The Effect of KIR B/X Genotype and Missing KIR Ligands In Haploidentical Hematopoietic Stem Cell Transplantation.

To study the prognostic impact of missing ligands for inhibitory killer-immunoglobulin receptor(KIR) and donor KIR genotype in haploidentical hematopoietic stem cell transplantation(HSCT).

HLA genotype of 14 patients (ALL 8 cases, AML 3 cases, CML 1 cases, NHL 1 cases and granulocytic sarcoma 1 case) and their donors was determined by polymerase chain reaction sequence oligonucleotide probes (PCR-SSOP) and sequence specific primers (PCR-SSP). The KIR genotype was determined by PCR-SSP.

1. Donors were divided into those with (n=9) KIR B/X and those with (n=5) KIR A/A. We found that the 2-year OS rate was higher with KIR B/X versus KIR A/A donors (33.3% vs 20%, P=0.308). Of the B/X group, most donors (77.8%) expressed activated KIR (aKIR) with 2DS4 or 2DS1. The 2-year OS rate was higher for those (n=5) with 1–2 aKIR than those (n=4) with 3–4 aKIR group (40% vs 25%). The GVHD incidence was slightly lower with 1–2 aKIR versus 3–4 aKIR donors (40% vs 50%).

2. Patients were divided into those with (n=11) and those without (n=3) missing 1 or more HLA class I ligands for donor inhibitory KIR. The 2-year OS rate for patients with and without missing KIR ligands was 36.4% and 0%,respectively(P=0.680)

In haploidentical HSCT, donor and recipient should be performed the high resolution HLA-Cw genotyping and KIR genotyping (A/A and B/x). Using donors with KIR B/X genotype or missing KIR ligands may be associated with improved OS and decreased GVHD.

No relevant conflicts of interest to declare.