Genetic landscape of human platelet antigen variants in the Indian population analysed from 1029 whole genomes.

Genetic variants in human platelet antigens (HPAs) considered allo- or auto antigens are associated with various disorders, including neonatal alloimmune thrombocytopenia, platelet transfusion refractoriness and post-transfusion purpura. Although global differences in genotype frequencies were observed, the distributions of HPA variants in the Indian population are largely unknown. This study aims to explore the landscape of HPA variants in India to provide a basis for risk assessment and management of related complications. Population-specific frequencies of genetic variants associated with the 35 classes of HPAs (HPA-1 to HPA-35) were estimated by systematically analysing genomic variations of 1029 healthy Indian individuals as well as from global population genome datasets. Allele frequencies of the most clinically relevant HPA systems in the Indian population were found as follows, HPA-1a - 0.884, HPA-1b - 0.117, HPA-2a - 0.941, HPA-2b - 0.059, HPA-3a - 0.653, HPA-3b - 0.347, HPA-4a - 0.999, HPA-4b - 0.0010, HPA-5a - 0.923, HPA-5b - 0.077, HPA-6a - 0.998, HPA-6b - 0.002, HPA-15a - 0.582 and HPA-15b - 0.418. This study provides the first comprehensive analysis of HPA allele and genotype frequencies using large scale representative whole genome sequencing data of the Indian population.

Simultaneous genotyping for human platelet antigen systems and HLA-A and HLA-B loci by targeted next-generation sequencing.

In order to treat the alloimmunization platelet transfusion refractoriness (PTR), human leukocyte antigen (HLA)-type and/or human platelet antigen (HPA)-type matched platelets between donors and patients are usually used. Therefore, genotyping of HLA-A and HLA-B loci, as well as HPA systems, for donors and patients, is of great significance. However, there is a rare report of genotyping for HLA-A and HLA-B loci as well as HPA systems at the same time. In this study, a high-throughput method for simultaneous genotyping of HLA-A and HLA-B loci, as well as HPA genotyping, was developed. A RNA capture probe panel was designed covering all exon sequences of the GP1BA, GP1BB, ITGA2, CD109, ITGB3, and ITGA2B genes and HLA-A and HLA-B loci. The HLA-A, HLA-B, and 34 HPA systems were genotyped using a targeted next-generation sequencing (NGS) method. The genotypes of the HLA-A and HLA-B loci, as well as the HPA, were assigned based on the nucleotides in the polymorphism sites. Using the NGS method, 204 unrelated blood specimens were successfully genotyped for all 34 HPA systems as well as HLA-A and HLA-B loci. The accuracy of the NGS method was 100%. Only HPA-2, HPA-3, HPA-5, HPA-6w, HPA-15, and HPA-21w showed polymorphism with frequencies of 0.9412, 0.6863, 0.9853, 0.9779, 0.4314, and 0.9951 for a allele, respectively. Thirty-two single nucleotide variants (SNVs) were detected. Of them, 12 SNVs can lead to amino acid change. HLA-A*11:01 and HLA-B*46:01 are the most common alleles for HLA-A and HLA-B loci. A targeted next-generation sequencing method for simultaneously genotyping HPA systems and HLA-A and HLA-B loci was first established, which could be used to create a database of HLA-typed and/or HPA-typed unrelated donors.

The relevance of a bank with genotyped platelets donors

ABSTRACT Objective: Describe the clinical and laboratory characteristics and the transfusion strategy of patients at Hospital Israelita Albert Einstein with platelet refractoriness and identify their etiological characteristics. Standardize the platelet immunofluorescence technique by flow cytometry as a test for platelet compatibility in immune platelet refractoriness in transfusion support. Methods: Review of medical records of refractory platelet patients followed at HIAE from January 2011 to May 2017. Clinical-demographic data, laboratory data and identification of the use of compatible genotyped platelets for patients in need of transfusion therapy were collected. The analyzed patients were classified according to the etiology of their platelet refractoriness. To standardize the FC-PIFT technique, blood group O platelets were incubated with serum from blood group AB donors and anti-IgG monoclonal antibody to determine the negative control. In order to verify the influence of the ABO system, monoclonal anti-IgG antibodies were incubated with blood group A or B platelets and with blood group O donor serum with isohemagglutinins below and above 1/64. Results: A total of 47 patients were evaluated, a 51% (24/47) preponderance of associated immune and non-immune factors (NIPR + IPR). The most common causes of NIPR + IPR were splenomegaly (54%) and the development of HLA antibodies (88%), consistent with the literature. For patients who required therapeutic transfusion, only a small portion received compatible genotyped platelets. Conclusion: Although 60% of patients could benefit from the therapeutic transfusion of genotyped platelets, only 10% were actually transfused with this type of blood component. This reaffirms the need for investments in a bank of genotyped platelet donors.

