Genotyping of HPA-1 to -7 and -15 in the Thai population using multiplex PCR

Background : Different polymerase chain reaction (PCR) techniques for human platelet antigens (HPA) genotyping have been implemented, in order to diagnose the clinical syndromes of patients with thrombocytopaenia and provide effective HPA‐matched platelet donors. Objectives : The aim of this study is to develop an in‐house multiplex PCR for HPA‐1 to ‐7 and ‐15 genotyping in the Thai population. Methods : One hundred DNA samples of known HPA genotyping by the PCR with sequence‐specific primers (PCR‐SSP), as previously described, were tested with the multiplex PCR. Additionally, 300 DNA samples of group O donors were tested for HPA‐1 to ‐7 and ‐15 genotyping using multiplex PCR. Results : The comparison of HPA‐1 to ‐7 and ‐15 genotype results between multiplex PCR and PCR‐SSP technique was in 100% concordance. Interestingly, HPA‐2b2b genotype was found in two samples; however, other low‐incidence genotypes such as HPA‐1b1b, HPA‐5b5b, HPA‐6b6b and HPA‐7b7b were not found in this study. Moreover, 30 samples were randomly tested twice for HPA genotyping using the multiplex PCR and demonstrated reproducible results. Conclusions : This study shows that the in‐house multiplex PCR is simple, cost‐effective and suitable for HPA genotyping for routine laboratories in other developing countries. Nevertheless, a large‐scale evaluation of this technique through multicentre analysis is suggested.     

The allele frequencies of HPA 1‐16 determined by PCR‐SSP in Chinese Cantonese donors

Background: Typing of human platelet antigens (HPA) has proven to be useful in some clinical situations related to platelet alloimmunization. Objective: The objective of this study was to investigate HPA 1–16 and to determine genotype and allele frequencies by polymerase chain reaction‐sequence specific primer (PCR‐SSP) in apheresis platelet donors in Guangzhou Blood Center. Methods: A total of 200 random samples from donors were involved in the study. Genotype and allele frequencies of HPA 1 to 16 were detected by PCR‐SSP method. Results: The frequencies obtained from these donors were 99·50 and 0·50% for HPA‐1a and ‐1b; 96·25 and 3·75% for HPA‐2a and ‐2b; 54·25 and 45·75% for HPA‐3a and ‐3b; 99·50 and 0·50% for HPA‐4a and ‐4b; 99·00 and 1·00% for HPA‐5a and ‐5b; 97·00 and 3·00% for HPA‐6a and ‐6b and 42·25 and 57·75% for HPA‐15a and ‐15b. There is only a/a homozygosis detected in HPA‐7, ‐8, ‐9, ‐10, ‐11, ‐12, ‐13, ‐14 and ‐16. In this study, none of HPA‐1b/ 1b, ‐2b/2b, ‐5b/5b homozygosis were detected which were found in other racial groups. One homozygosis of HPA‐6b/6b in 200 individuals was detected which was not found in a study involving 1000 Chinese ( Feng et al., 2006 ). Conclusion: The HPA‐3 and ‐15 appear to the highest priority and HPA‐2, ‐6, ‐5 ‐1 and ‐4 to be the second priority in Chinese Cantonese when it comes to the diagnosis of neonatal alloimmune thrombocytopenia and to provide the HPA‐matched platelet for patients with platelet transfusion refractoriness. The PCR‐SSP method makes it possible to detect genotype of HPA‐1 to ‐16 in less than 4 h and to establish a donor database for HPA genotype in a blood bank.     

