These adaptive NKG2C+ NK cells exhibit higher effector functions than canonical NKG2C− NK cells and have been associated with the control of HCMV infection in kidney transplant recipients and with protection from leukemia relapse after allogeneic hematopoietic stem cell transplantation (HSCT) (17, 19–24). Here, KLRC2 is linked to cytomegalovirus infection.