Th9 and bronchial asthma

Bronchial asthma(asthma) is a kind of chronic air way inflammatory diseases mediated by T lymphocytes,eosinophils,degranulated mast cells and their cytokines,T helper 2(Th2) cells as a subpopulation of CD4+ T cells played an important role in asthma pathogenesis.The cytokine IL-9 has largely been regarded as a Th2 cytokine that makes multifocal contributions to allergic disease,including asthma.Recent data identified a novel subset of T cells generated in presence of TGF-β and IL-4 that produces both IL-9 and IL-10,named cell.Th9 cells do not express any well-defined transcription factors like T-bet,GATA3,RORγt,emphasizing that Th9 cells are different from Th1,Th2 and Th17 populations.Th9 cells act as effector T cells and promote more severe and unusual tissue inflammation.The aim of this review is to combine data from human and animal models of allergic diseases,and propose how Th9 cells function in asthma.