We compared islet cell distributions and determined graded intensities of glutathione peroxidase1 (GPX1), a key enzymatic mediator involved in detoxifying hydrogen peroxide, by applying combined immunohistochemistry for GPX1, insulin and glucagon, in pancreatic sections from new-onset T1D (group 1), non-diabetic autoantibody-negative (group 2), non-diabetic autoantibody-positive (group 3) and long-term diabetic (group 4) donors. This evidence concerns the gene INS and type 1 diabetes mellitus.