β-Glucan exacerbates allergic asthma independent of fungal sensitization and promotes steroid-resistant T_H2/T_H17 responses

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• 作者：Zhonghua Zhang ; MD^a ; ^c ; Jocelyn M. Biagini Myers ; PhD^a ; ^c ; Eric B. Brandt ; PhD^a ; ^c ; Patrick H. Ryan ; PhD^b ; ^c ; Mark Lindsey ; BS^a ; ^c ; Rachael A. Mintz-Cole ; MD ; PhD^a ; ^c ; Tiina Reponen ; PhD^d ; Stephen J. Vesper ; PhD^f ; Frank Forde ; BS^a ; ^c ; Brandy Ruff ; BS^a ; ^c ; Stacey A. Bass ; AS^a ; ^c ; Grace K. LeMasters ; PhD^a ; ^c ; ^d ; David I. Bernstein ; MD^e ; James Lockey ; MD^d ; Alison L. Budelsky ; PhD^g ; Gurjit K. Khurana Hershey ; MD ; PhD^a ; ^c ; ^{Gurjit.Hershey@cchmc.org}
• 关键词：Childhood asthma ; β-glucan ; fungi ; house dust mite ; IL-17A ; fungal exposure ; allergy
• 刊名：Journal of Allergy and Clinical Immunology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：139
• 期：1
• 页码：54-65.e8
• 全文大小：4623 K
• 卷排序：139

文摘

Allergic sensitization to fungi has been associated with asthma severity. As a result, it has been largely assumed that the contribution of fungi to allergic disease is mediated through their potent antigenicity.ObjectiveWe sought to determine the mechanism by which fungi affect asthma development and severity.MethodsWe integrated epidemiologic and experimental asthma models to explore the effect of fungal exposure on asthma development and severity.ResultsWe report that fungal exposure enhances allergen-driven TH2 responses, promoting severe allergic asthma. This effect is independent of fungal sensitization and can be reconstituted with β-glucan and abrogated by neutralization of IL-17A. Furthermore, this severe asthma is resistant to steroids and characterized by mixed TH2 and TH17 responses, including IL-13+IL-17+CD4+ double-producing effector T cells. Steroid resistance is dependent on fungus-induced TH17 responses because steroid sensitivity was restored in IL-17rc−/− mice. Similarly, in children with asthma, fungal exposure was associated with increased serum IL-17A levels and asthma severity.ConclusionOur data demonstrate that fungi are potent immunomodulators and have powerful effects on asthma independent of their potential to act as antigens. Furthermore, our results provide a strong rationale for combination treatment strategies targeting IL-17A for this subgroup of fungus-exposed patients with difficult-to-treat asthma.