IFNG and allergic asthma: These studies suggest that antigen-specific γδ T cells are able to suppress the pathogenic Th2 response in allergic asthma, whereas a recent study by Chen et al. [67] found that the serum levels of IL-4 and IL-13 in peripheral blood of children with AR and asthma markedly decrease while IFN-γ increases after receiving SIT, suggesting that IFN-γ+γδ T cells might exert their Th2 immunosuppression under certain conditions like SIT.