Furthermore, abnormal T cell subsets, such as the decreases of CD3+ cell counts, CD4+ cell counts, and CD4+/CD8+ ratio, were observed in the diabetes group compared with the euglycemia group, and the presence of diabetes and secondary hyperglycemia were negatively correlated with CD3+ cell counts and CD4+/CD8+ ratio, which implies that the immune function of these patients was compromised. This evidence concerns the gene CD4 and diabetes mellitus.