The CD4 T cells' expression of IL-17 was significantly higher (p = .03) in recently diagnosed vs long-standing HLA-DRB1*03-DQA1*05-DQB1*02+ T1D patients.<h4>Conclusion</h4>GAD65 peptides, particularly those belonging to PP2, induced CD4 T cells to express IFN-γ and IL-17 cytokines in T1D patients, suggesting that group 2 peptides possibly presented by HLA-DR3 molecule to CD4 T cells shift immune balance toward inflammatory phenotype in patients. The gene discussed is HLA-DRB1; the disease is type 1 diabetes mellitus.