The reactivity of Bw4+ HLA-B and HLA-A alleles with kir3dll: Implications for patient and donor suitability for haploidentical stem cell transplantations

Abstract

Natural killer (NK)-cell alloreactivity can be exploited in haploidentical hematopoietic stem cell transplantation (HSCT). NK cells from donors whose HLA type includes Bw4, a public epitope present on a subset of HLA-B alleles, can be alloreactive toward recipients whose cells lack Bw4. Serologically detectable epitopes related to Bw4 also exist on a subset of HLA-A alleles, but the interaction of these alleles with KIR3DL1 is controversial. We therefore undertook a systematic analysis of the ability of most common HLA-B alleles and HLA-A alleles with Bw4 serologic reactivity to protect target cells from lysis by KIR3DL1-dependent NK cells. All Bw4- HLA-B alleles failed to protect target cells from lysis. All Bw4+ HLA-B alleles with the exception of HLA-B*1301 and-B*1302 protected targets from lysis. HLA-A*2402 and HLA-A*3201 unequivocally protected target cells from lysis, whereas HLA-A*2501 and HLA-A*2301 provided only weak protection from lysis. KIR3DL1-dependent alloreactive NK clones were identified in donors with HLAA*2402 but not in donors with HLAB*1301 or-B*1302. These findings clarify the HLA types that donors and recipients need in haploidentical HSCT and other NK allotherapies in order to benefit from NK alloreactivity. © 2008 by The American Society of Hematology.