colitis: New insight into relationship with disease activity and pathophysiology. PLoS One. 2013;**8**(10):e76532

[34] Lobos EA, Sharon P, Stenson WF. Chemotactic activity in inflammatory bowel disease. Role of leukotriene B4. Digestive Diseases and Sciences. 1987;**32**(12):1380-1388

[35] Nielsen OH, Bukhave K, Elmgreen J, Ahnfelt-Ronne I. Inhibition of 5-lipoxygenase pathway of arachidonic acid metabolism in human neutrophils by sulfasalazine and 5-aminosalicylic acid. Digestive Diseases and Sciences. 1987;**32**(6):577-582

[36] Nielsen OH, Verspaget HW, Elmgreen J. Inhibition of intestinal macrophage chemotaxis to leukotriene B4 by sulphasalazine, olsalazine, and 5-aminosalicylic acid. Alimentary Pharmacology & Therapeutics. 1988;**2**(3):203-211

[37] Sobhani I, Hochlaf S, Denizot Y, Vissuzaine C, Rene E, Benveniste J, et al. Raised concentrations of platelet activating factor in colonic mucosa of Crohn's disease patients. Gut. 1992;**33**(9):1220-1225

[38] Kald B, Olaison G, Sjodahl R, Tagesson C. Novel aspect of Crohn's disease: Increased content of plateletactivating factor in ileal and colonic mucosa. Digestion. 1990;**46**(4):199-204

[39] Wardle TD, Hall L, Turnberg LA. Platelet activating factor: Release from colonic mucosa in patients with ulcerative colitis and its effect on colonic secretion. Gut. 1996;**38**(3):355-361

[40] Eliakim R, Karmeli F, Razin E, Rachmilewitz D. Role of plateletactivating factor in ulcerative colitis. Enhanced production during active disease and inhibition by sulfasalazine and prednisolone. Gastroenterology. 1988;**95**(5):1167-1172

[41] Stenson WF, Mehta J, Spilberg I. Sulfasalazine inhibition of binding of N-formyl-methionyl-leucylphenylalanine (FMLP) to its receptor on human neutrophils. Biochemical Pharmacology. 1984;**33**(3):407-412

[42] Kanerud L, Hafstrom I, Ringertz B. Effect of sulphasalazine and sulphapyridine on neutrophil

**53**

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies…*

Arthritis and Rheumatism. 2000;**43**(9):1941-1950

2000;**119**(5):1209-1218

Liver. 2017;**11**(5):655-666

2017;**91**:1113-1121

Sinica. 2017;**38**(5):688-698

[55] Araujo DFS, Guerra GCB, Junior RFA, Antunes de Araujo A, Antonino de Assis PO, Nunes de Medeiros A, et al. Goat whey ameliorates intestinal inflammation on acetic acid-induced colitis in rats. Journal of Dairy Science. 2016;**99**(12):9383-9394

[53] Suluvoy JK, Sakthivel KM,

Guruvayoorappan C, Berlin Grace VM. Protective effect of *Averrhoa bilimbi* L. fruit extract on ulcerative colitis in Wistar rats via regulation of

inflammatory mediators and cytokines. Biomedicine & Pharmacotherapy.

[54] Xu B, Li YL, Xu M, Yu CC, Lian MQ, Tang ZY, et al. Geniposide ameliorates TNBS-induced experimental colitis in rats via reducing inflammatory cytokine release and restoring impaired intestinal barrier function. Acta Pharmacologica

[50] Weber CK, Liptay S, Wirth T, Adler G, Schmid RM. Suppression of NF-kappaB activity by sulfasalazine is mediated by direct inhibition of IkappaB kinases alpha and beta. Gastroenterology.

[51] Shin MR, Kim KJ, Kim SH, Kim SJ, Seo BI, An HJ, et al. Comparative evaluation between sulfasalazine alone and in combination with herbal medicine on DSS-induced ulcerative colitis mice. BioMed Research International. 2017;**2017**:6742652

[52] Han KH, Park JM, Jeong M, Han YM, Go EJ, Park J, et al. Heme oxygenase-1 induction and anti-inflammatory actions of *Atractylodes macrocephala* and *Taraxacum herba* extracts prevented colitis and was more effective than sulfasalazine in preventing relapse. Gut

*DOI: http://dx.doi.org/10.5772/intechopen.90009*

superoxide production: Role of cytosolic free calcium. Annals of the Rheumatic

[44] Dull BJ, Salata K, Van Langenhove A, Goldman P. 5-Aminosalicylate: Oxidation by activated leukocytes and protection of cultured cells from oxidative damage. Biochemical Pharmacology.

1987;**36**(15):2467-2472

1990;**31**(7):786-790

[45] Keshavarzian A, Morgan G, Sedghi S, Gordon JH, Doria M. Role of reactive oxygen metabolites in experimental colitis. Gut.

[46] Ahnfelt-Ronne I, Nielsen OH, Christensen A, Langholz E, Binder V, Riis P. Clinical evidence supporting the radical scavenger mechanism of 5-aminosalicylic acid. Gastroenterology.

1990;**98**(5 Pt 1):1162-1169

[47] Fujiwara M, Mitsui K,

responses and interleukin 2

Yamamoto I. Inhibition of proliferative

prevents T-helper 1 immune response by suppressing interleukin-12 production

productions by salazosulfapyridine and its metabolites. Japanese Journal of Pharmacology. 1990;**54**(2):121-131

[48] Kang BY, Chung SW, Im SY, Choe YK, Kim TS. Sulfasalazine

in macrophages. Immunology.

[49] Rodenburg RJ, Ganga A, van Lent PL, van de Putte LB, van Venrooij WJ. The antiinflammatory drug sulfasalazine inhibits tumor necrosis factor alpha expression in macrophages by inducing apoptosis.

1999;**98**(1):98-103

Diseases. 1990;**49**(5):296-300

[43] Neal TM, Winterbourn CC, Vissers MC. Inhibition of neutrophil degranulation and superoxide production by sulfasalazine. Comparison with 5-aminosalicylic acid, sulfapyridine and olsalazine. Biochemical Pharmacology. 1987;**36**(17):2765-2768

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies… DOI: http://dx.doi.org/10.5772/intechopen.90009*

superoxide production: Role of cytosolic free calcium. Annals of the Rheumatic Diseases. 1990;**49**(5):296-300

*Biological Therapy for Inflammatory Bowel Disease*

[35] Nielsen OH, Bukhave K,

of 5-lipoxygenase pathway of

and Sciences. 1987;**32**(6):577-582

[36] Nielsen OH, Verspaget HW, Elmgreen J. Inhibition of intestinal macrophage chemotaxis to leukotriene B4 by sulphasalazine, olsalazine, and 5-aminosalicylic acid. Alimentary Pharmacology & Therapeutics.

