 T helper h1 cells are known to have important roles in the destruction orand dedifferentiation of β-cells in type 1 diabetes T1D. Significant increase in IFN-γ-producing Th1 cells in the pancreas and in the serum levels were determined in type 1 diabetic patients at diabetes oneset. This data indicated that this proinflammatory mediator serve as a biomarker of advanced autoimmunity. We aimed to investigate the relationship between Th1 cytokines IFN-γ, IL-2 and TNF-α and T1D and the effect of those cytokines on β-cell function. 