Aspergillus fumigatus alkaline protease 1 (Alp1/Asp f13) in the airways correlates with asthma severity

• Published in: Journal of allergy and clinical immunology Vol. 141; no. 1; pp. 423 - 425.e7
• Main Authors: Basu, Trisha, Seyedmousavi, Seyedmojtaba, Sugui, Janyce A., Balenga, Nariman, Zhao, Ming, Kwon Chung, Kyung Joo, Biardel, Sabrina, Laviolette, Michel, Druey, Kirk M.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2018; Elsevier Limited
• Subjects: Allergens - immunology; Allergies; Aspergillus fumigatus; Aspergillus fumigatus - enzymology; Aspergillus fumigatus - immunology; Asthma; Asthma - diagnosis; Asthma - immunology; Bacterial Proteins - immunology; Corticosteroids; Cytokines; Endopeptidases - immunology; Gene expression; Humans; Leukocytes (eosinophilic); Mucous membrane; Neutrophils; Respiratory Mucosa - immunology; Respiratory Mucosa - microbiology; Respiratory Mucosa - pathology; Severity of Illness Index; Smooth muscle; Toll-like receptors
• ISSN: 0091-6749; 1097-6825; 1097-6825
• DOI: 10.1016/j.jaci.2017.07.034

Alp1 immunostaining in airways of patients receiving short- or long-acting β-agonists only was significantly less than in the airways of patients requiring long-acting β-agonists plus inhaled corticosteroids, and Alp1 quantities correlated with inhaled corticosteroid requirement (fluticasone equivalent dose; Fig 2, C and D). Because we detected Alp1 in bronchoalveolar lavage fluid of A fumigatus-sensitized and challenged mice but not naive mice by means of immunoblotting, we determined whether it could also be measured noninvasively in sputum from human subjects using immunoblotting. Chronic fungal exposure is linked to asthma exacerbations in both children and adults.4 In experimental models of asthma in mice, chronic respiratory inoculation with fungi induces a more severe asthma phenotype than inhalation of other allergens, such as house dust mite, through IL-33-dependent yet steroid-independent mechanisms.5 Alp1 is the major serine protease secreted by A fumigatus, and serine proteinase activity is crucial for A fumigatus to induce allergic airway inflammation and airway hyperresponsiveness.6,7 Here we found equivalent Alp1 quantities in the airways regardless of A fumigatus sensitivity and no correlation between sputum Alp1 levels and eosinophil counts, suggesting that an IgE/type 2 response to A fumigatus is not strictly required for the pathogenicity of Alp1 in asthmatic patients. Alp1 also activates mucin gene expression in airway epithelial cells, which could further impede fungal clearance. Because our study was retrospective and cross-sectional, we could not address the utility of Alp1 measurements to evaluate longitudinal parameters, including disease control and progression, or responses to specific treatments. Control subjects Patients with mild-to-moderate asthma (no Af sensitivity) Patients with mild-to-moderate asthma (Af sensitivity) Severe asthma (no Af sensitivity) Severe asthma (Af sensitivity) No. 10 7 7 8 7 Age (y)∗ 36.8 (21-66) 44.1 (18-61) 64.1 (51-78) 47.8 (25-71) 54.4 (23-79) BMI (kg/m2)† 28.23 (1.59) 30.64 (2.63) 25.37 (1.45) 28.40 (1.24) 30.64 (1.98) Male/female sex 6/4 5/2 4/3 4/4 2/5 Never/current/ex-smokers 8/0/2 2/2/3 3/2/2 3/0/5 3/0/4 Atopy‡ 9 (90) 7 (100) 5 (71.43) 6 (75) 7 (100) Positive Af skin prick test response‡ 3 (30) 0 (0) 7 (100) 0 (0) 7 (100) Sputum eosinophils (%) 3.1 (2.6) 2.8 (0.7) 10.96 (7.2) 2.2 (1.12) 13.1 (6.2) Sputum neutrophils (%) 30.8 (6.4) 48.9 (7.7) 60 (9.97) 52.7 (9.1) 45.7 (8.6) FEV1 (% predicted)∗ 103.6 (92-132) 75.6 (47-100) 68.1 (33-82) 77.7 (57-104) 70.0 (51-82) PC20FEV1 (mg/mL)§ >=16 2.31 0.11 5.29 (3.67-7.06) NA BD response (%)† −2.3 (1.86) 6.7 (3.70) 3.4 (2.38) 7.2 (2.47) 6.4 (2.58) ICSs‖ 0 (0) 7 (250-500) 7 (250-500) 8 (1000-3000) 7 (1000-1750) 1 D.W. Denning, C. Pashley, D. Hartl, A. Wardlaw, C. Godet, S. Del Giacco, Fungal allergy in asthma-state of the art and research needs, Clin Transl Allergy, Vol. 4, 2014, 14 2 N.A. Balenga, M. Klichinsky, Z. Xie, E.C. Chan, M. Zhao, J. Jude, A fungal protease allergen provokes airway hyper-responsiveness in asthma, Nat Commun, Vol. 6, 2015, 6763 3 J. Behnsen, F. Lessing, S. Schindler, D. Wartenberg, I.D. Jacobsen, M. Thoen, Secreted Aspergillus fumigatus protease Alp1 degrades human complement proteins C3, C4, and C5, Infect Immun, Vol. 78, 2010, 3585-3594 4 R. Agarwal, Severe asthma with fungal sensitization, Curr Allergy Asthma Rep, Vol. 11, 2011, 403-413 5 S. Castanhinha, R. Sherburn, S. Walker, A. Gupta, C.J. Bossley, J. Buckley, Pediatric severe asthma with fungal sensitization is mediated by steroid-resistant IL-33, J Allergy Clin Immunol, Vol. 136, 2015, 312-322.e7 6 S. Namvar, P. Warn, E. Farnell, M. Bromley, M. Fraczek, P. Bowyer, Aspergillus fumigatus, proteases, Asp f 5 and Asp f 13, are essential for airway inflammation and remodelling in a murine inhalation model, Clin Exp Allergy, Vol. 45, 2015, 982-993 7 V.O. Millien, W. Lu, J. Shaw, X. Yuan, G. Mak, L. Roberts, Cleavage of fibrinogen by proteinases elicits allergic responses through Toll-like receptor 4, Science, Vol. 341, 2013, 792-796 8 H.F. Kauffman, J.F. Tomee, M.A. van de Riet, A.J. Timmerman, P. Borger, Protease-dependent activation of epithelial cells by fungal allergens leads to morphologic changes and cytokine production, J Allergy Clin Immunol, Vol. 105, 2000, 1185-1193 9 P. Borger, G.H. Koeter, J.A. Timmerman, E. Vellenga, J.F. Tomee, H.F. Kauffman, Proteases from Aspergillus fumigatus induce interleukin (IL)-6 and IL-8 production in airway epithelial cell lines by transcriptional mechanisms, J Infect Dis, Vol. 180, 1999, 1267-1274