[37] Sobhani I, Hochlaf S, Denizot Y, Vissuzaine C, Rene E, Benveniste J, et al. Raised concentrations of platelet activating factor in colonic mucosa of Crohn's disease patients. Gut.

[38] Kald B, Olaison G, Sjodahl R, Tagesson C. Novel aspect of Crohn's disease: Increased content of plateletactivating factor in ileal and colonic mucosa. Digestion. 1990;**46**(4):199-204

[39] Wardle TD, Hall L, Turnberg LA. Platelet activating factor: Release from colonic mucosa in patients with ulcerative colitis and its effect on colonic secretion. Gut. 1996;**38**(3):355-361

[40] Eliakim R, Karmeli F, Razin E, Rachmilewitz D. Role of plateletactivating factor in ulcerative colitis. Enhanced production during active disease and inhibition by sulfasalazine and prednisolone. Gastroenterology.

[41] Stenson WF, Mehta J, Spilberg I. Sulfasalazine inhibition of binding of N-formyl-methionyl-leucylphenylalanine (FMLP) to its receptor on human neutrophils. Biochemical Pharmacology. 1984;**33**(3):407-412

[42] Kanerud L, Hafstrom I,

Ringertz B. Effect of sulphasalazine and sulphapyridine on neutrophil

1988;**95**(5):1167-1172

1988;**2**(3):203-211

1992;**33**(9):1220-1225

Elmgreen J, Ahnfelt-Ronne I. Inhibition

arachidonic acid metabolism in human neutrophils by sulfasalazine and

5-aminosalicylic acid. Digestive Diseases

Ljung R. Association of oral

glucocorticoid use with an increased risk of acute pancreatitis: A populationbased nested case-control study. JAMA Internal Medicine. 2013;**173**(6):444-449

[28] Kajiyama Y, Iijima Y, Chiba S, Furuta M, Ninomiya M, Izumi A, et al. Prednisolone causes anxiety- and depression-like behaviors and altered expression of apoptotic genes in mice hippocampus. Progress in Neuro-Psychopharmacology & Biological Psychiatry. 2010;**34**(1):159-165

[29] Wang ZJ, Zhang XQ, Cui XY, Cui SY, Yu B, Sheng ZF, et al. Glucocorticoid receptors in the locus coeruleus mediate sleep disorders caused by repeated corticosterone treatment. Scientific

[30] Stuck AE, Minder CE, Frey FJ. Risk of infectious complications in patients taking glucocorticosteroids. Reviews of Infectious Diseases. 1989;**11**(6):954-963

[32] Klotz U. Clinical pharmacokinetics of sulphasalazine, its metabolites and other prodrugs of 5-aminosalicylic acid. Clinical Pharmacokinetics.

[33] Masoodi M, Pearl DS, Eiden M, Shute JK, Brown JF, Calder PC, et al. Altered colonic mucosal polyunsaturated fatty acid (PUFA) derived lipid mediators in ulcerative colitis: New insight into relationship

[34] Lobos EA, Sharon P, Stenson WF. Chemotactic activity in inflammatory bowel disease. Role of leukotriene B4. Digestive Diseases and Sciences.

[31] Wollheim FA. Nanna Svartz (1890-1986): The first female professor of medicine in Sweden. Zeitschrift für Rheumatologie. 2017;**76**(9):813-819

Reports. 2015;**5**:9442

1985;**10**(4):285-302

with disease activity and pathophysiology. PLoS One.

1987;**32**(12):1380-1388

2013;**8**(10):e76532

**52**

[43] Neal TM, Winterbourn CC, Vissers MC. Inhibition of neutrophil degranulation and superoxide production by sulfasalazine. Comparison with 5-aminosalicylic acid, sulfapyridine and olsalazine. Biochemical Pharmacology. 1987;**36**(17):2765-2768

[44] Dull BJ, Salata K, Van Langenhove A, Goldman P. 5-Aminosalicylate: Oxidation by activated leukocytes and protection of cultured cells from oxidative damage. Biochemical Pharmacology. 1987;**36**(15):2467-2472

[45] Keshavarzian A, Morgan G, Sedghi S, Gordon JH, Doria M. Role of reactive oxygen metabolites in experimental colitis. Gut. 1990;**31**(7):786-790

[46] Ahnfelt-Ronne I, Nielsen OH, Christensen A, Langholz E, Binder V, Riis P. Clinical evidence supporting the radical scavenger mechanism of 5-aminosalicylic acid. Gastroenterology. 1990;**98**(5 Pt 1):1162-1169

[47] Fujiwara M, Mitsui K, Yamamoto I. Inhibition of proliferative responses and interleukin 2 productions by salazosulfapyridine and its metabolites. Japanese Journal of Pharmacology. 1990;**54**(2):121-131

[48] Kang BY, Chung SW, Im SY, Choe YK, Kim TS. Sulfasalazine prevents T-helper 1 immune response by suppressing interleukin-12 production in macrophages. Immunology. 1999;**98**(1):98-103

[49] Rodenburg RJ, Ganga A, van Lent PL, van de Putte LB, van Venrooij WJ. The antiinflammatory drug sulfasalazine inhibits tumor necrosis factor alpha expression in macrophages by inducing apoptosis. Arthritis and Rheumatism. 2000;**43**(9):1941-1950

[50] Weber CK, Liptay S, Wirth T, Adler G, Schmid RM. Suppression of NF-kappaB activity by sulfasalazine is mediated by direct inhibition of IkappaB kinases alpha and beta. Gastroenterology. 2000;**119**(5):1209-1218

[51] Shin MR, Kim KJ, Kim SH, Kim SJ, Seo BI, An HJ, et al. Comparative evaluation between sulfasalazine alone and in combination with herbal medicine on DSS-induced ulcerative colitis mice. BioMed Research International. 2017;**2017**:6742652

[52] Han KH, Park JM, Jeong M, Han YM, Go EJ, Park J, et al. Heme oxygenase-1 induction and anti-inflammatory actions of *Atractylodes macrocephala* and *Taraxacum herba* extracts prevented colitis and was more effective than sulfasalazine in preventing relapse. Gut Liver. 2017;**11**(5):655-666

[53] Suluvoy JK, Sakthivel KM, Guruvayoorappan C, Berlin Grace VM. Protective effect of *Averrhoa bilimbi* L. fruit extract on ulcerative colitis in Wistar rats via regulation of inflammatory mediators and cytokines. Biomedicine & Pharmacotherapy. 2017;**91**:1113-1121

[54] Xu B, Li YL, Xu M, Yu CC, Lian MQ, Tang ZY, et al. Geniposide ameliorates TNBS-induced experimental colitis in rats via reducing inflammatory cytokine release and restoring impaired intestinal barrier function. Acta Pharmacologica Sinica. 2017;**38**(5):688-698

