We also measured the frequency of S‐specific CD4+ T cells producing IL‐17A, IL‐21, IL‐13, and IL‐10, and while no differences in IL‐17A production were observed, S‐specific CD4+ T cells from T1D and T2D displayed an increased frequency of IL‐21‐, IL‐13‐, and IL‐10‐producing cells, suggesting a Th2‐ and Tfh‐biased helper T cell response to vaccination (Figure 4f). Here, IL21 is linked to type 1 diabetes mellitus.