The finding of increased frequency of NKp30 and NKp46 expressing CD56bright NK cells in HIV-HCV co-infection as compared to HIV mono-infection also supports a shift of the populations either due to increased apoptosis of activated CD56bright NK cells or an increase of ‘HCV-like’ CD56bright NK cells in case of NKp30 expression while indicating a unique and an important role of NKp46 in HIV-HCV co-infection. The gene discussed is NCR1; the disease is infection.