In vitro allogeneic NK cell killing of HIV-1 patient-derived CD4⁺ T cells as a function of KIR/HLA genotype. Differences between groups were analyzed by Kruskal-Wallis or Mann-Whitney U tests, horizontal lines represent median values. (A) Effect of centromeric KIR genotypes of NK cell donor. (B) Effect of missing self NK cell donor/HIV-1 patient KIR/HLA combinations. Missing self combinations are defined as NK cell donor inhibitory KIRs that recognize an HLA allotype present in the NK cell donor but that is lacking in the HIV-1 patient.¹¹  See “Results” and Table 4 for details. (C) Effect of allogeneic NK cell donor KIR3DS1 in combination with HIV-1 patient HLA-Bw4.