New K103 β3 allele identified in a context of severe neonatal thrombocytopenia

BACKGROUND: A new β3 allele was identified in a severe case of neonatal alloimmune thrombocytopenia (<7 × 10⁹/L). STUDY DESIGN AND METHODS: Diagnosis was done by use of monoclonal antibody–specific immobilization of platelet (PLT) antigen for serologic analyses and polymerase chain reaction (PCR)–sequence‐specific primers (SSP) and PCR–restriction fragment length polymorphism (RFLP) for genotyping. Direct sequencing of PCR product was done and mutant αIIbβ3 expressed in HEK‐293 cells. RESULTS: Serologic analysis revealed in the maternal serum an anti‐human PLT alloantigen (HPA)‐1a alloantibody associated to an anti‐α2β1. Anti‐HPA‐1a alloimmunization diagnosis was confirmed by genotyping showing maternofetal incompatibility. However, investigation of rare HPA polymorphisms revealed discrepant HPA‐16b assignation between PCR‐RFLP and PCR‐SSP. Sequencing revealed a new c.385C>A mutation in the β3 coding sequence resulting in a false assignation of the HPA‐16b allele by PCR‐RFLP. This mutation leads to a Q103K substitution in mature β3. The K103‐β3 form of the complex was expressed in HEK‐293 cells but did not react with the maternal serum. CONCLUSION: We have characterized a new rare allele (frequency < 1%) of β3 that yields false HPA‐16b genotyping in PCR‐RFLP. This new case of false typing assignation emphasizes the necessity to use two genotyping techniques in diagnosis. This particularly applies for rare HPA polymorphisms when PLT phenotyping cannot be used.     

High-throughput multiplex single-nucleotide polymorphism analysis for red cell and platelet antigen genotypes

BACKGROUND: Transfusion recipients who become alloimmunized to red cell or platelet (PLT) antigens require antigen-negative blood to limit adverse transfusion reactions. Blood collection facilities use regulated and unregulated antibodies to phenotype blood, the cost of which can be prohibitive depending on the antisera and demand. An alternative strategy is to screen blood for these antigens with genomic DNA and the associated single-nucleotide polymorphisms (SNPs). STUDY DESIGN AND METHODS: A multiplex polymerase chain reaction (PCR)-oligonucleotide extension assay was developed with genomic DNA and a SNP genotyping platform (GenomeLab SNPstream, Beckman Coulter) to identify SNPs related to D, C/c, E, S/s, K/k, Kp(a/b), Fy(a/b), FY0 (-33 promoter silencing polymorphism), Jk(a/b), Di(a/b), and human PLT antigen (HPA)-1a/1b. A total of 372 samples were analyzed for 12 SNPs. The genotypes were compared to the blood group and PLT antigen phenotypes. RESULTS: Individual sample results varied from 98 to 100 percent for 11 of 12 SNPs. D was correctly identified in 292 of 296 (98.6%) D+ donors. The RHCE exon 5 E/e SNP analysis had the lowest concordance (89.5%). Thirty-three R(1)R(1) and 1 r"r were correctly identified. PCR-restriction fragment length polymorphism (RFLP) on selected samples confirmed the presence of the FY0 silencing polymorphism in nine donors. Homozygous HPA-1b/1b was identified in four donors, which was confirmed by PCR-RFLP (n = 4) and anti-HPA-1a serology (n = 2). The two HPA-1a-negative donors were recruited into the plateletpheresis program. CONCLUSION: The platform has the capacity to genotype thousands of samples per day. The suite of SNPs provides genotype data for all blood donors within 36 hours of the start of testing.     

多重聚合酶链反应用于人血小板抗原-2、-4、-5系统基因分型的研究

目的建立用于检测人血小板抗原(HPA)-2、-4、-5系统基因型的多重聚合酶链反应(PCR)。方法在一个反应体系中同时扩增HPA-2、-4、-5系统特异性目的基因片段。用琼脂糖凝胶电泳确定HPA-2、-4、-5系统基因型;再用多重PCR对75名健康的单采血小板者进行HPA-2、-4-、5系统基因分型,分型结果与PCR-序列特异性引物(PCR-SSP)获得的结果进行比较。结果HPA-2、-4、-5系统分型的结果为:70名为2 a/2 a型,5名为2 a/2b型;73名为4 a/4 a型,2名为4 a/4b型;66名为5 a/5 a型,9名为5 a/5b型。未发现2b/2b、4b/4b及5b/5b纯合子个体。多重PCR结果与PCR-SSP方法获得的结果一致。结论多重PCR具有操作简便、快速、准确等特点,可以用于血小板血型抗原基因分型。     

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

Objectives: 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. Background: However, the pattern of HPA in Pakistani population is not known. Aim: 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. Materials and Methods: 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. Results: 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%. Conclusions: There is a need to establish donor registries typed for HPA in the transfusion centres of the country.     

