Human platelet antigen frequencies of platelet donors in the French population determined by polymerase chain reaction with sequence-specific primers.
ABSTRACT To prevent human platelet alloimmunization, Blood Transfusion Centres have to develop a strategy close to the erythrocytes' one. The first step of this strategy is to perform the HPA typing of donors with an accurate method. We applied the PCR-SSP to type 800 platelet donors in the HPA-1 and HPA-5 systems and 350 in the HPA-2 and HPA-3 ones. This study reports the human platelet antigen frequencies of four platelet-specific alloantigen systems in the French population. The results are quite similar to those currently published for Caucasian population frequencies. Low prevalences are observed for the HPA-1b, (2%), HPA-2b (0.6%) and HPA-5b (2%) groups. Furthermore, this study confirms the need to type donors and recipients in the HPA-1 system at least, in case of post-transfusion pupura and platelet refractoriness to platelet transfusion therapy.
- SourceAvailable from: Mirko Spiroski[Show abstract] [Hide abstract]
ABSTRACT: (Full text is available at http://www.manu.edu.mk/prilozi).Idiopathic thrombocytopenic purpura (ITP) is an autoimmune disease characterized by thrombocytopenia due to the presence of platelet autoantibodies specific for platelet membrane glycoproteins, such as GPIIb/IIIa, GPIb/IX and GPIa/IIa. These autoantibodies cause an accelerated clearance of opsonized platelets by phagocytes and inhibition of platelet production. Human platelet antigen (HPA) systems HPA-1, HPA-2, HPA-3 and HPA-5 are components of platelet GP complexes GPIIb/IIIa, GPIb/IX and GPIa/IIa. The HPA system consists of more than 12 bi-allelic antigen polymorphisms in which a base-pair substitution leads to change in an amino acid sequence of a membrane glycoprotein expressed on the platelet surface. The aim of this study was to examine the association of HPA-1, HPA-2, HPA-3 and HPA-5 polymorphisms with idiopathic thrombocytopenic purpura. We performed genotyping of HPA-1, HPA-2, HPA-3, and HPA-5 systems in 60 patients with ITP and 120 healthy participants. Genotyping of HPA-1, -2, -3, and -5 alleles were performed by PCR and RFLP methods by using specific primers and restriction enzymes. Allele and genotype frequencies of HPA-1, HPA-3, and HPA-5 were not significantly different between patients and healthy participants. After Bonferroni adjustment a significant association in ITP patients with HPA-2 alleles (P = 0.015, OR = 1.923, CI = 1.126-3.284) was found. Allele frequencies for HPA-2a were 0.852 in healthy participants and 0.750 in patients, and for HPA-2b 0.148 and 0.250 respectively. These results suggests that HPA-2b allele was more frequent in patients with ITP and may be involved in the formation of a specific autoepitope. Key words: idiopathic thrombocytopenic purpura, human platelet antigen systems, restrictiction fragment length polymorphisms.Prilozi / Makedonska akademija na naukite i umetnostite, Oddelenie za biološki i medicinski nauki = Contributions / Macedonian Academy of Sciences and Arts, Section of Biological and Medical Sciences 07/2012; 33(1):135-46.
- [Show abstract] [Hide abstract]
ABSTRACT: BACKGROUND: The human platelet alloantigen system HPA-1 in the Egyptian population was examined by polymerase chain reaction using sequence-specific primers (PCR-SSP). The objectives of this study were to evaluate the allele frequency of HPA-1a and -1b in healthy Egyptian individuals and compare these with the international literature. Human platelet antigen (HPA) systems are associated with alloimmunization and organ transplantation rejection as well as the development of cardiovascular disease. Of the various HPA systems, HPA-1 specifically has been considered to be the most important antigenic system implicated in the Caucasian population. No study has yet examined this system in the Egyptian populations, however. We therefore investigated the allele frequency of the HPA-1 system in the Egyptian population. FINDINGS: To determine the allele frequency of the HPA-1a and -1b, we tested genomic DNAs from 206 healthy, unrelated Egyptian individuals using PCR-SSP. Our results showed that the 1a/1a genotype was the most predominant (59.22%) followed by 1a/1b (34.95%) and 1b/1b (5.83%) with allele frequencies for 1a and 1b of 0.77 and 0.23, respectively, in the population. CONCLUSION: As compared with other geographic groups, a relatively high allele frequency of the HPA-1b in the Egyptian population may indicate a higher risk of alloimmunization. This study is the first to investigate the allele frequency of the HPA-1 system in the Egyptian population and serves as an outline for future clinical research associated with platelet disorders in this group.BMC Res Notes. 2:90.
- [Show abstract] [Hide abstract]
ABSTRACT: BACKGROUND AND OBJECTIVES: Foetal and neonatal alloimmune thrombocytopenia (FNAIT) is studied mainly in Caucasian populations. Severe thrombocytopenia (<50×10(9)/L) gives risk of haemorrhage and the most feared complication is intracranial haemorrhage (ICH). In Caucasian populations anti-human platelet antigen (HPA)-1a antibodies are the cause of FNAIT in >80% of the cases. The aims of this project were to study the gene frequencies of HPA-1-5 and 15 alleles in an Egyptian population (Arabic), and to determine the frequency of HPA-1a and -5b immunisations in a cohort of Egyptian pregnant women. MATERIALS AND METHODS: Altogether 6974 pregnant women were included in the study. Genotyping was performed by polymerase chain reaction and antibodies were detected by flow cytometry and enzyme-linked immunosorbent assay. HPA-1-5 and 15 alleles were studied in 367 individuals. RESULTS: The HPA genotypes differed from genotypes published from different Caucasian and Chinese (Han) populations in HPA-1, -2, -3, and -5 systems with significant higher frequency of HPA-1b, -2b and -5b. The rate of HPA-1a alloimmunisation was found comparable to Caucasian populations. Severe thrombocytopenia was found in two newborns. No bleeding complication was reported. Anti-HPA-5b antibodies were detected in 4.4% of the pregnant women. Clinical consequences of these antibodies were not studied. CONCLUSION: The HPA-1bb and -5bb genotypes are more frequent in the Egyptian Arabic population studied compared to Caucasian populations. FNAIT due to anti-HPA-1a and -5b antibodies must be suspected in cases of neonatal thrombocytopenia. Further large prospective studies are needed to increase the knowledge of clinical complications related to HPA alloantibodies in populations with different genetic backgrounds.Transfusion and Apheresis Science 05/2012; · 1.23 Impact Factor