Validating the HPA-1 to -5 and -15 Detection by Homemade PCR-SSP, Real-Time PCR, and PCR-RFLP Methods.

OBJECTIVE: Human platelet antigens (HPAs) are antigenic determinants on platelet membrane glycoproteins that stimulate the host's immune system and cause platelet destruction. In this study, we share our experience with implementing sequence-specific primer-polymerase chain reaction (PCR-SSP), real-time PCR, and PCR-RFLP (restriction fragment length polymorphism) and the validation process used to evaluate the results. METHODS: At the Ardabil Blood Transfusion Center, 10 samples were obtained from blood donors. Validation using PCR-SSP, real-time PCR, and PCR-RFLP methods for genotyping HPAs was done by sequencing. A commercial DNA sample and a commercial kit were also used for validation. RESULTS: The results of PCR-SSP, TaqMan Real-Time PCR, melting curve analysis (HPA-15), and PCR-RFLP (HPA-3) were 100% consistent with sequencing (gold standard) and commercial kit results. CONCLUSIONS: There was a 100% correlation between repeating the methods and the expected results for repeatability, and no false positives and negatives were observed.

Subamniotic Hemorrhage, a Possible New Presentation of Fetal and Neonatal Alloimmune Thrombocytopenia.

BACKGROUND: Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a rare fetal disease in which maternal antibodies directed toward fetal human platelet antigens (HPA) are formed during pregnancy and cause fetal thrombocytopenia. The diagnosis FNAIT is suspected when a fetus or neonate presents with signs of bleeding. CASE: We describe a pregnancy complicated by a placental hematoma in the 20th week of gestation as the first manifestation of FNAIT. Further evaluation showed signs of germinal matrix hemorrhage and HPA-5b allo-antibodies. After the diagnosis, intravenous immunoglobulin was administered weekly and a healthy daughter was born at 37 weeks. Histopathological analysis revealed that the hematoma was caused by a subamniotic hemorrhage of fetal origin. CONCLUSION: A subamniotic hematoma appears to be the first manifestation of FNAIT.

Analysis of Integrin αIIb Subunit Dynamics Reveals Long-Range Effects of Missense Mutations on Calf Domains.

Integrin αIIbß3, a glycoprotein complex expressed at the platelet surface, is involved in platelet aggregation and contributes to primary haemostasis. Several integrin αIIbß3 polymorphisms prevent the aggregation that causes haemorrhagic syndromes, such as Glanzmann thrombasthenia (GT). Access to 3D structure allows understanding the structural effects of polymorphisms related to GT. In a previous analysis using Molecular Dynamics (MD) simulations of αIIbCalf-1 domain structure, it was observed that GT associated with single amino acid variation affects distant loops, but not the mutated position. In this study, experiments are extended to Calf-1, Thigh, and Calf-2 domains. Two loops in Calf-2 are unstructured and therefore are modelled expertly using biophysical restraints. Surprisingly, MD revealed the presence of rigid zones in these loops. Detailed analysis with structural alphabet, the Proteins Blocks (PBs), allowed observing local changes in highly flexible regions. The variant P741R located at C-terminal of Calf-1 revealed that the Calf-2 presence did not affect the results obtained with isolated Calf-1 domain. Simulations for Calf-1 + Calf-2, and Thigh + Calf-1 variant systems are designed to comprehend the impact of five single amino acid variations in these domains. Distant conformational changes are observed, thus highlighting the potential role of allostery in the structural basis of GT.