Characterization of the alloreactive helper T-cell response to the platelet membrane glycoprotein IIIa (integrin-beta3) in human platelet antigen-1a alloimmunized human platelet antigen-1b1b women

BACKGROUND: The aims were to characterize the helper T‐cell response to platelet (PLT) glycoprotein (GP) IIIa, which stimulates the alloimmune antibody response to human PLT antigen (HPA)‐1a, to identify immunodominant epitopes and to examine the HLA Class II associations. STUDY DESIGN AND METHODS: Peripheral blood mononuclear cells (PBMNCs) were obtained from 21 HPA‐1b1b women who had an HPA‐1a–mismatched pregnancy, 14 of whom developed anti‐HPA‐1a, and 11 control donors. PBMNCs were stimulated with two panels of 15‐mer peptides corresponding to the HPA‐1a/1b polymorphic region, with either Leu³³ (‐1a) or Pro³³ (‐1b) at each possible position, and the proliferative responses were measured. HLA Class II and HPA genotyping was by conventional polymerase chain reaction–sequence‐specific priming. RESULTS: Peptides with Leu³³ at, or near, the C‐terminus contained an immunodominant epitope, stimulating proliferation by helper T cells from all nine women who had anti‐HPA‐1a at the time of testing; peptide L1 (Val¹⁹‐Leu³³) stimulated a response in 50 percent of these women. Their T cells did not respond to the corresponding HPA‐1b Pro³³ peptides, and responses to either peptide panel were rare in unimmunized women and controls. HLA‐DRB3*01+ was significantly overrepresented (p = 0.014) in alloimmunized women whose T cells responded to the major HPA‐1a Leu³³‐containing epitope. Conversely, HLA‐DRB1*15 was negatively associated (p = 0.014) with this response. CONCLUSIONS: The HPA‐1a polymorphic region of GPIIIa contains both the linear T‐cell and the conformational B‐cell epitopes. The immunodominant T‐cell epitope is constrained by HLA‐DRB3*01+, and if presented by a tolerogenic route, a peptide containing this epitope may form the basis for the prevention or reversal of the alloimmune response to HPA‐1a.     

The detection of platelet antibodies by simultaneous analysis of specific platelet antibodies and the monoclonal antibody–specific immobilization of platelet antigens: an interlaboratory comparison

BACKGROUND: Glycoprotein (GP)‐specific platelet (PLT) antibodies can cause allo‐ or autoimmune thrombocytopenia. Their detection is of high diagnostic value. The simultaneous analysis of specific PLT antibodies (SASPA) assay is based on simultaneous detection of various PLT‐specific antibodies by flow cytometry and has entered routine use in our Mannheim institution. In this study, we performed an interlaboratory comparison investigation of PLT‐specific antibodies using SASPA versus the “gold standard,” the monoclonal antibody–specific immobilization of PLT antigen (MAIPA) assay. STUDY DESIGN AND METHODS: Sera from 194 patients with suspected PLT allo‐ or autoantibodies were tested against GPIIb/IIIa, IX, Ia/IIa, IV, and HLA Class I by SASPA (in Mannheim) and MAIPA (in Vienna). All data were reported blinded to those from the respective other method. Sensitivity studies included dilution studies with known antibodies against HPA‐1a, ‐1b, ‐3b, ‐5b, and ‐15b and HLA Class I. RESULTS: Overall, results were concordant in 78.9%. The specificity and sensitivity of SASPA, based on the MAIPA results, were 97.3 and 86.3%, respectively, for the detection of alloantibodies. The respective results for the detection of autoantibodies were 95.3 and 44.9%. Serial dilution experiments with sera containing anti‐HPA1a, ‐1b, ‐3b, ‐5b, and ‐15b and anti‐HLA Class I revealed a higher sensitivity of the SASPA assay with all alloantibodies. CONCLUSION: In this first blind interlaboratory comparison, SASPA yielded similar results to those of MAIPA. The SASPA assay may be superior to the MAIPA assay for the detection of weak alloantibodies while simultaneous detection of a variety of antibody specificities or immunoglobulin classes and the need of fewer PLTs are obvious advantages.     

