Collectively, our findings suggest that enrichment of PPI5–12‐specific memory CD8+ T cell subsets in subjects with type 1 diabetes compared to non‐diabetic control subjects and polyclonal CD8+ T cells may reflect a driver role in relation to β cell killing, consistent with the accelerated loss of β cells that has been observed in HLA‐B*3906+ individuals, relative to patients with other HLA class I alleles 17, 20, 21, 22, 23, 24. The gene discussed is CD8A; the disease is type 1 diabetes mellitus.