Fetal and neonatal alloimmune thrombocytopenia: a late or missed diagnosis disease in fetal and perinatal health-care settings.

INTRODUCTION: Even though Fetal and Neonatal Alloimmune Thrombocytopenia (FNAIT) has been recognized as the main cause of primary hemorrhagic morbidity and mortality in fetuses and newborns, screening programs to detect pregnancies at risk have not yet been implemented in any country. Moreover, in spite of increased concerns about maternal, fetal and neonatal health care in general, this potentially lethal disease is still underdiagnosed. The aim of this report is to highlight the importance of considering FNAIT in fetal and perinatal health-care settings and show the usefulness of molecular tools in early diagnosis of this clinical entity. METHODS: DNA was extracted from whole blood from parents and newborns; genotyping was performed by in house PCR using sequence-specific primers for typing Human Platelet Antigens (HPA)-1 to -6, -9, and -15, and with commercial HPA-TYPE (BAG HealthCare, Lich, Germany). Anti-HPA antibodies in the maternal serum were detected by the Monoclonal Antibody Solid Phase Platelet antibody Test (MASPAT). Chloroquine-treated platelets were used for the discrimination of platelet-specific antibodies from anti-HLA antibodies. RESULTS: Patients 1 and 2 had severe thrombocytopenia due to incompatibility in HPA-1 and HPA-15, respectively. The third case was a thrombocytopenic neonate with severe bleeding complications other than ICH and in whom differential diagnosis between FNAIT and Von Willebrand congenital disease was necessary; incompatibility in HPA-15 was also demonstrated. Case 4 represents a missed diagnostic opportunity. CONCLUSION: This is the first report of FNAIT cases confirmed by molecular evidence and anti-HPA antibodies detection in Argentina. This report reinforces the relevance of early diagnosis of this clinical entity. Since the delay in FNAIT diagnosis could lead to severe consequences in the fetus and neonates, strategies to approach maternal, fetal, and perinatal health, as well as prevention policies aimed to reduce fetal and neonatal morbidity and mortality should focus on implementing programs to identify high-risk pregnancies and thus reduce thrombocytopenia-related complications in fetuses and newborns.

The relevance of a bank with genotyped platelets donors.

OBJECTIVE: Describe the clinical and laboratory characteristics and the transfusion strategy of patients at Hospital Israelita Albert Einstein with platelet refractoriness and identify their etiological characteristics. Standardize the platelet immunofluorescence technique by flow cytometry as a test for platelet compatibility in immune platelet refractoriness in transfusion support. METHODS: Review of medical records of refractory platelet patients followed at HIAE from January 2011 to May 2017. Clinical-demographic data, laboratory data and identification of the use of compatible genotyped platelets for patients in need of transfusion therapy were collected. The analyzed patients were classified according to the etiology of their platelet refractoriness. To standardize the FC-PIFT technique, blood group O platelets were incubated with serum from blood group AB donors and anti-IgG monoclonal antibody to determine the negative control. In order to verify the influence of the ABO system, monoclonal anti-IgG antibodies were incubated with blood group A or B platelets and with blood group O donor serum with isohemagglutinins below and above 1/64. RESULTS: A total of 47 patients were evaluated, a 51% (24/47) preponderance of associated immune and non-immune factors (NIPR + IPR). The most common causes of NIPR + IPR were splenomegaly (54%) and the development of HLA antibodies (88%), consistent with the literature. For patients who required therapeutic transfusion, only a small portion received compatible genotyped platelets. CONCLUSION: Although 60% of patients could benefit from the therapeutic transfusion of genotyped platelets, only 10% were actually transfused with this type of blood component. This reaffirms the need for investments in a bank of genotyped platelet donors.

Genotyping of Eight Human Platelet Antigen Systems in Serbian Blood Donors: Foundation for Platelet Apheresis Registry.