[55] Araujo DFS, Guerra GCB, Junior RFA, Antunes de Araujo A, Antonino de Assis PO, Nunes de Medeiros A, et al. Goat whey ameliorates intestinal inflammation on acetic acid-induced colitis in rats. Journal of Dairy Science. 2016;**99**(12):9383-9394

[56] Ito R, Kita M, Shin-Ya M, Kishida T, Urano A, Takada R, et al. Involvement of IL-17A in the pathogenesis of DSSinduced colitis in mice. Biochemical and Biophysical Research Communications. 2008;**377**(1):12-16

[57] Zou Y, Dai SX, Chi HG, Li T, He ZW, Wang J, et al. Baicalin attenuates TNBS-induced colitis in rats by modulating the Th17/Treg paradigm. Archives of Pharmacal Research. 2015;**38**(10):1873-1887

[58] Rousseaux C, Lefebvre B, Dubuquoy L, Lefebvre P, Romano O, Auwerx J, et al. Intestinal antiinflammatory effect of 5-aminosalicylic acid is dependent on peroxisome proliferatoractivated receptor-gamma. The Journal of Experimental Medicine. 2005;**201**(8):1205-1215

[59] Zhu JF, Xu Y, Zhao J, Li X, Meng X, Wang TQ, et al. IL-33 protects mice against DSS-induced chronic colitis by increasing both regulatory B cell and regulatory T cell responses as well as decreasing Th17 cell response. Journal of Immunology Research. 2018;**2018**:1827901

[60] Oh-Oka K, Kojima Y, Uchida K, Yoda K, Ishimaru K, Nakajima S, et al. Induction of colonic regulatory T cells by mesalamine by activating the aryl hydrocarbon receptor. Cellular and Molecular Gastroenterology and Hepatology. 2017;**4**(1):135-151

[61] Etchevers MJ, Aceituno M, Sans M. Are we giving azathioprine too late? The case for early immunomodulation in inflammatory bowel disease. World Journal of Gastroenterology. 2008;**14**(36):5512-5518

[62] Murray JE, Merrill JP, Harrison JH, Wilson RE, Dammin GJ. Prolonged survival of human-kidney homografts by immunosuppressive drug therapy.

The New England Journal of Medicine. 1963;**268**:1315-1323

[63] Yoshida S, Yamada M, Masaki S, Saneyoshi M. Utilization of 2′-deoxy-6-thioguanosine 5′-triphosphate in DNA synthesis in vitro by DNA polymerase alpha from calf thymus. Cancer Research. 1979;**39**(10):3955-3958

[64] Morley AA, Trainor KJ, Seshadri R, Ryall RG. Measurement of in vivo mutations in human lymphocytes. Nature. 1983;**302**(5904):155-156

[65] Krynetski EY, Krynetskaia NF, Yanishevski Y, Evans WE. Methylation of mercaptopurine, thioguanine, and their nucleotide metabolites by heterologously expressed human thiopurine S-methyltransferase. Molecular Pharmacology. 1995;**47**(6):1141-1147

[66] Thomas CW, Myhre GM, Tschumper R, Sreekumar R, Jelinek D, McKean DJ, et al. Selective inhibition of inflammatory gene expression in activated T lymphocytes: A mechanism of immune suppression by thiopurines. The Journal of Pharmacology and Experimental Therapeutics. 2005;**312**(2):537-545

[67] Chou AH, Tsai HF, Lin LL, Hsieh SL, Hsu PI, Hsu PN. Enhanced proliferation and increased IFNgamma production in T cells by signal transduced through TNF-related apoptosis-inducing ligand. Journal of Immunology. 2001;**167**(3):1347-1352

[68] Croft M. The role of TNF superfamily members in T-cell function and diseases. Nature Reviews. Immunology. 2009;**9**(4):271-285

[69] Remedios KA, Meyer L, Zirak B, Pauli ML, Truong HA, Boda D, et al. CD27 promotes CD4(+) effector T cell survival in response to tissue selfantigen. Journal of Immunology. 1 Aug 2019;**203**(3):639-646

**55**

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies…*

et al. Early preservation of effector functions followed by eventual T cell memory depletion: A model for the delayed onset of the effect of thiopurines. Gut. 2009;**58**(3):396-403

[77] Chiodini RJ, Dowd SE, Galandiuk S, Davis B, Glassing A. The predominant site of bacterial translocation across the intestinal mucosal barrier occurs at the advancing disease margin in Crohn's disease. Microbiology.

2016;**162**(9):1608-1619

2014;**20**(9):1487-1495

2842;**9**(1):2019

2016;**38**(5):621-627

2017;**7**(1):92

[78] Marinkovic G, Hamers AA, de Vries CJ, de Waard V. 6-Mercaptopurine

reduces macrophage activation and gut epithelium proliferation through inhibition of GTPase Rac1. Inflammatory Bowel Diseases.

[79] Khare V, Krnjic A, Frick A,

[80] Seinen ML, van Nieuw

Gmainer C, Asboth M, Jimenez K, et al. Mesalamine and azathioprine modulate junctional complexes and restore epithelial barrier function in intestinal inflammation. Scientific Reports.

Amerongen GP, de Boer NK, Mulder CJ, van Bezu J, van Bodegraven AA. Rac1 as a potential pharmacodynamic biomarker for thiopurine therapy in inflammatory bowel disease. Therapeutic Drug Monitoring.

[81] Nieto JC, Zamora C, Canto E, Garcia-Planella E, Gordillo J, Ortiz MA, et al. CSF-1 regulates the function of monocytes in Crohn's disease patients in remission. Scientific Reports.

[82] Bouma G, Baggen JM, van Bodegraven AA, Mulder CJ, Kraal G, Zwiers A, et al. Thiopurine treatment in patients with Crohn's disease leads to a selective reduction of an effector cytotoxic gene expression signature revealed by whole-genome expression

*DOI: http://dx.doi.org/10.5772/intechopen.90009*

decreased interferon-gamma production in patients with Crohn's disease on AZA therapy. Digestive Diseases and

[70] Cuffari C, Li DY, Mahoney J, Barnes Y, Bayless TM. Peripheral blood mononuclear cell DNA 6-thioguanine metabolite levels correlate with

Sciences. 2004;**49**(1):133-137

2014;**7**(6):1354-1365

2003;**111**(8):1133-1145

2003;**171**(5):2225-2232

[75] Weder B, Mozaffari M,

in inflammatory bowel disease, but inhibition induces lymphocyte apoptosis and ameliorates colitis in mice. Clinical and Experimental Immunology. 2018;**193**(3):346-360

[74] Salazar-Fontana LI, Barr V, Samelson LE, Bierer BE. CD28 engagement promotes actin

polymerization through the activation of the small rho GTPase Cdc42 in human T cells. Journal of Immunology.

