Frequency Of Human Platelet Antigens Research Articles

Frequency of Human Platelet Antigens -1 to -5 and -15 in Turkmen Blood Donors.

Due to the presence of platelet antigen polymorphisms, human platelet membrane glycoproteins can be identified as an alloantigen or autoantigen. The aim of this study was to determine the frequencies of human platelet antigens (HPAs)-1 to-5 and-15 in Turkmen blood donors and establish a panel of accredited HPAs negative donors as well as an HPA-typed platelet donor registry. HPA-1 to-5 and-15 typing was performed by the polymerase chain reaction-sequence-specific primer techniques on 80 unrelated Turkmen donors who were referred to Aq-Qala Blood Transfusion Center in Golestan Province from September 2018 to October 2019. The frequencies of HPA phenotypes were determined as follows: HPA-1aa: 92.5%, HPA-1ab: 7.5%, HPA-2aa: 77.5%, HPA-2ab: 20.0%, HPA-2bb: 2.5%, HPA-3aa: 75.3%, HPA-3ab: 50%, HPA-3bb: 11.2%, HPA-4aa: 100%, HPA-5aa: 78.5%, HPA-5ab: 21.5%, HPA-15aa: 41.2%, HPA-15ab: 56.2% and HPA-15bb: 17.5%. Determining the genotype of HPAs that play an important role in platelet refractory can improve the management of alloimmunization due to the incompatibility of HPAs between the recipients and donors. Therefore, the registration process for national platelet donors can help patients accelerate and improve the quality of transfused platelets.

Gene frequencies of human platelet antigen‐1 to ‐5 and ‐15 in the Iranian population

BackgroundAs the frequency of human platelet antigens varies between different ethnic groups and the data about the HPA gene frequency in Iran have been absent yet, the purpose of this study was to determine HPA‐1 to HPA‐5 and HPA‐15 allele frequency among Iranians.Materials and methodsHPA‐1, HPA‐2, HPA‐3, HPA‐4, HPA‐5 and HPA‐15 typing was performed by the polymerase chain reaction–sequence‐specific primer techniques (PCR‐SSP) for 210 subjects [Including 100 blood donors, 55 hematopoietic stem cell (HSC) recipient/donor pairs].ResultsThe frequencies of HPA phenotypes were determined as follows: HPA‐1a/1a: 98%, HPA‐1a/1b:2%, HPA‐2a/2a: 8/.5%, HPA‐2a/2b: 91·5%, HPA‐3a/3a: 21%, HPA‐3a/3b: 67·2%, HPA‐3b/3b: 22·8%, HPA‐4a/4a: 100%, HPA‐5a/5a: 99·5%, HPA‐5a/5b: 0·5%, HPA‐15a/15a: 14·2%, HPA‐15a/15b: 67·2% and HPA‐15b/15b: 18·6%.ConclusionHPA‐4b was absent and there was not any homozygosity for HPA‐1b/1b, HPA‐2b/2b and HPA‐5b/5b besides no HPA‐1b/b, HPA‐2b/b and HPA‐5b/b homozygosity was found. So it seems that HPA‐1a, HPA‐2a, HPA‐4a and HPA‐5a might not be involved in the alloimmunization and transfusion reactions on the Iranian population but HPA‐15a and HPA3a. Furthermore, extensive studies covering diverse ethnic groups, in the field of platelet immunobiology, will help to find the local pattern more precisely.

Human Platelet Antigens in Brazilian Multiethnic Populations: Occurrence of Regional Variation and Frequency in a Large Urban Center (Belo Horizonte)

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.