INTRODUCTION: The aim of this study was to investigate the allele and genotype frequencies of 8 human platelet antigen (HPA) systems among blood donors from the Blood Transfusion Institute of Serbia and to compare them with published studies. These data would be useful to establish the basis for a platelet apheresis donor registry. MATERIAL AND METHODS: Seventy-two unrelated male platelet apheresis/blood donors from Serbia were typed for 8 HPA systems (HPA-1 to HPA-6, HPA-9, and HPA-15) via the FluoGene method, based on polymerase chain reaction-sequence-specific amplification (PCR-SSP; PCR using sequence-specific primers) with fluorometric signal detection. Allele and genotype frequencies were estimated by direct counting and compared to the expected genotype frequencies according to the Hardy-Weinberg principle. The transfusion mismatch probability was calculated for every HPA specificity. RESULTS: The allele frequencies were: HPA-1a, 0.868; HPA-1b, 0.132; HPA-2a, 0.917; HPA-2b, 0.083; HPA-3a, 0.611; HPA-3b, 0.389; HPA-5a, 0.903; HPA-5b, 0.097; HPA-9a, 0.993; HPA-9b, 0.007; HPA-15a, 0.472; and HPA-15b, 0.528. For HPA-4 and HPA-6 only allele a was detected. DISCUSSION: The HPA allele frequencies of European populations showed no significant differences in comparison with our results. Statistically significant differences were revealed in comparison with some populations of non-European origin. In the tested donors no HPA-2 bb genotype was detected, but we found 1 donor with the rare HPA-9b allele. The biggest transfusion mismatch probability in the Serbian population is for systems HPA-15 (37.4%) and HPA-3 (36.2%), which means that more than a third of random transfusions could cause mismatch in these systems. This study was enabled by the introduction of molecular HPA typing, and it provides initial results of the HPA allele and genotype frequencies in the population of blood donors in Serbia. They will be used to provide a compatible blood supply on demand for treating patients with alloimmune thrombocytopenic disorders. The successful implementation of PCR-SSP with fluorometric signal detection could be further complemented in the future by the introduction of high-throughput methods, which will largely depend on the available financial resources.

Genotyping of Human Platelet Antigen-1 to -5 and -15 by Polymerase Chain Reaction with Sequence-specific Primers (PCR-SSP) and Real-time PCR in Azeri Blood Donors.

Human platelet antigens (HPAs) are glycoproteins on the platelet surface that a single nucleotide mutation in the coding region gene could lead to the variation of different HPA polymorphisms. These antigens have shown variation among different races and may trigger immune responses during blood transfusion and pregnancy. Genotyping of HPAs is useful for managing these reactions and establishing a platelet registry to decrease platelet transfusion reactions. This study aimed to compare allelic and genotype frequencies of human platelet antigens in the Azeri ethnicity by TaqMan Real-time and polymerase chain reaction with sequence-specific primers (PCR-SSP) methods. DNA was extracted from the whole blood of 100 Azeri blood donors in the Ardabil Blood Transfusion Center. Genotyping of HPA-1 to -5 and -15 was performed by TaqMan Real-time PCR, and PCR-SSP and consistency of results were evaluated. The results of PCR-SSP and TaqMan Real-time PCR showed complete consistency. The allele frequencies were 91.5% and 8.5% for HPA-1a and -1b; 88% and 12% for HPA-2a and -2b; 58% and 42 % for HPA-3a and -3b; 100% for HPA-4a; 91% and 9% for HPA-5a and -5b; 56.5% and 43.5% for HPA-15a and -15b alleles. Not incompatibility was detected in HPAs genotyping by PCR-SSP and TaqMan Real-time PCR so that real-time PCR can be used as a robust and quick method for HPA genotyping. We found differences between Azeri blood donors and previously reported HPAs alleles' frequency in other ethnicities in the country. This fact highlights the need for a platelet registry to recruit platelet donors from different ethnicities and increase the number of donors by using faster methods.

A nait-associated and previously unreported mutation in the ITGB3 gene with a low frequency in the local population.

