**5.2 Immune cell signatures of IBD subtypes**

An elaborated knowledge of the inflammatory landscape and immune markers of IBD in circulation and tissues become essential for the effective disease management in IBD subtypes. In this view, Mitsialis *et al.* carried out multidimensional immunophenotyping of colonic mucosa and peripheral blood of IBD (UC & CD) and non-IBD subjects to provide a deep understanding of the disease-specific immunophenotypes in UC and CD (**Figure 2**) [57]. Active ulcerative colitis (UCa) mucosa had relatively more B cells and fewer T cells and cytokine-producing effector memory (EM)-T cell subsets- IFNG+ TNF+ were reduced whereas IL17A++CD161+ subsets were enriched. CXCR3<sup>+</sup> plasmablasts were found to be expanded in UCa. HLA-DR+ CD38+ memory regulatory T cells (mTregs) were also abundant in UCa and co-expressed various chemokine receptors implying an activated memory phenotype. UCa mucosa was enriched with granulocytes expressing chemokine receptors (CXCR3, CCR6) and unconventional granulocyte markers (HLA-DR, CD38, and CD56) described to be up-regulated on granulocytes in other human diseases (**Table 2**).

### **Figure 2.**

*Disease-specific immunosignatures of Crohn's disease (CD) and Ulcerative colitis (UC) mucosa and periphery.*

*Host-Microbiota Interplay in IBD: The Emerging Role of Extracellular Vesicles, Perinatal… DOI: http://dx.doi.org/10.5772/intechopen.104696*


### **Table 2.**

*Disease specific alterations of immune cells in IBD subtypes.*

In case of active Crohn's disease mucosa (CDa), HLA-DR<sup>+</sup> CD38<sup>+</sup> T cells coexpressing IFNG<sup>+</sup> TNF<sup>+</sup> were diminished whereasIL17A<sup>+</sup> HLA-DR<sup>+</sup> CD38<sup>+</sup> CD161<sup>+</sup> DN EM T cells and IL1B<sup>+</sup> HLA-DR<sup>+</sup> CD38<sup>+</sup> T cells demonstrated expansion. IL1B<sup>+</sup> IFNG<sup>+</sup> TNF<sup>+</sup> naïve B-cell clusters were augmented in CDa mucosa and included CD44++ (marker of activated B cells), CCR7+ , AHR<sup>+</sup> , HLA-DR<sup>+</sup> , CD38<sup>+</sup> and CD11C<sup>+</sup> , a marker expressed in B cells and proficient in antigen presentation linked with autoimmunity [57]. Total CD14<sup>+</sup> as well as IL1B+ macrophages/monocytes clusters were increased in peripheral CDa. Innate lymphoid cells (ILCs) signatures could differentiate Crohn's disease from ulcerative colitis. ILC1 and ILC1-like clusters were increased more in the mucosa in case of CDa than UCa whereas ILC3 were specifically reduced in UCa mucosa (**Table 2**). These findings could be explored for targeted therapeutics and possibly harnessed for personalized approaches to IBD therapy in the future.
