CD4 and type 1 diabetes mellitus: Confirming earlier observations in other diseases, the pro-inflammatory interleukin IL-6 was expressed in all immune cell subtypes [16–18, 44] during the inflammation process in the T1D pancreas, while IL-17A was only expressed in the subgroup of the γ,δ T cells and CD4 T helper cells [4–6, 9] comprising about 10% of the immune cells in the pancreatic islet.