Clinical advancement observed after allergen immunotherapy for allergic diseases, such as asthma, is associated with the induction of IL‐10‐ and TGF‐β‐producing Tr‐1 cells and Foxp3‐expressing IL‐10 T cells, which results in the suppression of Th2 cytokines 46. This evidence concerns the gene TGFB1 and allergic disease.