**Table 4.**

*Diagnostic criteria for invasive pulmonary aspergillosis (IPA) of patients in ICU (AspICU) or with influenza (IAPA) or SARS-CoV-2 (CAPA) coinfections (PCR: polymerase chain reaction; ICU: intensive care unit; RT-PCR: Real-time polymerase chain reaction; BAL: bronchoalveolar lavage; GM: galactomannan; LFA: lateral flow assay) [31, 125–127].*

#### Aspergillus-*Human Interactions: From the Environment to Clinical Significance DOI: http://dx.doi.org/10.5772/intechopen.98509*

*Aspergillus* endophthalmitis and keratitis, cutaneous aspergillosis, and *Aspergillus* peritonitis, intravenous voriconazole is still the first-line therapy [2]. For IPA in ICU patients, patients with hematological malignancies, or solid organ transplants, IAPA, and CAPA, voriconazole and isavuconazole are still recommended as the first-line treatment (**Table 5**).

Voriconazole is metabolized at the liver via CYP2C19 and CYP3A4 [135]. Medications with CYP2C19 and CYP3A4-dependent metabolism, antacids, proton pump inhibitors may affect serum voriconazole levels [136]. Adverse reactions and toxicity of voriconazole are associated with higher serum voriconazole levels [137]. Common adverse reactions include reversible visual disturbances, hepatotoxicity, photosensitivity, reversible visual or auditory hallucinations, tachyarrhythmias, and QT interval prolongations [137, 138]. Isavuconazole is a second-generation broad-spectrum triazole requiring a loading dose with a five-day half-life [139]. Isavuconazole has fewer adverse reactions in photosensitivity, hepatotoxicity, visual abnormality, and less drug–drug interaction [140–142]. Isavuconazole is a CYP3A4 inhibitor and can decrease the metabolism of sirolimus, tacrolimus, cyclosporine, and digoxin, leading to increased levels of these agents [142]. Furthermore, isavuconazole can induce dose-dependent QTc shortening [143]. Isavuconazole was shown to be non-inferior to voriconazole to treat invasive mold disease from the SECURE trial [144]. Posaconazole is also a broad-spectrum triazole used mainly for prophylaxis and salvage treatment of invasive fungal infections [145]. A suspension form of posaconazole has unpredictable bioavailability and needs a high-fat meal for better absorption [146]. However, tablet and IV formulations overcome this limitation. Posaconazole strongly inhibits CYP3A4 and is metabolized through UGT1A4 [145]. Using CYP3A4 substrates with posaconazole should be cautious [145]. The common adverse effects of posaconazole are gastrointestinal disturbances, hepatotoxicity, rashes, fever, hypokalemia, hypomagnesemia, and QTc prolongation [145].

Amphotericin B, a polyene antifungal agent binding to ergosterol in the fungal cell membrane, has many forms, i.e., conventional with deoxycholate and lipidbased form [2, 147]. Conventional amphotericin B has common adverse effects, including acute reactions after infusion (fever, chills, nausea), phlebitis, hypokalemia, hypomagnesemia, and nephrotoxicity (usually from renal tubular acidosis). The lipid-based form has less nephrotoxicity than the conventional form [2]. Nevertheless, acute infusion reactions may still present in liposomal amphotericin B [148]. In addition, hypokalemia, hypomagnesemia, mild bilirubin, alkaline phosphatase elevations are also present occasionally in lipid-based amphotericin B [2]. Lipid-based amphotericin B is recommended for alternative treatment of invasive aspergillosis in case that azoles cannot be used [2].

Echinocandins, e.g., caspofungin, micafungin, is a non-competitive β-1,3 D-glucan synthase inhibitor leading to loss of fungal cell wall's strength and integrity [149, 150]. Echinocandins have fewer adverse reactions and fewer drug–drug interactions [149, 150]. Echinocandins are recommended for salvage therapy or in azole-resistant *Aspergillus* infections combined with azoles for invasive aspergillosis treatment (**Table 5**) [2, 151–153].

Therapeutic drug monitoring (TDM) of azoles, e.g., voriconazole, posaconazole, isavuconazole, is necessary, especially in elderly patients, obese patients, critically ill patients, and patients with potential azole drug–drug interactions [2]. For treatment of IA, IDSA recommended TDM of voriconazole at a trough level of >1–1.5 μg/mL but less than 5–6 μg/mL to prevent neurotoxicity [2]. American Society of Transplantation Infection Diseases Community of Practice (AST) recommended TDM of posaconazole (suspension and tablet form) and isavuconazole at a trough level of >1–1.25 μg/mL and 2–3 μg/mL, respectively [154]. Timing


Aspergillus-*Human Interactions: From the Environment to Clinical Significance DOI: http://dx.doi.org/10.5772/intechopen.98509*

#### **Table 5.**

*Treatment of invasive pulmonary aspergillosis (IPA) in ICU patients, patients with hematological malignancies, or solid organ transplants, influenza-associated pulmonary aspergillosis (IAPA), and COVID-19 associated pulmonary aspergillosis (CAPA) (AML: acute myeloid leukemia; MDS: myelodysplastic syndrome; HSCT: hematological stem cell transplantation).*

for measuring serum trough concentration of voriconazole, posaconazole, and isavuconazole is at 5–7 days, after 5 days, and within 7 days, respectively [154]. For prophylaxis, International Society for Heart and Lung Transplantation (ISHLT) recommended TDM of voriconazole and posaconazole at a trough level of ≥1 μg/ mL and > 0.7 μg/mL, respectively [155]. Additionally, in CAPA, ECMM/ISHAM

recommended weekly TDM of voriconazole and posaconazole at a trough level of 2–6 μg/mL and 1–3.75 μg/mL, respectively [127].

#### **5. Azole-resistant** *Aspergillus*

#### **5.1 Etiology and clinical significance**

Voriconazole and isavuconazole are the first-line therapy of invasive aspergillosis [2, 129, 130]. Furthermore, azoles, i.e., posaconazole and voriconazole, are also used as prophylaxis of invasive aspergillosis in patients with hematological malignancies and solid organ transplantation [131–134]. Therefore, azoles are important antifungal agents to combat invasive aspergillosis. Unfortunately, azole-resistant *Aspergillus fumigatus* strains are emerging and increasing, leading to increased treatment failure and mortality [156, 157]. The etiology of these emerging azole-resistant *A. fumigatus* (ARAF) may be from the environmental selective pressure associated with azole fungicides in the agricultural area, including Europe, Asia, Latin America, the Midwest, and Southeast states of the USA [158–161]. The supporting evidence of environment-derived ARAF is that ARAF strains were recovered from azole-naive patients [158, 162–165]. In addition, the most common mutations at the *cyp51A* gene (encoding lanosterol 14-α demethylase) causing azole resistance in ARAF strains, which are TR34/L98H and TR46/Y121F/T289A mutations, were also recovered from patients' homes and surroundings [166–171].

Azole fungicides, i.e., bromuconazole, difenoconazole, epoxiconazole, enilconazole, metconazole, prochloraz, propiconazole, prothioconazole-desthio, and tebuconazole, play an important role in the development of environment-derived azole-resistant *Aspergillus* isolates leading to cross resistance to medical azoles [169, 172, 173].

Antifungal susceptibility tests (AST) of *Aspergillus* species are essential for screening azole-resistant *Aspergillus* isolates. The indications to perform *Aspergillus* AST are that the fungus is recovered from sterile sites in regions with high azoleresistant rates, including long-term azole treatment in chronic bronchopulmonary aspergillosis and breakthrough *Aspergillus* infections or recurrent or persistent infections [2, 128, 174].

The standard antifungal susceptibility testing of filamentous fungi to observe the minimum inhibitory concentration (MIC) using broth microdilution assays was described by the Clinical and Laboratory Standards Institute (CLSI) and the European Union Committee on Antimicrobial Susceptibility Testing (EUCAST) [175, 176]. To determine antifungal resistance of *Aspergillus* species, e.g., *A. flavus, A. fumigatus, A. niger, A. terreus,* CLSI and EUCAST utilized two values, which are epidemiological cutoff values (ECVs or ECOFFs) and clinical breakpoints (BP) (**Table 6**). ECVs for CLSI and ECOFFs for EUCAST of each antifungal agent against each *Aspergillus* originate from MIC distribution of the wild-type *Aspergillus* population [175–178]. These values can divide *Aspergillus* strains into two groups, which are wild-type and non-wild-type strains. Non-wild-type strains may resist those antifungal agents [175, 176, 178]. Clinical breakpoints are based on antifungal pharmacodynamics, pharmacokinetics, data from clinical trials, and patient outcomes [175, 176, 178]. Resistance is determined by the MICs over R (resistant) (**Table 6**). For EUCAST, another value is the area of technical uncertainty (ATU), which is the value that needs to be addressed before reporting these results, i.e., repeating the test, using a genotypic test, changing the susceptibility category, or including ATU as a part of the report [176].


#### Aspergillus-*Human Interactions: From the Environment to Clinical Significance DOI: http://dx.doi.org/10.5772/intechopen.98509*

#### **Table 6.**

*Interpretation of antifungal susceptibility tests and epidemiological cutoff values (ECVs) of Aspergillus species according to CLSI M59 and M61, 2020 and EUCAST BP ECOFF version 2, 2020 (S: susceptible, I: intermediate, R: resistant, ATU: Area of Technical Uncertainty) [175–177].*

Molecular methods to detect *CYP51A* mutations, e.g., TR34/L98H, TR46/Y121F, are established by using classic PCRs with sequencing, real-time PCRs, loopmediated isothermal amplification (LAMP), or whole-genome sequencing (WGS) [179]. These molecular methods have a high negative predictive value to rule out these resistant strains' infections [179]. However, they had narrow coverage and mutations at this point depending on association data between mutations and antifungal resistance property. Furthermore, commercial tools are still not approved by the US FDA [179].

#### **5.2 Management of azole-resistant** *Aspergillus* **and novel antifungal candidates**

Overexpression with a tandem repeat in the promoter area (TR34 or TR46) and point mutations (L98H or Y121F/T289A) in the *cyp51A* gene, encoding azole's target called lanosterol 14-α demethylase, would lead to azole resistance in *Aspergillus* 

*fumigatus* including voriconazole and isavuconazole [156, 178]. To treat these azole-resistant *Aspergillus* infections, monotherapy of each azole should be avoided, especially in areas with more than 10% of azole resistance prevalence [180]. In areas with high rates of azole resistance, liposomal amphotericin B and a combination of voriconazole and echinocandin should be considered [2, 127, 128, 156, 180]. Therefore, the prevalence of azole-resistant *Aspergillus* strains using conventional culturing methods together with broth microdilution assays or using molecular biology (RT-PCR) is essential to decide the optimal treatment and to choose suitable antifungal agents to get rid of these infections [156, 179].

From the increased speed of azole-resistant *Aspergillus* strains, novel antifungal agents with high efficacy and fewer side effects are crucial to combat these infections with very high mortality [156]*.* However, discovering these novel antifungal agents has many steps and methods to evaluate both *in vitro* and *in vivo* analyses for both antifungal activity and toxicity [181, 182]. The first step for screening antifungal activity has many methods depending on the screening purpose [181]. To observe the antifungal activity of novel antifungal candidates, the broth microdilution method is the standard method to provide the MICs [183]. This method is perfect for various compounds requiring high throughput assays [181]. Furthermore, this method requires a small number of compounds and can apply to different *Aspergillus* species simultaneously [181]. To observe combinatorial effects between novel antifungal candidates and current antifungal agents, checkerboard assays are used to determine the fractional inhibitory concentration index (FICI) [184, 185]. The FICI is calculated using the sum of the fractional inhibitory concentration (FIC1) of the first compound, which is MIC1 + 2 of the combination of the first and the second compounds divided by MIC1 of the first compound alone, and the FIC2 of the second compound [184, 185]. Synergistic, additive, indifferent, and antagonistic effects are defined by FICI ≤0.5; >0.5–1; >1–4; and > 4, respectively [184–186]. For the cytotoxicity effects on human epithelial cells, many *in vitro* colorimetric assays, including mammalian tissue culture systems and vital dyes, are used, such as Alamar blue, MTT, XTT (tetrazolium) assays [181]. Next steps after *in vitro* studies to prove the antifungal activity and toxicity, *in vivo* animal models are used to study pharmacodynamics and pharmacokinetics, including *in vivo* antifungal activity and *in vivo* toxicity [181]. Then, these antifungal candidates would follow through the clinical trial phase I (safety), phase II (checking effectiveness), phase III (confirming effectiveness, side effects), and get approved [181, 182, 187].

Many novel antifungal compounds against both classical targets and novel targets are in clinical trials (**Table 7**) [262]. Novel targets against *Aspergillus* species include glycosylphosphatidylinositol (GPI) anchor protein, dihydroorotate dehydrogenase in pyrimidine synthesis, fungal mitochondrial respiration chain, siderophore iron transporter, Heat shock protein 90 (Hsp90), calcineurin, histone deacetylase (HDAC), inositol phosphorylceramide (IPC) synthase, chitin synthase, and sphingolipid pathway (**Table 7**). Nevertheless, more clinical trials are on the way for these agents before using them in the clinical practice against antifungal-resistant *Aspergillus/*fungal strains.

In addition, enzymes in the *Aspergillus* trehalose biosynthesis pathway, i.e., trehalose-6-phosphate synthase, trehalose-6-phosphate phosphatase, trehalase enzymes, were identified as important virulence factors, including proteins related to the trehalose pathway, i.e., *Af*SsdA, *Af*TslA [103, 105, 263, 264]. The trehalose pathway in *A. fumigatus* is associated with cell wall integrity and fungal virulence *in vivo* [103, 264, 265]. However, inhibitors of this pathway are still lacking and under-investigated. Validamycin A is one of the inhibitors of trehalase enzymes and was first demonstrated its strong antifungal activity against a plant fungal


#### Aspergillus-*Human Interactions: From the Environment to Clinical Significance DOI: http://dx.doi.org/10.5772/intechopen.98509*


**Table 7.**

*Summary of novel antifungal agents against classical targets and novel targets for Aspergillus infections.*

#### *The Genus* Aspergillus *- Pathogenicity, Mycotoxin Production and Industrial Applications*

Aspergillus-*Human Interactions: From the Environment to Clinical Significance DOI: http://dx.doi.org/10.5772/intechopen.98509*

pathogen, *Rhizoctonia solani* [266–269]. Furthermore, validamycin A has antifungal activity against *Candida albicans* and *Aspergillus flavus* [186, 270]. Validamycin A also possesses combinatorial effects with conventional amphotericin B against *A. flavus* [186]. Nevertheless, *in vivo* experiments are still necessary to verify an antifungal activity of validamycin A. Additionally, the high-osmolarity glycerol (HOG)-mitogen-activated protein kinase (MAPK) signaling pathway is associated with trehalose production and stress response in *A. fumigatus* [271–274]. This signaling pathway may be another good antifungal target to be developed in the future. Therefore, there are many more pathways involved with *Aspergillus* virulence, and there are so many unexplored areas in *Aspergillus* pathogenesis to develop novel antifungal candidates. With this knowledge, we could overcome the shortage of antifungal agents against many more antifungal-resistant *Aspergillus* strains to emerge very soon.

#### **6. Conclusion**

*Aspergillus* species are common fungi found everywhere around humans. They adapt and express many virulence factors to survive inside hosts and cause infections in immunocompromised hosts. Recently, new risk factors that cause severe invasive pulmonary aspergillosis are ICU patients with influenza infections or COVID-19 infections. The diagnosis of invasive aspergillosis, especially without proven tissue or culture evidence, is still challenging. New molecular methods, i.e., nucleic acid assays, lateral flow assays, are introduced for supporting the diagnosis of probable and possible invasive aspergillosis. Nevertheless, voriconazole and isavuconazole are the first-line therapy in IPA in ICU patients, patients with hematological malignancies, patients with IAPA, and CAPA. Furthermore, posaconazole is the principal antifungal agent for the prophylactic treatment of IPA in patients with hematological malignancies. Additionally, emerging azoleresistant *Aspergillus* strains are increasing, and the management against these azole-resistant *Aspergillus* strains is the combination therapy between azoles and echinocandins, including liposomal amphotericin B. Although novel antifungal agents against *Aspergillus* species are on their way, antimicrobial stewardship of existing antifungal agents is also crucial to prevent further breakthrough antifungal-resistant strains in the future. With our better understanding of *Aspergillus* pathogenesis, the shortage of antifungal agents against *Aspergillus* and its resistant strains would no longer be for the better lives of patients suffering from *Aspergillus* infections.

#### **Acknowledgements**

The author would like to thank the Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok and Bamrasnaradura Infectious Diseases Institute (BIDI), Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand for all their supports.

#### **Conflict of interest**

The author declares no conflict of interest.

#### **Author details**

Arsa Thammahong Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand

\*Address all correspondence to: arsa.t@chula.ac.th

© 2021 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.

Aspergillus-*Human Interactions: From the Environment to Clinical Significance DOI: http://dx.doi.org/10.5772/intechopen.98509*

#### **References**

[1] Latge JP, Chamilos G. *Aspergillus fumigatus* and Aspergillosis in 2019. Clin Microbiol Rev. 2019;33(1).

[2] Patterson TF, Thompson GR, 3rd, Denning DW, Fishman JA, Hadley S, Herbrecht R, et al. Practice Guidelines for the Diagnosis and Management of Aspergillosis: 2016 Update by the Infectious Diseases Society of America. Clin Infect Dis. 2016;63(4):e1-e60.

[3] Sugui JA, Kwon-Chung KJ, Juvvadi PR, Latge JP, Steinbach WJ. *Aspergillus fumigatus* and related species. Cold Spring Harb Perspect Med. 2014;5(2):a019786.

[4] Brown GD, Denning DW, Gow NA, Levitz SM, Netea MG, White TC. Hidden killers: human fungal infections. Sci Transl Med. 2012;4(165):165rv13.

[5] Fracchiolla NS, Sciume M, Orofino N, Guidotti F, Grancini A, Cavalca F, et al. Epidemiology and treatment approaches in management of invasive fungal infections in hematological malignancies: Results from a single-centre study. PLoS One. 2019;14(5):e0216715.

[6] Slavin MA, Chakrabarti A. Opportunistic fungal infections in the Asia-Pacific region. Med Mycol. 2012;50(1):18-25.

[7] Kriengkauykiat J, Ito JI, Dadwal SS. Epidemiology and treatment approaches in management of invasive fungal infections. Clin Epidemiol. 2011;3: 175-91.

[8] Pfaller MA, Diekema DJ. Epidemiology of invasive mycoses in North America. Crit Rev Microbiol. 2010;36(1):1-53.

[9] Lehrnbecher T, Frank C, Engels K, Kriener S, Groll AH, Schwabe D. Trends in the postmortem epidemiology of

invasive fungal infections at a university hospital. J Infect. 2010;61(3):259-65.

[10] Chakrabarti A, Chatterjee SS, Das A, Shivaprakash MR. Invasive aspergillosis in developing countries. Med Mycol. 2011;49 Suppl 1:S35-47.

[11] Chakrabarti A, Chatterjee SS, Shivaprakash MR. Overview of opportunistic fungal infections in India. Nihon Ishinkin Gakkai Zasshi. 2008;49(3):165-72.

[12] Thammahong A, Thayidathara P, Suksawat K, Chindamporn A. Epidemiology of invasive Aspergillosis in a tertiary-care hospital of Thailand, 2006-2011. Mycoses. 2012;55:230-.