BACKGROUND: Neonatal alloimmune thrombocytopenia is a rare but potentially severe postnatal complication caused by maternal allo-antibodies against platelet antigens of the newborn. In relatively few cases, immunisation against low-frequency antigens has been reported. METHODS: Platelet antigens of a newborn with severe thrombocytopenia and his family members were investigated by serological and molecular biological methods. A real-time PCR assay was developed to reliably detect this mutation in pools of DNA from up to seven individuals. RESULTS: Serological testing showed positive reactions of maternal plasma with paternal platelets but not with conventional platelet donor panels. Sequencing of the ITGB3 gene revealed a G > A polymorphism in position c.1915 of exon 12 for the father, the newborn and three of four paternal relatives. Screening of samples from a local population of 1575 Caucasian blood donors identified only a single individual with this mutation. CONCLUSION: This finding of a previously unreported private platelet antigen demonstrates that the identification of the target glycoprotein by MAIPA assay followed by sequencing of the affected gene can be combined with an efficient population screening by real-time PCR with pooling of DNA samples.

Correlation between human platelet antigen polymorphisms and platelet parameters / 中国输血杂志

【Objective】 To investigate the correlation between human platelet antigens (HPA) polymorphisms and platelet parameters. 【Methods】 The HPA-2, HPA-3, HPA-5 and HPA-15 genotypes of 139 healthy Chinese Han individuals were detected using TaqMan-MGB probe real-time PCR, while platelet parameters including platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW) and platelet-large cell ratio (P-LCR) were measured using hematology cell analyzer. 【Results】 The PLT was significantly lower in the individuals with HPA-2aa genotype compared to those with HPA-2ab [(234.35±50.10)×103/μL vs (269.58±41.66)×103/μL, P<0.05], while the PLT was significantly higher in individuals with HPA-5aa and HPA-15aa genotypes compared to those with HPA-5ab and HPA-15ab/bb [HPA-5: (239.36±49.81)×103/μL vs (200.29±48.02)×103/μL; HPA-15: (251.00±58.41)×103/μL vs (231.29±45.20)×103/μL, P<0.05], respectively. The MPV, PDW and P-LCR were significantly lower in individuals with HPA-5aa genotype compared to those with HPA-5ab [mpv: (10.01±0.72)fL vs (10.94±1.01)fL; PDV: (11.94%±1.35%) vs (14.25%±2.78%); P-LCR: (25.32%±5.03%) vs (31.73%±6.39%), P<0.05], but did not differ among the HPA-2 and HPA-15 genotypes. Besides, no significant differences in platelet parameters of individuals with HPA-3aa and HPA-3ab/bb genotypes were notable(P>0.05). HPA-2, -5 and -15 polymorphisms were identified as independent factors for platelet count, and HPA-5 polymorphism was an independent factor for platelet volume, revealed by multiple linear regression analysis. 【Conclusion】 HPA-2, -5 and -15 polymorphisms are correlated with platelet count, and HPA-5 polymorphism is correlated with platelet volume.

Genotyping of HPA-1-29bw in platelet donors in Nanjing, China / 中国输血杂志

【Objective】 To analyze the allele frequencies of the human platelet antigens 1-29 system (HPA-1-29bw) in Nanjing Han platelet donors, so as to provide references for compatible platelet transfusion. 【Methods】 HPA genotyping was performed by Sanger sequencing method in 900 Nanjing Han regular platelet donors who donated at Jiangsu Province Blood Center from February to September 2019. The frequencies of alleles and genotype were calculated using direct counting method. 【Results】 The HPA allele frequencies in Nanjing Han platelet donors were HPA-1a 0.9950, 1b 0.0050, 2a 0.9467, 2b 0.0533, 3a 0.5850, 3b 0.4150, 4a 0.9989, 4b 0.0011, 5a 0.9822, 5b 0.0178, 6a 0.9828, 6b 0.0172, 11a 0.9994, 11b 0.0006, 15a 0.5317, 15b 0.4683, 21a 0.9928 and 21b 0.0072, respectively. Only a allele was detected in HPA-7-10w, -12-14w, -16-20w and -22-29bw systems.The highest mismatch rate of HPA genes in 900 platelet donors was HPA-15 system, followed by HPA-3 system, with the rate of 37.40%(337/900) and 36.77%(331/900), respectively. One heterozygote was detected in HPA-11w system. 【Conclusion】 The chracteristics of HPA alleles frequencies in Nanjing Han platelet donors is that HPA-15 and HPA-3 are the most common heterozygotes, which should be paid attention to in local clinical transfusion.

