Presently, most evidence suggests that in T1DM, β-cells are killed by cytotoxic CD8+ T cells reacting to a variety of islet-specific antigens including GAD.52,53 This raises the question as to whether in the patients with T1DM and GAD-TLE, the same GAD-specific CTLs are involved in the destruction of both pancreatic islets and CNS neurons. This evidence concerns the gene CD8A and type 1 diabetes mellitus.