KLRK1 and type 1 diabetes mellitus: A reduced number and decreased cytolytic activity of NK cells along with downregulation of activating receptors (e.g., NKG2D, NKp46, NKp30) or increased expression of inhibitory receptors (e.g., KIR2DL3) in peripheral blood mononuclear cells have been reported in T1DM patients (182, 195, 197–200), highlighting an association between NK cells and T1DM disease stage or risk (42, 201).