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.

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.

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.

Conocimientos actuales sobre la patogénesis, presentación clínica, diagnóstico y manejo de la trombocitopenia neonatal aloinmune / Current knowledge on neonatal alloimmune thrombocytopenia's pathogenesis, clinical presentation, diagnostic and management

Introducción: La trombocitopenia neonatal aloinmune es una enfermedad producida por anticuerpos maternos contra antígenos plaquetarios fetales heredados del padre. Puede ser causa de hemorragia intracraneal y conducir a la muerte o discapacidad en el feto/neonato. Aunque es la causa más grave de trombocitopenia en el neonato y la más común en los recién nacidos a término, en general ha sido poco investigada. Objetivos: Exponer los conocimientos actuales sobre la patogénesis, presentación clínica, diagnóstico y del manejo pre- y posnatal de la trombocitopenia neonatal aloinmune, Métodos: Se realizó una revisión de la literatura, en inglés y español, a través del sitio web PubMed y el motor de búsqueda Google académico de artículos publicados en los últimos 10 años. Se hizo un análisis y resumen de la bibliografía revisada. Resultados: Los anticuerpos IgG maternos son transportados a través de la placenta a la circulación fetal, opsonizan las plaquetas fetales que son removidas por fagocitosis. Los antígenos más implicados son el HPA-1a y HPA-4a. La fisiopatología de la enfermedad es muy similar a la enfermedad hemolítica perinatal, pero aún no se han implementado programas de pesquisa y el diagnóstico se realiza después del nacimiento del niño afectado de trombocitopenia, hemorragia intracraneal o muerte in útero de causa no explicada. Consideraciones finales: El impacto clínico de la trombocitopenia neonatal aloinmune y las oportunidades de tratamiento potencian la necesidad de implantar programas de pesquisa para la detección de fetos en riesgo de padecer esta enfermedad(AU)

Introduction: Neonatal alloimmune thrombocytopenia is a disease produced by maternal antibodies against fetal platelet antigens inherited from the father. It can be a cause of intracranial hemorrhage and lead to death or disability in the fetus / neonate. Although it is the most serious cause of thrombocytopenia in newborns and the most common in full-term infants, it has generally been poorly investigated. Objectives: To approximate to current knowledge about the pathogenesis, clinical presentation, diagnosis and pre- and post-natal management of neonatal alloimmune thrombocytopenia. Methods: A review of literature, in English and Spanish, through PubMed website and Google scholar search engine of articles published in the last 10 years was conducted. An analysis and summary of the reviewed bibliography was made. Results: Maternal IgG antibodies are transported through the placenta to the fetal circulation, opsonizing fetal platelets that are removed by phagocytosis. The most involved antigens are HPA-1a and HPA-4a. The pathophysiology of this disease is very similar to perinatal hemolytic disease, but research programs have not been implemented yet and diagnosis is made after birth of children affected by thrombocytopenia, intracranial hemorrhage or in uterus death by unexplained causes. Final considerations: Clinical impacts of neonatal alloimmune thrombocytopenia and treatment opportunities enhance the need to implement screening programs for the detection of fetuses at risk of suffering from this disease(AU)

Anticuerpos antiplaquetarios en pacientes cubanos en espera de trasplante renal / Platelet antibodies in cuban patients waiting for renal transplantation

Introducción: Los antígenos específicos de plaquetas, conocidos como antígenos de plaquetas humanas (HPA, del inglés human platelet antigens), se incluyen dentro del espectro de antígenos de histocompatibilidad no-HLA, debido a que los anticuerpos anti-HPA participan en el rechazo del trasplante, además de ser causa del fenómeno de refractariedad plaquetaria. Objetivo: Caracterizar los anticuerpos contra antígenos específicos de plaquetas en pacientes cubanos en espera de trasplante renal. Métodos: Se investigaron muestras de sangre de 901 pacientes mediante la técnica de inmovilización de antígenos plaquetarios con anticuerpos monoclonales. Resultados: En 78 pacientes se detectaron anticuerpos anti-HPA, que en el 87,17 por ciento reconocían los antígenos presentes en el complejo GP-IIb/IIIa. Estos anticuerpos fueron del tipo IgG en el 78,2 por ciento, IgA en el 11,53 por ciento e IgM en el 46,15 por ciento. Conclusiones: En pacientes cubanos en espera de trasplante renal son frecuentes los Ac anti-HPA, en su mayoría del tipo IgG dirigidos contra antígenos presentes en el complejo GP-IIb/IIIa(AU)

Introduction: Platelet-specific antigens, known as human platelet antigens (HPA), are included within the spectrum of non-HLA histocompatibility antigens, because HPA antibodies participate in the rejection of transplantation, besides being a cause of the phenomenon of platelet refractoriness. Objective: To characterize antibodies against platelet-specific antigens in Cuban patients awaiting kidney transplantation. Methods: The technique monoclonal antibodies immobilized platelets antigens was applied to blood samples from 901 patients. Results: HPA antibodies were detected in 78 patients, which in 87.17 percent recognized the antigens present in the GP-IIb / IIIa complex. These antibodies were in 78.2 percent of the IgG class, in 11.53 percent IgA and IgM in 46.15 percent. Conclusions: HPA antibodies, mostly of the IgG class and directed to antigens present in the GP-IIb/IIIa complex, are common in Cuban patients awaiting kidney transplantation(AU)

