To investigate the role of FOXP3 in the effects of miRNA-221-5p on Th17/Treg ratio in asthma, si-FOXP3 was employed to suppress the protein expression of FOXP3 and induced that of RORγt in in vitro model of asthma following miRNA-221-5p, compared with miRNA-221-5p group (Fig. 8A–C). This evidence concerns the gene FOXP3 and asthma.