After recent descriptions of accumulation of NKG2A+ NK cells during acute primary EBV infection in a humanized mouse model, with increased tumor rates after NK depletion [14] and in peripheral blood of IM patients [15], we were intrigued to determine the EBV restriction capacity of tonsillar CD56brightNKG2A+ compared to other tonsillar NK cell subsets in our previously described transformation restriction assay [13]. The gene discussed is KLRC1; the disease is Epstein-Barr virus infection.