Finally, a third example of a new discovery coming from studying humans with immunodeficiencies was that of X-linked recessive mutations inMAGT1, which causes EBV susceptibility and predisposition to lymphoma by impairing NKG2D expression for anti-viral natural killer (NK) cell activity against EBV-infected cells and immunodeficiency by impairing magnesium-dependent calcium signaling in T cells38,39. The gene discussed is KLRK1; the disease is immunodeficiency disease.