Authors:
A. Torío Ruiz (Albacete, ES)
M. Pascual-Cascón (Málaga, ES)
R. Recio-Romero (Málaga, ES)
I. Méndez-López (Málaga, ES)
I. Vidales-Mancha (Málaga, ES)
M. Ortiz-Pareja (Málaga, ES)
M. Cuesta-Casas (Málaga, ES)
A. Caballero-González (Málaga, ES)
A. Heiniger-Mazo (Málaga, ES)
In haploidentical stem cell transplantation (SCT), the selection of the "ideal donor" is not performed in a standardised way according to the KIR genotype expressed by potential donors. We retrospectively analyzed 30 patients and their donors submitted to haploidentical SCT at our centre. All patients were prepared with a conditioning regimen including thiotepa-busulfan-fludarabine with high doses of post-transplant cyclophosphamide (CyPT) and tacrolimus as prophylaxis of graft-versus-host disease (GvHD). HLA and KIR genotyping was performed by PCR-SSO using One Lambda commercial kits. The genotypic variables under study were: donor AA / Bx haplotype, donor B content (classified as neutral, better, best, according to Cooley et al., 2010), KIR inhibitor mismatches, presence of KIR2DS1 and KIR3DS1 in donor, mismatching in KIR ligands in the GVH direction, mismatching in KIR ligands in the HvG direction. We analysed the impact of these KIR genotype variables on overall survival (OS), GvHD free survival, and event-free survival (EFS). Even with our small sample size, statistical significance was found when we analysed the effect of the presence of mismatches on KIR ligands in GvH direction in relation to the diagnosis of chronic GvHD (54% vs. 100%, p = 0.004). Significance was also found when we compared the effect of the presence of AA or Bx haplotype of the donor with the diagnosis of chronic GVHD (50% vs. 86%, p = 0.033). We did not find statistical significance, in spite of the previous data in the literature that relate the existence of mismatches in KIR inhibitors or the presence of certain KIR genotypes (2DS1+, 3DS1+) with post-transplantation evolution regarding OS or EFS. Our results show that KIR genotyping can provide useful information to choose the donor for the haploidentical SCT without T-depletion with high doses of CyPT. Donors with a B haplotype that do not show incompatibilities of KIR ligands in the GvH direction could provide a lower risk of GvHD.