Rapid genotyping of blood group antigens by multiplex polymerase chain reaction and DNA microarray hybridization

BACKGROUND: In the Netherlands, 500,000 blood donors are active. Blood of all donors is currently typed serologically for ABO, the Rh phenotype, and K. Only a subset of donors is typed twice for a larger set of red cell (RBC) and/or platelet (PLT) antigens. To increase the direct availability of typed RBCs and PLTs, a high-throughput technique is being developed to genotype the whole donor cohort for all clinically relevant RBC and PLT antigens. STUDY DESIGN AND METHODS: A multiplex polymerase chain reaction was developed to both amplify and fluorescently label 19 gene fragments of RBC and PLT antigens in one reaction. To test the setup of the genotyping method by microarray, a pilot study with human PLT antigen (HPA)-typed donor samples was performed. On each slide, 12 arrays are present containing 20 probes per PLT antigen system (28 for HPA-3). The allele-specific oligohybridization method was used to discriminate between two different alleles. RESULTS: Two blinded panels encompassing 94 donors were genotyped for HPA-1 through -5 and -15; no discrepancies were found compared to their serologic typing (HPA-1, -2, -3, -4, and -5) and genotyping (HPA-15; TaqMan, Applied Biosystems). CONCLUSION: This study shows that the HPA microarray provides a reliable and fast genotyping procedure. With further development an automated throughput for complete typing of large donor cohorts can be obtained.     

多重聚合酶链反应-微流芯片检测人血小板抗原系统基因型方法的建立与应用

目的建立人血小板抗原（HPA）-2、4、5系统基因型的检测方法。方法用多重聚合酶链反应和微流芯片检测方法，通过设计9条特异性引物、优化反应体系和反应条件，在一个体系中同时扩增HPA-2、4、5系统特异性的目的基因片段，利用微流芯片快速检测HPA-2、4、5系统基因型；并把分型结果与采用聚合酶链反应．序列特异性引物（PCR-SSP）获得的结果进行比较。结果对35名健康单采血小板者进行HPA-2、4、5系统分型的结果为：33名为2a／2a型，2名为2a／2b型；34名为4a／4a型，1名为4a／4b型；29名为5a／5a型，6名为5a／5b型。未发现2b／2b、4b／4b及5b／5b纯合子个体。该结果与PCR．SSP方法获得的结果完全一致。结论该方法可快速、准确地用于血小板血型抗原基因分型，尤其适合于大样本检测。     

Rapid and reliable genotyping of human platelet antigen (HPA)-1, -2, -3, -4, and -5 a/b and Gov a/b by melting curve analysis

BACKGROUND: The probability for occurrence of neonatal alloimmune thrombocytopenic purpura (NAITP) depends largely on the frequency of each individual phenotype in various populations. In caucasians, antibodies to human platelet antigen (HPA)-1a are the major cause of neonatal alloimmune thrombocytopenic purpura, whereas in the Japanese population, antibodies to HPA-4b is most frequently involved in NAITP. Conventional PCR techniques for platelet antigen genotyping rely on sequence-specific primers (SSPs) and detection by gel electrophoresis, a method which is laborious and time consuming. New PCR technology, measuring the match of a hybridization probe with its target and thereby allowing simultaneous detection of both alleles, provides an efficient tool for genotyping of the HPA systems. STUDY DESIGN AND METHODS: A total of 105 healthy blood donors were genotyped for HPA-1, -2, -3, -4, and -5 a/b and Gov a/b with new primers and probes designed for mutation detection by melting curve analysis (using LightCycler technology). Donor DNA was independently genotyped by an allele-specific assay, using SSPs, in a reference laboratory. RESULTS: There was full concordance between the two genotyping methods, and genotype frequencies were comparable with previous studies in caucasians. CONCLUSION: We present rapid and reliable detection systems for HPA-1, -2, -3, -4, and -5 a/b and Gov a/b based on mutation detection of both alleles simultaneously by melting curve analysis. As the Gov system has been reported to have similar frequency of involvement in alloimmune thrombocytopenia as HPA-5, the opportunity for genotyping should aid the diagnosis of such patients.     

