CD8A and type 1 diabetes mellitus: Cytotoxic CD8+ T cells are theprominent T cells infiltrating the islets that mediate directβ-cell destruction through perforin and granzyme B (6).CD8+ T cells producing interferon gamma (IFN-γ) andtumor necrosis factor alpha (TNF-α) as the predominant Tcell population infiltrate the islets of patients who died atthe onset of T1D (1).