The presence of hPPI-specific CD4+ T cells in the peripheral blood of T1D diabetic patients was analyzed by ex vivo proliferative assay and compared with HLA-DQ8 healthy donor and type 2 diabetes (T2D) patients as controls in order to address whether hPPI regions recognized in human matched with peptides recognized in YES-RIP-hB7.1 mice. This evidence concerns the gene CD4 and type 2 diabetes mellitus.