In our own research, a higher percentage of CD8+ T lymphocytes expressing the early activation markers, CD69 (p = 0.003), CD4+ CD69+ T lymphocytes (p = 0.029), as well as the CD3+ T lymphocytes expressing the late activation marker, CD25 (p = 0.004), along with the CD4+CD25+ phenotype (p = 0.044) in patients with diabetes than in a control group. This evidence concerns the gene CD4 and diabetes mellitus.