Low-avidity anti-HPA-1a alloantibodies are capable of antigen-positive platelet destruction in the NOD/SCID mouse model of alloimmune thrombocytopenia

BACKGROUND: Neonatal alloimmune thrombocytopenia (NAIT) is mostly caused by maternal antibodies against human platelet antigen 1a (HPA‐1a) expressed on glycoprotein (GP) IIb/IIIa. Accumulated evidence indicated that anti‐HPA‐1a could be overlooked by standard methods due to low avidity. Low‐avidity HPA‐1a antibodies were shown to be detectable by surface plasmon resonance (SPR). We sought to investigate the frequency and in vivo relevance of low‐avidity anti‐HPA‐1a. STUDY DESIGN AND METHODS: A retrospective cohort consisting of 82 HPA‐1bb mothers of HPA‐1ab newborns with thrombocytopenia was analyzed using standard serologic methods. Maternal immunoglobulin (Ig)G fractions were investigated for low‐avidity antibodies in SPR using purified GPIIb/IIIa (HPA‐1a or ‐1b). The capability of HPA‐1a antibodies to clear platelets (PLTs) in vivo was analyzed using the NOD/SCID mouse model of alloimmune thrombocytopenia. RESULTS: HPA antibodies were detectable in sera from 68 of 82 (83%) mothers using standard serologic methods and undetectable in 14 of 82 sera. In SPR, IgG fractions of sera reacting positive in monoclonal antibody immobilization of PLT antigen (MAIPA) assay showed specific binding to an HPA‐1a flow cell (mean, 87 ± 21 resonance units [RU]). When MAIPA‐negative sera were tested in SPR, binding with low avidity was observed in 7 of 14 to HPA‐1a (mean, 31 ± 5 RU), but not to HPA‐1b flow cell (mean, 5 ± 2 RU). In vivo, low‐avidity antibodies were capable of clearing HPA‐1ab PLTs but not HPA‐1bb PLTs in a NOD/SCID mouse model. Elimination kinetics were slower than observed with MAIPA‐positive antibodies. CONCLUSIONS: Low‐avidity HPA‐1a antibodies are present in a significant number of NAIT cases and, although they can escape detection by standard serology, they harbor the capability of PLT destruction in vivo.     

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for genotyping of human platelet-specific antigens

BACKGROUND: Genotyping of single-nucleotide polymorphisms (SNPs) using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is an emerging technique, where finally tools for end users have become available to design primers and analyze SNPs of their own interest. This study investigated the potential of this technique in platelet (PLT) genotyping and developed a validated method for genotyping of clinical relevant human PLT antigens (HPAs).
STUDY DESIGN AND METHODS: A multiplex assay using MALDI-TOF MS to analyze six HPA loci (HPA-1, HPA-2, HPA-3, HPA-4, HPA-5, and HPA-15) simultaneously in a single reaction was applied for the genotyping of 100 DNA samples from a cohort of plateletpheresis donors and a patient population (n = 20) enriched for rare alleles. The genotyping results using MALDI-TOF MS were validated by the comparison with the results from typing by polymerase chain reaction with sequence-specific primers and conventional DNA sequencing.
RESULTS: Both homozygous and heterozygous genotypes of HPA-1 to -5 and -15 of the 120 individuals were easily identified by a six-plexed assay on MALDI-TOF MS. The three approaches achieved a 100 percent concordance for the genotyping results of the six HPA loci.
CONCLUSION: Compared to conventional methods, the MALDI-TOF MS showed several advantages, such as a high velocity, the ability to perform multiplexed assays in a single reaction, and automated high-throughput analysis of samples. This enables cost-efficient large-scale PLT genotyping for clinical applications.     

