RESUMO
BACKGROUND: Rapid platelet engraftment has several economic benefits by reducing the cost of supportive therapy as well as reducing the risk of fatal bleeding due to severe thrombocytopenia. Based on these considerations, we genotyped human platelet alloantigens (HPA) to evaluate the effect of minor transplantation antigen mismatches on the rate and speed of platelet recovery and clinical outcome of transplantation. METHODS: Thirty-five patients with various hematologic diseases transplanted between January 2001 and August 2004 were included. Genomic DNA was isolated from peripheral blood of donor-recipient pairs before transplantation. HPA-1, -2, -3, -4, -5, and -6 genotyping was performed by poly-merase chain reaction (PCR)-sequence specific primers (SSP). The effects of HPA compatibility on platelet recovery, incidences of graft-versus-host disease (GVHD) and relapse, and overall survival was investigated. RESULTS: There were no significant differences in platelet recovery according to HPA matching status. We observed no statistically significant differences in the occurrence of relapse and overall survival according to HPA-1, -2, and -3 matched/mismatched groups of patients, whereas HPA-3 mismatching was found to have a significant effect on GVHD development. There was also no difference in GVHD occurrence according to HPA-1 and -2 matched or mismatched transplants. CONCLUSIONS: Since platelet recovery in the HPA-1, -2, -3, and -5 matched/mismatched groups is not significantly different, the seems that platelet glycoprotein (GP) does not seem to act as a factor influencing the homing of hematopoietic stem cells. The finding that HPA-3 incompatibility may be involved in GVHD can be of importance. If a role for HPA-3 as minor histocompatibility antigens is confirmed by additional studies, we can ameliorate the outcome of allogeneic stem cell transplantation by typing of HPA and selecting the most closely related donors.