CTLA4 and asthma: Several studies have supported the gender-dependent gene-environment interactions on asthma development, such as polymorphisms of CTLA-4 [26], GSTM1 [94, 95], GSTP1 [96], IL-13 [97], IL-1Ra [98], βAR [99], TGF-beta1 [100], HLA-G [101, 102], CD14 [103–106], and TLR2 [107], may influence the development of asthma through interactions with other maternal environmental factors, such as maternal tobacco smoke exposure, maternal atopy, or maternal prenatal exposure to a farming environment.