Genetic polymorphism of HPA1-17 alloantigen system in the Achang and Jingpo populations population in Yunnan.

BACKGROUND: Human platelet alloantigen (HPA) is part of the platelet membrane structure, named HPA1- 17 system. This study aimed to investigate platelet alloimmunity in the Achang and Jingpo population, ethnic minority specific, to establish a typed platelet donor data bank in Yunnan's ethnic minority areas. METHODS: In this study, samples from 139 unrelated healthy cases from the Achang population, 148 cases of the Jingpo population, and 150 healthy cases from Yunnan's Han population were collected as a control. PCR-sequence specific primers (PCR-SSP) methods were respectively adopted to genotype HPA-1-17. The frequency of genes and genotypes was calculated separately, and the frequency distribution of alleles in the Achang population was compared with that of the Han population. RESULTS: Monomorphic HPA-7-14 and HPA-16 and 17 were found in the samples from the Han population, while HPA-b was not found in any of these samples. In HPA-1, 2, 4, 5, and 6, aa homozygosity was predominant. Monomorphic HPA-7, HPA-9-14 and HPA-16 were found in the samples from the Achang population, while HPA-b was not found. In HPA-1, 2, 4, 5, 6, 8, and 17, aa homozygosity was predominant. The genotype results of the HPA-4, 7, HPA9-12, HPA14, 16-17 antigen systems in the Jingpo population were all aa, while the HPA-b was not detected. In HPA-1, 2, 5, 6, 8 and 13, aa homozygosity was predominant. HPA-3, 15 showed the greatest heterozygosity among the three populations. The frequency of HPA-1a in the Achang population in Yunnan was significantly different from that in the Han population (P<0.05). There was no difference in the HPA system of the Jingpo population, but the HPA-2a system was different between the Achang and Jingpo populations (P<0.05). CONCLUSIONS: In Yunnan, the distribution of the allele polymorphism of HPA-1-17 in the Achang and Jingpo population is similarly distributed to that in the Han population and exhibits their own characteristic. Therefore, a database of platelet donor typing of the ethnic group should be established.

A new efficient tool for non-invasive diagnosis of fetomaternal platelet antigen incompatibility.

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is the consequence of platelet destruction by maternal alloantibodies against fetal human platelet antigens (HPA). This may result in intracranial haemorrhages (ICH) or even fetal death. Currently, fetal HPA genotyping is performed using invasive procedures. Here, we carried out a proof-of-concept study for non-invasive prenatal diagnosis of fetal platelet genotyping in four HPA systems (HPA-1, -3, -5 and-15) by droplet digital polymerase chain reaction (ddPCR) using cell-free DNA extracts from the plasma of 47 pregnant women with suspected, or history of, FNAIT. Results showed that 74% (35/47) of pregnant women presented incompatibility in at least one HPA system, and 38% (18/47) of cases presented HPA-1 incompatibility, including nine women with multiple incompatibilities. ICH occurred in one case of profound fetal thrombocytopenia with HPA-15 incompatibility, confirming the need for non-invasive prenatal genotyping in systems other than HPA-1. Fetal HPA genotypes predicted by ddPCR were confirmed in all FNAIT cases after amniocentesis or delivery. Fetal HPA genotyping on maternal plasma based on ddPCR is a fast, safe and reliable non-invasive method. This technique will be useful for the early identification of pregnancies at high risk of FNAIT requiring antenatal management to minimize the risk of fetal/neonatal haemorrhage.

High-Throughput Screening of Blood Donors for Twelve Human Platelet Antigen Systems Using Next-Generation Sequencing Reveals Detection of Rare Polymorphisms and Two Novel Protein-Changing Variants.

