KLRC2 and cytomegalovirus infection: The mechanism of HCMV-adaptive NKG2C+ NK cells in the blood of patients with a history of HCMV infection was ultimately proven to depend on the recognition of UL40 encoded HCMV peptides, which stabilize and load on HLA-E by NKG2C (Hammer et al., 2018; Rolle et al., 2018).