Biedermann L, Mamie C, Moncsek A, Wang L, et al. BCL-2 levels do not predict azathioprine treatment response

[76] Ben-Horin S, Goldstein I, Fudim E, Picard O, Yerushalmi Z, Barshack I,

[71] Kurmaeva E, Lord JD, Zhang S, Bao JR, Kevil CG, Grisham MB, et al. T cell-associated alpha4beta7 but not alpha4beta1 integrin is required for the induction and perpetuation of chronic colitis. Mucosal Immunology.

[72] Quemeneur L, Gerland LM, Flacher M, Ffrench M, Revillard JP, Genestier L. Differential control of cell cycle, proliferation, and survival of primary T lymphocytes by purine and pyrimidine nucleotides. Journal of Immunology. 2003;**170**(10):4986-4995

[73] Tiede I, Fritz G, Strand S, Poppe D, Dvorsky R, Strand D, et al. CD28 dependent Rac1 activation is the molecular target of azathioprine in primary human CD4+ T lymphocytes. The Journal of Clinical Investigation.

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies… DOI: http://dx.doi.org/10.5772/intechopen.90009*

[70] Cuffari C, Li DY, Mahoney J, Barnes Y, Bayless TM. Peripheral blood mononuclear cell DNA 6-thioguanine metabolite levels correlate with decreased interferon-gamma production in patients with Crohn's disease on AZA therapy. Digestive Diseases and Sciences. 2004;**49**(1):133-137

*Biological Therapy for Inflammatory Bowel Disease*

[56] Ito R, Kita M, Shin-Ya M, Kishida T, Urano A, Takada R, et al. Involvement of IL-17A in the pathogenesis of DSSinduced colitis in mice. Biochemical and Biophysical Research Communications.

The New England Journal of Medicine.

[63] Yoshida S, Yamada M, Masaki S, Saneyoshi M. Utilization of 2′-deoxy-6-thioguanosine 5′-triphosphate in DNA synthesis in vitro by DNA polymerase alpha from calf thymus. Cancer Research.

[64] Morley AA, Trainor KJ, Seshadri R, Ryall RG. Measurement of in vivo mutations in human lymphocytes. Nature. 1983;**302**(5904):155-156

[65] Krynetski EY, Krynetskaia NF, Yanishevski Y, Evans WE. Methylation of mercaptopurine, thioguanine, and their nucleotide metabolites by heterologously expressed human thiopurine S-methyltransferase. Molecular Pharmacology. 1995;**47**(6):1141-1147

[66] Thomas CW, Myhre GM,

The Journal of Pharmacology and Experimental Therapeutics.

[67] Chou AH, Tsai HF, Lin LL, Hsieh SL, Hsu PI, Hsu PN. Enhanced proliferation and increased IFNgamma production in T cells by signal transduced through TNF-related apoptosis-inducing ligand. Journal of Immunology. 2001;**167**(3):1347-1352

[68] Croft M. The role of TNF superfamily members in T-cell

2019;**203**(3):639-646

function and diseases. Nature Reviews. Immunology. 2009;**9**(4):271-285

[69] Remedios KA, Meyer L, Zirak B, Pauli ML, Truong HA, Boda D, et al. CD27 promotes CD4(+) effector T cell survival in response to tissue selfantigen. Journal of Immunology. 1 Aug

2005;**312**(2):537-545

Tschumper R, Sreekumar R, Jelinek D, McKean DJ, et al. Selective inhibition of inflammatory gene expression in activated T lymphocytes: A mechanism of immune suppression by thiopurines.

1963;**268**:1315-1323

1979;**39**(10):3955-3958

[57] Zou Y, Dai SX, Chi HG, Li T,

TNBS-induced colitis in rats by modulating the Th17/Treg paradigm. Archives of Pharmacal Research.

[58] Rousseaux C, Lefebvre B, Dubuquoy L, Lefebvre P,

antiinflammatory effect of

2005;**201**(8):1205-1215

2018;**2018**:1827901

Romano O, Auwerx J, et al. Intestinal

[59] Zhu JF, Xu Y, Zhao J, Li X, Meng X, Wang TQ, et al. IL-33 protects mice against DSS-induced chronic colitis by increasing both regulatory B cell and regulatory T cell responses as well as decreasing Th17 cell response. Journal of Immunology Research.

[60] Oh-Oka K, Kojima Y, Uchida K, Yoda K, Ishimaru K, Nakajima S, et al. Induction of colonic regulatory T cells by mesalamine by activating the aryl hydrocarbon receptor. Cellular and Molecular Gastroenterology and Hepatology. 2017;**4**(1):135-151

[61] Etchevers MJ, Aceituno M, Sans M. Are we giving azathioprine

[62] Murray JE, Merrill JP, Harrison JH, Wilson RE, Dammin GJ. Prolonged survival of human-kidney homografts by immunosuppressive drug therapy.

too late? The case for early immunomodulation in inflammatory bowel disease. World Journal of Gastroenterology.

2008;**14**(36):5512-5518

5-aminosalicylic acid is dependent on peroxisome proliferatoractivated receptor-gamma. The Journal of Experimental Medicine.

He ZW, Wang J, et al. Baicalin attenuates

2008;**377**(1):12-16

2015;**38**(10):1873-1887

**54**

[71] Kurmaeva E, Lord JD, Zhang S, Bao JR, Kevil CG, Grisham MB, et al. T cell-associated alpha4beta7 but not alpha4beta1 integrin is required for the induction and perpetuation of chronic colitis. Mucosal Immunology. 2014;**7**(6):1354-1365

[72] Quemeneur L, Gerland LM, Flacher M, Ffrench M, Revillard JP, Genestier L. Differential control of cell cycle, proliferation, and survival of primary T lymphocytes by purine and pyrimidine nucleotides. Journal of Immunology. 2003;**170**(10):4986-4995

[73] Tiede I, Fritz G, Strand S, Poppe D, Dvorsky R, Strand D, et al. CD28 dependent Rac1 activation is the molecular target of azathioprine in primary human CD4+ T lymphocytes. The Journal of Clinical Investigation. 2003;**111**(8):1133-1145

[74] Salazar-Fontana LI, Barr V, Samelson LE, Bierer BE. CD28 engagement promotes actin polymerization through the activation of the small rho GTPase Cdc42 in human T cells. Journal of Immunology. 2003;**171**(5):2225-2232

[75] Weder B, Mozaffari M, Biedermann L, Mamie C, Moncsek A, Wang L, et al. BCL-2 levels do not predict azathioprine treatment response in inflammatory bowel disease, but inhibition induces lymphocyte apoptosis and ameliorates colitis in mice. Clinical and Experimental Immunology. 2018;**193**(3):346-360

[76] Ben-Horin S, Goldstein I, Fudim E, Picard O, Yerushalmi Z, Barshack I,

et al. Early preservation of effector functions followed by eventual T cell memory depletion: A model for the delayed onset of the effect of thiopurines. Gut. 2009;**58**(3):396-403