[13] Graf K, Khani SM, Ott E, Mattner F, Gastmeier P, Sohr D, et al. Five-years surveillance of invasive aspergillosis in a university hospital. BMC Infect Dis. 2011;11:163.

[14] Gangneux JP, Camus C, Philippe B. Epidemiology of invasive aspergillosis and risk factors in non neutropaenic patients. Rev Mal Respir. 2010;27(8): e34-46.

[15] Nucci M, Queiroz-Telles F, Tobon AM, Restrepo A, Colombo AL. Epidemiology of opportunistic fungal infections in Latin America. Clin Infect Dis. 2010;51(5):561-70.

[16] Neofytos D, Fishman JA, Horn D, Anaissie E, Chang CH, Olyaei A, et al. Epidemiology and outcome of invasive fungal infections in solid organ transplant recipients. Transpl Infect Dis. 2010;12(3):220-9.

[17] Kontoyiannis DP, Marr KA, Park BJ, Alexander BD, Anaissie EJ, Walsh TJ, et al. Prospective surveillance for invasive fungal infections in hematopoietic stem cell transplant recipients, 2001-2006: overview of the Transplant-Associated

Infection Surveillance Network (TRANSNET) Database. Clin Infect Dis. 2010;50(8):1091-100.

[18] Pappas PG, Alexander BD, Andes DR, Hadley S, Kauffman CA, Freifeld A, et al. Invasive fungal infections among organ transplant recipients: results of the Transplant-Associated Infection Surveillance Network (TRANSNET). Clin Infect Dis. 2010;50(8):1101-11.

[19] Neofytos D, Horn D, Anaissie E, Steinbach W, Olyaei A, Fishman J, et al. Epidemiology and outcome of invasive fungal infection in adult hematopoietic stem cell transplant recipients: analysis of Multicenter Prospective Antifungal Therapy (PATH) Alliance registry. Clin Infect Dis. 2009;48(3):265-73.

[20] Azie N, Neofytos D, Pfaller M, Meier-Kriesche HU, Quan SP, Horn D. The PATH (Prospective Antifungal Therapy) Alliance(R) registry and invasive fungal infections: update 2012. Diagnostic microbiology and infectious disease. 2012;73(4):293-300.

[21] Robin C, Cordonnier C, Sitbon K, Raus N, Lortholary O, Maury S, et al. Mainly Post-Transplant Factors Are Associated with Invasive Aspergillosis after Allogeneic Stem Cell Transplantation: A Study from the Surveillance des Aspergilloses Invasives en France and Societe Francophone de Greffe de Moelle et de Therapie Cellulaire. Biol Blood Marrow Transplant. 2019;25(2):354-61.

[22] Siopi M, Karakatsanis S, Roumpakis C, Korantanis K, Sambatakou H, Sipsas NV, et al. A Prospective Multicenter Cohort Surveillance Study of Invasive Aspergillosis in Patients with Hematologic Malignancies in Greece: Impact of the Revised EORTC/MSGERC 2020 Criteria. J Fungi (Basel). 2021;7(1).

[23] Herbrecht R, Bories P, Moulin JC, Ledoux MP, Letscher-Bru V. Risk

stratification for invasive aspergillosis in immunocompromised patients. Ann N Y Acad Sci. 2012;1272:23-30.

[24] Ghez D, Calleja A, Protin C, Baron M, Ledoux MP, Damaj G, et al. Early-onset invasive aspergillosis and other fungal infections in patients treated with ibrutinib. Blood. 2018;131(17):1955-9.

[25] Chamilos G, Lionakis MS, Kontoyiannis DP. Call for Action: Invasive Fungal Infections Associated With Ibrutinib and Other Small Molecule Kinase Inhibitors Targeting Immune Signaling Pathways. Clin Infect Dis. 2018;66(1):140-8.

[26] Bazaz R, Denning DW. Subacute Invasive Aspergillosis Associated With Sorafenib Therapy for Hepatocellular Carcinoma. Clin Infect Dis. 2018;67(1): 156-7.

[27] Hill JA, Li D, Hay KA, Green ML, Cherian S, Chen X, et al. Infectious complications of CD19-targeted chimeric antigen receptor-modified T-cell immunotherapy. Blood. 2018;131(1):121-30.

[28] Park JH, Romero FA, Taur Y, Sadelain M, Brentjens RJ, Hohl TM, et al. Cytokine Release Syndrome Grade as a Predictive Marker for Infections in Patients With Relapsed or Refractory B-Cell Acute Lymphoblastic Leukemia Treated With Chimeric Antigen Receptor T Cells. Clin Infect Dis. 2018;67(4):533-40.

[29] Benjamim CF, Lundy SK, Lukacs NW, Hogaboam CM, Kunkel SL. Reversal of long-term sepsis-induced immunosuppression by dendritic cells. Blood. 2005;105(9):3588-95.

[30] Taccone FS, Van den Abeele AM, Bulpa P, Misset B, Meersseman W, Cardoso T, et al. Epidemiology of invasive aspergillosis in critically ill patients: clinical presentation,

Aspergillus-*Human Interactions: From the Environment to Clinical Significance DOI: http://dx.doi.org/10.5772/intechopen.98509*

underlying conditions, and outcomes. Crit Care. 2015;19:7.

[31] Schauwvlieghe A, Rijnders BJA, Philips N, Verwijs R, Vanderbeke L, Van Tienen C, et al. Invasive aspergillosis in patients admitted to the intensive care unit with severe influenza: a retrospective cohort study. Lancet Respir Med. 2018;6(10):782-92.

[32] Huang L, Zhang Y, Hua L, Zhan Q. Diagnostic value of galactomannan test in non-immunocompromised critically ill patients with influenza-associated aspergillosis: data from three consecutive influenza seasons. Eur J Clin Microbiol Infect Dis. 2021.

[33] Waldeck F, Boroli F, Suh N, Wendel Garcia PD, Flury D, Notter J, et al. Influenza-associated aspergillosis in critically-ill patients-a retrospective bicentric cohort study. Eur J Clin Microbiol Infect Dis. 2020;39(10): 1915-23.

[34] van de Veerdonk FL, Kolwijck E, Lestrade PP, Hodiamont CJ, Rijnders BJ, van Paassen J, et al. Influenza-Associated Aspergillosis in Critically Ill Patients. Am J Respir Crit Care Med. 2017;196(4):524-7.

[35] Cornillet A, Camus C, Nimubona S, Gandemer V, Tattevin P, Belleguic C, et al. Comparison of epidemiological, clinical, and biological features of invasive aspergillosis in neutropenic and nonneutropenic patients: a 6-year survey. Clin Infect Dis. 2006;43(5): 577-84.

[36] Jenks JD, Nam HH, Hoenigl M. Invasive aspergillosis in critically ill patients: Review of definitions and diagnostic approaches. Mycoses. 2021.

[37] Arastehfar A, Carvalho A, van de Veerdonk FL, Jenks JD, Koehler P, Krause R, et al. COVID-19 Associated Pulmonary Aspergillosis (CAPA)-From Immunology to Treatment. J Fungi (Basel). 2020;6(2).

[38] Mohamed A, Rogers TR, Talento AF. COVID-19 Associated Invasive Pulmonary Aspergillosis: Diagnostic and Therapeutic Challenges. J Fungi (Basel). 2020;6(3).

[39] Lai CC, Yu WL. COVID-19 associated with pulmonary aspergillosis: A literature review. J Microbiol Immunol Infect. 2021;54(1):46-53.

[40] Apostolopoulou A, Esquer Garrigos Z, Vijayvargiya P, Lerner AH, Farmakiotis D. Invasive Pulmonary Aspergillosis in Patients with SARS-CoV-2 Infection: A Systematic Review of the Literature. Diagnostics (Basel). 2020;10(10).

[41] Marr KA, Platt A, Tornheim JA, Zhang SX, Datta K, Cardozo C, et al. Aspergillosis Complicating Severe Coronavirus Disease. Emerg Infect Dis. 2021;27(1).

[42] Machado M, Valerio M, Alvarez-Uria A, Olmedo M, Veintimilla C, Padilla B, et al. Invasive pulmonary aspergillosis in the COVID-19 era: An expected new entity. Mycoses. 2021;64(2):132-43.

[43] Costantini C, van de Veerdonk FL, Romani L. Covid-19-Associated Pulmonary Aspergillosis: The Other Side of the Coin. Vaccines (Basel). 2020;8(4).

[44] Koehler P, Bassetti M, Chakrabarti A, Chen SCA, Colombo AL, Hoenigl M, et al. Defining and managing COVID-19-associated pulmonary aspergillosis: the 2020 ECMM/ISHAM consensus criteria for research and clinical guidance. Lancet Infect Dis. 2020.

[45] Chong WH, Neu KP. The Incidence, Diagnosis, and Outcomes of COVID-19 associated Pulmonary Aspergillosis (CAPA): A Systematic Review. J Hosp Infect. 2021.

[46] Mitaka H, Kuno T, Takagi H, Patrawalla P. Incidence and Mortality of COVID-19-associated Pulmonary Aspergillosis: A Systematic Review and Meta-analysis. Mycoses. 2021.

[47] Hohl TM, Feldmesser M. *Aspergillus fumigatus*: principles of pathogenesis and host defense. Eukaryot Cell. 2007;6(11):1953-63.

[48] O'Meara TR, Cowen LE. Hsp90 dependent regulatory circuitry controlling temperature-dependent fungal development and virulence. Cell Microbiol. 2014;16(4):473-81.

[49] Robbins N, Uppuluri P, Nett J, Rajendran R, Ramage G, Lopez-Ribot JL, et al. Hsp90 governs dispersion and drug resistance of fungal biofilms. PLoS Pathog. 2011;7(9): e1002257.

[50] Schneider A, Blatzer M, Posch W, Schubert R, Lass-Florl C, Schmidt S, et al. *Aspergillus fumigatus* responds to natural killer (NK) cells with upregulation of stress related genes and inhibits the immunoregulatory function of NK cells. Oncotarget. 2016;7(44): 71062-71.

[51] Friedrich D, Fecher RA, Rupp J, Deepe GS, Jr. Impact of HIF-1alpha and hypoxia on fungal growth characteristics and fungal immunity. Microbes Infect. 2017;19(3):204-9.

[52] Barker BM, Kroll K, Vodisch M, Mazurie A, Kniemeyer O, Cramer RA. Transcriptomic and proteomic analyses of the *Aspergillus fumigatus* hypoxia response using an oxygen-controlled fermenter. BMC genomics. 2012;13:62.

[53] Blatzer M, Barker BM, Willger SD, Beckmann N, Blosser SJ, Cornish EJ, et al. SREBP coordinates iron and ergosterol homeostasis to mediate triazole drug and hypoxia responses in the human fungal pathogen *Aspergillus fumigatus*. PLoS Genet. 2011;7(12): e1002374.

[54] Chung D, Barker BM, Carey CC, Merriman B, Werner ER, Lechner BE, et al. ChIP-seq and in vivo transcriptome analyses of the *Aspergillus fumigatus* SREBP SrbA reveals a new regulator of the fungal hypoxia response and virulence. PLoS Pathog. 2014;10(11): e1004487.

[55] Losada L, Barker BM, Pakala S, Pakala S, Joardar V, Zafar N, et al. Large-scale transcriptional response to hypoxia in *Aspergillus fumigatus* observed using RNAseq identifies a novel hypoxia regulated ncRNA. Mycopathologia. 2014;178(5-6):331-9.

[56] Vodisch M, Scherlach K, Winkler R, Hertweck C, Braun HP, Roth M, et al. Analysis of the *Aspergillus fumigatus* proteome reveals metabolic changes and the activation of the pseurotin A biosynthesis gene cluster in response to hypoxia. J Proteome Res. 2011;10(5): 2508-24.

[57] Shibuya K, Paris S, Ando T, Nakayama H, Hatori T, Latge JP. Catalases of *Aspergillus fumigatus* and inflammation in aspergillosis. Nihon Ishinkin Gakkai Zasshi. 2006;47(4): 249-55.

[58] Paris S, Wysong D, Debeaupuis JP, Shibuya K, Philippe B, Diamond RD, et al. Catalases of *Aspergillus fumigatus*. Infect Immun. 2003;71(6):3551-62.

[59] Lambou K, Lamarre C, Beau R, Dufour N, Latge JP. Functional analysis of the superoxide dismutase family in *Aspergillus fumigatus*. Mol Microbiol. 2010;75(4):910-23.

[60] Kurucz V, Kruger T, Antal K, Dietl AM, Haas H, Pocsi I, et al. Additional oxidative stress reroutes the global response of *Aspergillus fumigatus* to iron depletion. BMC genomics. 2018;19(1):357.

[61] Burns C, Geraghty R, Neville C, Murphy A, Kavanagh K, Doyle S.

Aspergillus-*Human Interactions: From the Environment to Clinical Significance DOI: http://dx.doi.org/10.5772/intechopen.98509*

Identification, cloning, and functional expression of three glutathione transferase genes from *Aspergillus fumigatus*. Fungal Genet Biol. 2005;42(4):319-27.

[62] Grahl N, Dinamarco TM, Willger SD, Goldman GH, Cramer RA. *Aspergillus fumigatus* mitochondrial electron transport chain mediates oxidative stress homeostasis, hypoxia responses and fungal pathogenesis. Mol Microbiol. 2012;84(2):383-99.

[63] Leal SM, Jr., Vareechon C, Cowden S, Cobb BA, Latge JP, Momany M, et al. Fungal antioxidant pathways promote survival against neutrophils during infection. J Clin Invest. 2012;122(7):2482-98.

[64] Macheleidt J, Mattern DJ, Fischer J, Netzker T, Weber J, Schroeckh V, et al. Regulation and Role of Fungal Secondary Metabolites. Annu Rev Genet. 2016;50:371-92.

[65] Valiante V. The Cell Wall Integrity Signaling Pathway and Its Involvement in Secondary Metabolite Production. J Fungi (Basel). 2017;3(4).

[66] Raffa N, Keller NP. A call to arms: Mustering secondary metabolites for success and survival of an opportunistic pathogen. PLoS Pathog. 2019;15(4): e1007606.

[67] Amitani R, Taylor G, Elezis EN, Llewellyn-Jones C, Mitchell J, Kuze F, et al. Purification and characterization of factors produced by *Aspergillus fumigatus* which affect human ciliated respiratory epithelium. Infect Immun. 1995;63(9):3266-71.

[68] Sugui JA, Pardo J, Chang YC, Zarember KA, Nardone G, Galvez EM, et al. Gliotoxin is a virulence factor of *Aspergillus fumigatus*: gliP deletion attenuates virulence in mice immunosuppressed with hydrocortisone. Eukaryot Cell. 2007;6(9):1562-9.

[69] Spikes S, Xu R, Nguyen CK, Chamilos G, Kontoyiannis DP, Jacobson RH, et al. Gliotoxin production in *Aspergillus fumigatus* contributes to host-specific differences in virulence. J Infect Dis. 2008;197(3):479-86.

[70] Scharf DH, Heinekamp T, Remme N, Hortschansky P, Brakhage AA, Hertweck C. Biosynthesis and function of gliotoxin in *Aspergillus fumigatus*. Appl Microbiol Biotechnol. 2012;93(2):467-72.

[71] Brown R, Priest E, Naglik JR, Richardson JP. Fungal Toxins and Host Immune Responses. Frontiers in microbiology. 2021;12:643639.

[72] Amare MG, Keller NP. Molecular mechanisms of *Aspergillus flavus* secondary metabolism and development. Fungal Genet Biol. 2014;66:11-8.

[73] Amaike S, Keller NP. *Aspergillus flavus*. Annu Rev Phytopathol. 2011;49:107-33.

[74] Fuller KK, Dunlap JC, Loros JJ. Light-regulated promoters for tunable, temporal, and affordable control of fungal gene expression. Appl Microbiol Biotechnol. 2018;102(9):3849-63.

[75] Fuller KK, Ringelberg CS, Loros JJ, Dunlap JC. The fungal pathogen *Aspergillus fumigatus* regulates growth, metabolism, and stress resistance in response to light. mBio. 2013;4(2).

[76] Fuller KK, Cramer RA, Zegans ME, Dunlap JC, Loros JJ. *Aspergillus fumigatus* Photobiology Illuminates the Marked Heterogeneity between Isolates. mBio. 2016;7(5).

[77] Chen S, Fuller KK, Dunlap JC, Loros JJ. Circadian Clearance of a Fungal Pathogen from the Lung Is Not Based on Cell-intrinsic Macrophage Rhythms. J Biol Rhythms. 2018;33(1): 99-105.

[78] Sriranganadane D, Waridel P, Salamin K, Reichard U, Grouzmann E, Neuhaus JM, et al. *Aspergillus* protein degradation pathways with different secreted protease sets at neutral and acidic pH. J Proteome Res. 2010;9(7):3511-9.

[79] Ries LN, Beattie SR, Espeso EA, Cramer RA, Goldman GH. Diverse Regulation of the CreA Carbon Catabolite Repressor in *Aspergillus nidulans*. Genetics. 2016;203(1):335-52.

[80] Beattie SR, Mark KMK, Thammahong A, Ries LNA, Dhingra S, Caffrey-Carr AK, et al. Filamentous fungal carbon catabolite repression supports metabolic plasticity and stress responses essential for disease progression. PLoS Pathog. 2017;13(4): e1006340.

[81] de Assis LJ, Manfiolli A, Mattos E, Fabri J, Malavazi I, Jacobsen ID, et al. Protein Kinase A and High-Osmolarity Glycerol Response Pathways Cooperatively Control Cell Wall Carbohydrate Mobilization in *Aspergillus fumigatus*. mBio. 2018;9(6).

[82] Panepinto JC, Oliver BG, Fortwendel JR, Smith DL, Askew DS, Rhodes JC. Deletion of the *Aspergillus fumigatus* gene encoding the Ras-related protein RhbA reduces virulence in a model of Invasive pulmonary aspergillosis. Infect Immun. 2003;71(5):2819-26.

[83] Dietl AM, Amich J, Leal S, Beckmann N, Binder U, Beilhack A, et al. Histidine biosynthesis plays a crucial role in metal homeostasis and virulence of *Aspergillus fumigatus*. Virulence. 2016;7(4):465-76.

[84] Hensel M, Arst HN, Jr., Aufauvre-Brown A, Holden DW. The role of the *Aspergillus fumigatus* areA gene in invasive pulmonary aspergillosis. Molecular & general genetics: MGG. 1998;258(5):553-7.

[85] Blatzer M, Latge JP. Metalhomeostasis in the pathobiology of the opportunistic human fungal pathogen *Aspergillus fumigatus*. Curr Opin Microbiol. 2017;40:152-9.

[86] Fleck CB, Schobel F, Brock M. Nutrient acquisition by pathogenic fungi: nutrient availability, pathway regulation, and differences in substrate utilization. Int J Med Microbiol. 2011;301(5):400-7.

[87] Zacharias CA, Sheppard DC. The role of *Aspergillus fumigatus* polysaccharides in host-pathogen interactions. Curr Opin Microbiol. 2019;52:20-6.

[88] Hatinguais R, Willment JA, Brown GD. PAMPs of the Fungal Cell Wall and Mammalian PRRs. Curr Top Microbiol Immunol. 2020;425:187-223.

