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BACKGROUND:Immune platelet refractoriness is mainly caused by human leukocyte antigen antibodies (80-90% of cases) and, to a lesser extent, by human platelet antigen antibodies. Refractoriness can be diagnosed by laboratory tests and patients should receive compatible platelet transfusions. A fast, effective and low cost antibody-screening method which detects platelet human leukocyte/platelet antigen antibodies is essential in the management of immune platelet refractoriness. OBJECTIVE: The aim of this study was to evaluate the efficiency of the flow cytometry platelet immunofluorescence test to screen for immune platelet refractoriness. METHODS: A group of prospective hematologic patients with clinically suspected platelet refractoriness treated in a referral center in Campinas, SP during July 2006 and July 2011 was enrolled in this study. Platelet antibodies were screened using the flow cytometry platelet immunofluorescence test. Anti-human leukocyte antigen antibodies were detected by commercially available methods. The sensitivity, specificity and predictive values of the immunofluorescence test were determined taking into account that the majority of antiplatelet antibodies presented human leukocyte antigen specificity. RESULTS: Seventy-six samples from 32 female and 38 male patients with a median age of 43.5 years (range: 5-84 years) were analyzed. The sensitivity of the test was 86.11% and specificity 75.00% with a positive predictive value of 75.61% ...
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Antigens, Human Platelet , Blood Platelets , Flow Cytometry , Histocompatibility , LeukocytesABSTRACT
Objective To establish the platelet antigen panel for identifying the specificity of platelet antibodies which cause platelet transfusion refractoriness and neonatal alloimmune thrombocytopenia and provide evidence for clinical therapy and platelet genotyping research.Methods Based on the frequency distribution of human platelet alloantigen (HPA)-1 to HPA-16 gene in China, the frequencies of HPA-1 to HPA-6,HPA-15 alleles in blood group O donors were genotyped by the polymerase chain reaction with sequence-specific primers (PCR-SSP) method, and suitable donors were chosen to establish platelet-specific antigen panel.Using the established platelet-specific antigen panel, the specificity of platelet antibodies caused by alloimmune reaction was identified by using simplified sensitized erythrocyte platelet serology assay (SEPSA).Results Eleven ptatelet donors with blood group O were chosen to establish platelet-specific antigen panel which can identify specificity of HPA-1 to HPA-6, HPA-15 antibodies.One case of HPA-4b (Penb) and two cases of HPA-15a (Govb) platelet specific antibodies were detected in 1 120 samples.Conclusion Identifying the specific platelet antibodies using platelet specific antigen panel has profound significance on increasing the safety and effectiveness of clinical platelet transfusion and prevention of neonatal alloimmune thrombocytopenia.
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Objective To establish a PCR sequencing-based typing (PCR-SBT) method for simultaneous genotyping of human platelet antigen HPA-1 to HPA-16w.Methods All DNA polymorphism sites of HPA-1 to HPA-16w were obtained from the immuno polymorphism database.The specific primers were designed using Primer Premier 5.0 software to amplify nucleotide acid fragments encompassing each HPA polymorphism site.The primer sequence and PCR condition were optimized to obtain specific and single amplification product.The PCR product was purified and then sequenced to determine the HPA genotypes.Two standard DNA samples were detected using the HPA PCR-SBT method to examine the accuracy d this method.Sixteen reference samples (including 6 interference samples with HPA gene mutations) provided by 14th platelet immunology workshop of international society of blood transfusion (ISBT) in 2008 were also tested by this home-brew HPA PCR-SBT method.Results Total eleven pairs of primers were designed to amplify and sequence the sixteen HPA systems.The HPA genotypes of two standard samples were 1aa/2aa/3ab/4aa/5ab/6aa/7aa/8aa/9aa/10aa/11aa/12aa/13aa/14aa/15aa/16aa and 1aa/ 2aa/3aa/4aa/5aa/6aa/7aa/8aa/9aa/10aa/11aa/12aa/13aa/14aa/15aa/16aa,respectively.The 256 HPA genotypes of 16 reference samples were clear.128 genotypes among them were completely accordance with the results provided by ISBT report.Conclusions The PCR-SBT assay combining high-throughput DNA sequencer established in the study provides a simple,rapid and accurate method for HPA-1 to HPA-16w systems genotyping.The assay is suitable for routine clinical HPA genotyping and shows a broad prospect in further applications.
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Objective To develop a polymerase chain reaction restriction fragment length polymorphism (PCR RFLP) method using designed primers for determining the genotype of humen platelet antigens (HPA)5 system. Methods HPA 5 system of 25 healthy blood donors were genotyped using PCR RFLP method. The results obtained by PCR RFLP were compared with those determined by allele specific oligonucleotid hybridization (PCR ASO). Results The results of HPA 5 system obtained by PCR RFLP in 25 health donors were as follows: 24 of aa, 1 of ab and 0 of bb. All were in good agreement with those determined by PCR ASO. Conclusions Because PCR RFLP method is plain, fast and reliable for HPA 5 system genotyping, it is suitable for the diagnosis and therapy of neonatal alloimmune thrombocytopenia, posttransfusion purpura, platelet transfusion refractoriness and so on..