Although CD8 T cells are the most predominant immune infiltrates in human insulitis [1], autoreactive CD4 T cells are also involved in the pathogenesis of T1D and CD4 T cell responses to proinsulin, GAD, and IA-2 were identified in the islets of donors with T1D (8, 22, 23). The gene discussed is CD8A; the disease is type 1 diabetes mellitus.