[89] Ahamefula Osibe D, Lei S, Wang B, Jin C, Fang W. Cell wall polysaccharides from pathogenic fungi for diagnosis of fungal infectious disease. Mycoses. 2020;63(7):644-52.

[90] Fontaine T, Latge JP. Galactomannan Produced by *Aspergillus fumigatus*: An Update on the Structure, Biosynthesis and Biological Functions of an Emblematic Fungal Biomarker. J Fungi (Basel). 2020;6(4).

[91] Beauvais A, Latge JP. Special Issue: Fungal Cell Wall. J Fungi (Basel). 2018;4(3).

[92] Gow NAR, Latge JP, Munro CA. The Fungal Cell Wall: Structure, Biosynthesis, and Function. Microbiol Spectr. 2017;5(3).

[93] Valsecchi I, Lai JI, Stephen-Victor E, Pille A, Beaussart A, Lo V, et al. Assembly and disassembly of *Aspergillus fumigatus* conidial rodlets. Cell Surf. 2019;5:100023.

Aspergillus-*Human Interactions: From the Environment to Clinical Significance DOI: http://dx.doi.org/10.5772/intechopen.98509*

[94] Valsecchi I, Dupres V, Stephen-Victor E, Guijarro JI, Gibbons J, Beau R, et al. Role of Hydrophobins in *Aspergillus fumigatus*. J Fungi (Basel). 2017;4(1).

[95] Valsecchi I, Dupres V, Michel JP, Duchateau M, Matondo M, Chamilos G, et al. The puzzling construction of the conidial outer layer of *Aspergillus fumigatus*. Cell Microbiol. 2019;21(5):e12994.

[96] Tsai HF, Wheeler MH, Chang YC, Kwon-Chung KJ. A developmentally regulated gene cluster involved in conidial pigment biosynthesis in *Aspergillus fumigatus*. J Bacteriol. 1999;181(20):6469-77.

[97] Bayry J, Beaussart A, Dufrene YF, Sharma M, Bansal K, Kniemeyer O, et al. Surface structure characterization of *Aspergillus fumigatus* conidia mutated in the melanin synthesis pathway and their human cellular immune response. Infect Immun. 2014;82(8):3141-53.

[98] Fontaine T, Delangle A, Simenel C, Coddeville B, van Vliet SJ, van Kooyk Y, et al. Galactosaminogalactan, a new immunosuppressive polysaccharide of *Aspergillus fumigatus*. PLoS Pathog. 2011;7(11):e1002372.

[99] Briard B, Muszkieta L, Latge JP, Fontaine T. Galactosaminogalactan of *Aspergillus fumigatus*, a bioactive fungal polymer. Mycologia. 2016;108(3):572-80.

[100] Gravelat FN, Beauvais A, Liu H, Lee MJ, Snarr BD, Chen D, et al. *Aspergillus* galactosaminogalactan mediates adherence to host constituents and conceals hyphal beta-glucan from the immune system. PLoS Pathog. 2013;9(8):e1003575.

[101] Lee MJ, Geller AM, Bamford NC, Liu H, Gravelat FN, Snarr BD, et al. Deacetylation of Fungal Exopolysaccharide Mediates Adhesion and Biofilm Formation. mBio. 2016;7(2):e00252-16.

[102] Lee MJ, Liu H, Barker BM, Snarr BD, Gravelat FN, Al Abdallah Q, et al. The Fungal Exopolysaccharide Galactosaminogalactan Mediates Virulence by Enhancing Resistance to Neutrophil Extracellular Traps. PLoS Pathog. 2015;11(10):e1005187.

[103] Thammahong A, Caffrey-Card AK, Dhingra S, Obar JJ, Cramer RA. *Aspergillus fumigatus* Trehalose-Regulatory Subunit Homolog Moonlights To Mediate Cell Wall Homeostasis through Modulation of Chitin Synthase Activity. mBio. 2017;8(2).

[104] Thammahong A, Puttikamonkul S, Perfect JR, Brennan RG, Cramer RA. Central Role of the Trehalose Biosynthesis Pathway in the Pathogenesis of Human Fungal Infections: Opportunities and Challenges for Therapeutic Development. Microbiol Mol Biol Rev. 2017;81(2).

[105] Thammahong A, Dhingra S, Bultman KM, Kerkaert JD, Cramer RA. An Ssd1 Homolog Impacts Trehalose and Chitin Biosynthesis and Contributes to Virulence in *Aspergillus fumigatus*. mSphere. 2019;4(3).

[106] Pirofski LA, Casadevall A. The damage-response framework of microbial pathogenesis and infectious diseases. Adv Exp Med Biol. 2008;635:135-46.

[107] Park SJ, Mehrad B. Innate immunity to *Aspergillus* species. Clin Microbiol Rev. 2009;22(4):535-51.

[108] Moldoveanu B, Gearhart AM, Jalil BA, Saad M, Guardiola JJ. Pulmonary Aspergillosis: Spectrum of Disease. Am J Med Sci. 2021;361(4): 411-9.

[109] Donnelly JP, Chen SC, Kauffman CA, Steinbach WJ, Baddley JW, Verweij PE, et al. Revision and Update of the Consensus Definitions of Invasive Fungal Disease From the European Organization for Research and Treatment of Cancer and the Mycoses Study Group Education and Research Consortium. Clin Infect Dis. 2020;71(6):1367-76.

[110] Walsh TJ, Hayden RT, Larone DH. Larone's medically important fungi: a guide to identification2018.

[111] Park SY, Kim SH, Choi SH, Sung H, Kim MN, Woo JH, et al. Clinical and radiological features of invasive pulmonary aspergillosis in transplant recipients and neutropenic patients. Transpl Infect Dis. 2010;12(4):309-15.

[112] de Heer K, Gerritsen MG, Visser CE, Leeflang MM. Galactomannan detection in bronchoalveolar lavage fluid for invasive aspergillosis in immunocompromised patients. Cochrane Database Syst Rev. 2019;5:CD012399.

[113] Leeflang MM, Debets-Ossenkopp YJ, Wang J, Visser CE, Scholten RJ, Hooft L, et al. Galactomannan detection for invasive aspergillosis in immunocompromised patients. Cochrane Database Syst Rev. 2015(12):CD007394.

[114] Chong GM, Maertens JA, Lagrou K, Driessen GJ, Cornelissen JJ, Rijnders BJ. Diagnostic Performance of Galactomannan Antigen Testing in Cerebrospinal Fluid. J Clin Microbiol. 2016;54(2):428-31.

[115] Duarte RF, Sanchez-Ortega I, Cuesta I, Arnan M, Patino B, Fernandez de Sevilla A, et al. Serum galactomannan-based early detection of invasive aspergillosis in hematology patients receiving effective antimold prophylaxis. Clin Infect Dis. 2014;59(12):1696-702.

[116] Cruciani M, White PL, Mengoli C, Loffler J, Morton CO, Klingspor L, et al. The impact of anti-mould prophylaxis on *Aspergillus* PCR blood testing for the diagnosis of invasive aspergillosis. J Antimicrob Chemother. 2021;76(3): 635-8.

[117] Mikulska M, Furfaro E, De Carolis E, Drago E, Pulzato I, Borghesi ML, et al. Use of *Aspergillus fumigatus* real-time PCR in bronchoalveolar lavage samples (BAL) for diagnosis of invasive aspergillosis, including azole-resistant cases, in high risk haematology patients: the need for a combined use with galactomannan. Med Mycol. 2019;57(8):987-96.

[118] Heldt S, Prattes J, Eigl S, Spiess B, Flick H, Rabensteiner J, et al. Diagnosis of invasive aspergillosis in hematological malignancy patients: Performance of cytokines, Asp LFD, and *Aspergillus* PCR in same day blood and bronchoalveolar lavage samples. J Infect. 2018;77(3):235-41.

[119] Shokouhi S, Mirzaei J, Sajadi MM, Javadi A. Comparison of serum PCR assay and histopathology for the diagnosis of invasive aspergillosis and mucormycosis in immunocompromised patients with sinus involvement. Curr Med Mycol. 2016;2(4):46-8.

[120] Dannaoui E, Gabriel F, Gaboyard M, Lagardere G, Audebert L, Quesne G, et al. Molecular Diagnosis of Invasive Aspergillosis and Detection of Azole Resistance by a Newly Commercialized PCR Kit. J Clin Microbiol. 2017;55(11):3210-8.

[121] White PL, Wingard JR, Bretagne S, Loffler J, Patterson TF, Slavin MA, et al. *Aspergillus* Polymerase Chain Reaction: Systematic Review of Evidence for Clinical Use in Comparison With Antigen Testing. Clin Infect Dis. 2015;61(8):1293-303.

[122] Freeman Weiss Z, Leon A, Koo S. The Evolving Landscape of Fungal

Aspergillus-*Human Interactions: From the Environment to Clinical Significance DOI: http://dx.doi.org/10.5772/intechopen.98509*

Diagnostics, Current and Emerging Microbiological Approaches. J Fungi (Basel). 2021;7(2).

[123] Loeffler J, Mengoli C, Springer J, Bretagne S, Cuenca-Estrella M, Klingspor L, et al. Analytical Comparison of In Vitro-Spiked Human Serum and Plasma for PCR-Based Detection of *Aspergillus fumigatus* DNA: a Study by the European *Aspergillus* PCR Initiative. J Clin Microbiol. 2015;53(9): 2838-45.

[124] White PL, Barnes RA, Springer J, Klingspor L, Cuenca-Estrella M, Morton CO, et al. Clinical Performance of *Aspergillus* PCR for Testing Serum and Plasma: a Study by the European *Aspergillus* PCR Initiative. J Clin Microbiol. 2015;53(9):2832-7.

[125] Blot SI, Taccone FS, Van den Abeele AM, Bulpa P, Meersseman W, Brusselaers N, et al. A clinical algorithm to diagnose invasive pulmonary aspergillosis in critically ill patients. Am J Respir Crit Care Med. 2012;186(1): 56-64.

[126] Verweij PE, Rijnders BJA, Bruggemann RJM, Azoulay E, Bassetti M, Blot S, et al. Review of influenza-associated pulmonary aspergillosis in ICU patients and proposal for a case definition: an expert opinion. Intensive Care Med. 2020;46(8):1524-35.

[127] Koehler P, Bassetti M, Chakrabarti A, Chen SCA, Colombo AL, Hoenigl M, et al. Defining and managing COVID-19-associated pulmonary aspergillosis: the 2020 ECMM/ISHAM consensus criteria for research and clinical guidance. The Lancet Infectious Diseases. 2020.

[128] Ullmann AJ, Aguado JM, Arikan-Akdagli S, Denning DW, Groll AH, Lagrou K, et al. Diagnosis and management of *Aspergillus* diseases: executive summary of the 2017

ESCMID-ECMM-ERS guideline. Clin Microbiol Infect. 2018;24 Suppl 1:e1-e38.

[129] Cuenca-Estrella M, Kett DH, Wauters J. Defining standards of CARE for invasive fungal diseases in the ICU. J Antimicrob Chemother. 2019;74(Suppl 2):ii9-ii15.

[130] Azoulay E, Afessa B. Diagnostic criteria for invasive pulmonary aspergillosis in critically ill patients. Am J Respir Crit Care Med. 2012;186(1): 8-10.

[131] Tissot F, Agrawal S, Pagano L, Petrikkos G, Groll AH, Skiada A, et al. ECIL-6 guidelines for the treatment of invasive candidiasis, aspergillosis and mucormycosis in leukemia and hematopoietic stem cell transplant patients. Haematologica. 2017;102(3): 433-44.

[132] Maertens JA, Girmenia C, Bruggemann RJ, Duarte RF, Kibbler CC, Ljungman P, et al. European guidelines for primary antifungal prophylaxis in adult haematology patients: summary of the updated recommendations from the European Conference on Infections in Leukaemia. J Antimicrob Chemother. 2018;73(12):3221-30.

[133] Wang J, Zhou M, Xu JY, Zhou RF, Chen B, Wan Y. Comparison of Antifungal Prophylaxis Drugs in Patients With Hematological Disease or Undergoing Hematopoietic Stem Cell Transplantation: A Systematic Review and Network Meta-analysis. JAMA Netw Open. 2020;3(10):e2017652.

[134] Garcia-Vidal C, Carratala J, Lortholary O. Defining standards of CARE for invasive fungal diseases in solid organ transplant patients. J Antimicrob Chemother. 2019;74(Suppl 2):ii16-ii20.

[135] Dolton MJ, McLachlan AJ. Voriconazole pharmacokinetics and exposure-response relationships:

assessing the links between exposure, efficacy and toxicity. Int J Antimicrob Agents. 2014;44(3):183-93.

[136] Mikus G, Scholz IM, Weiss J. Pharmacogenomics of the triazole antifungal agent voriconazole. Pharmacogenomics. 2011;12(6):861-72.

[137] Mitsani D, Nguyen MH, Shields RK, Toyoda Y, Kwak EJ, Silveira FP, et al. Prospective, observational study of voriconazole therapeutic drug monitoring among lung transplant recipients receiving prophylaxis: factors impacting levels of and associations between serum troughs, efficacy, and toxicity. Antimicrob Agents Chemother. 2012;56(5):2371-7.

[138] Elewa H, El-Mekaty E, El-Bardissy A, Ensom MH, Wilby KJ. Therapeutic Drug Monitoring of Voriconazole in the Management of Invasive Fungal Infections: A Critical Review. Clin Pharmacokinet. 2015;54(12):1223-35.

[139] Miceli MH, Kauffman CA. Isavuconazole: A New Broad-Spectrum Triazole Antifungal Agent. Clin Infect Dis. 2015;61(10):1558-65.

[140] Falci DR, Pasqualotto AC. Profile of isavuconazole and its potential in the treatment of severe invasive fungal infections. Infect Drug Resist. 2013;6:163-74.

[141] Livermore J, Hope W. Evaluation of the pharmacokinetics and clinical utility of isavuconazole for treatment of invasive fungal infections. Expert Opin Drug Metab Toxicol. 2012;8(6):759-65.

[142] Ellsworth M, Ostrosky-Zeichner L. Isavuconazole: Mechanism of Action, Clinical Efficacy, and Resistance. J Fungi (Basel). 2020;6(4).

[143] Keirns J, Desai A, Kowalski D, Lademacher C, Mujais S, Parker B, et al. QT Interval Shortening With Isavuconazole: In Vitro and In Vivo Effects on Cardiac Repolarization. Clin Pharmacol Ther. 2017;101(6):782-90.

[144] Maertens JA, Raad, II, Marr KA, Patterson TF, Kontoyiannis DP, Cornely OA, et al. Isavuconazole versus voriconazole for primary treatment of invasive mould disease caused by *Aspergillus* and other filamentous fungi (SECURE): a phase 3, randomisedcontrolled, non-inferiority trial. Lancet. 2016;387(10020):760-9.

[145] Van Daele R, Spriet I, Maertens J. Posaconazole in prophylaxis and treatment of invasive fungal infections: a pharmacokinetic, pharmacodynamic and clinical evaluation. Expert Opin Drug Metab Toxicol. 2020;16(7):539-50.

[146] Courtney R, Wexler D, Radwanski E, Lim J, Laughlin M. Effect of food on the relative bioavailability of two oral formulations of posaconazole in healthy adults. Br J Clin Pharmacol. 2004;57(2):218-22.

[147] Anderson TM, Clay MC, Cioffi AG, Diaz KA, Hisao GS, Tuttle MD, et al. Amphotericin forms an extramembranous and fungicidal sterol sponge. Nat Chem Biol. 2014;10(5):400-6.

[148] Roden MM, Nelson LD, Knudsen TA, Jarosinski PF, Starling JM, Shiflett SE, et al. Triad of acute infusion-related reactions associated with liposomal amphotericin B: analysis of clinical and epidemiological characteristics. Clin Infect Dis. 2003;36(10):1213-20.

[149] Chen SC, Slavin MA, Sorrell TC. Echinocandin antifungal drugs in fungal infections: a comparison. Drugs. 2011;71(1):11-41.

[150] Denning DW. Echinocandin antifungal drugs. Lancet. 2003; 362(9390):1142-51.

Aspergillus-*Human Interactions: From the Environment to Clinical Significance DOI: http://dx.doi.org/10.5772/intechopen.98509*

[151] Wurthwein G, Cornely OA, Trame MN, Vehreschild JJ, Vehreschild MJ, Farowski F, et al. Population pharmacokinetics of escalating doses of caspofungin in a phase II study of patients with invasive aspergillosis. Antimicrob Agents Chemother. 2013;57(4):1664-71.

[152] Hiemenz JW, Raad, II, Maertens JA, Hachem RY, Saah AJ, Sable CA, et al. Efficacy of caspofungin as salvage therapy for invasive aspergillosis compared to standard therapy in a historical cohort. Eur J Clin Microbiol Infect Dis. 2010;29(11): 1387-94.

[153] Heinz WJ, Buchheidt D, Ullmann AJ. Clinical evidence for caspofungin monotherapy in the first-line and salvage therapy of invasive *Aspergillus* infections. Mycoses. 2016;59(8):480-93.

[154] Husain S, Camargo JF. Invasive Aspergillosis in solid-organ transplant recipients: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice. Clin Transplant. 2019;33(9): e13544.

[155] Husain S, Sole A, Alexander BD, Aslam S, Avery R, Benden C, et al. The 2015 International Society for Heart and Lung Transplantation Guidelines for the management of fungal infections in mechanical circulatory support and cardiothoracic organ transplant recipients: Executive summary. J Heart Lung Transplant. 2016;35(3):261-82.

[156] Jeanvoine A, Rocchi S, Bellanger AP, Reboux G, Millon L. Azole-resistant *Aspergillus fumigatus*: A global phenomenon originating in the environment? Med Mal Infect. 2020;50(5):389-95.

[157] Berkow EL, Nunnally NS, Bandea A, Kuykendall R, Beer K, Lockhart SR. Detection of TR34/L98H CYP51A Mutation through Passive Surveillance for Azole-Resistant *Aspergillus fumigatus* in the United States from 2015 to 2017. Antimicrob Agents Chemother. 2018;62(5).

[158] Chowdhary A, Kathuria S, Xu J, Meis JF. Emergence of azole-resistant *aspergillus fumigatus* strains due to agricultural azole use creates an increasing threat to human health. PLoS Pathog. 2013;9(10):e1003633.

[159] Toyotome T. Resistance in the Environmental Pathogenic Fungus *Aspergillus fumigatus*. Med Mycol J. 2019;60(3):61-3.

[160] Resendiz-Sharpe A, Dewaele K, Merckx R, Bustamante B, Vega-Gomez MC, Rolon M, et al. Triazole-Resistance in Environmental *Aspergillus fumigatus* in Latin American and African Countries. J Fungi (Basel). 2021;7(4).

[161] Toda M, Beer KD, Kuivila KM, Chiller TM, Jackson BR. Trends in Agricultural Triazole Fungicide Use in the United States, 1992-2016 and Possible Implications for Antifungal-Resistant Fungi in Human Disease. Environ Health Perspect. 2021;129(5): 55001.

[162] van der Linden JW, Snelders E, Kampinga GA, Rijnders BJ, Mattsson E, Debets-Ossenkopp YJ, et al. Clinical implications of azole resistance in *Aspergillus fumigatus*, The Netherlands, 2007-2009. Emerg Infect Dis. 2011;17(10):1846-54.

