KLRC2 and cytomegalovirus infection: For example, Brunetta et al. detected HCMV IgG in HIV-infected patients and found that the proportion of NKG2C+ NK cells was upregulated in IgG-positive patients (31); however, anti-HCMV IgM and HCMV nucleic acid, indicating current CMV infection, were not tested in previous studies.