Association between CD158b monoKIR NK-cell frequency and donor HLA-C ligands. The percentages of CD158b monoKIR NK cells among total or CD158b⁺ NK cells were determined in (A) 40 healthy subjects (C1/C1: n = 14, C1/C2: n = 14, C2/C2: n = 12) and in (B) 26 post-HLA-C–mismatched HSCT samples (donor C1/C1: n = 12, donor C1/C2: n = 10, donor C2/C2: n = 4) and plotted against HLA-C ligands. *P < .05, **P < .01.