KLRC2 and viral infectious disease: We hypothesize that this phenotype of higher CD57+ and lower NKp46 expression in NK cells could represent different stages of a chronic viral infection, and together with high NKG2C expression, could be consistent with HCMV infection reactivation or latency, whereas low CD57+ and high NKp46 together with low NKG2C expression in NK cells could be associated with reactivation or latency of EBV infection.