[77] Chiodini RJ, Dowd SE, Galandiuk S, Davis B, Glassing A. The predominant site of bacterial translocation across the intestinal mucosal barrier occurs at the advancing disease margin in Crohn's disease. Microbiology. 2016;**162**(9):1608-1619

[78] Marinkovic G, Hamers AA, de Vries CJ, de Waard V. 6-Mercaptopurine reduces macrophage activation and gut epithelium proliferation through inhibition of GTPase Rac1. Inflammatory Bowel Diseases. 2014;**20**(9):1487-1495

[79] Khare V, Krnjic A, Frick A, Gmainer C, Asboth M, Jimenez K, et al. Mesalamine and azathioprine modulate junctional complexes and restore epithelial barrier function in intestinal inflammation. Scientific Reports. 2842;**9**(1):2019

[80] Seinen ML, van Nieuw Amerongen GP, de Boer NK, Mulder CJ, van Bezu J, van Bodegraven AA. Rac1 as a potential pharmacodynamic biomarker for thiopurine therapy in inflammatory bowel disease. Therapeutic Drug Monitoring. 2016;**38**(5):621-627

[81] Nieto JC, Zamora C, Canto E, Garcia-Planella E, Gordillo J, Ortiz MA, et al. CSF-1 regulates the function of monocytes in Crohn's disease patients in remission. Scientific Reports. 2017;**7**(1):92

[82] Bouma G, Baggen JM, van Bodegraven AA, Mulder CJ, Kraal G, Zwiers A, et al. Thiopurine treatment in patients with Crohn's disease leads to a selective reduction of an effector cytotoxic gene expression signature revealed by whole-genome expression profiling. Molecular Immunology. 2013;**54**(3-4):472-481

[83] Lord JD, Shows DM. Thiopurine use associated with reduced B and natural killer cells in inflammatory bowel disease. World Journal of Gastroenterology. 2017;**23**(18):3240-3251

[84] Ben-Horin S, Waterman M, Kopylov U, Yavzori M, Picard O, Fudim E, et al. Addition of an immunomodulator to infliximab therapy eliminates antidrug antibodies in serum and restores clinical response of patients with inflammatory bowel disease. Clinical Gastroenterology and Hepatology. 2013;**11**(4):444-447

[85] McCarthy NE, Bashir Z, Vossenkamper A, Hedin CR, Giles EM, Bhattacharjee S, et al. Proinflammatory Vdelta2+ T cells populate the human intestinal mucosa and enhance IFNgamma production by colonic alphabeta T cells. Journal of Immunology. 2013;**191**(5):2752-2763

[86] McCarthy NE, Hedin CR, Sanders TJ, Amon P, Hoti I, Ayada I, et al. Azathioprine therapy selectively ablates human Vdelta2(+) T cells in Crohn's disease. The Journal of Clinical Investigation. 2015;**125**(8):3215-3225

[87] Quaglio AE, Castilho AC, Di Stasi LC. Experimental evidence of heparanase, Hsp70 and NF-kappaB gene expression on the response of antiinflammatory drugs in TNBS-induced colonic inflammation. Life Sciences. 2015;**141**:179-187

[88] Makitalo L, Rintamaki H, Tervahartiala T, Sorsa T, Kolho KL. Serum MMPs 7-9 and their inhibitors during glucocorticoid and anti-TNFalpha therapy in pediatric inflammatory bowel disease. Scandinavian Journal of Gastroenterology. 2012;**47**(7):785-794

[89] Makitalo L, Sipponen T, Karkkainen P, Kolho KL, Saarialho-Kere U. Changes in matrix metalloproteinase (MMP) and tissue inhibitors of metalloproteinases (TIMP) expression profile in Crohn's disease after immunosuppressive treatment correlate with histological score and calprotectin values. International Journal of Colorectal Disease. 2009;**24**(10):1157-1167

[90] Hooper KM, Casanova V, Kemp S, Staines KA, Satsangi J, Barlow PG, et al. The inflammatory bowel disease drug azathioprine induces autophagy via mTORC1 and the unfolded protein response sensor PERK. Inflammatory Bowel Diseases. 2019

[91] Farber S, Diamond LK. Temporary remissions in acute leukemia in children produced by folic acid antagonist, 4-aminopteroyl-glutamic acid. The New England Journal of Medicine. 1948;**238**(23):787-793

[92] Goldin A, Venditti JM, Humphreys SR, Dennis D, Mantel N, Greenhouse SW. A quantitative comparison of the antileukemic effectiveness of two folic acid antagonists in mice. Journal of the National Cancer Institute. 1955;**15**(6):1657-1664

[93] Skeel RT, Sawicki WL, Cashmore AR, Bertino JR. Inhibition of DNA synthesis in normal and malignant human cells by triazinate (Baker's antifol) and methotrexate. Cancer Research. 1976;**36**(10):3659-3664

[94] Chouela EN, Mejer LI, Mom AM. Tissue immunology in psoriasis. I. Changes in the immunologic mechanism caused by methotrexate. Medicina Cutánea Ibero-Latino-Americana. 1975;**3**(2):167-172

[95] Hall GH, Jones BJ, Head AC, Jones VE. Intra-articular methotrexate. Clinical and laboratory study in

**57**

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies…*

[102] Seitz M, Dewald B, Ceska M, Gerber N, Baggiolini M. Interleukin-8 in inflammatory rheumatic diseases: Synovial fluid levels, relation to rheumatoid factors, production by mononuclear cells, and effects of gold sodium thiomalate and methotrexate.

Rheumatology International.

[103] Krump E, Lemay G, Borgeat P. Adenosine A2 receptor-induced

[104] Riksen NP, Barrera P, van den Broek PH, van Riel PL, Smits P, Rongen GA. Methotrexate modulates the kinetics of adenosine in humans in vivo. Annals of the Rheumatic Diseases. 2006;**65**(4):465-470

[105] Longhi MS, Moss A, Bai A, Wu Y, Huang H, Cheifetz A, et al. Characterization of human CD39+ Th17 cells with suppressor activity and modulation in inflammatory bowel disease. PLoS One. 2014;**9**(2):e87956

[106] Calne RY, Rolles K, White DJ, Thiru S, Evans DB, McMaster P, et al. Cyclosporin a initially as the only immunosuppressant in 34 recipients of cadaveric organs: 32 kidneys, 2 pancreases, and 2 livers. Lancet.

[107] Cohen RD, Stein R, Hanauer SB. Intravenous cyclosporin in ulcerative colitis: A five-year experience. The American Journal of Gastroenterology.

1979;**2**(8151):1033-1036

1999;**94**(6):1587-1592

1994;**61**(4):308-313

1992;**13**(4):136-142

[108] Graham RM. Cyclosporine: Mechanisms of action and toxicity. Cleveland Clinic Journal of Medicine.