[163] Chowdhary A, Kathuria S, Randhawa HS, Gaur SN, Klaassen CH, Meis JF. Isolation of multiple-triazoleresistant *Aspergillus fumigatus* strains carrying the TR/L98H mutations in the cyp51A gene in India. J Antimicrob Chemother. 2012;67(2):362-6.

[164] Snelders E, van der Lee HA, Kuijpers J, Rijs AJ, Varga J, Samson RA, et al. Emergence of azole resistance in *Aspergillus fumigatus* and spread of a single resistance mechanism. PLoS Med. 2008;5(11):e219.

[165] Meis JF, Chowdhary A, Rhodes JL, Fisher MC, Verweij PE. Clinical implications of globally emerging azole resistance in *Aspergillus fumigatus*. Philos Trans R Soc Lond B Biol Sci. 2016;371(1709).

[166] Mellado E, Garcia-Effron G, Alcazar-Fuoli L, Melchers WJ, Verweij PE, Cuenca-Estrella M, et al. A new *Aspergillus fumigatus* resistance mechanism conferring in vitro crossresistance to azole antifungals involves a combination of cyp51A alterations. Antimicrob Agents Chemother. 2007;51(6):1897-904.

[167] Snelders E, Huis In 't Veld RA, Rijs AJ, Kema GH, Melchers WJ, Verweij PE. Possible environmental origin of resistance of *Aspergillus fumigatus* to medical triazoles. Applied and environmental microbiology. 2009;75(12):4053-7.

[168] Mortensen KL, Mellado E, Lass-Florl C, Rodriguez-Tudela JL, Johansen HK, Arendrup MC. Environmental study of azole-resistant *Aspergillus fumigatus* and other aspergilli in Austria, Denmark, and Spain. Antimicrob Agents Chemother. 2010;54(11):4545-9.

[169] Chowdhary A, Kathuria S, Xu J, Sharma C, Sundar G, Singh PK, et al. Clonal expansion and emergence of environmental multiple-triazoleresistant *Aspergillus fumigatus* strains carrying the TR(3)(4)/L98H mutations in the cyp51A gene in India. PLoS One. 2012;7(12):e52871.

[170] Badali H, Vaezi A, Haghani I, Yazdanparast SA, Hedayati MT, Mousavi B, et al. Environmental study of azole-resistant *Aspergillus fumigatus* with TR34/L98H mutations in the

cyp51A gene in Iran. Mycoses. 2013;56(6):659-63.

[171] van der Linden JW, Camps SM, Kampinga GA, Arends JP, Debets-Ossenkopp YJ, Haas PJ, et al. Aspergillosis due to voriconazole highly resistant *Aspergillus fumigatus* and recovery of genetically related resistant isolates from domiciles. Clin Infect Dis. 2013;57(4):513-20.

[172] Snelders E, Camps SM, Karawajczyk A, Schaftenaar G, Kema GH, van der Lee HA, et al. Triazole fungicides can induce crossresistance to medical triazoles in *Aspergillus fumigatus*. PLoS One. 2012;7(3):e31801.

[173] Jorgensen KM, Helleberg M, Hare RK, Jorgensen LN, Arendrup MC. Dissection of the Activity of Agricultural Fungicides against Clinical *Aspergillus* Isolates with and without Environmentally and Medically Induced Azole Resistance. J Fungi (Basel). 2021;7(3).

[174] Bassetti M, Vena A, Bouza E, Peghin M, Munoz P, Righi E, et al. Antifungal susceptibility testing in *Candida, Aspergillus* and *Cryptococcus* infections: are the MICs useful for clinicians? Clin Microbiol Infect. 2020;26(8):1024-33.

[175] CLSI. Performance Standards for Antifungal Susceptibility Testing of Filamentous Fungi. 2nd ed. CLSI supplement M61. Wayne, PA: Clinical and Laboratory Standards Institute; 2020.

[176] The European Committee on Antimicrobial Susceptibility Testing. Overview of antifungal ECOFFs and clinical breakpoints for yeasts, moulds and dermatophytes using the EUCAST E.Def 7.3, E.Def 9.3 and E.Def 11.0 procedures. Version 2, 2020. http://www.eucast.org.

Aspergillus-*Human Interactions: From the Environment to Clinical Significance DOI: http://dx.doi.org/10.5772/intechopen.98509*

[177] CLSI. Epidemiological Cutoff Values for Antifungal Susceptibility Testing. 3rd ed. CLSI supplement M59. Wayne, PA: Clinical and Laboratory Standards Institute; 2020.

[178] Wiederhold NP, Patterson TF. Emergence of Azole Resistance in *Aspergillus*. Semin Respir Crit Care Med. 2015;36(5):673-80.

[179] Garcia-Effron G. Molecular Markers of Antifungal Resistance: Potential Uses in Routine Practice and Future Perspectives. J Fungi (Basel). 2021;7(3).

[180] Verweij PE, Ananda-Rajah M, Andes D, Arendrup MC, Bruggemann RJ, Chowdhary A, et al. International expert opinion on the management of infection caused by azole-resistant *Aspergillus fumigatus*. Drug Resist Updat. 2015;21-22:30-40.

[181] Scorzoni L, Sangalli-Leite F, de Lacorte Singulani J, de Paula ESAC, Costa-Orlandi CB, Fusco-Almeida AM, et al. Searching new antifungals: The use of in vitro and in vivo methods for evaluation of natural compounds. J Microbiol Methods. 2016;123:68-78.

[182] Perfect JR. The antifungal pipeline: a reality check. Nat Rev Drug Discov. 2017;16(9):603-16.

[183] CLSI. Reference Method for Broth Dilution Antifungal Susceptibility Testing of Filamentous Fungi. 3ed ed. CLSI standard M38. Wayne, PA: Clinical and Laboratory Standards Institute; 2017.

[184] Odds FC. Synergy, antagonism, and what the chequerboard puts between them. J Antimicrob Chemother. 2003;52(1):1.

[185] Meletiadis J, Pournaras S, Roilides E, Walsh TJ. Defining fractional inhibitory concentration index cutoffs for additive interactions based on

self-drug additive combinations, Monte Carlo simulation analysis, and in vitro-in vivo correlation data for antifungal drug combinations against *Aspergillus fumigatus*. Antimicrob Agents Chemother. 2010;54(2):602-9.

[186] Plabutong N, Ekronarongchai S, Niwetbowornchai N, Edwards SW, Virakul S, Chiewchengchol D, et al. The Inhibitory Effect of Validamycin A on *Aspergillus flavus*. Int J Microbiol. 2020;2020:3972415.

[187] Umscheid CA, Margolis DJ, Grossman CE. Key concepts of clinical trials: a narrative review. Postgrad Med. 2011;123(5):194-204.

[188] Aigner M, Lass-Florl C. Encochleated Amphotericin B: Is the Oral Availability of Amphotericin B Finally Reached? J Fungi (Basel). 2020;6(2).

[189] Santangelo R, Paderu P, Delmas G, Chen ZW, Mannino R, Zarif L, et al. Efficacy of oral cochleate-amphotericin B in a mouse model of systemic candidiasis. Antimicrob Agents Chemother. 2000;44(9):2356-60.

[190] Zarif L, Graybill JR, Perlin D, Najvar L, Bocanegra R, Mannino RJ. Antifungal activity of amphotericin B cochleates against *Candida albicans* infection in a mouse model. Antimicrob Agents Chemother. 2000;44(6):1463-9.

[191] Lu R, Hollingsworth C, Qiu J, Wang A, Hughes E, Xin X, et al. Efficacy of Oral Encochleated Amphotericin B in a Mouse Model of Cryptococcal Meningoencephalitis. mBio. 2019;10(3).

[192] Skipper CP, Atukunda M, Stadelman A, Engen NW, Bangdiwala AS, Hullsiek KH, et al. Phase I EnACT Trial of the Safety and Tolerability of a Novel Oral Formulation of Amphotericin B. Antimicrob Agents Chemother. 2020;64(10).

[193] Kovacs R, Toth Z, Locke JB, Forgacs L, Kardos G, Nagy F, et al. Comparison of In Vitro Killing Activity of Rezafungin, Anidulafungin, Caspofungin, and Micafungin against Four *Candida auris* Clades in RPMI-1640 in the Absence and Presence of Human Serum. Microorganisms. 2021;9(4).

[194] Ham YY, Lewis JS, 2nd, Thompson GR, 3rd. Rezafungin: a novel antifungal for the treatment of invasive candidiasis. Future Microbiol. 2021;16:27-36.

[195] Miesel L, Cushion MT, Ashbaugh A, Lopez SR, Ong V. Efficacy of Rezafungin in Prophylactic Mouse Models of Invasive Candidiasis, Aspergillosis, and Pneumocystis Pneumonia. Antimicrob Agents Chemother. 2021;65(3).

[196] Garcia-Effron G. Rezafungin-Mechanisms of Action, Susceptibility and Resistance: Similarities and Differences with the Other Echinocandins. J Fungi (Basel). 2020;6(4).

[197] Zhao Y, Perlin DS. Review of the Novel Echinocandin Antifungal Rezafungin: Animal Studies and Clinical Data. J Fungi (Basel). 2020;6(4).

[198] Wiederhold NP, Najvar LK, Jaramillo R, Olivo M, Wickes BL, Catano G, et al. Extended-Interval Dosing of Rezafungin against Azole-Resistant *Aspergillus fumigatus*. Antimicrob Agents Chemother. 2019;63(10).

[199] Wiederhold NP, Locke JB, Daruwala P, Bartizal K. Rezafungin (CD101) demonstrates potent in vitro activity against *Aspergillus*, including azole-resistant *Aspergillus fumigatus* isolates and cryptic species. J Antimicrob Chemother. 2018;73(11):3063-7.

[200] Sofjan AK, Mitchell A, Shah DN, Nguyen T, Sim M, Trojcak A, et al. Rezafungin (CD101), a next-generation echinocandin: A systematic literature review and assessment of possible place in therapy. J Glob Antimicrob Resist. 2018;14:58-64.

[201] Helleberg M, Jorgensen KM, Hare RK, Datcu R, Chowdhary A, Arendrup MC. Rezafungin In Vitro Activity against Contemporary Nordic Clinical *Candida* Isolates and *Candida auris* Determined by the EUCAST Reference Method. Antimicrob Agents Chemother. 2020;64(4).

[202] Pfaller MA, Carvalhaes C, Messer SA, Rhomberg PR, Castanheira M. Activity of a Long-Acting Echinocandin, Rezafungin, and Comparator Antifungal Agents Tested against Contemporary Invasive Fungal Isolates (SENTRY Program, 2016 to 2018). Antimicrob Agents Chemother. 2020;64(4).

[203] Thompson GR, Soriano A, Skoutelis A, Vazquez JA, Honore PM, Horcajada JP, et al. Rezafungin versus Caspofungin in a Phase 2, Randomized, Double-Blind Study for the Treatment of Candidemia and Invasive Candidiasis- The STRIVE Trial. Clin Infect Dis. 2020.

[204] Jallow S, Govender NP. Ibrexafungerp: A First-in-Class Oral Triterpenoid Glucan Synthase Inhibitor. J Fungi (Basel). 2021;7(3).

[205] Apgar JM, Wilkening RR, Parker DL, Jr., Meng D, Wildonger KJ, Sperbeck D, et al. Ibrexafungerp: An orally active beta-1,3-glucan synthesis inhibitor. Bioorg Med Chem Lett. 2021;32:127661.

[206] Ghannoum M, Arendrup MC, Chaturvedi VP, Lockhart SR, McCormick TS, Chaturvedi S, et al. Ibrexafungerp: A Novel Oral Triterpenoid Antifungal in

Aspergillus-*Human Interactions: From the Environment to Clinical Significance DOI: http://dx.doi.org/10.5772/intechopen.98509*

Development for the Treatment of *Candida auris* Infections. Antibiotics (Basel). 2020;9(9).

[207] Petraitis V, Petraitiene R, Katragkou A, Maung BBW, Naing E, Kavaliauskas P, et al. Combination Therapy with Ibrexafungerp (Formerly SCY-078), a First-in-Class Triterpenoid Inhibitor of (1-->3)-beta-d-Glucan Synthesis, and Isavuconazole for Treatment of Experimental Invasive Pulmonary Aspergillosis. Antimicrob Agents Chemother. 2020;64(6).

[208] Davis MR, Donnelley MA, Thompson GR. Ibrexafungerp: A novel oral glucan synthase inhibitor. Med Mycol. 2020;58(5):579-92.

[209] Spec A, Pullman J, Thompson GR, Powderly WG, Tobin EH, Vazquez J, et al. MSG-10: a Phase 2 study of oral ibrexafungerp (SCY-078) following initial echinocandin therapy in nonneutropenic patients with invasive candidiasis. J Antimicrob Chemother. 2019;74(10):3056-62.

[210] Larkin EL, Long L, Isham N, Borroto-Esoda K, Barat S, Angulo D, et al. A Novel 1,3-Beta-d-Glucan Inhibitor, Ibrexafungerp (Formerly SCY-078), Shows Potent Activity in the Lower pH Environment of Vulvovaginitis. Antimicrob Agents Chemother. 2019;63(5).

[211] Garvey EP, Sharp AD, Warn PA, Yates CM, Atari M, Thomas S, et al. The novel fungal CYP51 inhibitor VT-1598 displays classic dose-dependent antifungal activity in murine models of invasive aspergillosis. Med Mycol. 2020;58(4):505-13.

[212] Hargrove TY, Garvey EP, Hoekstra WJ, Yates CM, Wawrzak Z, Rachakonda G, et al. Crystal Structure of the New Investigational Drug Candidate VT-1598 in Complex with *Aspergillus fumigatus* Sterol 14alpha-Demethylase Provides Insights into Its

Broad-Spectrum Antifungal Activity. Antimicrob Agents Chemother. 2017;61(7).

[213] Elewski B, Brand S, Degenhardt T, Curelop S, Pollak R, Schotzinger R, et al. A phase II, randomized, double-blind, placebo-controlled, dose-ranging study to evaluate the efficacy and safety of VT-1161 oral tablets in the treatment of patients with distal and lateral subungual onychomycosis of the toenail. Br J Dermatol. 2021;184(2): 270-80.

[214] Monk BC, Keniya MV, Sabherwal M, Wilson RK, Graham DO, Hassan HF, et al. Azole Resistance Reduces Susceptibility to the Tetrazole Antifungal VT-1161. Antimicrob Agents Chemother. 2019;63(1).

[215] Wiederhold NP, Xu X, Wang A, Najvar LK, Garvey EP, Ottinger EA, et al. In Vivo Efficacy of VT-1129 against Experimental Cryptococcal Meningitis with the Use of a Loading Dose-Maintenance Dose Administration Strategy. Antimicrob Agents Chemother. 2018;62(11).

[216] Wiederhold NP, Najvar LK, Garvey EP, Brand SR, Xu X, Ottinger EA, et al. The Fungal Cyp51 Inhibitor VT-1129 Is Efficacious in an Experimental Model of Cryptococcal Meningitis. Antimicrob Agents Chemother. 2018;62(9).

[217] Schell WA, Jones AM, Garvey EP, Hoekstra WJ, Schotzinger RJ, Alexander BD. Fungal CYP51 Inhibitors VT-1161 and VT-1129 Exhibit Strong In Vitro Activity against *Candida glabrata* and *C. krusei* Isolates Clinically Resistant to Azole and Echinocandin Antifungal Compounds. Antimicrob Agents Chemother. 2017;61(3).

[218] Nielsen K, Vedula P, Smith KD, Meya DB, Garvey EP, Hoekstra WJ, et al. Activity of VT-1129 against *Cryptococcus neoformans* clinical isolates with high

fluconazole MICs. Med Mycol. 2017;55(4):453-6.

[219] Warrilow AG, Parker JE, Price CL, Nes WD, Garvey EP, Hoekstra WJ, et al. The Investigational Drug VT-1129 Is a Highly Potent Inhibitor of *Cryptococcus* Species CYP51 but Only Weakly Inhibits the Human Enzyme. Antimicrob Agents Chemother. 2016;60(8):4530-8.

[220] Lockhart SR, Fothergill AW, Iqbal N, Bolden CB, Grossman NT, Garvey EP, et al. The Investigational Fungal Cyp51 Inhibitor VT-1129 Demonstrates Potent In Vitro Activity against *Cryptococcus neoformans* and *Cryptococcus gattii*. Antimicrob Agents Chemother. 2016;60(4):2528-31.

[221] Murray A, Cass L, Ito K, Pagani N, Armstrong-James D, Dalal P, et al. PC945, a Novel Inhaled Antifungal Agent, for the Treatment of Respiratory Fungal Infections. J Fungi (Basel). 2020;6(4).

[222] Cass L, Murray A, Davis A, Woodward K, Albayaty M, Ito K, et al. Safety and nonclinical and clinical pharmacokinetics of PC945, a novel inhaled triazole antifungal agent. Pharmacol Res Perspect. 2021;9(1): e00690.

[223] Pagani N, Armstrong-James D, Reed A. Successful salvage therapy for fungal bronchial anastomotic infection after -lung transplantation with an inhaled triazole anti-fungal PC945. J Heart Lung Transplant. 2020;39(12): 1505-6.

[224] Rudramurthy SM, Colley T, Abdolrasouli A, Ashman J, Dhaliwal M, Kaur H, et al. In vitro antifungal activity of a novel topical triazole PC945 against emerging yeast *Candida auris*. J Antimicrob Chemother. 2019;74(10):2943-9.

[225] Colley T, Sehra G, Daly L, Kimura G, Nakaoki T, Nishimoto Y, et al. Antifungal synergy of a topical triazole, PC945, with a systemic triazole against respiratory *Aspergillus fumigatus* infection. Scientific reports. 2019;9(1):9482.

[226] Kimura G, Nakaoki T, Colley T, Rapeport G, Strong P, Ito K, et al. In Vivo Biomarker Analysis of the Effects of Intranasally Dosed PC945, a Novel Antifungal Triazole, on *Aspergillus fumigatus* Infection in Immunocompromised Mice. Antimicrob Agents Chemother. 2017;61(9).

[227] Colley T, Alanio A, Kelly SL, Sehra G, Kizawa Y, Warrilow AGS, et al. In Vitro and In Vivo Antifungal Profile of a Novel and Long-Acting Inhaled Azole, PC945, on *Aspergillus fumigatus* Infection. Antimicrob Agents Chemother. 2017;61(5).

[228] Badali H, Patterson HP, Sanders CJ, Mermella B, Gibas CFC, Ibrahim AS, et al. Manogepix, the Active Moiety of the Investigational Agent Fosmanogepix, Demonstrates In vitro Activity against Members of the *Fusarium oxysporum* and *Fusarium solani* Species Complexes. Antimicrob Agents Chemother. 2021.

[229] Lee A, Wang N, Carter CL, Zimmerman M, Dartois V, Shaw KJ, et al. Therapeutic Potential of Fosmanogepix (APX001) for Intraabdominal Candidiasis: from Lesion Penetration to Efficacy in a Mouse Model. Antimicrob Agents Chemother. 2021;65(4).

[230] Petraitiene R, Petraitis V, Maung BBW, Mansbach RS, Hodges MR, Finkelman MA, et al. Efficacy and Pharmacokinetics of Fosmanogepix (APX001) in the Treatment of *Candida* Endophthalmitis and Hematogenous Meningoencephalitis in Nonneutropenic Rabbits. Antimicrob Agents Chemother. 2021;65(3).

