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.
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ABSTRACT: Severe neonatal alloimmune thrombocytopenia and patients with HPA-1a-specific antibodies require transfusion of HPA-1a-negative platelets. Identifying HPA-1a-negative donors requires simple and reliable typing methods. Most existing techniques use polyclonal antibodies, are time consuming and involve platelet isolation. We have used a horseradish peroxidase (HRP)-conjugated recombinant IgG1 anti-HPA-1a (CAMTRAN007) to develop a rapid and reliable enzyme-linked immunosorbent assay (ELISA), which eliminates sample preparation and reduces the incubation and wash steps associated with traditional sandwich ELISAs. The assay uses simultaneous incubation of the monoclonal antibody RFGP56 to capture GPIIbIIIa from whole blood and the recombinant IgG1 antibody to detect captured HPA-1a antigen. It allows 96 samples to be typed in less than 1 h and can be used on stored samples. Initial testing of 85 samples of known HPA-1a genotype demonstrated that HPA-1a-negative samples had OD values of < 0.266, whereas HPA-1a-positive samples had OD values of > 0.6. Testing of 1862 random donor samples in two blood centres confirmed these OD cut-off values and identified 45 HPA-1a-negative samples (2.4%), all except one giving OD values of < 0.2. The remaining HPA-1a-negative sample had an OD value of 0.303. The HPA-1a status on all the negative samples and an equivalent number of randomly selected positive samples was confirmed by flow cytometry and polymerase chain reaction with sequence-specific primers (PCR- SSP).British Journal of Haematology 02/2000; 108(2). · 4.94 Impact Factor
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ABSTRACT: BACKGROUND: Polymorphisms of the human platelet alloantigens (HPA) arise from single base pair substitutions in alleles and lead to changes in amino acids of glycoproteins expressed on platelets. The aim of this study was to determine the gene frequencies of the five common HPA (HPA-1 to -5) in Egyptians and Jordanians and to compare these data with those established for other populations. MATERIALS AND METHODS: HPA genotyping was done by polymerase chain reaction with sequence-specific primers. RESULTS: The gene frequencies obtained in Egyptians were: HPA-1a/b, 0.767/0.233; HPA-2a/b, 0.759/0.241; HPA-3a/b, 0.704/0.296; HPA-4a/b, 1/0; HPA-5a/b, 0.728/0.272, while the frequencies in Jordanians were: HPA-1a/b, 0.821/0.179; HPA-2a/b, 0.877/0.123; HPA-3a/b, 0.660/0.340; HPA-4a/b, 1/0; HPA-5a/b, 0.795/0.205. The observed gene frequencies in both populations were in Hardy-Weinberg equilibrium. The gene frequencies for HPA-2b and HPA-5b among Egyptians were the highest reported among Arabs. Except for HPA-2, there were no significant differences in the distribution of HPA-1 to -5 between the two populations. CONCLUSION: The distributions of HPA alleles among Egyptians and Jordanians are similar to those reported for other Arabs. This study reports the first data on gene frequencies of HPA in Egyptians and Jordanians.Blood transfusion = Trasfusione del sangue 05/2013; · 1.86 Impact Factor
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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.