Induction of Foxp3 gene expression by inhaled corticoids in cough variant asthma

Objective To investigate the changes of regulatory T cells in cough variant asthma(CVA) and the effect of inhaled corticoids on the expression of Foxp3.Methods CVA patients were treated with inhaled fluticasone propionate for 6 months.Before and after treatment,the provocative concentration of methacholine causing a 20% fall in forced expiratory volume in one second(PC20-FEV_1) was tested,and the percentage of CD4+CD25+Foxp3+T cells in periphery blood CD4+ T cells,and the expression of Foxp3 mRNA were examined with flow cytometry and RT-PCR respectively.Results The percentage of CD4+CD25+Foxp3+T cells and expression of Foxp3 mRNA in CVA patients was lower than that in the healthy individuals,and the treatment with ICS increased the percentage of CD4+CD25+Foxp3+T cells and expression of Foxp3 mRNA,together with elevated PC20-FEV_1.Conclusion ICS can successfully decrease bronchial hyperreactivity,and this effects may partially due to the induction of CD4+CD25+Foxp3+Tcells.