In the case report of a 3 year-old patient with T−B+NK+ severe combined immunodeficiency (SCID), NKG2C+ NK cells were the sole provider of protective immunity against CMV after significant expansion of IFN-γ-producing CD16+CD94−NKG2C+ NK cells (Kuijpers et al., 2008). This evidence concerns the gene KLRC2 and severe combined immunodeficiency.