KIR2DL2-associated changes in KIR2DL1 expression are independent of the presence of cognate HLA-C ligands and expression of KIR2DS1. (A) Frequency of single-KIR2DL1⁺ NK cells is shown for donors with group B haplotypes (A/B and B/B) who were divided into 9 groups according to the allelic state of the KIR2DL2/3 gene and the HLA-C ligands C1 and C2. (B) All 16 different clonotypes that express KIR2DL1 are shown for C2/C2 donors with zero (□), 1 (), or 2 () copies of the KIR2DL2 gene. (C) Frequency of single-KIR2DL1⁺, KIR2DL1⁺KIR2DS1⁺, and single-KIR2DS1⁺ NK cells was measured with multicolor flow cytometric analysis with the following antibody combinations: KIR2DL1(143211)–FITC, CD158a,h(EB6)–APC, KIR3DL1/KIR2DL2/3/NKG2A-PE, CD56-PC5 and CD3-ECD. Donors had a KIR2DL1⁺/KIR2DS1⁺ genotype (n = 29) and were divided into KIR2DL2⁻KIR2DL3⁺, KIR2DL2⁺KIR2DL3⁺, and KIR2DL2⁺KIR2DL3⁻ as indicated on the x-axis. Statistical significance was determined by ANOVA as *P < .05, **P < .01, ***P < .001).