RESUMEN
<p><b>OBJECTIVE</b>To study the impacts of HIV/HCV co-infection to NK cells by investigating the changes of frequencies and functions of NK cells in HIV/HCV co-infected patients.</p><p><b>METHODS</b>Frequencies and counts of NK cells were measured in patients with HIV mono-infection, HCV monoinfection, HIV/HCV co-infection and health control (HC) group by flow cytometer (FCM). After stimulated with PMA and K562 cells, PBMCs were examined the proportion of IFN-gamma+ NK cells by FCM. Proportion of killed K562 cells were detected to analyze the killing functions of NK cells.</p><p><b>RESULTS</b>The frequencies of NK cells, the percentages of IFN-gamma+ NK cells as well as the functions of NK cells killing the K562 cells in HIV/HCV co-infection, HIV mono-infection and HCV mono-infection groups were all lower than those of HC group significantly, the absolute counts and killing functions of NK cells in co-infection group were significantly lower than those of HIV or HCV mono-infection group.</p><p><b>CONCLUSIONS</b>The counts and functions of NK cells were affected more in HIV/HCV co-infections than those in HIV or HCV mono-infection.</p>