[109] Schreiber SL, Crabtree GR. The mechanism of action of cyclosporin a and FK506. Immunology Today.

inhibition of leukotriene B4 synthesis in whole blood ex vivo. British Journal of Pharmacology. 1996;**117**(8):1639-1644

1992;**12**(4):159-164

*DOI: http://dx.doi.org/10.5772/intechopen.90009*

rheumatoid and psoriatic arthritis. Annals of the Rheumatic Diseases.

[96] Kozarek RA, Patterson DJ, Gelfand MD, Botoman VA, Ball TJ, Wilske KR. Methotrexate induces clinical and histologic remission in patients with refractory inflammatory bowel disease. Annals of Internal Medicine.

[97] Feagan BG, Rochon J, Fedorak RN, Irvine EJ, Wild G, Sutherland L, et al. Methotrexate for the treatment of Crohn's disease. The North American Crohn's study group investigators. The New England Journal of Medicine.

1978;**37**(4):351-356

1989;**110**(5):353-356

1995;**332**(5):292-297

2014;**5**(3):113-121

2010;**13**(4):288-293

1998;**102**(2):322-328

[101] Genestier L, Paillot R, Fournel S, Ferraro C, Miossec P, Revillard JP. Immunosuppressive properties of methotrexate: Apoptosis and clonal deletion of activated peripheral T cells. The Journal of Clinical Investigation.

[100] Malaviya AN, Sharma A, Agarwal D, Kapoor S, Garg S, Sawhney S. Low-dose and high-dose methotrexate are two different drugs in practical terms. International Journal of Rheumatic Diseases.

[98] Borren NZ, Luther J,

Colizzo FP, Garber JG, Khalili H, Ananthakrishnan AN. Low-dose methotrexate has similar outcomes to high-dose methotrexate in combination with anti-TNF therapy in inflammatory bowel diseases. Journal of Crohn's and Colitis. 14 Aug 2019;**13**(8):990-995

[99] Swaminath A, Taunk R, Lawlor G. Use of methotrexate in inflammatory bowel disease in 2014: A user's guide. World Journal of Gastrointestinal Pharmacology and Therapeutics.

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies… DOI: http://dx.doi.org/10.5772/intechopen.90009*

rheumatoid and psoriatic arthritis. Annals of the Rheumatic Diseases. 1978;**37**(4):351-356

*Biological Therapy for Inflammatory Bowel Disease*

[89] Makitalo L, Sipponen T, Karkkainen P, Kolho KL, Saarialho-

Kere U. Changes in matrix

Bowel Diseases. 2019

1948;**238**(23):787-793

1955;**15**(6):1657-1664

[93] Skeel RT, Sawicki WL,

[92] Goldin A, Venditti JM,

metalloproteinase (MMP) and tissue inhibitors of metalloproteinases (TIMP) expression profile in Crohn's disease after immunosuppressive treatment correlate with histological score and calprotectin values. International Journal of Colorectal Disease. 2009;**24**(10):1157-1167

[90] Hooper KM, Casanova V, Kemp S, Staines KA, Satsangi J, Barlow PG, et al. The inflammatory bowel disease drug azathioprine induces autophagy via mTORC1 and the unfolded protein response sensor PERK. Inflammatory

[91] Farber S, Diamond LK. Temporary remissions in acute leukemia in children produced by folic acid antagonist, 4-aminopteroyl-glutamic acid. The New England Journal of Medicine.

Humphreys SR, Dennis D, Mantel N, Greenhouse SW. A quantitative comparison of the antileukemic effectiveness of two folic acid antagonists in mice. Journal of the National Cancer Institute.

Cashmore AR, Bertino JR. Inhibition of DNA synthesis in normal and malignant human cells by triazinate (Baker's antifol) and methotrexate. Cancer Research. 1976;**36**(10):3659-3664

[94] Chouela EN, Mejer LI, Mom AM. Tissue immunology in psoriasis. I. Changes in the immunologic mechanism caused by methotrexate. Medicina Cutánea Ibero-Latino-Americana. 1975;**3**(2):167-172

[95] Hall GH, Jones BJ, Head AC, Jones VE. Intra-articular methotrexate. Clinical and laboratory study in

profiling. Molecular Immunology.

2013;**54**(3-4):472-481

[83] Lord JD, Shows DM. Thiopurine use associated with reduced B and natural killer cells in inflammatory bowel disease. World Journal of Gastroenterology.

2017;**23**(18):3240-3251

[84] Ben-Horin S, Waterman M, Kopylov U, Yavzori M, Picard O, Fudim E, et al. Addition of an immunomodulator to infliximab therapy eliminates antidrug antibodies in serum and restores clinical response of patients with inflammatory bowel disease. Clinical Gastroenterology and Hepatology. 2013;**11**(4):444-447

[85] McCarthy NE, Bashir Z,

T cells. Journal of Immunology.

[86] McCarthy NE, Hedin CR, Sanders TJ, Amon P, Hoti I, Ayada I, et al. Azathioprine therapy selectively

ablates human Vdelta2(+) T cells in Crohn's disease. The Journal of Clinical Investigation.

[87] Quaglio AE, Castilho AC, Di Stasi LC. Experimental evidence of heparanase, Hsp70 and NF-kappaB gene expression on the response of antiinflammatory drugs in TNBS-induced colonic inflammation. Life Sciences.

[88] Makitalo L, Rintamaki H, Tervahartiala T, Sorsa T, Kolho KL. Serum MMPs 7-9 and their inhibitors during glucocorticoid and anti-TNFalpha therapy in pediatric inflammatory bowel disease. Scandinavian Journal of Gastroenterology. 2012;**47**(7):785-794

2015;**125**(8):3215-3225

2015;**141**:179-187

2013;**191**(5):2752-2763

Vossenkamper A, Hedin CR, Giles EM, Bhattacharjee S, et al. Proinflammatory Vdelta2+ T cells populate the human intestinal mucosa and enhance IFNgamma production by colonic alphabeta

**56**

[96] Kozarek RA, Patterson DJ, Gelfand MD, Botoman VA, Ball TJ, Wilske KR. Methotrexate induces clinical and histologic remission in patients with refractory inflammatory bowel disease. Annals of Internal Medicine. 1989;**110**(5):353-356

[97] Feagan BG, Rochon J, Fedorak RN, Irvine EJ, Wild G, Sutherland L, et al. Methotrexate for the treatment of Crohn's disease. The North American Crohn's study group investigators. The New England Journal of Medicine. 1995;**332**(5):292-297

[98] Borren NZ, Luther J, Colizzo FP, Garber JG, Khalili H, Ananthakrishnan AN. Low-dose methotrexate has similar outcomes to high-dose methotrexate in combination with anti-TNF therapy in inflammatory bowel diseases. Journal of Crohn's and Colitis. 14 Aug 2019;**13**(8):990-995

