More in detail, Garg and colleagues revealed that the presence of an autoimmune disease-associated IL-2RA haplotype in T1D subjects associates with reduced IL-2 responsiveness in Treg cells, which correlates with a lower Foxp3 expression and impaired suppression of CD4+CD25− T cells [Figure 3; (250)]. This evidence concerns the gene CD4 and type 1 diabetes mellitus.