Human platelet antigens frequencies in Maori and Polynesian populations

Allele frequencies of human platelet antigens (HPA) reflect population history and possibility of platelet-specific alloimmunization. Here, we report on screening of variants at HPA loci for Polynesian and Maori subjects. Our aims are to evaluate new HPA genotyping methods, compile and analyse new HPA datasets for these subjects, use HPA data for tracing ancestry, migration patterns, genetic admixture and its potential influence on health. A total of 75 Maori and 25 Polynesian DNA samples were genotyped using commercial BAGene HPA-TYPE DNA-SSP kits, BLOODchip hybridization SNP assays and DNA sequence based typing. Genotyping was successful and cross validation of PCR-SSP and BLOODchip gave 100% agreement. Among the HPA loci tested, only six are dimorphic (HPA-1 to -3, -5, -6 and -15) and all others are monomorphic. The Polynesians and Maori have the 'a' allele form as the most common for all loci except HPA-15. The newly observed HPA data as well as principal coordinate analysis clearly indicate genetic contributions from both, Asia and Australasia in Maori and Polynesian populations together with recent admixture with Europeans. In addition, different prevalences of HPA alleles among Polynesian, Maori and European populations contribute towards different risk profiles for platelet-specific alloimmunization. This is the first report for these populations and our findings are of direct practical relevance for blood transfusion centres, the management of pregnancies, assessment of neonatal alloimmune thrombocytopenia and management of multi-transfused patients.

Frequency of human platelet antigens in oncohematological patients with thrombocytopenia and the probability of incompatibility to platelet transfusions

ObjectiveThe objective of this study was to evaluate the frequencies of human platelet antigens in oncohematological patients with thrombocytopenia and to analyze the probability of their incompatibility with platelet transfusions.MethodsPlatelet antigen genotyping was performed by sequence-specific primer polymerase chain reaction (SSP-PCR) for the HPA-1a, HPA-1b, HPA-2a, HPA-2b, HPA-3a, HPA-3b, HPA-4a, HPA-4b, HPA-5a, HPA-5b; HPA-15a, HPA-15b alleles in 150 patients of the Hematology Service of the Hospital das Clínicas (FMUSP).ResultsThe allele frequencies found were: HPA-1a: 0.837; HPA-1b: 0.163; HPA-2a: 0.830; HPA-2b: 0.170; HPA-3a: 0.700; HPA-3b: 0.300; HPA-4a: 1; HPA-4b: 0; HPA-5a: 0.887; HPA-5b: 0.113; HPA-15a: 0.457 and HPA-15b: 0.543.ConclusionsData from the present study showed that the A allele is more common in the population than the B allele, except for HPA-15. This suggests that patients homozygous for the B allele are more predisposed to present alloimmunization and refractoriness to platelet transfusions by immune causes. Platelet genotyping could be of great value in the diagnosis of alloimmune thrombocytopenia and to provide compatible platelet concentrates for these patients.

Comments on: frequency of human platelet antigens in oncohematological patients with thrombocytopenia and the probability of incompatibility to platelet transfusions

Comments on: frequency of human platelet antigens in oncohematological patients with thrombocytopenia and the probability of incompatibility to platelet transfusions

Human platelet antigen allele frequencies and new mutations on platelet glycoprotein genes in the Chinese Han population

The frequencies of human platelet antigens (HPAs) vary between different populations. In this study, we determined the HPA allele frequencies in the Chinese Han population and identified situation of incompatibility possibly leading to alloimmunisation. A total of 750 volunteer blood donors of the Chinese Han population were genotyped for HPA-1 to -17w systems. HPA genotyping was determined by polymerase chain reaction sequence-based typing. Among the 17 HPA systems, the allele frequency is different from other populations. We noted the absence of HPA-7bw to HPA-14bw, HPA-16bw and HPA-17bw alleles in the population. The estimated incompatibility probabilities regarding platelet antigens 1 to 6w and 15 systems after transfusion of random donor platelet were from 0·004 to 0·373. Thirteen glycoprotein alleles were observed in the population. In addition, we identified 16 novel mutations on the glycoprotein genes separated from HPA polymorphisms, including GP1BA (517-525delAAC), ITGA2B (2722C>T and IVS26+85T>C), ITGA2 (1521C>T, 2474T>G and IVS20+10 G>C), ITGB3 (1476G>A, IVS10+19C>A, 1813G>A, IVS11+21G>A, IVS11+152A>G and IVS11-104T>C), GP1BB (IVS1-79G>A, IVS1-27C>T and 129G>A) and CD109 (2139A>G). Five of them could lead to amino acid deletion, substitution or premature stop codon in corresponding glycoprotein. There was a high degree of polymorphism of the membrane glycoprotein genes related to human platelet alloantigen-1 to -17w systems in the Chinese Han population. These data could have some impact on the diagnosis, prevention and treatment of alloimmune thrombocytopenia.

