Thus, while only about 50% of IL‐21‐producing CD4+ T cells in HC were co‐expressing IL‐10, more than 85% and 95% S‐specific IL‐21‐producing CD4+ T cells were also producing IL‐10 in T1D and T2D, respectively (Figure 4J). This evidence concerns the gene CD4 and type 1 diabetes mellitus.