Frequency of human platelet antigens in oncohematological patients with thrombocytopenia and the probability of incompatibility to platelet transfusions

OBJECTIVE: The objective of this study was to evaluate the frequencies of human platelet antigens in oncohematological patients with thrombocytopenia and to analyze the probability of their incompatibility with platelet transfusions. METHODS: Platelet antigen genotyping was performed by sequence-specific primer polymerase chain reaction (SSP-PCR) for the HPA-1a, HPA-1b, HPA-2a, HPA-2b, HPA-3a, HPA-3b, HPA-4a, HPA-4b, HPA-5a, HPA-5b; HPA-15a, HPA-15b alleles in 150 patients of the Hematology Service of the Hospital das Clínicas (FMUSP). RESULTS: The allele frequencies found were: HPA-1a: 0.837; HPA-1b: 0.163; HPA-2a: 0.830; HPA-2b: 0.170; HPA-3a: 0.700; HPA-3b: 0.300; HPA-4a: 1; HPA-4b: 0; HPA-5a: 0.887; HPA-5b: 0.113; HPA-15a: 0.457 and HPA-15b: 0.543. CONCLUSIONS: Data from the present study showed that the A allele is more common in the population than the B allele, except for HPA-15. This suggests that patients homozygous for the B allele are more predisposed to present alloimmunization and refractoriness to platelet transfusions by immune causes. Platelet genotyping could be of great value in the diagnosis of alloimmune thrombocytopenia and to provide compatible platelet concentrates for these patients.

Effects of Human Platelet Antigen Genotyping on Platelet Engraftment and Graft-Versus-Host Disease after Hematopoietic Stem Cell Transplantation / 대한진단검사의학회지

BACKGROUND: Rapid platelet engraftment has several economic benefits by reducing the cost of supportive therapy as well as reducing the risk of fatal bleeding due to severe thrombocytopenia. Based on these considerations, we genotyped human platelet alloantigens (HPA) to evaluate the effect of minor transplantation antigen mismatches on the rate and speed of platelet recovery and clinical outcome of transplantation. METHODS: Thirty-five patients with various hematologic diseases transplanted between January 2001 and August 2004 were included. Genomic DNA was isolated from peripheral blood of donor-recipient pairs before transplantation. HPA-1, -2, -3, -4, -5, and -6 genotyping was performed by poly-merase chain reaction (PCR)-sequence specific primers (SSP). The effects of HPA compatibility on platelet recovery, incidences of graft-versus-host disease (GVHD) and relapse, and overall survival was investigated. RESULTS: There were no significant differences in platelet recovery according to HPA matching status. We observed no statistically significant differences in the occurrence of relapse and overall survival according to HPA-1, -2, and -3 matched/mismatched groups of patients, whereas HPA-3 mismatching was found to have a significant effect on GVHD development. There was also no difference in GVHD occurrence according to HPA-1 and -2 matched or mismatched transplants. CONCLUSIONS: Since platelet recovery in the HPA-1, -2, -3, and -5 matched/mismatched groups is not significantly different, the seems that platelet glycoprotein (GP) does not seem to act as a factor influencing the homing of hematopoietic stem cells. The finding that HPA-3 incompatibility may be involved in GVHD can be of importance. If a role for HPA-3 as minor histocompatibility antigens is confirmed by additional studies, we can ameliorate the outcome of allogeneic stem cell transplantation by typing of HPA and selecting the most closely related donors.

Genotype Frequencies of Platelet Glycoprotein IIIa-Specific Antigens and Granulocyte Antigens In Korean Pregnant Women* / 대한수혈학회지

BACKROUND: Polymorphism of glycoprotein IIIa on human platelets is one of the factors in alloimmunization that causes neonatal alloimmune thrombocytopenia (NATP), and the granulocyte antigens NA1 and NA2 are often targets of granulocytes antibodies causing neonatal alloimmune neutropenia (NANP). Currently, serotyping relies on the properties of the typing sera or antibodies and technique used. Genotyping circumvents the problems associated with serotyping. METHODS: The genomic DNA of 200 unrelated pregnant women admitted to Taegu Fatima Hospital was typed for three platelet glycoprotein IIIa-specific antigens (HPA-1, HPA-4, and HPA-6w) and granulocyte antigens (NA1 and NA2). Allele specific amplification test using primer designed to study HPA-1 and HPA-4, restriction fragment length polymorphism to study HPA-6w, and sequence specific primers for NA1 and NA2 were used for genotyping. RESULTS: The genotype frequencies were HPA-1(a+b-) 100%, HPA-4 (a+b-) 97.5%, HPA-4(a+b+) 2.5%, HPA-6w(a+b-) 97%, and HPA-6w(a+b+) 3%. These frequencies are similar to Japanese but different from Caucasian. The gene frequencies of NA1 and NA2 were 0.56 and 0.44 respectively. There are no cases of alloimmune thrombocytopenia and neutropenia in newborns from the 200 studied women. CONCLUSIONS: The differences in genotype frequencies among platelet glycoprotein IIIa-specific antigens and in the gene frequencies of NA in Koreans are shown as compared with other ethnic groups. Therefore it is needed to find the proper screening target antigens and antibodies for Korean NATP and NANP patients.