KIR2DS4 and acute leukemia: No differences in the frequency of KIR genes, HLA-I ligands (HLA-C1, -C2, -A*03/A*11, -Bw4, Bw4-80T, Bw4-80I, or KIR2S4-ligands) or KIR/HLA-I ligand interactions were found between controls and patients with any type of acute leukemia, except for a higher frequency of KIR2DS4-ligands in total patients than in controls (71.0% vs. 53.0%, p = 0.009, Pc = 0.045).