应用PCR—SSP方法进行人类血小板抗原1～6系统的基因分型

目的研究采用PCR—SSP技术，建立人类血小板抗原1．6系统（HPA—1，2，3，4，5，6）的基因分型方法。方法合成18条序列特异性引物，通过调节引物浓度、Mg^2＋离子浓度和探索最佳PCR扩增条件．建立HPA—1．6系统同步基因分型技术。对第10届及第11届国际输血协会（ISBT）血小板基因定型协作组送检的考核样本进行盲检来验证。并应用该技术对198名深圳地区健康的血小板志愿捐献者进行基因分型。结果应用本研究的方法，对第10届及第11届ISBT送检的考核样本进行基因分型，结果与ISBT公布的结果完全一致，符合率达100％。对198名随机的血小板志愿捐献者观察到的基因频率分别是：HPA—1a和1b为0．9924和0．0076，HPA-2a和2b为0．9545和0．0455，HPA-3a和3b为0．5556和0．4444，HPA-4a和4b为0．9975和0．0025，HPA-5a和5b为0．9848和0．0152，HPA-6a和6b为0．9798和0．0202。结论本研究建立的HPA基因分型技术具有简便、快速、准确的特点，适合于常规HPA基因分型，具有广泛的应用前景。     

血小板谱抗原的建立及其在鉴定血小板特异性抗体中的应用

目的 建立血小板谱抗原,鉴定引起血小板输注无效和新生儿血小板减少性紫癜的血小板特异性抗体,为血小板血型研究和临床治疗提供依据。方法根据中国人群人类血小板同种抗原(HPA)-1-HPA-16等位基因频率分布资料,利用聚合酶链反应-序列特异引物(PCR-SSP)技术对O型血小板供者进行HPA-1-HPA-6、HPA-15分型,筛选合适的供者,组成血小板谱抗原。通过建立的血小板谱抗原,利用简易致敏红细胞血小板血清学技术(SEPSA)鉴定同种免疫反应产生的血小板抗体的特异性。结果从O型血小板供者中筛选出11名供者,建立了血小板特异性抗体鉴定谱抗原。其可鉴定HPA-1-HPA-6,HPA-15抗体的特异性。在所筛检1 120份样本中,有3例患者检出HPA抗体,其中HPA-4b(Penb)抗体1例,HPA-15a(Govb)抗体2例。结论通过血小板谱抗原鉴定血小板抗体的特异性,对提高临床输注血小板的安全性和有效性,以及预防新生儿血小板减少性紫癜有积极的意义.     

Gene frequencies of platelet‐specific antigens in Croatian population

The human platelet antigens (HPA) are genetically defined polymorphisms expressed on platelet membrane glycoproteins. As platelet antigens are very important in several clinical situations and in population genetics, we used the polymerase chain reaction with sequence‐specific primers (PCR‐SSP) to investigate HPA‐1, ‐2, ‐3 and ‐5 allele frequencies in the Croatian population. The HPA frequencies obtained in 219 Croatians were: 1a–0·854, 1b–0·146, 2a–0·890, 2b–0·110, 3a–0·575, 3b–0·425, 5a–0·895 and 5b–0·105. These data are similar to the frequencies reported in most European studies with some significant differences in HPA‐2 when compared with the Dutch and German population, in HPA‐3 when compared with the Swiss population and in HPA‐5 when compared with the Finnish population. The three most common condensed HPA genotypes in the Croatian population were: HPA‐1a/a, ‐2a/a, ‐3a/b, ‐5‐a/a (0·283), HPA‐1a/a, ‐2a/a, ‐3a/a, ‐5‐a/a (0·137) and HPA‐1a/b, ‐2a/a, ‐3a/b, ‐5‐a/a (0·087). Data obtained in this study can be used for better understanding and treatment of immune‐mediated platelet disorders in our population.     