[99] Swaminath A, Taunk R, Lawlor G. Use of methotrexate in inflammatory bowel disease in 2014: A user's guide. World Journal of Gastrointestinal Pharmacology and Therapeutics. 2014;**5**(3):113-121

[100] Malaviya AN, Sharma A, Agarwal D, Kapoor S, Garg S, Sawhney S. Low-dose and high-dose methotrexate are two different drugs in practical terms. International Journal of Rheumatic Diseases. 2010;**13**(4):288-293

[101] Genestier L, Paillot R, Fournel S, Ferraro C, Miossec P, Revillard JP. Immunosuppressive properties of methotrexate: Apoptosis and clonal deletion of activated peripheral T cells. The Journal of Clinical Investigation. 1998;**102**(2):322-328

[102] Seitz M, Dewald B, Ceska M, Gerber N, Baggiolini M. Interleukin-8 in inflammatory rheumatic diseases: Synovial fluid levels, relation to rheumatoid factors, production by mononuclear cells, and effects of gold sodium thiomalate and methotrexate. Rheumatology International. 1992;**12**(4):159-164

[103] Krump E, Lemay G, Borgeat P. Adenosine A2 receptor-induced inhibition of leukotriene B4 synthesis in whole blood ex vivo. British Journal of Pharmacology. 1996;**117**(8):1639-1644

[104] Riksen NP, Barrera P, van den Broek PH, van Riel PL, Smits P, Rongen GA. Methotrexate modulates the kinetics of adenosine in humans in vivo. Annals of the Rheumatic Diseases. 2006;**65**(4):465-470

[105] Longhi MS, Moss A, Bai A, Wu Y, Huang H, Cheifetz A, et al. Characterization of human CD39+ Th17 cells with suppressor activity and modulation in inflammatory bowel disease. PLoS One. 2014;**9**(2):e87956

[106] Calne RY, Rolles K, White DJ, Thiru S, Evans DB, McMaster P, et al. Cyclosporin a initially as the only immunosuppressant in 34 recipients of cadaveric organs: 32 kidneys, 2 pancreases, and 2 livers. Lancet. 1979;**2**(8151):1033-1036

[107] Cohen RD, Stein R, Hanauer SB. Intravenous cyclosporin in ulcerative colitis: A five-year experience. The American Journal of Gastroenterology. 1999;**94**(6):1587-1592

[108] Graham RM. Cyclosporine: Mechanisms of action and toxicity. Cleveland Clinic Journal of Medicine. 1994;**61**(4):308-313

[109] Schreiber SL, Crabtree GR. The mechanism of action of cyclosporin a and FK506. Immunology Today. 1992;**13**(4):136-142

[110] Fellman CL, Archer TM, Stokes JV, Wills RW, Lunsford KV, Mackin AJ. Effects of oral cyclosporine on canine T-cell expression of IL-2 and IFN-gamma across a 12-h dosing interval. Journal of Veterinary Pharmacology and Therapeutics. 2016;**39**(3):237-244

[111] Pallet N, Fernandez-Ramos AA, Loriot MA. Impact of immunosuppressive drugs on the metabolism of T cells. International Review of Cell and Molecular Biology. 2018;**341**:169-200

[112] Nemlander A, Hayry P. Effect of cyclosporin a on the generation of cytotoxic T lymphocytes in mouse mixed lymphocyte culture. Scandinavian Journal of Immunology. 1980;**12**(6):493-498

[113] Rao A, Luo C, Hogan PG. Transcription factors of the NFAT family: Regulation and function. Annual Review of Immunology. 1997;**15**:707-747

[114] Steiner S, Daniel C, Fischer A, Atreya I, Hirschmann S, Waldner M, et al. Cyclosporine a regulates proinflammatory cytokine production in ulcerative colitis. Archivum Immunologiae et Therapiae Experimentalis (Warsz). 2015;**63**(1):53-63

[115] Hoffmann M, Schwertassek U, Seydel A, Weber K, Falk W, Hauschildt S, et al. A refined and translationally relevant model of chronic DSS colitis in BALB/c mice. Laboratory Animals. 2018;**52**(3):240-252

[116] Godat S, Fournier N, Safroneeva E, Juillerat P, Nydegger A, Straumann A, et al. Frequency and type of drugrelated side effects necessitating treatment discontinuation in the Swiss inflammatory bowel disease cohort. European Journal of Gastroenterology & Hepatology. 2018;**30**(6):612-620

[117] Kino T, Hatanaka H, Hashimoto M, Nishiyama M, Goto T, Okuhara M, et al.

FK-506, a novel immunosuppressant isolated from a *Streptomyces*. I. Fermentation, isolation, and physicochemical and biological characteristics. Journal of Antibiotics (Tokyo). 1987;**40**(9):1249-1255

[118] Staatz CE, Tett SE. Clinical pharmacokinetics and pharmacodynamics of tacrolimus in solid organ transplantation. Clinical Pharmacokinetics. 2004;**43**(10):623-653

[119] Ordonez-Robles M, Santos-Beneit F, Martin JF. Unraveling nutritional regulation of tacrolimus biosynthesis in *Streptomyces tsukubaensis* through omic approaches. Antibiotics (Basel). 2018;**7**(2)

[120] Xu J, Feng Y, Song G, Gong Q, Yin L, Hu Y, et al. Tacrolimus reverses UVB irradiation-induced epidermal langerhans cell reduction by inhibiting TNF-alpha secretion in keratinocytes via regulation of NF-kappaB/p65. Frontiers in Pharmacology. 2018;**9**:67

[121] Li Y, Guptill JT, Russo MA, Massey JM, Juel VC, Hobson-Webb LD, et al. Tacrolimus inhibits Th1 and Th17 responses in MuSK-antibody positive myasthenia gravis patients. Experimental Neurology. 2019;**312**:43-50

[122] Elloumi HZ, Maharshak N, Rao KN, Kobayashi T, Ryu HS, Muhlbauer M, et al. A cell permeable peptide inhibitor of NFAT inhibits macrophage cytokine expression and ameliorates experimental colitis. PLoS One. 2012;**7**(3):e34172

[123] van Lierop PP, de Haar C, Lindenbergh-Kortleve DJ, Simons-Oosterhuis Y, van Rijt LS, Lambrecht BN, et al. T-cell regulation of neutrophil infiltrate at the early stages of a murine colitis model. Inflammatory Bowel Diseases. 2010;**16**(3):442-451

[124] Yago T, Nanke Y, Kawamoto M, Yamanaka H, Kotake S. Tacrolimus

**59**

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies…*

*DOI: http://dx.doi.org/10.5772/intechopen.90009*

osteoclastogenesis induced by IL-17 from human monocytes alone and suppresses human Th17 differentiation.

