Upon stimulation with peptides of islet autoantigens, these T cells respond and secrete cytokines such as interferon-γ, IL-10, and IL-17 which can be measured in subjects with type 1 diabetes and used to illustrate the heterogeneity of the disease (2–4) Furthermore, T cell responses elicited against peptides of proinsulin distinguish age-related heterogeneity in type 1 diabetes pathogenesis (4). This evidence concerns the gene IL17A and type 1 diabetes mellitus.