Human platelet antigen allele frequencies in different Algerian populations

The frequencies of human platelet antigens (HPAs) vary between different populations and are a major determinant for the prevalence of HPA alloimmunization and its clinically associated entities. No report on HPA prevalence has previously been published for the Algerian populations which are ethnically diverse. The aim of this study was to determine the HPA allele frequencies in Algerian populations and to identify situations of incompatibility possibly leading to alloimmunization. A total of 485 healthy volunteer Algerian blood donors from different regions and representing different ethnic groups were included. HPA genotyping was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and/or polymerase chain reaction-sequence specific primer (PCR-SSP). The HPA-1 allele frequencies were close to the frequencies found in Caucasian populations. The presence of the molecule human leukocyte antigen (HLA)-DRB3*0101 (17.9%) increases the risk of alloimmunization. We observed an increase in the frequency of homozygous HPA-5b, particularly in the population of Annaba (7.61%) and the Mzab population (5.13%). The allele frequency HPA-2b (0.193-0.147) was similar to that seen in Sub-Saharan African populations. The high frequency of homozygotic HPA-2b (Kabyle 5%; Mzab 2.44% and Annaba 2.19%) could increase the risk of alloimmunization. GPIIb A(k) mutation (2614C>A) was found in these populations. This study is the first to report on HPA allele frequencies in Algerian populations. High allele frequencies were observed for HPA-1b (0.209-0.112), HPA-3b (0.411-0.312) and HPA-5b (0.217-0.087), leading to a high risk of alloimmunization in this population, especially the Mzab and the population of Annaba. Our results could have some impact in the diagnosis, prevention and treatment of alloimmune thrombocytopenia.

Human platelet antigen polymorphisms (HPA-1, -2, -3, -4, -5 and -15) in major ethnic groups of Pakistan

Gene frequencies of human platelet antigens (HPA) determine the magnitude of platelet immunological disorders like neonatal alloimmune thrombocytopenia, platelet refractoriness and ease of availability of particular HPA-typed platelet donors in a given community. However, the pattern of HPA in Pakistani population is not known. The aim of present study was to determine the gene frequencies of HPA (HPA-1 to -5 and -15) in individuals belonging to major ethnic groups and castes of Pakistani population. HPA genotyping was done in 593 individuals belonging to all ethnic groups of Pakistan, by polymerase chain reaction-sequence specific primers with detection on polyacrylamide electrophoresis. The gene frequencies of the 'a' and 'b' alleles of HPA-1 to -5 and -15 in Pakistanis were as follows: HPA-1a/b, 0.885/0.115; HPA-2a/b, 0.92/0.08; HPA-3a/b, 0.69/0.31; HPA-4a/b, 1/0; HPA-5a/b, 0.9/0.1; HPA-15a/b, 0.59/0.41. Except for significant difference regarding gene frequency of HPA-3 between Pathans and Sindhis, there was no significant difference of HPA-1 to -5 and -15 between major ethnic groups of Pakistan. The estimated mismatch probability regarding platelet antigens 1-5 and 15 in Pakistanis, after transfusion of random donor platelets, is from 14 to 37%. The expected incidence of neonatal alloimmune thrombocytopenia due to anti-HPA-1a in Pakistani pregnant females is < 1 of 1000 pregnancies and 8-12 of 1000 in case of anti-HPA-5b. Homozygosity of HPA-1b, -2b and -5b genotypes ranged from 1 to 2% in the Pakistani population, whereas homozygosity of HPA-3b and -15b was 11 and 18%. There is a need to establish donor registries typed for HPA in the transfusion centres of the country.