[125] van Dieren JM, Lambers ME, Kuipers EJ, Samsom JN, van der Woude CJ, Nieuwenhuis EE. Local immune regulation of mucosal inflammation by tacrolimus. Digestive Diseases and Sciences.

[126] Aiko S, Conner EM, Fuseler JA, Grisham MB. Effects of cyclosporine or FK506 in chronic colitis. The Journal of Pharmacology and Experimental Therapeutics. 1997;**280**(2):1075-1084

Takahashi K, Fujimoto T, Kasumi E, Yoden A, et al. Tacrolimus (FK506) suppresses TNF-alpha-induced CCL2 (MCP-1) and CXCL10 (IP-10) expression via the inhibition of p38 MAP kinase activation in human colonic myofibroblasts. International Journal of Molecular Medicine.

potently inhibits human

2010;**55**(9):2514-2519

[127] Aomatsu T, Imaeda H,

2012;**30**(5):1152-1158

2019;**39**(8):737-744

[128] Matsumoto S, Otake H, Sekine M, Uehara T, Miyatani H, Mashima H. Appropriate timing of discontinuation of tacrolimus therapy for refractory ulcerative colitis. Clinical Drug Investigation. Aug

Cytokine. 2012;**59**(2):252-257

*Traditional Drugs: Mechanisms of Immunosuppressor and Corticosteroid Therapies… DOI: http://dx.doi.org/10.5772/intechopen.90009*

potently inhibits human osteoclastogenesis induced by IL-17 from human monocytes alone and suppresses human Th17 differentiation. Cytokine. 2012;**59**(2):252-257

*Biological Therapy for Inflammatory Bowel Disease*

FK-506, a novel immunosuppressant

I. Fermentation, isolation, and physicochemical and biological characteristics.

isolated from a *Streptomyces*.

Journal of Antibiotics (Tokyo).

[119] Ordonez-Robles M, Santos-Beneit F, Martin JF. Unraveling nutritional regulation of tacrolimus biosynthesis in *Streptomyces tsukubaensis* through omic approaches. Antibiotics

[120] Xu J, Feng Y, Song G, Gong Q, Yin L, Hu Y, et al. Tacrolimus reverses UVB irradiation-induced epidermal langerhans cell reduction by inhibiting TNF-alpha secretion in keratinocytes via regulation of NF-kappaB/p65. Frontiers in Pharmacology. 2018;**9**:67

[121] Li Y, Guptill JT, Russo MA,

patients. Experimental Neurology.

[122] Elloumi HZ, Maharshak N, Rao KN, Kobayashi T, Ryu HS, Muhlbauer M, et al. A cell permeable peptide inhibitor of NFAT inhibits macrophage cytokine expression and ameliorates experimental colitis. PLoS

[123] van Lierop PP, de Haar C, Lindenbergh-Kortleve DJ,

Simons-Oosterhuis Y, van Rijt LS, Lambrecht BN, et al. T-cell regulation of neutrophil infiltrate at the early stages of a murine colitis model. Inflammatory Bowel Diseases. 2010;**16**(3):442-451

[124] Yago T, Nanke Y, Kawamoto M, Yamanaka H, Kotake S. Tacrolimus

positive myasthenia gravis

One. 2012;**7**(3):e34172

2019;**312**:43-50

Massey JM, Juel VC, Hobson-Webb LD, et al. Tacrolimus inhibits Th1 and Th17 responses in MuSK-antibody

1987;**40**(9):1249-1255

(Basel). 2018;**7**(2)

[118] Staatz CE, Tett SE. Clinical pharmacokinetics and pharmacodynamics of tacrolimus in solid organ transplantation. Clinical Pharmacokinetics. 2004;**43**(10):623-653

[110] Fellman CL, Archer TM, Stokes JV, Wills RW, Lunsford KV, Mackin AJ. Effects of oral cyclosporine on canine T-cell expression of IL-2 and IFN-gamma across a 12-h dosing interval. Journal of Veterinary Pharmacology and Therapeutics.

[111] Pallet N, Fernandez-Ramos AA, Loriot MA. Impact of immunosuppressive drugs on the metabolism of T cells. International Review of Cell and Molecular Biology. 2018;**341**:169-200

[112] Nemlander A, Hayry P. Effect of cyclosporin a on the generation of cytotoxic T lymphocytes in mouse mixed lymphocyte culture. Scandinavian Journal of Immunology.

[113] Rao A, Luo C, Hogan PG. Transcription factors of the NFAT family: Regulation and function. Annual Review of Immunology. 1997;**15**:707-747

[114] Steiner S, Daniel C, Fischer A, Atreya I, Hirschmann S, Waldner M, et al. Cyclosporine a regulates proinflammatory cytokine production in ulcerative colitis. Archivum Immunologiae et Therapiae Experimentalis (Warsz).

[115] Hoffmann M, Schwertassek U,

[116] Godat S, Fournier N, Safroneeva E, Juillerat P, Nydegger A, Straumann A, et al. Frequency and type of drugrelated side effects necessitating treatment discontinuation in the Swiss inflammatory bowel disease cohort. European Journal of Gastroenterology & Hepatology. 2018;**30**(6):612-620

[117] Kino T, Hatanaka H, Hashimoto M, Nishiyama M, Goto T, Okuhara M, et al.

Seydel A, Weber K, Falk W, Hauschildt S, et al. A refined and translationally relevant model of chronic DSS colitis in BALB/c mice. Laboratory Animals.

2016;**39**(3):237-244

1980;**12**(6):493-498

2015;**63**(1):53-63

2018;**52**(3):240-252

**58**

[125] van Dieren JM, Lambers ME, Kuipers EJ, Samsom JN, van der Woude CJ, Nieuwenhuis EE. Local immune regulation of mucosal inflammation by tacrolimus. Digestive Diseases and Sciences. 2010;**55**(9):2514-2519

[126] Aiko S, Conner EM, Fuseler JA, Grisham MB. Effects of cyclosporine or FK506 in chronic colitis. The Journal of Pharmacology and Experimental Therapeutics. 1997;**280**(2):1075-1084

[127] Aomatsu T, Imaeda H, Takahashi K, Fujimoto T, Kasumi E, Yoden A, et al. Tacrolimus (FK506) suppresses TNF-alpha-induced CCL2 (MCP-1) and CXCL10 (IP-10) expression via the inhibition of p38 MAP kinase activation in human colonic myofibroblasts. International Journal of Molecular Medicine. 2012;**30**(5):1152-1158

[128] Matsumoto S, Otake H, Sekine M, Uehara T, Miyatani H, Mashima H. Appropriate timing of discontinuation of tacrolimus therapy for refractory ulcerative colitis. Clinical Drug Investigation. Aug 2019;**39**(8):737-744

Section 3

Anti-TNF Therapy

**61**
