Following identification of DRA1*0101/DRB1*0401-retricted IGRP23-35 and IGRP247-259 and DRA1*0101/DRB1*0301-retricted IGRP13-25 and IGRP226-238 epitopes, IGRP-specific CD4+ T cells have been detected in more than 80% of DRB1*0401 or DRB1*0301 healthy and T1D subjects [94]. This evidence concerns the gene CD4 and type 1 diabetes mellitus.