Frequency of human platelet antigens among blood donors in northeastern Thailand

Abstract

Platelet transfusions have been widely used in Thailand, but little is known about the phenotyping of human platelet antigens. Whole blood was collected from 483 blood donors for preparation of platelets. An improved mixed passive hemagglutination assay was used for this study. Frequencies demonstrated were 100 percent for HPA-1a (PlA1), 15.94 percent for HPA-2b (Siba), 60.25 percent for HPA-3a (Baka), 98.76 percent for HPA-4a (Yukb), 1.86 percent for HPA-4b (Yuka), 5.38 percent for HPA-5b (Br(a)), and 97.72 percent for Naka. HPA-1a was found in 100 percent of Thais, which is the same frequency as in other Asian populations but somewhat different from that in whites (97.9%). Therefore, HPA-1a will not cause neonatal alloimmune thrombocytopenia or post-transfusion purpura in Thais. According to the frequencies of HPA-2b, HPA-3a, HPA-4a, HPA-4b, HPA-5b, and Naka antigens, they may induce neonatal alloimmune thrombocytopenia, posttransfusion purpura, and platelet refractoriness in Thais.