Gene frequencies of human platelet antigens in the Macedonian population

Human platelet antigen (HPA) systems consist of more than 12 bi-allelic antigen polymorphisms. Due to these polymorphisms, platelet-membrane glycoproteins can be recognized as alloantigens or autoantigens and can cause conditions such as fetomaternal alloimmune thrombocytopenia, post-transfusion refractoriness to platelets, and post-transfusion throbocytopenic purpura. The purpose of this study was to investigate the distribution of HPA-1, -2, -3, and -5 in Macedonian population by using the polymerase chain reaction and restriction fragment length polymorphism. The allele frequencies were 0.865 for HPA-1a, 0.135 for HPA-1b, 0.852 for HPA-2a, 0.148 for HPA-2b, 0.578 for HPA-3a, 0.422 for HPA-3b, 0.909 for HPA-5a, and 0.091 for HPA-5b. Results of our study were not significantly different from those reported in the other European studies. Our population displayed the highest frequency for HPA-2b allele (0.148) reported among European population.

Eleven human platelet systems studied in the Vietnamese and Ma'ohis Polynesian populations.

The frequencies of human platelet antigens (HPA) are variable among different ethnic groups. Platelet phenotyping and genotyping in different populations are important to the clinical implications of antiplatelet alloimmunization. No report on HPA prevalence has been published concerning the Vietnamese Kinh and Ma'ohis Polynesian populations. Recent anthropological and genetic marker studies suggest that these two groups have a common origin in East Asia, so we have conducted a combined study concerning the frequency of HPA-1 to HPA-11w systems (excluding HPA-8w) and Gov in these two populations. The results demonstrate a similar pattern of prevalence between Ma'ohis and most of the Asian populations. However, it should be noted that the frequency of HPA-2 is closer to northern Caucasian frequencies than to Asian frequencies. The population of Kinh shows an HPA distribution that is closer to the Chinese population than to the northeastern Thais except for HPA-3, closer to the Indonesian population. Given HPA-3 gene frequency distribution fetomaternal incompatibility could occur more frequently with the risk of alloantibody production.

Gene frequencies of human platelet antigens in the Tunisian population.

Gene frequencies for the human platelet antigens HPA-1, -3 and -5 in the Tunisian population were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) on 93 volunteer blood donors (78 were tested for HPA-1, 90 for HPA-3 and 93 for HPA-5). This study shows the highest frequencies of the HPA-1b (0.25) and HPA-5b (0.22) yet recorded. These antigens are considered as markers of a high risk of platelet alloimmunisation in other populations, and for this reason particular attention should be paid in the case of pregnancy or blood transfusion in this population. The 9 base pair deletion located in intron 21 of the GPIIb gene associated with HPA-3b determinant is present in this population. No individual showed the polymorphism associated with HPA-1b (T-->G at codon 40 of the GPIIIa).

Gene frequencies of human platelet antigens on glycoprotein IIIa in Japanese.

Polymorphism of glycoprotein IIIa on human platelets is one of the factors in alloimmunization that causes neonatal alloimmune thrombocytopenia and refractoriness to platelet transfusion. DNA typing methods were originally developed to determine the genotypes of five human platelet antigen (HPA) systems located on glycoprotein IIIa: HPA-1, HPA-4, HPA-6W, HPA-7W and HPA-8W. The gene frequencies of these platelet antigens were determined by DNA typing of 331 unrelated Japanese donors. The gene frequencies of the low-frequency antigens were 0.002, 0.011, and 0.027 for HPA-1b, HPA-4b, and HPA-6W(b), respectively. All 331 Japanese donors tested were HPA-7W(a/a) and HPA-8W(a/a). Moreover, in the present study, none of the donors tested had two or more of these low-frequency antigens. The risk of neonatal alloimmune thrombocytopenia and refractoriness to platelet transfusion induced by the antigens of the HPA-1, HPA-7W, and HPA-8W systems was extremely rare in Japanese. However, attention must be paid to the involvement of the HPA-4 and HPA-6W systems in these clinical disorders.

Frequency of human platelet antigens among blood donors in northeastern Thailand

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.