title: The human platelet alloantigen profile in blood donors from Amazonas, Brazil.
abstract: BACKGROUND
  Human platelet antigens (HPAs) are alloantigens derived from polymorphisms in platelet-surface glycoproteins. The occurrence of alloantibodies against HPAs can lead to platelet destruction and subsequent thrombocytopenia. Brazilians have a high rate of racial admixture, and the knowledge of HPA polymorphisms in particular donors from north Brazil, who have a large Amerindian influence, is a relevant strategy to prevent alloimmunisation.
  
  
  OBJECTIVE
  Our aim was investigate the HPA allele's frequencies in the Amazonas blood donors.
  
  
  METHODS
  We performed HPA genotyping among 200 Amazonas blood donors by microarray for 11 HPA biallelic systems, including six of the most clinically significant systems (HPA-1 to -5 and -15) and five others (HPA-6 to -9 and -11) that have been also associated with alloimmunisation, amounting to 22 HPA alleles.
  
  
  RESULTS
  The obtained allele frequencies were compared with data of 38 populations worldwide to determine the hierarchical relationship and estimated the probability of mismatch platelets. The allele frequencies were 0·862 for HPA-1a, 0·137 for HPA-1b, 0·852 for HPA-2a, 0·147 for HPA-2b, 0·665 for HPA-3a, 0·335 for HPA-3b, 0·995 for HPA-4a, 0·005 for HPA-4b, 0·892 for HPA-5a, 0·107 for HPA-5b, 0·997 for HPA-9a, 0·005 for HPA-9b, 0·502 for HPA-15a and 0·497 for HPA-15b. The incompatibility risks are higher for HPA-15 and HPA-3, followed by HPA-1, -2 and -5.
  
  
  CONCLUSIONS
  We found differences among populations worldwide, and it is interesting to note the indigenous and European influences in this region, reinforcing the heterogeneity in the ancestry of Brazilians. The results will be helpful in providing information for platelet transfusion to avoid alloimmunisation.
authors.affiliation: Pós-Graduação em Ciências Aplicadas à Hematologia, Universidade do Estado do Amazonas e Fundação de Hematologia e Hemoterapia do Amazonas, Manaus, Brazil.
authors.forename: C N
authors.initials: CN
authors.lastname: Portela
authors.affiliation: Serviço de Imunologia, Hospital Universitário Professor Edgard Santos, Universidade Federal da Bahia; Departamento de Ciências da Biointeração, Instituto de Ciências da Saúde, Instituto de Ciência e Tecnologia em Doenças Tropicais, Salvador, Brazil.
authors.forename: A
authors.initials: A
authors.lastname: Schriefer
authors.affiliation: Pós-Graduação em Ciências Aplicadas à Hematologia, Universidade do Estado do Amazonas e Fundação de Hematologia e Hemoterapia do Amazonas, Manaus, Brazil.|Laboratório de Imunohematologia Molecular, Fundação de Hematologia e Hemoterapia do Amazonas, Manaus, Brazil.
authors.forename: S R L
authors.initials: SR
authors.lastname: Albuquerque
authors.affiliation: Centro de Ciências Biológicas e da Saúde, Universidade Federal do Mato Grosso do Sul, Campo Grande, Brazil.
authors.forename: R T
authors.initials: RT
authors.lastname: Perdomo
authors.affiliation: Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Amazonas, Manaus, Brazil.
authors.forename: A F A
authors.initials: AF
authors.lastname: Parente
authors.affiliation: Instituto de Ciências Exatas e Tecnologia, Universidade Federal do Amazonas, Itacoatiara, Brazil.
authors.forename: S S
authors.initials: SS
authors.lastname: Weber
mesh_terms: D000483:Alleles; D016824:Antigens, Human Platelet / Q000235:genetics*; D001782:Blood Donors; D001938:Brazil; D005260:Female; D005838:Genotype; D060005:Genotyping Techniques; D006801:Humans; D008297:Male
chemical_list: D016824:Antigens, Human Platelet
keywords: alloantigen; alloimmunization; genotyping; glycoprotein; platelets