IFNG and HIV-1 infection: As a potential mechanism explaining the overall reduced proportion of NK cells able to produce IFN-γ we determined the levels of expression of CD16 (Figures S3A,B in Supplementary Material), which correlated positively with IFN-γ production (r = 0.5573, p = 0.0132), suggesting that CD16 downregulation or shedding during chronic HIV-1 infection may impair the overall functional ability of NK cells.