In the combined analysis of genes unique to DR and those in common with diabetes mellitus at the threshold of <0.05, we identified C2, C4A, CD8A, HLA-DRB5, and HLA-DQA2, which have been associated with lymphocyte-mediated immunity (FDR 2.96 × 10−2). This evidence concerns the gene HLA-DQA2 and diabetes mellitus.