Taken together, by analysing the TCR repertoires of IGRP265-273 directed CD8+ T cells from patients with type 1 diabetes, we identified dominant IGRP265-273–specific clonotypes that were persistent in sequential samples and common usage of IGRP265-273–specific CD8+ T cell-derived TCR α-chains between individuals. This evidence concerns the gene CD8A and type 1 diabetes mellitus.