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Elevated levels of circulating CD 4 + CRT h2 + T cells characterize severe asthma
Author(s) -
Palikhe N. S.,
Laratta C.,
Nahirney D.,
Vethanayagam D.,
Bhutani M.,
Vliagoftis H.,
Cameron L.
Publication year - 2016
Publication title -
clinical and experimental allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 154
eISSN - 1365-2222
pISSN - 0954-7894
DOI - 10.1111/cea.12741
Subject(s) - asthma , microbiology and biotechnology , chemistry , immunology , medicine , biology
Summary Background Chemoattractant receptor‐homologous molecule expressed on Th2 cells ( CRT h2) is a receptor for PGD 2 and expressed by T cells, eosinophils, basophils, and ILC 2 cells. CRT h2 expression by CD 4 + T cells identifies the Th2 subset, and these cells have been characterized as allergen‐specific central memory Th2 cells. Recently, activation of the PGD 2 ‐ CRT h2 pathway in the lungs was associated with severe asthma. Objective To assess circulating levels of Th2 cells and related mediators in severe asthma and those who experience asthma exacerbations. Methods Peripheral blood cells expressing CRT h2 were characterized by flow cytometry and qRT ‐ PCR . Serum IL ‐13 and PGD 2 were measured by ELISA and compared with asthma severity and tendency to exacerbate. Results Severe asthmatics had more circulating CD 4 + CRT h2 + T cells, CRT h2 and GATA 3 mRNA , and a higher level of serum IL ‐13 compared to mild/moderate asthmatics. The proportion of CD 4 + CRT h2 + T cells was associated with lower lung function and was highest in severe asthmatics that exacerbated in the last year. Circulating CD 4 + CRT h2 + T cells, unlike eosinophils, were positively correlated with inhaled steroid dose. Conclusions and Clinical Relevance Elevated levels of circulating CD 4 + CRT h2 + T cells are a feature of severe asthma, despite high‐dose corticosteroids. Tracking the systemic level of these cells may help identify type 2 severe asthmatics at risk of exacerbation.