A study investigating the impact of KIRs and their ligands on the outcome of unrelated HSCT was conducted in a cohort of transfusion-dependent beta-thalassemia patients.47,48 Donors and recipients were divided into two groups according to combinations of group A and group B KIR haplotypes: those homozygous for KIR haplotype A (AA) and those either heterozygous or homozygous for KIR haplotype B (AB+BB). The gene discussed is KIR3DL1; the disease is beta thalassemia.