KLRC2 and cytomegalovirus infection: While correlations of HCMV seropositivity with a high frequency of NKG2C (and CD57) expression in humans serve as good surrogate markers for latent HCMV infection47–50, identification of subsets of adaptive NK cells that bear the imprint of HCMV infection has provided a molecular basis for an interrogation of altered functional responses in these adaptive NK cells.