Notably, a reduction in diabetes incidence in mice treated with Ins15–23/β2 microglobulin/CD3ζ T cells was observed; however, neither Ins15–23/β2 microglobulin/CD3ζ nor IGRP206–214/β2 microglobulin/CD3ζ T cells showed the reducing effect. This evidence concerns the gene HLA-G and diabetes mellitus.