Aspergillus-*Human Interactions: From the Environment to Clinical Significance DOI: http://dx.doi.org/10.5772/intechopen.98509*

[231] Shaw KJ, Ibrahim AS. Fosmanogepix: A Review of the Firstin-Class Broad Spectrum Agent for the Treatment of Invasive Fungal Infections. J Fungi (Basel). 2020;6(4).

[232] Gebremariam T, Alkhazraji S, Alqarihi A, Wiederhold NP, Shaw KJ, Patterson TF, et al. Fosmanogepix (APX001) Is Effective in the Treatment of Pulmonary Murine Mucormycosis Due to Rhizopus arrhizus. Antimicrob Agents Chemother. 2020;64(6).

[233] Alkhazraji S, Gebremariam T, Alqarihi A, Gu Y, Mamouei Z, Singh S, et al. Fosmanogepix (APX001) Is Effective in the Treatment of Immunocompromised Mice Infected with Invasive Pulmonary Scedosporiosis or Disseminated Fusariosis. Antimicrob Agents Chemother. 2020;64(3).

[234] Gebremariam T, Alkhazraji S, Gu Y, Singh S, Alqarihi A, Shaw KJ, et al. Galactomannan Is a Biomarker of Fosmanogepix (APX001) Efficacy in Treating Experimental Invasive Pulmonary Aspergillosis. Antimicrob Agents Chemother. 2019;64(1).

[235] Wiederhold NP, Najvar LK, Shaw KJ, Jaramillo R, Patterson H, Olivo M, et al. Efficacy of Delayed Therapy with Fosmanogepix (APX001) in a Murine Model of *Candida auris* Invasive Candidiasis. Antimicrob Agents Chemother. 2019;63(11).

[236] Shaw KJ, Schell WA, Covel J, Duboc G, Giamberardino C, Kapoor M, et al. In Vitro and In Vivo Evaluation of APX001A/APX001 and Other Gwt1 Inhibitors against *Cryptococcus*. Antimicrob Agents Chemother. 2018;62(8).

[237] Su H, Zhu M, Tsui CK, van der Lee H, Tehupeiory-Kooreman M, Zoll J, et al. Potency of olorofim (F901318) compared to contemporary antifungal agents against clinical *Aspergillus fumigatus* isolates, and review of azole

resistance phenotype and genotype epidemiology in China. Antimicrob Agents Chemother. 2021.

[238] Singh A, Singh P, Meis JF, Chowdhary A. In vitro activity of the novel antifungal olorofim against dermatophytes and opportunistic moulds including *Penicillium* and *Talaromyces* species. J Antimicrob Chemother. 2021;76(5):1229-33.

[239] du Pre S, Beckmann N, Almeida MC, Sibley GEM, Law D, Brand AC, et al. Effect of the Novel Antifungal Drug F901318 (Olorofim) on Growth and Viability of *Aspergillus fumigatus*. Antimicrob Agents Chemother. 2018;62(8).

[240] Wiederhold NP. Review of T-2307, an Investigational Agent That Causes Collapse of Fungal Mitochondrial Membrane Potential. J Fungi (Basel). 2021;7(2).

[241] Yamashita K, Miyazaki T, Fukuda Y, Mitsuyama J, Saijo T, Shimamura S, et al. The Novel Arylamidine T-2307 Selectively Disrupts Yeast Mitochondrial Function by Inhibiting Respiratory Chain Complexes. Antimicrob Agents Chemother. 2019;63(8).

[242] Mitsuyama J, Nomura N, Hashimoto K, Yamada E, Nishikawa H, Kaeriyama M, et al. In vitro and in vivo antifungal activities of T-2307, a novel arylamidine. Antimicrob Agents Chemother. 2008;52(4):1318-24.

[243] Mammen MP, Armas D, Hughes FH, Hopkins AM, Fisher CL, Resch PA, et al. First-in-Human Phase 1 Study To Assess Safety, Tolerability, and Pharmacokinetics of a Novel Antifungal Drug, VL-2397, in Healthy Adults. Antimicrob Agents Chemother. 2019;63(11).

[244] Dietl AM, Misslinger M, Aguiar MM, Ivashov V, Teis D, Pfister J, et al. The Siderophore Transporter Sit1 Determines Susceptibility to the Antifungal VL-2397. Antimicrob Agents Chemother. 2019;63(10).

[245] Kovanda LL, Sullivan SM, Smith LR, Desai AV, Bonate PL, Hope WW. Population Pharmacokinetic Modeling of VL-2397, a Novel Systemic Antifungal Agent: Analysis of a Singleand Multiple-Ascending-Dose Study in Healthy Subjects. Antimicrob Agents Chemother. 2019;63(6).

[246] Mahmoudi S, Rezaie S, Daie Ghazvini R, Hashemi SJ, Badali H, Foroumadi A, et al. In Vitro Interaction of Geldanamycin with Triazoles and Echinocandins Against Common and Emerging *Candida* Species. Mycopathologia. 2019;184(5):607-13.

[247] Ma C, Chen J, Li P. Geldanamycin induces apoptosis and inhibits inflammation in fibroblast-like synoviocytes isolated from rheumatoid arthritis patients. J Cell Biochem. 2019;120(9):16254-63.

[248] Ochel HJ, Eichhorn K, Gademann G. Geldanamycin: the prototype of a class of antitumor drugs targeting the heat shock protein 90 family of molecular chaperones. Cell Stress Chaperones. 2001;6(2):105-12.

[249] High KP. The antimicrobial activities of cyclosporine, FK506, and rapamycin. Transplantation. 1994;57(12):1689-700.

[250] Gao L, Sun Y. In vitro interactions of antifungal agents and tacrolimus against *Aspergillus* biofilms. Antimicrob Agents Chemother. 2015;59(11):7097-9.

[251] Lee Y, Lee KT, Lee SJ, Beom JY, Hwangbo A, Jung JA, et al. In Vitro and In Vivo Assessment of FK506 Analogs as Novel Antifungal Drug Candidates. Antimicrob Agents Chemother. 2018;62(11).

[252] Pandit RT. Antifungal effects of cyclosporine A. Cornea. 2003;22(1):92-3.

[253] Robbins N, Leach MD, Cowen LE. Lysine deacetylases Hda1 and Rpd3 regulate Hsp90 function thereby governing fungal drug resistance. Cell Rep. 2012;2(4):878-88.

[254] Wurtele H, Tsao S, Lepine G, Mullick A, Tremblay J, Drogaris P, et al. Modulation of histone H3 lysine 56 acetylation as an antifungal therapeutic strategy. Nat Med. 2010;16(7):774-80.

[255] Zhong W, Jeffries MW, Georgopapadakou NH. Inhibition of inositol phosphorylceramide synthase by aureobasidin A in *Candida* and *Aspergillus* species. Antimicrob Agents Chemother. 2000;44(3):651-3.

[256] Teymuri M, Shams-Ghahfarokhi M, Razzaghi-Abyaneh M. Inhibitory effects and mechanism of antifungal action of the natural cyclic depsipeptide, aureobasidin A against *Cryptococcus neoformans*. Bioorg Med Chem Lett. 2021;41:128013.

[257] Munusamy K, Vadivelu J, Tay ST. A study on *Candida* biofilm growth characteristics and its susceptibility to aureobasidin A. Rev Iberoam Micol. 2018;35(2):68-72.

[258] Tan HW, Tay ST. The inhibitory effects of aureobasidin A on *Candida* planktonic and biofilm cells. Mycoses. 2013;56(2):150-6.

[259] Larwood DJ. Nikkomycin Z-Ready to Meet the Promise? J Fungi (Basel). 2020;6(4).

[260] Lazzarini C, Haranahalli K, Rieger R, Ananthula HK, Desai PB, Ashbaugh A, et al. Acylhydrazones as Antifungal Agents Targeting the Synthesis of Fungal Sphingolipids. Antimicrob Agents Chemother. 2018;62(5).

Aspergillus-*Human Interactions: From the Environment to Clinical Significance DOI: http://dx.doi.org/10.5772/intechopen.98509*

[261] Lazzarini C, Haranahalli K, McCarthy JB, Mallamo J, Ojima I, Del Poeta M. Preclinical Evaluation of Acylhydrazone SB-AF-1002 as a Novel Broad-Spectrum Antifungal Agent. Antimicrob Agents Chemother. 2020;64(9).

[262] Yu Y, Albrecht K, Groll J, Beilhack A. Innovative therapies for invasive fungal infections in preclinical and clinical development. Expert Opin Investig Drugs. 2020;29(9):961-71.

[263] Svanstrom A, van Leeuwen MR, Dijksterhuis J, Melin P. Trehalose synthesis in *Aspergillus niger*: characterization of six homologous genes, all with conserved orthologs in related species. BMC Microbiol. 2014;14:90.

[264] Al-Bader N, Vanier G, Liu H, Gravelat FN, Urb M, Hoareau CM, et al. Role of trehalose biosynthesis in *Aspergillus fumigatus* development, stress response, and virulence. Infect Immun. 2010;78(7):3007-18.

[265] Puttikamonkul S, Willger SD, Grahl N, Perfect JR, Movahed N, Bothner B, et al. Trehalose 6-phosphate phosphatase is required for cell wall integrity and fungal virulence but not trehalose biosynthesis in the human fungal pathogen *Aspergillus fumigatus*. Mol Microbiol. 2010;77(4):891-911.

[266] Shibata M, Mori K, Hamashima M. Inhibition of hyphal extension factor formation by validamycin in *Rhizoctonia solani*. J Antibiot (Tokyo). 1982;35(10): 1422-3.

[267] Shibata M, Uyeda M, Mori K. Stimulation of the extension of validamycin-inhibited hyphae by the hyphal extension factor present in *Rhizoctonia solani.* J Antibiot (Tokyo). 1981;34(4):447-51.

[268] Shibata M, Uyeda M, Mori K. Reversal of validamycin inhibition by the hyphal extract of *Rhizoctonia solani*. J Antibiot (Tokyo). 1980;33(6):679-81.

[269] Suami T, Ogawa S, Chida N. The revised structure of validamycin A. J Antibiot (Tokyo). 1980;33(1):98-9.

[270] Guirao-Abad JP, Sanchez-Fresneda R, Valentin E, Martinez-Esparza M, Arguelles JC. Analysis of validamycin as a potential antifungal compound against *Candida albicans*. Int Microbiol. 2013;16(4):217-25.

[271] Ji Y, Yang F, Ma D, Zhang J, Wan Z, Liu W, et al. HOG-MAPK signaling regulates the adaptive responses of *Aspergillus fumigatus* to thermal stress and other related stress. Mycopathologia. 2012;174(4):273-82.

[272] Day AM, Quinn J. Stress-Activated Protein Kinases in Human Fungal Pathogens. Front Cell Infect Microbiol. 2019;9:261.

[273] Hagiwara D, Takahashi H, Kusuya Y, Kawamoto S, Kamei K, Gonoi T. Comparative transcriptome analysis revealing dormant conidia and germination associated genes in *Aspergillus* species: an essential role for AtfA in conidial dormancy. BMC genomics. 2016;17:358.

[274] Hagiwara D, Suzuki S, Kamei K, Gonoi T, Kawamoto S. The role of AtfA and HOG MAPK pathway in stress tolerance in conidia of *Aspergillus fumigatus*. Fungal Genet Biol. 2014;73:138-49.

#### **Chapter 3**

## Immunopathogenesis of Aspergillosis

*Shreya Singh, Rimjhim Kanaujia and Shivaprakash M. Rudramurthy*

#### **Abstract**

*Aspergillus* species are ubiquitous saprophytes and opportunistic pathogens causing wide spectrum of diseases in humans depending on the host immune status. Following pathogen entry, various soluble bronchopulmonary factors enhance conidial clearance. However, due to virulence factors and poor host immune response *Aspergillus* conidia bind and damage the airway epithelium. The host immune cells like neutrophils and macrophages recognise *Aspergillus* spp. through various pathogen recognition receptors and form reactive oxygen species which mediate conidial killing. Neutrophils also attack extracellular hyphae by oxidative attack, non-oxidative granule proteins and neutrophil extracellular traps. In case of adaptive immunity, Th1 cells are crucial sources of IFN-γ mediated protective immunity*.* The Th17 also display a highly pro-inflammatory which is counterbalanced by a Treg cell. B cells and antibodies also enhance fungal clearance although excessive IgE production may result in atopy. The immune responses are influenced by changes in production of short-chain fatty acids by the gut microbiome which primes cells toward Th2 responses, and this is synchronized by the Innate lymphoid cells. This review provides comprehensive knowledge of various virulence factors of *Aspergillus*, antifungal host defences including innate and humoral immune response and regulation of host immunity by microbiome.

**Keywords:** Immunity, pathogenesis, aspergillus, genetic polymorphism, virulence

#### **1. Introduction**

*Aspergillus* species are globally ubiquitous saprophytes and are also opportunistic pathogens which have evolved in the environment and adapted to invade and proliferate within the human host. It can cause serious invasive infections. Invasive aspergillosis (IA) is associated with high mortality and morbidity which makes it essential to understand the factors involved in disease pathogenesis. The interplay between *Aspergillus* spp. and various components of the host immune system influences disease progression. Agent factors such as conidia size, temperature tolerance, hydrophobin /melanin expression etc. which contribute to virulence must be studied. Additionally, comprehensive knowledge of the host defenses, innate and humoral immune response, genetic susceptibility to *Aspergillus* and the role of microbiome in modulating immune response is important to study the disease immunopathogenesis.

In the genus *Aspergillus, Aspergillus fumigatus* is most commonly reported from human infections, followed by *A. flavus*, *A. terreus* and other uncommon species like *A. niger* and *A. nidulans* [1, 2]. It can cause plethora of infections, depending

on the immune status of the host as immunocompetent individuals with asthma or cystic fibrosis are predisposed to a hypersensitive response while Invasive aspergillosis (IA) is seen in severely immunocompromised patients.

A better understanding of the interplay between the host immune system and *Aspergillus* is important to understand disease pathology and can provide us with useful insights regarding potential therapeutic targets. In this review, we will thus discuss the pathogen related virulence factors, clinical spectrum of diseases caused by it, its interaction with various components of the host immune system, factors involved in regulating the anti-fungal immune response and will also give an overview of the genetic polymorphisms in immune pathways that predispose to aspergillosis. *Aspergillus* and disease pathology and progression are the result of both fungal growth and the host response.

#### **2. Virulence factors**

The various virulence factors involved in the pathogenesis of aspergillosis are summarized in **Table 1.**


#### **Table 1.**

*Virulence factors of* Aspergillus *species.*

## **3. Risk factors and clinical spectrum**

An elaborate range of diseases can be caused by *Aspergillus* species and the clinical spectrum depends on the immune status of the infected host. Correlation of clinical spectrum of aspergillosis and immune status in various condition has been depicted in **Figure 1**.

**Immunocompetent Patient***:* In immunocompetent individuals *Aspergillus* spp. remain colonized as a saprophytic fungus. *Aspergillus* spp. can colonize in preexisting cavities due to bronchiectasis, tuberculosis, cavitary neoplasia or sarcoidosis and cause chronic non-invasive infections like chronic pulmonary aspergillosis (CPA) [18, 19].

**Hyper responsive or Atopic Patient:** A hypersensitive response in these individuals in various forms like Allergic bronchopulmonary aspergillosis (ABPA), severe asthma with fungal sensitization (SAFS) and allergic rhinitis [20]. This is commonly seen in patients with cystic fibrosis (CF) and poorly controlled or steroid-refractory asthma [20]. In cases of CF, inflammation of bronchial mucosa and abnormal mucus can result in fungal colonization and up to 10% patients develop sensitization to *A. fumigatus* [21]*.* This can further progress to ABPA suggesting the importance of testing such patients with markers of immune hyper-reactivity.

**Immunocompromised Patient**: IA is a dreaded, life-threatening disease with a high mortality ranging from 40–80% [22, 23]. It is commonly seen in are individuals with hematological malignancies such as acute leukemia; solid-organ and hematopoietic stem cell transplant patients; patients on prolonged corticosteroid or chemotherapy. Invasive pulmonary aspergillosis (IPA) is also reported in patients with history of influenza or coronavirus disease and those receiving broadspectrum antibiotics [24, 25]. Genetic susceptibly to IA is also seen in patients

#### **Figure 1.**

*Correction of clinical spectrum of* Aspergillosis *and immune status in various condition. \*CID: Congenital immunodeficiency disorders includes chronic granulomatous disease, CARD9 deficiency, leukocyte adhesion deficiency, Job's syndrome, pulmonary alveolar proteinosis.*

with congenital immune deficiencies like Caspase recruitment domain-containing protein-9 (CARD-9) deficiency and Chronic granulomatous disease [26, 27].

#### **4. Pathogenesis**

The range of ailments caused by *Aspergillus* depends on the host immune status. In atopic individuals the T helper 2 lymphocyte leads to hypersensitive response with increase in eosinophil counts and serum IgE levels. Formation of non-invasive aspergillomas is seen in CPA following repeated exposure to conidia in pre-existing cavitary lesions. IA is a destructive form of *Aspergillus*-related disease seen commonly in immunocompromised and critically ill patients.

#### **5. Pathogen entry**

The mode of reproduction in *Aspergillus* is predominantly asexual by formation of conidia (2–5 μm in size) which are ubiquitously present in the environment. These dormant conidia disperse in air easily due to their small size and common occurrence in soil, seeds and grains, decaying vegetation etc. and humans can inhale several hundred conidia per day. *Aspergillus* spp. are also found indoors in moisture damaged buildings both at homes and healthcare facilities [28] . There are therefore recommendations to avoid known sources of fungal proliferation (plants and flowers) in indoor places as they can serve as natural niches for fungal growth [29].

Conidia being small bypass the natural host nasal and bronchial defenses. The rodlet layer forms a hydrophobic layer outside conidia and protects it from host defenses and reach the lung alveoli. Natural defenses like mucociliary clearance and cough reflex are further compromised in intubated and mechanically ventilated patients. Also, the tracheal and bronchial epithelium is injured and provides easier passage for fungal conidia to the lower respiratory tract. Among healthy hosts, neutrophils and macrophages effectively clear the *Aspergillus* conidia. However, in immunocompromised patients, few conidia start swelling and become metabolically active after losing the outermost rodlet layer. These conidia, then germinate to produce fungal hyphae and cause a spectrum of invasive diseases.

#### **6. Interaction with the innate immune system**

The interaction of *Aspergillus* with cells of the innate immune system is depicted in **Figure 2**.

#### **6.1 Soluble lung components**

Various soluble factors found in the bronchopulmonary fluid are involved in *Aspergillus* defense including pathogen recognition receptors (PRRs) like C-type lectins, mannose binding ligand (MBL), Surfactant proteins (SP) – A and –D and pentraxin (PTX). These soluble factors enhance complement activation and phagocytosis of conidia, thus contributing to its clearance.