人类血小板抗原1～4系统基因分型

目的 :建立人类血小板抗原 1～ 4系统序列特异性引物 (PCR SSP)分型方法。方法 :合成 14条引物 ,采用PCR SSP方法对 2 5名健康献血者的HPA 1～ 4系统进行基因分型 ;分型结果与采用等位基因特异性寡核苷酸点杂交 (PCR ASO)获得的结果进行比较。结果 :以PCR SSP方法对HPA 4个系统进行分型均取得了明确、满意的结果 ,且与PCR ASO方法获得的结果完全一致。结论 :人类血小板抗原PCR SSP基因分型方法具有简便、快速、准确等优点 ,具有广泛的应用前景。     

Multicolor real-time polymerase chain reaction genotyping of six human platelet antigens using displacing probes

BACKGROUND: Several genotyping methods for six clinically relevant human platelet antigens (HPAs) have been reported. A four-color real-time polymerase chain reaction (PCR) method using displacing probes for genotyping of the six HPAs is described. STUDY DESIGN AND METHODS: Primers and four differently fluorophor-labeled displacing probes were designed and synthesized to detect single-nucleotide polymorphisms responsible for each of the HPA-1, -2, -3, -4, -5, and -15 genotypes. Two HPA systems were analyzed in a single PCR procedure. After validation with samples of known genotypes, a total of 150 blood samples from healthy donors were genotyped. The results were compared with PCR with sequence-specific primers (SSP), PCR-restriction fragment length polymorphism (RFLP), and/or direct DNA sequencing. The frequencies of each HPA allele were calculated. RESULTS: Unequivocal real-time PCR genotyping results were obtained with minimal manual manipulation and carryover contamination. All 150 blood samples were correctly genotyped as confirmed by PCR-SSP, PCR-RFLP, and/or direct DNA sequencing. The allelic frequencies of HPA-1 through -5 and -15 among the Chinese population in Xiamen were comparable with those previously reported with Chinese living in other territories. For each specimen, genotyping of all six HPA biallelic systems was achieved in three tubes of PCR within 90 minutes and with material cost of no more than $1. CONCLUSION: Genotyping of HPA with real-time PCR using displacing probes is more rapid and reliable compared with PCR-SSP and PCR-RFLP methods and is more affordable than existing real-time PCR-based HPA genotyping assays. Thus, our approach is more suitable for routine HPA analysis and ideal for both urgent clinical testing and high-throughput screening.     

The frequency of human platelet antigen (HPA) genotypes in the Polish population

The human platelet antigens (HPA1–5) in the Polish population were investigated using the PCR with sequence specific primers (SSP). The HPA gene frequency was: 1a — 0.874, 1b — 0.126; 2a — 0.898, 2b — 0.102; 3a — 0.592, 3b — 0.408; 4a — 1.00, 4b — 0.00; 5a — 0.937, 5b — 0.063. The HPA2 and HPA5 differed from those observed in some other European populations — German and both German and Austrian, respectively. The HPA5 alleles frequency was most similar to those observed in the Finnish population. The modification of SSP described allowed the genotyping of HPA1–4 under the same PCR conditions.     

PCR-SSP检测血小板同种抗原2、3、5系统基因型

目的：建立血小板同种抗原2、3、5系统基因分型方法，以检测人群中HPA－2、3、5系统基因频率。方法：标本DNA的抽提采用快速盐析法，HPA－2、3、5系统基因分型采用PCR－SSP方法。结果：在本研究对象中HPA－2系统：a/a基因型频率为0.806,a/b基因型频率为0/194;a基因频率为0.903,b基因频率为0.097。HPA－3系统:a/a基因型频率为0.421,a/b基因型频率为0.509,b/b基因型频率为0.070,a基因频率为0676,b基因频率为0.324。HPA－5系统：a/a基因型频率为0.933,a/b基因型频率为0.067;a基因频率为0.967,b基因频率为0.033。结论：该方法可鉴定出HPA－2，3、5系统基因型。