A role for NK cells in HIV-1 infection is supported by epidemiological studies linking specific KIR/HLA combinations with HIV-1 infection outcome (6, 7), functional studies where protective KIR alleles are associated with enhanced NK cell cytolytic function in vitro (8) and evidence of HIV-1 having evolved strategies to evade NK cell recognition (9). This evidence concerns the gene KIR3DL1 and HIV-1 infection.