Although components of the complement system are predominant in serum they can also be found at lower levels in bronchial and alveolar fluid. Conidia and hyphae of *Aspergillus* species have been shown to bind to C3 followed by its cleavage to a ligand for phagocytic complement receptors iC3b. It has been reported

#### **Figure 2.**

*Innate immune response to* Aspergillus *infection. The conidia of* Aspergillus *spp. are inhaled and enter the lung where they encounter various soluble lung components including antibodies, complement factors and antimicrobial compounds. Those conidia which swell and undergoes germination further interact with a variety of innate immune cells including alveolar macrophages, dendritic cells, and NK cells. Conidial germination and development of hyphal forms is also prevented by neutrophils.*

that the common pathogens *A. fumigatus* and *A. flavus* bind to fewer C3 molecules compared to other to species making their complement-mediated phagocytosis and killing, less effective [30]. Hyphae and conidia from various *Aspergillus* spp. bind to alternative complement receptors like complement inhibitor factor H and the factor H family protein FFHL-1 which prevents complement cascade activation thereby protecting the fungus [31]. *A. fumigatus* and *A. flavus* have also been seen to produce a soluble complement-inhibitory factor which inhibits the activation of the alternative complement pathway [32]. This also acts as a defense mechanism of these species contributing to their overall pathogenesis.

#### **6.2 Respiratory epithelial cells**

The airway epithelial cells are the first cells to encounter inhaled *Aspergillus* conidia, which bind to it via sialic acid residues and subsequently modulate it. Other conidial proteins also mediate binding to fibrinogen, laminin and fibronectin which are all linked with lung injury indicating a role in adhesion and colonization [30]. A broad range of antimicrobial peptides of the defensin family are produced by the respiratory epithelial cells. Although the contribution of airway epithelial cells is less robust than that of the alveolar macrophages and germinating conidia and hyphae of *Aspergillus* are recognized by various PRRs on epithelial cells and subsequently assist in initiating pro-inflammatory response.

The proteases secreted by *A. fumigatus* cause desquamation and shrinkage of the respiratory epithelial cells along with actin cytoskeletal rearrangement with loss of cellular attachment and focal contact, thus assisting in invasion by germinating hyphae [33]. Secondary metabolites like gliotoxin, fumagillin, helvolic acid, verruculogen also damage airway epithelium and interfere with mucocilliary clearance [30, 34].

#### **6.3 Pathogen recognition by innate immune cells**

The recognition of *Aspergillus* by host immune cells is mostly via the PRRs – TLR1, TLR2, TLR4, TLR6 and the C-type lectin receptor i.e. dectin-1 [35]. TLR2 recognizes both hyphal and conidial form, while TLR4 recognizes only the hyphal morphology [36, 37]. The protective role of TLR4 mediated immune recognition has been seen in allogeneic hematopoietic stem cell transplant patients where it is observed that TLR4 polymorphisms are associated with IA [38]. The critical role of TLR6 in regulation of allergic inflammatory response in chronic fungalinduced asthma was studied by Moreira et al. in mice and the absence of TLR6 was found to be associated with less production of IL-23 and Th17 responses causing exacerbation of asthma [39]. Interestingly, the inflammatory response to *A. fumigatus* is intact in alveolar macrophages even in the setting of TLR2 deficiency and mice with defects in TLR2/TLR4 or its downstream effectors (like MyD88) have higher susceptibility to *A. fumigatus* lung infection, only in the setting of neutropenia [40–42].

Dectin – 1 is also an important PRR recognizing beta (1,3)-glucan on *Aspergillus* in both immunosuppressed and immunocompetent hosts. Although beta (1,3)-glucan is usually masked by the rodlet layer on resting conidia, the conidial swelling on entry in host epithelium exposes it, causing dectin – 1 mediated recognition and phagocytosis. Macrophages stimulation by *A. fumigatus* conidia increases intracellular PRR expression as well eg. Nucleotide-binding oligomerization domain (NOD) proteins ((NOD1 and NOD2) followed by production of proinflammatory cytokines which contribute to innate immune response [43].

#### **6.4 Alveolar macrophages**

Alveolar macrophages recognize and phagocytose fungal (1,3)-glucan bound to dectin-1. Internalization of conidia occurs within 2 hours and then conidial swelling begins [44]. This is an important requirement for induction of reactive oxygen species (ROS) production by the macrophage. Kinetic studies indicate that maximum ROS production occurs after 3 hours of phagocytosis resulting in fungistatic inhibition of germ tube formation due to which conidia are unable to germinate [44]. In immunosuppressed mice, although corticosteroid intake does not directly affect the internalization of conidia by alveolar macrophages there is impaired killing of *A. fumigatus* conidia due to defective production of ROS thereby increasing susceptibility to IA [44, 45]. The exact mechanisms of conidial killing by ROS are unknown and could be via direct toxicity or by acting as a cofactor for other phagolysosomal toxic molecules like elastase, cathepsins, proteases and chitinases [46]. In addition to phagolysosome acidification, phosphatidylinositol (PI) 3-kinase activity is also an important requirement for proper killing of conidia [47].

Neutrophils and macrophages produce nitric oxide (NO) and reactive nitrogen intermediates (RNI) that can also contribute to conidial killing. However, the expression of nitrogen oxidative species (NOS) which is seen in classically activated or M1 macrophages does not have much effect on conidial killing. A study by Lapp et al., reported that in *A. fumigatus* genes encoding flavohemoglobins (*FhpA* and

#### *Immunopathogenesis of Aspergillosis DOI: http://dx.doi.org/10.5772/intechopen.98782*

*FhpB*) which converts NO to nitrate and *S*-nitrosoglutathione reductase (*GnoA*) which reduce *S*-nitrosoglutathione to ammonium and glutathione disulphide are observed [48]*.* Although, these genes play a major role in detoxification of host derived RNI, they were not found to be essential for virulence*.*

Following macrophage phagocytosis, dihydroxynapthalene-melanin (DHN-melanin) of *A. fumigatus* prevents the phagolysosome acidification allowing conidial germination. However, *A. terreus* conidia lack the genes for DHN-melanin synthesis and instead produce a different type of melanin, i.e., Asp-melanin [49]. Although Asp-melanin does not impede acidification of phagolysosome it hampers phagocytosis and contributes to the survival and long-term persistence of *A. terreus* even in acidic environment.

In a study by Bhatia et al., alveolar macrophages were found to express Arginase 1 (Arg1) a key marker of alternatively activated macrophages (AAMs)/M2 macrophages after infection by *A. fumigatus* [50]. These macrophages efficiently phagocytose conidia and play a crucial role in pathogen clearance. The activation of macrophages is also followed by translocation of mitogen-activated protein kinases (MAPKs) to the nucleus where they phosphorylate the transcription factor NF-kappa B, thus activating a pro-inflammatory immune response.

#### **6.5 Neutrophils**

Neutrophils are professional phagocytes playing a pivotal role in innate immunity. Neutrophil recruitment is essential for effective *Aspergillus* clearing as they attack the germinating conidia and extracellular hyphae which have escaped macrophage surveillance. Neutrophils utilize TLR2, TLR4 and dectin-1, to identify and respond to *Aspergillus.* It can also be recognized directly by the complement receptor 3 (CD3, i.e., CD 11b/CD18), antigen–antibody complex detection by the Fcγ receptors (FcγR) or indirectly by opsonisation by various soluble components in lung environment.

In a study by Braem et al., higher deposition of the serum C3b was reported on germ tubes and swollen conidia compared to dormant conidia [51]. Also, patchy deposition of both C3b and immunoglobulin G (IgG) is seen over dormant conidia compared to uniform deposits on other morphotypes.

The release of chemotactic molecules, like C5a, increases migration of neutrophil to the infection site. The soluble mammalian extracellular β-galactose-binding lectin, galectin-3 is released in infected host tissues and facilitates neutrophil recruitment to the site of *A*. *fumigatus* infection by directly stimulating neutrophil motility in addition to exhibiting with both antimicrobial and immunomodulatory activities [52].

Neutrophil mediated killing involves both oxidative killing by NADPH oxidase which generates superoxide and myeloperoxidase and non-oxidative granule proteins containing various compounds with antimicrobial activity e.g., defensins, serine proteases, lysozyme, pentraxin-3 and lactoferrin [53]. Neutrophils attach to hyphae, spread over their surfaces, and degranulate thereby damaging the fungal hyphae. Neutrophils form aggregates in the lung and restrict conidial germination via lactoferrin mediated sequestration of iron [54]. Also, neutrophils produce lipocalin-1, which sequesters fungal siderophores thereby inhibiting fungal growth [55].

Another neutrophil dependent defense is the formation of neutrophil extracellular traps (NETs). Conidia and germ tubes of the *A. fumigatus* have been shown to trigger the formation of NETs. Pathogens in contact with the NETs become immobilized, limiting the spread of the infection. Calprotectin, a chelator of Zn2+ and Mn2+ ions is also produced by neutrophils and is associated with the *Aspergillus*-induced

NETs [56, 57]. Thus, in view of the important role that neutrophils play against *Aspergillus*, it is no surprize that patients with qualitative or quantitative defects in the neutrophils experience a greater risk of IA. It is worth mentioning however, that neutrophils may act as double-edged swords, since these are needed for fungal eradication but can also cause further lung injury by release of proteases and ROS. Thus, stringent regulatory mechanisms are essential to balance the protective activity and immunopathological responses for efficient control of the *Aspergillus.*

#### **6.6 Natural killer cells**

There is growing evidence suggesting the role of NK cells in immune response against *Aspergillus* spp. Direct antifungal activity via cytotoxic molecules like perforin and NK cell derived cytokines and interferon modulate the activation of other immune cells. *A. fumigatus* activates NK cells resulting in the production of low-levels of TNF-α, IFN-γ and lytic granules and release of fungal DNA [58]. These cells are a major source of early IFN-gamma production in the lungs of neutropenic patient with IA causing higher expression of IFN-inducible chemokines and subsequently enhancing macrophage antimicrobial effects. Studies in mice-models also suggest a critical role of NK cells in the pulmonary clearance of *A. fumigatus* [59]*.*

Interestingly, in a study by Santiago et al., down-regulation of NK cell activating receptors NKG2D and NKp46 and a failure of full granule release was observed on contact of NK cells with *A. fumigatus* hyphae [59]. They also reported *A. fumigatus*mediated NK cell immune-paresis which reduces cytokine-mediated response causing immune evasion during pulmonary aspergillosis [59]. Characterization of the clinical impact of NK cells in antifungal host immune response is still in its nascent stage as it involves complex interplay between multiple arms of the immune system [60].

#### **6.7 Dendritic cells**

Dendritic cells (DCs) bridge the innate and adaptive immune responses. They not only sense and patrol the lung environment but also initiate host response by antigen presentation which primes the T cell responses and causes cytokine secretion. Immature DCs are phagocytic and constantly perform surveillance of the lung environment while expressing PRRs like TLR 1, 2, 3, 4, 6 and Dectin-1 on cell surface that recognize various pathogen-associated molecular patterns (PAMPs). After phagocytosis, *A. fumigatus* conidia have been reported to escape from DCs, whereas some species like *A. terreus* persist with long-term survival, protecting them from anti-fungal action [49].

Typically, DCs are of two types, the plasmacytoid (pDCs) which are IFNα (type I interferon)-producing cells with a significant role in antifungal response and Classical (cDCs) which remain in the lymphoid tissue and cross-present antigens to T cells [61]. There is considerable plasticity in the functional activity of pulmonary DCs depending on the morphology of invading fungus [62].


#### *Immunopathogenesis of Aspergillosis DOI: http://dx.doi.org/10.5772/intechopen.98782*


#### **7. Interaction with the adaptive immune system**

The adaptive immune response to *Aspergillus* infection is depicted in **Figure 3**.

#### **7.1 Role of T-cells**

Antigen-specific Th1 cells are crucial sources of IFN-γ mediated protective immunity to *A. fumigatus* [18, 58]. Peripheral blood of healthy adult donors has been found to have *A. fumigatus* specific effector/memory CD4 T cells with Th1 phenotype [63, 64]. A Th17 phenotype is noted in lung-derived *Aspergillus-*specific T cells [65]. IL-22 is produced by Th17 cells and has shown to play a crucial role in regulating *Aspergillus* induced asthma [66]. Like neutrophils, Th17 responses represent a "double-edged sword". During pulmonary fungal infections, the Th17 cell usually display a highly pro-inflammatory profile, which is detrimental to the infected host.

The Th2 cell-mediated immune responses along with Th1 and Th17 induces chronic pulmonary inflammation and lead to significant lung damage [67, 68]. This

#### **Figure 3.**

*Adaptive immune response to* aspergillus *infection.* Aspergillus *spp. antigens are presented to naive T cells in peripheral lymphoid organs by dendritic cells and macrophages which further induces inflammation with coevolution of Th1, Th2, and Th17 response. B cells are also stimulated resulting in formation of anti-fungal antibody producing plasma cells.*

allows influx of macrophages followed by differentiation of both M1 and M2 subtypes [69]. These macrophages and T cells play a key role subsequently promoting extensive remodeling of medium- and small-sized pulmonary arteries. Pulmonary artery pathology including an increase in intimal area, smooth muscle proliferation, calcification of elastic membrane, and narrowed arterial lumens is seen in those with fatal asthma [70].

In healthy subjects, a strong Treg response has been seen as a part of the normal physiological T-cell repertoire which counterbalances the *A. fumigatus* specific T cells [71]. This intriguing finding raises the possibility that colonizing *A. fumigatus* may selectively promote Treg responses and subsequently limit antifungal immune activity. Activation of indoleamine 2,3- dioxygenase (IDO) as a regulator of infection-linked tissue pathology is now being recognized as it acts via local tryptophan depletion, or generation of immunomodulatory metabolites. Interaction of TLRs with PAMPs induces IDO which regulates the inflammatory/anti-inflammatory status of the innate immune cell and modifies the local tissue microenvironment. There is also activation of GCN2, a T-cell stress-response kinase which senses amino acid starvation and impairs lymphocyte proliferation while enhancing polarization toward a Treg phenotype [72]. In patients of CF with ABPA, dysregulation of the IDO pathway is seen at both the genetic and transcriptional levels, leading to an imbalanced Th17/Treg with high Th2 polarization resulting in chronic inflammation and significant lung damage in response to *A. fumigatus* [73].

#### **7.2 Role of B-cells**

In a study by Montagnoli et al., the role of B cells and antibodies in the generation of antifungal immune resistance was studied in B cell-deficient (*μ*MT) mice which were infected with *A. fumigatus* [74]*.* They reported that, although passive transfer of antibodies helped in fungal clearance, a compensatory increase in both innate and Th1-mediated resistance to infection was seen in *μ*MT mice with aspergillosis. This suggests that in the absence of opsonizing antifungal antibodies, the nature of the interaction between the innate immune cells and with fungi may be modified with subsequent development of long-lasting antifungal immunity [74].

Chen et al., demonstrated that basophil interaction with IgD bound antigens and activation of TLRs induces expression of B-cell-activating factor (BAFF), an important regulator of B-cell activation, proliferation, and immunoglobulin production. This results in IgG and IgE production by B cells, pointing to a role of basophils in adaptive immune responses [75]. In a study by Boita et al. stimulation of basophil membrane by *Aspergillus* resulted in upregulation of BAFF expression in patients with SAFS and ABPA. These patients had high IgE suggesting the role of basophils in polyclonal IgE production [76].

#### **8. Role of the microbiome**

Host immune responses are influenced by changes in the gut microbiome. Shortchain fatty acids (SCFAs) produced by the gut microbiome are recognized by innate immune cells like macrophages and neutrophils expressing G-coupled protein receptor GPR43 [77]. The gut microbiome also plays a crucial role in anti-*Aspergillus* host defense by coordinating lymphocyte subsets at the mucosal level in distant organs such as the lungs. Although, fungal microbiome compromise <0.1% of total microbiome, fungal cell components such as β-glucans may influence immune responses as perceived by their role in autoimmune diseases [78]. *In-vivo* studies in mice have revealed that intake of SCFA (propionate/butyrate) or supplementation

#### *Immunopathogenesis of Aspergillosis DOI: http://dx.doi.org/10.5772/intechopen.98782*

of diet with fermentable fibers which increases SCFA producing bacteria, increases the generation of DCs and macrophages in the lung and bone marrow with increased phagocytic capacity [79–81]. These alterations also reduce the ability to prime cells toward Th2 responses lowering DC ability to induce *Aspergillus*-allergic inflammation [82].

The intestinal segmented filamentous bacterium (SFB) have been shown to induce Th17 cells producing IL-17 and IL-22 in the lamina propria of the gut and can even regulate pulmonary adaptive immune response by increasing Th17 responses in the lung [83, 84]. However, it is important to determine whether lung microbiome also has similar Th17-polarizing ability which can influence anti-*Aspergillus* host response.

It has also been observed that in germ-free mice, the absence of commensal gut microbiota leads to increase susceptibility to pulmonary viral infections. Hence, the gut microbiome can influence pulmonary immune responses by release of type 1 IFN [85, 86]. Intestinal colonization of microorganism is necessary for cytotoxic activity by NK-cell, CD8+ T-cell clonal expansion, and production of specific antibodies [85].

Recently, innate lymphoid cells (ILCs) have emerged as an important cell population that has the capacity to synchronize microbiome-related immune regulation [87]. ILCs can express functional TLR2 which on stimulation induces IL-2 production, subsequently increasing the expression of IL-22, enhancing the allergic airway responses induced by *Aspergillus* spp [88]. It has also been observed that commensal bacterial limit the production of serum IgE levels which directly influences bone marrow - basophil precursors, leading to increased allergic airway responses [89].

The treatment of diseases like COPD with steroids and bronchodilators, may also alter the microbiome [90] which can subsequently increase the risk of colonization and infection by *Aspergillus* spp. In patients with Influenza, significant changes in the lung microbiome have been observed with a relative abundance of *Firmicutes* and *Proteobacteria* more specifically, *Pseudomonas* spp., which contributes to secondary invasive infections by *Aspergillus* spp. [91, 92]. Other factors like antibiotic exposure can also influence the micro-environment of the microbiome, which can affect the pulmonary immune responses to *Aspergillus* causing allergic airway diseases [93]. In patients with CF, interaction between fungal and bacterial pathogens and their biofilms may influence pathogenicity which can be observed by significant decrease in *Aspergillus* in the sputum on treatment with anti-pseudomonal antibiotics [94, 95].

#### **9. Genetic susceptibility to aspergillosis**

The genetic polymorphisms within pattern recognition receptors PRRs (*TLR1, TLR2, TLR4, TLR5, TLR6, TLR9, Dectin-1, Dectin-2, DC-SIGN, MASP, MBL, PTX-3* surfactant protein-A2 and plaminogen) cytokines (*IL1, IL10,* IFN- γ, *CXCL10, ARNT2,)* and their receptors (*CX3CR1* and IL-4Rα) is depicted in –**Table 2**.

