Background: The frequency of human platelet antigens (HPA) varies according to ethnicity, which causes differences in the morbidity of alloimmune and autoimmune thrombocytopenic disorders in different populations. Studies on HPA frequencies in Brazil have reported differences among Brazilian populations produced by the diverse degrees of admixture throughout the country. Methods: In the present study, we investigated the variation of HPA distribution in Brazil, compared with worldwide populations, and describe the frequencies of HPA-1, -2, -3, -5, and -15 in a large urban center in Southern Brazil (Belo Horizonte) based on a sample of blood donors. Results: The principal component analysis and the dendrogram based on genetic distance revealed a clear relationship between Brazilian populations and the groups formed by European and African populations. The coefficients of variation for HPA allele frequencies suggest that Brazilian populations presented variations for HPA alleles comparable with the populations from continental groups. In Belo Horizonte, the allele a frequencies for HPA-1, -2, -3, -5 and -15 were 0.8575, 0.8400, 0.6225, 0.8525 and 0.5825 respectively. The genotypes with higher frequencies were a/a (72-74%), except for HPA-3 and -15, whose heterozygous a/b genotypes were shown to be more prevalent (43.5 and 44.5%, respectively). Conclusion: We confirmed the heterogeneity of HPA antigens in Brazilian populations, reinforcing the importance of HPA panels composed of regional blood donors, or a national panel that contemplates the specificities of the different regions of the country, in order to provide support in platelet transfusions and to minimize the risks associated with HPA alloimmunization. The evaluation of HPA data from Belo Horizonte represents the initial step toward the development of a genotyped platelet donor registry in order to treat HPA alloimmunized patients in this region.

中文翻译：

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巴西多民族人群中的人类血小板抗原：大城市中心（贝洛奥里藏特）的区域变异和频率发生

背景：人类血小板抗原（HPA）的频率因种族而异，这导致不同人群的同种免疫和自身免疫性血小板减少症的发病率存在差异。对巴西 HPA 频率的研究报告了巴西人口因全国不同程度的混合而产生的差异。方巴西（贝洛奥里藏特）基于献血者样本。结果：基于遗传距离的主成分分析和树状图揭示了巴西人群与欧洲和非洲人群形成的群体之间的明确关系。HPA 等位基因频率的变异系数表明，巴西人口的 HPA 等位基因变异与大陆群体的人口相当。在贝洛奥里藏特，HPA-1、-2、-3、-5 和 -15 的等位基因 a 频率分别为 0.8575、0.8400、0.6225、0.8525 和 0.5825。频率较高的基因型是 a/a (72-74%)，除了 HPA-3 和 -15，其杂合 a/b 基因型更为普遍（分别为 43.5% 和 44.5%）。结论：我们证实了巴西人群中 HPA 抗原的异质性，加强了由区域献血者组成的 HPA 小组的重要性，或一个考虑该国不同地区特殊性的国家小组，以便为​​血小板输注提供支持，并将与 HPA 同种免疫相关的风险降至最低。贝洛奥里藏特对 HPA 数据的评估代表了开发基因型血小板供体登记系统以治疗该地区 HPA 同种异体免疫患者的第一步。