BACKGROUND: Exposure to non-matching human platelet alloantigens (HPA) may result in alloimmunization. Antibodies to HPA can be responsible for post-transfusion purpura, refractoriness to donor platelets, and fetal and neonatal alloimmune thrombocytopenia. For the supply of compatible apheresis platelet concentrates, the HPA genotypes are determined in a routine manner. METHODS: Here, we describe a novel method for genotyping twelve different HPA systems simultaneously, including HPA-1 to HPA-5, HPA-9w, HPA-10w, HPA-16w, HPA-19w, HPA-27w, and the novel HPA-34w by means of amplicon-based next-generation sequencing (NGS). Blood donor samples of 757 individuals with a migration background and 547 of Western European ancestry were genotyped in a mass-screening setup. An in-house software was developed for fast and automatic analysis. TaqMan assay and Sanger sequencing results served for validation of the NGS workflow. Finally, blood donors were divided in several groups based on their country of origin and the allele frequencies were compared. RESULTS: For 1,299 of 1,304 samples (99.6%) NGS was successfully performed. The concordance with TaqMan assay and Sanger sequencing results was 99.8%. Allele-calling dropouts that were observed for two samples with the TaqMan assay caused by rare single nucleotide polymorphisms were resolved by NGS. Additionally, twenty rare and two novel variants in the coding regions of the genes ITGB3, GPB1A, ITGBA2, and CD109 were detected. The determined allele frequencies were similar to those published in the gnomAD database. CONCLUSIONS: No significant differences were observed in the distribution of allele frequencies of HPA-1 through HPA-5 and HPA-15 throughout the analyzed groups except for a lower allele frequency for the HPA-1b allele in the group of donors with Southern Asian ancestry. In contrast, other nucleotide variants that have not yet been phenotypically characterized occurred three times more often in blood donors with a migration background. High-throughput amplicon-based NGS is a reliable method for screening HPA genotypes in a large sample cohort simultaneously. It is easily upgradeable for genotyping additional targets without changing the setup or the analysis pipeline. Mass-screening methods will help building up blood donor registries to provide matched blood products.

Progress and development of platelet antibody detection.

Human platelet antibody (HPA) detection is necessary for the diagnosis and therapeutic decisions for refractoriness to platelet transfusions, post transfusion purpura and fetal and neonatal alloimmune thrombocytopenia. In the last four to five decades many new developments, both in knowledge and methods, have increased the quality of platelet serology. However, the quest for the optimal antibody detection method(s) encountered, sometimes unexpected, difficulties. In this review the various aspects concerning platelet antibody test methods and detection of platelet antibodies both for the diagnostic and screening setting are discussed.

Human platelet antigen polymorphisms and the risk of chronic Chagas disease cardiomyopathy.

Human platelet antigen (HPA) polymorphisms are considered to be a risk factor for cardiac and vascular diseases, but the role of HPA in chronic Chagas disease cardiomyopathy (CCC) is not available. Therefore, the aim of this study was to investigate the association of HPA polymorphisms, HPA-1, HPA-2, HPA-3, HPA-5 and HPA-15, in the severity of left ventricular systolic dysfunction (LVSD) in CCC patients. For this, 229 CCC patients were separated into three groups: without LVSD, mild/moderate LVSD and severe LVSD. PCR-SSP was performed for HPA genotyping and the risk was assessed using SNPStats software. HPA-1 allele and genotype frequencies were lower in mild/moderate LVSD patients compared to other groups, without statistical significance. After stratified analyzes, the HPA-3a/3b genotype frequency was lower in women with severe LVSD compared to those without LVSD (OR:0.29; 95% CI: 0.10-0.84). In conclusion, HPA-3 variant could be a protection factor for CCC in the female patients.

Human platelet antigen-3 polymorphism as a risk factor for rheumatological manifestations in hepatitis C

Abstract INTRODUCTION: Hepatitis C virus (HCV) infection is involved in the pathogenesis of autoimmune and rheumatic disorders. Although the human platelet antigens (HPA) polymorphism are associated with HCV persistence, they have not been investigated in rheumatological manifestations (RM). This study focused on verifying associations between allele and genotype HPA and RM in patients with chronic hepatitis C. METHODS: Patients (159) with chronic hepatitis C of both genders were analyzed. RESULTS: Women showed association between HPA-3 polymorphisms and RM. CONCLUSIONS: An unprecedented strong association between rheumatological manifestations and HPA-3 polymorphism, possibly predisposing women to complications during the disease course, was observed.