#### **10. Conclusion**

The clinical spectrum of *Aspergillus* related infections depends on the host immune status ranging from allergic manifestations in immunocompetent atopic individuals to invasive disease in immunosuppressed individuals. Various components of the innate and adaptive immune system form an intricate network modulating host response to *Aspergillus* exposure. Many future studies are required to study


#### *Immunopathogenesis of Aspergillosis DOI: http://dx.doi.org/10.5772/intechopen.98782*


#### *The Genus* Aspergillus *- Pathogenicity, Mycotoxin Production and Industrial Applications*


TLR-Toll-like receptor, IL – Interleukin, PRR – Pathogen Recognition Receptor, *Th – T helper cells, DC-SIGN - Dendritic Cell-Specific Intercellular adhesion molecule-3-Grabbing Non-integrin, PTX3- Pentraxin,* MASP2 - Mannose-binding lectin-associated serine protease, MBL - Mannose-binding lectin*, CXCL - chemokine (C-X-C motif) ligand,* ARNT2 - *Aryl hydrocarbon receptor nuclear translocator 2, IL-4R alpha - Interleukin 4 receptor alpha, TNFR2 - TNF receptor type 2,* IRF4 *Interferon regulatory factor - 4,* CX3CR1 *- CX3C chemokine receptor 1, IA- invasive aspergillosis, IPA- invasive pulmonary aspergillosis, CCPA- Chronic cavitary pulmonary aspergillosis, ABPA – Allergic bronchopulmonary aspergillosis, CNPA – Chronic necrotizing pulmonary aspergillosis, HSCT-Hematopoietic stem cell transplantation, EORTC- European Organization for Research and Treatment of Cancer.*

#### **Table 2.**

*Summary of immune system related genes mediating susceptibility to aspergillosis.*

the association and impact of the complex interactions between the gut/pulmonary microbiome and the immune system in *Aspergillus*-related diseases. An understanding of the immune pathogenesis of aspergillosis can help in the development of strategies targeting *Aspergillus* itself as well as pulmonary or systemic immunity by influencing the host immune system, the microbiome and/or its metabolites.

#### **Acknowledgements**

All artworks are original and was prepared using the trial version of the online Biorender software.

#### **Author details**

Shreya Singh, Rimjhim Kanaujia and Shivaprakash M. Rudramurthy\* Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India

\*Address all correspondence to: mrshivprakash@yahoo.com

© 2021 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.

*Immunopathogenesis of Aspergillosis DOI: http://dx.doi.org/10.5772/intechopen.98782*

#### **References**

[1] Chakrabarti A: *Fungal infections in Asia : Eastern frontier of mycology*. Elsevier India 2014.

[2] Chakrabarti A, Chatterjee SS, Das A, Shivaprakash MR: Invasive aspergillosis in developing countries. *Medical Mycology* 2011:S35–S47.

[3] Holdom MD, Hay RJ, Hamilton AJ: Purification, n-terminal amino acid sequence and partial characterization of a Cu,Zn superoxide dismutase from the pathogenic fungus *Aspergillus fumigatus*. *Free Radic Res* 1995, 22:519-531.

[4] Kothary MH, Chase T, Macmillan JD: Correlation of elastase production by some strains of *Aspergillus fumigatus* with ability to cause pulmonary invasive aspergillosis in mice. *Infect Immun* 1984, 43:320-325.

[5] Ramesh M V, Sirakova T, Kolattukudy PE: Isolation, characterization, and cloning of cDNA and the gene for an elastinolytic serine proteinase from *Aspergillus flavus. Infect Immun* 1994, 62:79-85.

[6] Sirakova TD, Markaryan A, Kolattukudy PE: Molecular cloning and sequencing of the cDNA and gene for a novel elastinolytic metalloproteinase from *Aspergillus fumigatus* and its expression in *Escherichia coli. Infect Immun* 1994, 62:4208-4218.

[7] Reichard U, Eiffert H, Rüchel R: Purification and characterization of an extracellular aspartic proteinase from *Aspergillus fumigatus. Med Mycol* 1994, 32:427-436.

[8] Calera JA, Paris S, Monod M, Hamilton AJ, Debeaupuis JP, Diaquin M, López-Medrano R, Leal F, Latgé JP: Cloning and disruption of the antigenic catalase gene of *Aspergillus fumigatus*. *Infect Immun* 1997, 65:4718-4724.

[9] Krappmann S, Bignell EM, Reichard U, Rogers T, Haynes K, Braus GH: The *Aspergillus fumigatus* transcriptional activator CpcA contributes significantly to the virulence of this fungal pathogen. *Mol Microbiol* 2004, 52:785-799.

[10] Mullbacher A, Eichner RD: Immunosuppression in vitro by a metabolite of a human pathogenic fungus. *Proc Natl Acad Sci* 1984, 81:3835-3837.

[11] Mullbacher A, Waring P, Eichner Rd: Identification of an agent in cultures of *Aspergillus fumigatus* displaying anti-phagocytic and immunomodulating activity in vitro. *Microbiology* 1985, 131:1251-1258.

[12] Latgé JP, Moutaouakil M, Debeaupuis JP, Bouchara JP, Haynes K, Prévost MC: The 18-kilodalton antigen secreted by *Aspergillus fumigatus*. *Infect Immun* 1991, 59:2586-2594.

[13] Paris S, Monod M, Diaquin M, Lamy B, Arruda LK, Punt PJ, Latgé JP: A transformant of *Aspergillus fumigatus* deficient in the antigenic cytotoxin ASPFI. *FEMS Microbiol Lett* 1993, 111:31-36.

[14] Robens JF, Richard JL: Aflatoxins in Animal and Human Health. *Rev Environ Contam Toxicol.* 1992:69-94.

[15] Eissenberg LG, Schlesinger PH, Goldman WE: Phagosome-Lysosome Fusion in P388D1 macrophages infected with *Histoplasma capsulatum*. *J Leukoc Biol* 1988, 43:483-491.

[16] Hermanowski-Vosatka A, Detmers PA, Götze O, Silverstein SC, Wright SD: Clustering of ligand on the surface of a particle enhances adhesion to receptor-bearing cells. *J Biol Chem* 1988, 263:17822-7.

[17] Valsecchi I, Dupres V, Stephen-Victor E, Guijarro JI, Gibbons J, Beau R, Bayry J, Coppee JY, Lafont F, et al.: Role of Hydrophobins in *Aspergillus fumigatus*. *J Fungi* (Basel). 2017, 24;4:2.

[18] Alastruey-Izquierdo A, Cadranel J, Flick H, Godet C, Hennequin C, Hoenigl M, Kosmidis C, Lange C, Munteanu O, Page I, et al.: Treatment of Chronic Pulmonary Aspergillosis: Current Standards and Future Perspectives. *Respiration* 2018, 96:159-170.

[19] Denning DW, Cadranel J, Beigelman-Aubry C, Ader F, Chakrabarti A, Blot S, Ullmann AJ, Dimopoulos G, Lange C: Chronic pulmonary aspergillosis: Rationale and clinical guidelines for diagnosis and management. *Eur Respir J* 2016, 47:45-68.

[20] Agarwal R, Chakrabarti A, Shah A, Gupta D, Meis JF, Guleria R, Moss R, Denning DW: Allergic bronchopulmonary aspergillosis: Review of literature and proposal of new diagnostic and classification criteria. *Clin Exp Allergy* 2013, doi:10.1111/cea.12141.

[21] Singh M, Paul N, Singh S, Nayak GR: Asthma and Fungus: Role in Allergic Bronchopulmonary Aspergillosis (ABPA) and Other Conditions. *Indian J Pediatr* 2018, 85:899-904.

[22] Azie N, Neofytos D, Pfaller M, Meier-Kriesche HU, Quan SP, Horn D: The PATH (Prospective Antifungal Therapy) Alliance® registry and invasive fungal infections: Update 2012. *Diagn Microbiol Infect Dis* 2012, 73:293-300.

[23] Brown GD, Denning DW, Gow NAR, Levitz SM, Netea MG, White TC: Hidden Killers: Human Fungal Infections. *Sci Transl Med* 2012, 4:165rv13-165rv13.

[24] Alangaden GJ, Wahiduzzaman M, Chandrasekar PH: Aspergillosis: The Most Common Community-Acquired Pneumonia with Gram-Negative Bacilli as Copathogens in Stem Cell Transplant Recipients with Graft-versus-Host Disease. *Clin Infect Dis* 2002, 35:659-664.

[25] Schauwvlieghe AFAD, Rijnders BJA, Philips N, Verwijs R, Vanderbeke L, Van Tienen C, Lagrou K, Verweij PE, Van de Veerdonk FL, Gommers D, et al.: Invasive aspergillosis in patients admitted to the intensive care unit with severe influenza: a retrospective cohort study. *Lancet Respir Med* 2018, 6:782-792.

[26] Drummond RA, Franco LM, Lionakis MS: Human CARD9: A Critical Molecule of Fungal Immune Surveillance. *Front Immunol* 2018, 9.

[27] Hodiamont CJ, Dolman KM, Ten berge IJM, Melchers WJG, Verweij PE, Pajkrt D: Multiple-azole-resistant *Aspergillus fumigatus* osteomyelitis in a patient with chronic granulomatous disease successfully treated with long-term oral posaconazole and surgery. *Med Mycol* 2009, 47:217-220.

[28] Mousavi B, Hedayati MT, Hedayati N, Ilkit M, Syedmousavi S: *Aspergillus* species in indoor environments and their possible occupational and public health hazards. *Curr Med Mycol* 2016, 2:36-42.

[29] Hedayati MT, Mohseni-Bandpi A, Moradi S: A survey on the pathogenic fungi in soil samples of potted plants from Sari hospitals, Iran. *J Hosp Infect* 2004, 58:59-62.

[30] Dagenais TRT, Keller NP: Pathogenesis of *Aspergillus fumigatus* in invasive aspergillosis. *Clin Microbiol Rev* 2009, 22:447-465.

[31] Vogl G, Lesiak I, Jensen DB, Perkhofer S, Eck R, Speth C,

#### *Immunopathogenesis of Aspergillosis DOI: http://dx.doi.org/10.5772/intechopen.98782*

Lass-Flörl C, Zipfel PF, Blom AM, Dierich MP, et al.: Immune evasion by acquisition of complement inhibitors: The mould *Aspergillus* binds both factor H and C4b binding protein. *Mol Immunol* 2008, 45:1485-1493.

[32] Washburn RG, DeHart DJ, Agwu DE, Bryant-Varela BJ, Julian NC: *Aspergillus fumigatus* complement inhibitor: production, characterization, and purification by hydrophobic interaction and thin-layer chromato graphy. *Infect Immun* 1990, 58.

[33] Kogan TV, Jadoun J, Mittelman L, Hirschberg K, Osherov N: Involvement of Secreted *Aspergillus fumigatus* Proteases in Disruption of the Actin Fiber Cytoskeleton and Loss of Focal Adhesion Sites in Infected A549 Lung Pneumocytes. *J Infect Dis* 2004, 189:1965-1973.

[34] Arias M, Santiago L, Vidal-García M, Redrado S, Lanuza P, Comas L, Domingo MP, Rezusta A, Gálvez EM: Preparations for invasion: Modulation of host lung immunity during pulmonary aspergillosis by gliotoxin and other fungal secondary metabolites. *Front Immunol* 2018, 9:2549.

[35] Sales-Campos H, Tonani L, Cardoso CRB, Kress MRVZ: The immune interplay between the host and the pathogen in *Aspergillus fumigatus* lung infection. *Biomed Res Int* 2013, 2013.

[36] Rosentul DC, Delsing CE, Jaeger M, Plantinga TS, Oosting M, Costantini I, Venselaar H, Joosten LAB, van der Meer JWM, Dupont B, et al.: Gene polymorphisms in pattern recognition receptors and susceptibility to idiopathic recurrent vulvovaginal candidiasis. *Front Microbiol* 2014, 5:483.

[37] Netea MG, Warris A, Van Der Meer JWM, Fenton MJ, Verver-Janssen TJG, Jacobs LEH, Andresen T, Verweij PE, Kullberg BJ: *Aspergillus fumigatus* evades immune recognition during germination through loss of toll-like receptor-4-mediated signal transduction. *J Infect Dis* 2003, 188:320-326.

[38] Bochud P-Y, Chien JW, Marr KA, Leisenring WM, Upton A, Janer M, Rodrigues SD, Li S, Hansen JA, Zhao LP, et al.: Toll-like Receptor 4 Polymorphisms and Aspergillosis in Stem-Cell Transplantation. *N Engl J Med* 2008, 359:1766-1777.

[39] Moreira AP, Cavassani KA, Ismailoglu UB, Hullinger R, Dunleavy MP, Knight DA, Kunkel SL, Uematsu S, Akira S, Hogaboam CM: The protective role of TLR6 in a mouse model of asthma is mediated by IL-23 and IL-17A. *J Clin Invest* 2011, 121:4420-4432.

[40] Bretz C, Gersuk G, Knoblaugh S, Chaudhary N, Randolph-Habecker J, Hackman RC, Staab J, Marr KA: MyD88 signaling contributes to early pulmonary responses to *Aspergillus fumigatus*. *Infect Immun* 2008, 76:952-958.

[41] Bellocchio S, Montagnoli C, Bozza S, Gaziano R, Rossi G, Mambula SS, Vecchi A, Mantovani A, Levitz SM, Romani L: The Contribution of the Toll-Like/IL-1 Receptor Superfamily to Innate and Adaptive Immunity to Fungal Pathogens In Vivo. *J Immunol* 2004, 172:3059-3069.

[42] Dubourdeau M, Athman R, Balloy V, Huerre M, Chignard M, Philpott DJ, Latgé J-P, Ibrahim-Granet O: *Aspergillus fumigatus* Induces Innate Immune Responses in Alveolar Macrophages through the MAPK Pathway Independently of TLR2 and TLR4. *J Immunol* 2006, 177:3994-4001.

[43] Li ZZ, Tao LL, Zhang J, Zhang HJ, Qu JM: Role of NOD2 in regulating the immune response to *Aspergillus* 

*fumigatus. Inflamm Res* 2012, 61: 643-648.

[44] Philippe B, Ibrahim-Granet O, Prévost MC, Gougerot-Pocidalo MA, Perez MS, Van der Meeren A, Latgé JP: Killing of *Aspergillus fumigatus* by alveolar macrophages is mediated by reactive oxidant intermediates. *Infect Immun* 2003, 71:3034-3042.

[45] De Castro CMMB, Manhães De Castro R, Fernandes De Medeiros A, Queirós Santos A, Ferreira E Silva WT, De Lima Filho JL: Effect of stress on the production of O2- in alveolar macrophages. *J Neuroimmunol* 2000, 108:68-72.

[46] Reeves EP, Lu H, Jacobs HL, Messina CGM, Bolsover S, Gabellall G, Potma EO, Warley A, Roes J, Segal AW: Killing activity of neutrophils is mediated through activation of proteases by K+ flux. *Nature* 2002, 416:291-297.

[47] Ibrahim-Granet O, Philippe B, Boleti H, Boisvieux-Ulrich E, Grenet D, Stern M, Latgé JP: Phagocytosis and intracellular fate of *Aspergillus fumigatus* conidia in alveolar macrophages. *Infect Immun* 2003, 71:891-903.

[48] Lapp K, Vödisch M, Kroll K, Strassburger M, Kniemeyer O, Heinekamp T, Brakhage AA: Characterization of the *Aspergillus fumigatus* detoxification systems for reactive nitrogen intermediates and their impact on virulence. *Front Microbiol* 2014, 5:469.

[49] Hsieh SH, Kurzai O, Brock M: Persistence within dendritic cells marks an antifungal evasion and dissemination strategy of *Aspergillus terreus. Sci Rep* 2017, 7:1-11.

[50] Bhatia S, Fei M, Yarlagadda M, Qi Z, Akira S, Saijo S, Iwakura Y, van Rooijen N, Gibson GA, St. Croix CM, et al.: Rapid host defense against

*Aspergillus fumigatus* involves alveolar macrophages with a predominance of alternatively activated phenotype. *PLoS One* 2011, 6.

[51] Braem SGE, Rooijakkers SHM, van Kessel KPM, de Cock H, Wösten HAB, van Strijp JAG, Haas P-JA: Effective Neutrophil Phagocytosis of *Aspergillus fumigatus* Is Mediated by Classical Pathway Complement Activation. *J Innate Immun* 2015, 7:364-374.

[52] Snarr BD, St-Pierre G, Ralph B, Lehoux M, Sato Y, Rancourt A, Takazono T, Baistrocchi SR, Corsini R, Cheng MP, et al.: Galectin-3 enhances neutrophil motility and extravasation into the airways during *Aspergillus fumigatus* infection. *PLOS Pathog* 2020, 16:e1008741.

[53] Feldmesser M: Role of neutrophils in invasive aspergillosis. *Infect Immun* 2006, 74:6514-6516.

[54] Gazendam RP, van Hamme JL, Tool ATJ, Hoogenboezem M, van den Berg JM, Prins JM, Vitkov L, van de Veerdonk FL, van den Berg TK, Roos D, et al.: Human Neutrophils Use Different Mechanisms To Kill *Aspergillus fumigatus* Conidia and Hyphae: Evidence from Phagocyte Defects. *J Immunol* 2016, 196:1272-1283.

[55] Leal SM, Roy S, Vareechon C, Carrion S de J, Clark H, Lopez-Berges MS, diPietro A, Schrettl M, Beckmann N, Redl B, et al.: Targeting Iron Acquisition Blocks Infection with the Fungal Pathogens *Aspergillus fumigatus* and *Fusarium oxysporum*. *PLoS Pathog* 2013, 9.

[56] Clark HL, Jhingran A, Sun Y, Vareechon C, de Jesus Carrion S, Skaar EP, Chazin WJ, Calera JA, Hohl TM, Pearlman E: Zinc and Manganese Chelation by Neutrophil S100A8/A9 (Calprotectin) Limits Extracellular *Aspergillus fumigatus*

*Immunopathogenesis of Aspergillosis DOI: http://dx.doi.org/10.5772/intechopen.98782*

Hyphal Growth and Corneal Infection . *J Immunol* 2016, 196:336-344.

[57] McCormick A, Heesemann L, Wagener J, Marcos V, Hartl D, Loeffler J, Heesemann J, Ebel F: NETs formed by human neutrophils inhibit growth of the pathogenic mold *Aspergillus fumigatus*. *Microbes Infect* 2010, 12:928-936.

[58] Park SJ, Hughes MA, Burdick M, Strieter RM, Mehrad B: Early NK Cell-Derived IFN-γ Is Essential to Host Defense in Neutropenic Invasive Aspergillosis. *J Immunol* 2009, 182:4306-4312.

[59] Santiago V, Rezvani K, Sekine T, Stebbing J, Kelleher P, Armstrong-James D: Human NK Cells Develop an Exhaustion Phenotype During Polar Degranulation at the *Aspergillus fumigatus* Hyphal Synapse. *Front Immunol* 2018, 9:2344.

[60] Zhang X, He D, Gao S, Wei Y, Wang L: *Aspergillus fumigatus* enhances human NK cell activity by regulating M1 macrophage polarization. *Mol Med Rep* 2019, 20:1241-1249.

[61] Reizis B, Bunin A, Ghosh HS, Lewis KL, Sisirak V: Plasmacytoid dendritic cells: Recent progress and open questions. *Annu Rev Immunol* 2011, 29:163-183.

[62] Bozza S, Gaziano R, Spreca A, Bacci A, Montagnoli C, di Francesco P, Romani L: Dendritic Cells Transport Conidia and Hyphae of *Aspergillus fumigatus* from the Airways to the Draining Lymph Nodes and Initiate Disparate Th Responses to the Fungus. *J Immunol* 2002, 168:1362-1371.

[63] Beck O, Topp MS, Koehl U, Roilides E, Simitsopoulou M, Hanisch M, Sarfati J, Latgé JP, Klingebiel T, Einsele H, et al.: Generation of highly purified and functionally active human TH1 cells against *Aspergillus fumigatus. Blood* 2006, 107:2562-2569.

[64] Vogel K, Pierau M, Arra A, Lampe K, Schlueter D, Arens C, Brunner-Weinzierl MC: Developmental induction of human T-cell responses against *Candida albicans* and *Aspergillus fumigatus. Sci Rep* 2018, 8:16904.

[65] Jolink H, de Boer R, Hombrink P, Jonkers RE, van Dissel JT, Falkenburg JHF, Heemskerk MHM: Pulmonary immune responses against *Aspergillus fumigatus* are characterized by high frequencies of IL-17 producing T-cells. *J Infect* 2017, 74:81-88.

[66] Lilly LM, Gessner MA, Dunaway CW, Metz AE, Schwiebert L, Weaver CT, Brown GD, Steele C: The β-Glucan Receptor Dectin-1 Promotes Lung Immunopathology during Fungal Allergy via IL-22. *J Immunol* 2012, 189:3653-3660.

[67] Murdock BJ, Shreiner AB, McDonald RA, Osterholzer JJ, White ES, Toews GB, Huffnagle GB: Coevolution of TH1, TH2, and TH17 responses during repeated pulmonary exposure to *Aspergillus fumigatus* conidia. *Infect Immun* 2011, 79:125-135.

[68] Shreiner AB, Murdock BJ, Akha AAS, Falkowski NR, Christensen PJ, White ES, Hogaboam CM, Huffnagle GB: Repeated exposure to *Aspergillus fumigatus* conidia results in CD4 + T cell-dependent and -independent pulmonary arterial remodeling in a mixed th1/th2/th17 microenvironment that requires interleukin-4 (IL-4) and IL-10. *Infect Immun* 2012, 80:388-397.

[69] Arora S, Olszewski MA, Tsang TM, McDonald RA, Toews GB, Huffnagle GB: Effect of cytokine interplay on macrophage polarization during chronic pulmonary infection with *Cryptococcus neoformans*. *Infect Immun* 2011, 79:1915-1926.

[70] Shiang C, Mauad T, Senhorini A, De Araújo BB, Ferreira DS, Da Silva LFF, Dolhnikoff M, Tsokos M, Rabe KF, Pabst R: Pulmonary periarterial inflammation in fatal asthma. *Clin Exp Allergy* 2009, 39:1499-1507.

[71] Dewi IMW, van de Veerdonk FL, Gresnigt MS: The multifaceted role of T-helper responses in host defense against *Aspergillus fumigatus. J Fungi* 2017, 3.

[72] Munn DH, Sharma MD, Baban B, Harding HP, Zhang Y, Ron D, Mellor AL: GCN2 kinase in T cells mediates proliferative arrest and anergy induction in response to indoleamine 2,3-dioxygenase. *Immunity* 2005, 22:633-642.

[73] Iannitti RG, Carvalho A, Cunha C, De Luca A, Giovannini G, Casagrande A, Zelante T, Vacca C, Fallarino F, Puccetti P, et al.: Th17/Treg imbalance in murine cystic fibrosis is linked to indoleamine 2,3-dioxygenase deficiency but corrected by kynurenines. *Am J Respir Crit Care Med* 2013, 187:609-620.

[74] Montagnoli C, Bozza S, Bacci A, Gaziano R, Mosci P, Morschhäuser J, Pitzurra L, Kopf M, Cutler J, Romani L: A role for antibodies in the generation of memory antifungal immunity. *Eur J Immunol* 2003, 33:1193-1204.

[75] Chen K, Xu W, Wilson M, He B, Miller NW, Bengtén E, Edholm ES, Santini PA, Rath P, Chiu A, et al.: Immunoglobulin D enhances immune surveillance by activating antimicrobial, proinflammatory and B cell-stimulating programs in basophils. *Nat Immunol* 2009, 10:889-898.

[76] Boita Enrico Heffler Stefano Pizzimenti Alberto Raie Elona Saraci Paola Omedè Claudia Bussolino Caterina Bucca Giovanni Rolla M, Mauriziano Umberto OI: Regulation of B-Cell-Activating Factor Expression on the

Basophil Membrane of Allergic Patients. *Int Arch Allergy Immunol* 2015, 166:208-212.

[77] Kim CH: Immune regulation by microbiome metabolites. *Immunology* 2018, 154:220-229.

[78] Galloway-Peña JR, Kontoyiannis DP: The gut mycobiome: The overlooked constituent of clinical outcomes and treatment complications in patients with cancer and other immunosuppressive conditions. *PLOS Pathog* 2020, 16:e1008353.

[79] Wu T, Li H, Su C, Xu F, Yang G, Sun K, Xu M, Lv N, Meng B, Liu Y, et al.: Microbiota-Derived Short-Chain Fatty Acids Promote LAMTOR2-Mediated Immune Responses in Macrophages. *mSystems* 2020, 5.

[80] Schulthess J, Pandey S, Capitani M, Rue-Albrecht KC, Arnold I, Franchini F, Chomka A, Ilott NE, Johnston DGW, Pires E, et al.: The Short Chain Fatty Acid Butyrate Imprints an Antimicrobial Program in Macrophages. *Immunity* 2019, 50:432-445.e7.

[81] Ciarlo E, Heinonen T, Herderschee J, Fenwick C, Mombelli M, Le Roy D, Roger T: Impact of the microbial derived short chain fatty acid propionate on host susceptibility to bacterial and fungal infections in vivo. *Sci Rep* 2016, 6:1-15.

[82] Trompette A, Gollwitzer ES, Yadava K, Sichelstiel AK, Sprenger N, Ngom-Bru C, Blanchard C, Junt T, Nicod LP, Harris NL, et al.: Gut microbiota metabolism of dietary fiber influences allergic airway disease and hematopoiesis. *Nat Med* 2014, 20:159-166.

[83] Ivanov II, Atarashi K, Manel N, Brodie EL, Shima T, Karaoz U, Wei D, Goldfarb KC, Santee CA, Lynch S V., et al.: Induction of Intestinal Th17 Cells by Segmented Filamentous Bacteria. *Cell* 2009, 139:485-498.

*Immunopathogenesis of Aspergillosis DOI: http://dx.doi.org/10.5772/intechopen.98782*

[84] McAleer JP, Nguyen NLH, Chen K, Kumar P, Ricks DM, Binnie M, Armentrout RA, Pociask DA, Hein A, Yu A, et al.: Pulmonary Th17 antifungal immunity is regulated by the gut microbiome. *J Immunol* 2016, 197:97-107.

[85] Ganal SC, Sanos SL, Kallfass C, Oberle K, Johner C, Kirschning C, Lienenklaus S, Weiss S, Staeheli P, Aichele P, et al.: Priming of natural killer cells by nonmucosal mononuclear phagocytes requires instructive signals from commensal microbiota. *Immunity* 2012, 37:171-186.

[86] Abt MC, Osborne LC, Monticelli LA, Doering TA, Alenghat T, Sonnenberg GF, Paley MA, Antenus M, Williams KL, Erikson J, et al.: Commensal bacteria calibrate the activation threshold of innate antiviral immunity. *Immunity* 2012, 37: 158-170.

[87] Sonnenberg GF, Artis D: Innate Lymphoid Cell Interactions with Microbiota: Implications for Intestinal Health and Disease. *Immunity* 2012, 37:601-610.

[88] Crellin NK, Trifari S, Kaplan CD, Satoh-Takayama N, Di Santo JP, Spits H: Regulation of cytokine secretion in human CD127+ LTi-like innate lymphoid cells by toll-like receptor 2. *Immunity* 2010, 33:752-764.

[89] Hill DA, Siracusa MC, Abt MC, Kim BS, Kobuley D, Kubo M, Kambayashi T, Larosa DF, Renner ED, Orange JS, et al.: Commensal bacteriaderived signals regulate basophil hematopoiesis and allergic inflammation. *Nat Med* 2012, 18:538-546.

[90] Pragman AA, Kim HB, Reilly CS, Wendt C, Isaacson RE: The Lung Microbiome in Moderate and Severe Chronic Obstructive Pulmonary Disease. *PLoS One* 2012, 7.

[91] Lynch S V.: Viruses and microbiome alterations. In *Annals of the American Thoracic Society*. . Ann Am Thorac Soc; 2014.

[92] Leung RKK, Zhou JW, Guan W, Li SK, Yang ZF, Tsui SKW: Modulation of potential respiratory pathogens by pH1N1 viral infection. *Clin Microbiol Infect* 2013, 19:930-935.

[93] Noverr MC, Noggle RM, Toews GB, Huffnagle GB: Role of antibiotics and fungal microbiota in driving pulmonary allergic responses. *Infect Immun* 2004, 72:4996-5003.

[94] Amin R, Dupuis A, Aaron SD, Ratjen F: The effect of chronic infection with *Aspergillus fumigatus* on lung function and hospitalization in patients with cystic fibrosis. *Chest* 2010, 137:171-176.

[95] Baxter CG, Rautemaa R, Jones AM, Kevin Webb A, Bull M, Mahenthiralingam E, Denning DW: Intravenous antibiotics reduce the presence of *Aspergillus* in adult cystic fibrosis sputum. *Thorax* 2013, 68:652-657.

[96] Kesh S, Mensah NY, Peterlongo P, Jaffe D, Hsu K, VAN DEN Brink M, O'reilly R, Pamer E, Satagopan J, Papanicolaou GA: TLR1 and TLR6 polymorphisms are associated with susceptibility to invasive aspergillosis after allogeneic stem cell transplantation. *Ann N Y Acad Sci* 2005, 1062:95-103.

[97] Lamoth F, Rubino I, Bochud P-Y: Immunogenetics of invasive aspergillosis. *Med Mycol* 2011, 49:S125–S136.

[98] Carvalho A, Pasqualotto AC, Pitzurra L, Romani L, Denning DW, Rodrigues F: Polymorphisms in toll-like receptor genes and susceptibility to pulmonary aspergillosis. *J Infect Dis* 2008, 197:618-621.

[99] de Boer MGJ, Jolink H, Halkes CJM, van der Heiden PLJ, Kremer D, Falkenburg JHF, van de Vosse E, van Dissel JT: Influence of Polymorphisms in Innate Immunity Genes on Susceptibility to Invasive Aspergillosis after Stem Cell Transplantation. *PLoS One* 2011, 6:e18403.

[100] Grube M, Loeffler J, Mezger M, Krüger B, Echtenacher B, Hoffmann P, Edinger M, Einsele H, Andreesen R, Holler E: TLR5 stop codon polymorphism is associated with invasive aspergillosis after allogeneic stem cell transplantation. *Med Mycol* 2013, 51:818-825.

[101] Pamer EG: TLR Polymorphisms and the Risk of Invasive Fungal Infections . *N Engl J Med* 2008, 359:1836-1838.

[102] Cunha C, Di Ianni M, Bozza S, Giovannini G, Zagarella S, Zelante T, D'Angelo C, Pierini A, Pitzurra L, Falzetti F, et al.: Dectin-1 Y238X polymorphism associates with susceptibility to invasive aspergillosis in hematopoietic transplantation through impairment of both recipient- and donor-dependent mechanisms of antifungal immunity. *Blood* 2010, 116:5394-5402.

[103] Chai LYA, de Boer MGJ, van der Velden WJFM, Plantinga TS, van Spriel AB, Jacobs C, Halkes CJM, Vonk AG, Blijlevens NM, van Dissel JT, et al.: The Y238X Stop Codon Polymorphism in the Human β-Glucan Receptor Dectin-1 and Susceptibility to Invasive Aspergillosis. *J Infect Dis* 2011, 203:736-743.

[104] Sainz J, Lupiáñez CB, Segura-Catena J, Vazquez L, Ríos R, Oyonarte S, Hemminki K, Försti A, Jurado M: Dectin-1 and DC-SIGN polymorphisms associated with invasive pulmonary aspergillosis infection. *PLoS One* 2012, 7.

[105] Cunha C, Aversa F, Lacerda JF, Busca A, Kurzai O, Grube M, Löffler J, Maertens JA, Bell AS, Inforzato A, et al.: Genetic PTX3 Deficiency and Aspergillosis in Stem-Cell Transplantation. *N Engl J Med* 2014, 370:421-432.

[106] Wójtowicz A, Lecompte TD, Bibert S, Manuel O, Rüeger S, Berger C, Boggian K, Cusini A, Garzoni C, Hirsch H, et al.: PTX3 Polymorphisms and Invasive Mold Infections after Solid Organ Transplant. *Clin Infect Dis* 2015, 61:619-622.

[107] Sainz J, Pérez E, Hassan L, Moratalla A, Romero A, Collado MD, Jurado M: Variable Number of Tandem Repeats of TNF Receptor Type 2 Promoter as Genetic Biomarker of Susceptibility to Develop Invasive Pulmonary Aspergillosis. *Hum Immunol* 2007, 68:41-50.

[108] Vaid M, Kaur S, Sambatakou H, Madan T, Denning DW, Sarma PU: Distinct alleles of mannose-binding lectin (MBL) and surfactant proteins A (SP-A) in patients with chronic cavitary pulmonary aspergillosis and allergic bronchopulmonary aspergillosis. *Clin Chem Lab Med* 2007, 45:183-186.

[109] Kaur S, Gupta VK, Thiel S, Sarma PU, Madan T: Protective role of mannan-binding lectin in a murine model of invasive pulmonary aspergillosis. *Clin Exp Immunol* 2007, 148:382-389.

[110] Crosdale DJ, Poulton K V., Ollier WE, Thomson W, Denning DW: Mannose-binding lectin gene polymorphisms as a susceptibility factor for chronic necrotizing pulmonary aspergillosis. *J Infect Dis* 2001, 184:653-656.

[111] Borta S, Popetiu R, Donath-Miklos I, Puschita M: Genetic Polymorphism of MBL 2 in Patients

*Immunopathogenesis of Aspergillosis DOI: http://dx.doi.org/10.5772/intechopen.98782*

with Allergic Bronchial Asthma. *Maedica (Buchar)* 2019, 14:208-212.

[112] Lambourne J, Agranoff D, Herbrecht R, Buchbinder A, Willis F, Letscher-Bru V, Agrawal S, Doffman S, Johnson E, White PL, et al.: Association of mannose-binding lectin deficiency with acute invasive aspergillosis in immunocompromised patients. *Clin Infect Dis* 2009, 49:1486-1491.

[113] Carvalho A, Cunha C, Di Ianni M, Pitzurra L, Aloisi T, Falzetti F, Carotti A, Bistoni F, Aversa F, Romani L: Prognostic significance of genetic variants in the IL-23/Th17 pathway for the outcome of T cell-depleted allogeneic stem cell transplantation. *Bone Marrow Transplant* 2010, 45:1645-1652.

[114] Zaas AK, Liao G, Chien JW, Weinberg C, Shore D, Giles SS, Marr KA, Usuka J, Burch LH, Perera L, et al.: Plasminogen alleles influence susceptibility to invasive aspergillosis. *PLoS Genet* 2008, 4.

[115] Cunha C, Rodrigues F, Zelante T, Aversa F, Romani L, Carvalho A: Genetic susceptibility to aspergillosis in allogeneic stem-cell transplantation. In *Medical Mycology*. . Oxford Academic; 2011:S137–S143.

[116] Tanpaibule T, Jinawath N, Taweewongsounton A, Niparuck P, Rotjanapan P: Genetic Risk Surveillance for Invasive Aspergillosis in Hematology Patients: A Prospective Observational Study. *Infect Dis Ther* 2020, 9:807-821.

[117] Saxena S, Madan T, Shah A, Muralidhar K, Sarma PU: Association of polymorphisms in the collagen region of SP-A2 with increased levels of total IgE antibodies and eosinophilia in patients with allergic bronchopulmonary aspergillosis. *J Allergy Clin Immunol* 2003, 111:1001-1007.

[118] Madan T, Kaur S, Saxena S, Singh M, Kishore U, Thiel S, Reid KBM, Sarma PU: Role of collectins in innate immunity against aspergillosis. *Med Mycol* 2005, 43:155-163.

[119] Guo Y, Kasahara S, Jhingran A, Tosini NL, Zhai B, Aufiero MA, Mills KAM, Gjonbalaj M, Espinosa V, Rivera A, et al.: During *Aspergillus* Infection, Monocyte-Derived DCs, Neutrophils, and Plasmacytoid DCs Enhance Innate Immune Defense through CXCR3-Dependent Crosstalk. *Cell Host Microbe* 2020, 28:104-116.e4.

[120] Fisher CE, Hohl TM, Fan W, Storer BE, Levine DM, Zhao LP, Martin PJ, Warren EH, Boeckh M, Hansen JA: Validation of single nucleotide polymorphisms in invasive aspergillosis following hematopoietic cell transplantation. *Blood* 2017, 129:2693-2701.

[121] Mezger M, Steffens M, Beyer M, Manger C, Eberle J, Toliat MR, Wienker TF, Ljungman P, Hebart H, Dornbusch HJ, et al.: Polymorphisms in the chemokine (C-X-C motif) ligand 10 are associated with invasive aspergillosis after allogeneic stem-cell transplantation and influence CXCL10 epression in monocyte-derived dendritic cells. *Blood* 2008, 111:534-536.

[122] Lupiañez CB, Martínez-Bueno M, Sánchez-Maldonado JM, Badiola J, Cunha C, Springer J, Lackner M, Segura-Catena J, Canet LM, Alcazar-Fuoli L, et al.: Polymorphisms within the ARNT2 and CX3CR1 genes are associated with the risk of developing invasive aspergillosis. *Infect Immun* 2020, 88:882-901.

[123] Lupiañez CB, Canet LM, Carvalho A, Alcazar-Fuoli L, Springer J, Lackner M, Segura-Catena J, Comino A, Olmedo C, Ríos R, et al.: Polymorphisms in host immunity-modulating genes and risk of invasive aspergillosis: Results

from the AspBIOmics Consortium. *Infect Immun* 2016, 84:643-657.

[124] Brouard J, Knauer N, Boelle PY, Corvol H, Henrion-Caude A, Flamant C, Bremont F, Delaisi B, Duhamel JF, Marguet C, et al.: Influence of interleukin-10 on *Aspergillus fumigatus* infection in patients with cystic fibrosis. *J Infect Dis* 2005, 191:1988-1991.

[125] Seo KW, Kim DH, Sohn SK, Lee NY, Chang HH, Kim SW, Jeon SB, Baek JH, Kim JG, Suh JS, et al.: Protective role of interleukin-10 promoter gene polymorphism in the pathogenesis of invasive pulmonary aspergillosis after allogeneic stem cell transplantation. *Bone Marrow Transplant* 2005, 36:1089-1095.

[126] Sainz J, Hassan L, Perez E, Romero A, Moratalla A, López-Fernández E, Oyonarte S, Jurado M: Interleukin-10 promoter polymorphism as risk factor to develop invasive pulmonary aspergillosis. *Immunol Lett* 2007, 109:76-82.

[127] Knutsen AP, Kariuki B, Consolino JD, Warrier MR: IL-4 alpha chain receptor (IL-4Rα) polymorphisms in allergic bronchopulmonary sspergillosis. *Clin Mol Allergy* 2006, 4.

[128] Lupiañez CB, Villaescusa MT, Carvalho A, Springer J, Lackner M, Sánchez-Maldonado JM, Canet LM, Cunha C, Segura-Catena J, Alcazar-Fuoli L, et al.: Common genetic polymorphisms within NFκB-related genes and the risk of developing invasive aspergillosis. *Front Microbiol* 2016, 7:1243.

## Section 2
