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Background: Antibodies against human platelet antigens (HPAs) cause thrombocytopenias. It is thus important to know the frequency of "b" allotypes in each HPA system for the diagnosis and treatment of anti-HPA antibody-mediated thrombocytopenia., Study Design and Methods: Genomic DNA was extracted from peripheral blood cells obtained from 2170 blood donors in Japan and was subjected to high-resolution melt (HRM) analysis using polymerase chain reaction for each of the HPA genes, using 23 primer pairs. For genotyping, the resulting amplicons were classified based on their HRM curves. In some cases, direct sequence analysis was performed after HRM analysis to determine nucleotide substitutions. In cases where amino acid substitutions were predicted, protein expression levels were examined in a cell line using 293T cells., Results: The frequencies of each of the HPA-b genotypes were as follows: HPA-1b, 0.4%; HPA-2b, 11.8%; HPA-3b, 41.3%; HPA-4b, 0.8%; HPA-5b, 4.3%; HPA-6b, 1.9%; HPA-15b, 48.8%; HPA-21b, 0.6%; and "b" allotype in the other HPA systems, 0.0%. Twenty-eight variants were found; nine of them were predicted to cause amino acid substitution. However, expression analysis revealed that they did not affect protein expression levels on the cell surface., Conclusion: Nine HPA systems are of primary importance in Japan in potentially triggering thrombocytopenia via the HPA antibodies. Similar studies in other countries or races, together with ours, could provide basic information for clinicians in multiethnic societies., (© 2020 AABB.)

Background and Objectives: At Japanese Red Cross (JRC) Blood Centers, all donated blood is screened for hepatitis C virus (HCV) by serological and nucleic acid amplification testing. Donor plasma that tested reactive for anti-HCV by serological test is disqualified even if the donor tests negative for HCV RNA. These test results reflect both true-positive results because of past HCV infection and false-positive results because the cross-reactivity of plasma IgG, which current testing methods are unable to distinguish. To characterize these antibody test results, we examined the neutralizing activity of these plasma samples., Material and Methods: Donor plasma samples that tested reactive for anti-HCV by serological test but negative for HCV RNA (n = 43) were analysed for determining their neutralizing activities measured by the inhibition of the cellular entry of pseudoparticles harbouring HCV envelope glycoproteins (HCVpp)., Results: Strong and broad neutralizing activities against HCVpp entry similar to the samples that tested reactive for anti-HCV serological test and positive for HCV RNA (considered to be derived from individuals with chronic HCV infection) were observed in three of 43 plasma samples from donors who tested anti-HCV reactive but HCV RNA negative., Conclusion: By examining the neutralizing activities of plasma samples, we identified individuals with a past HCV infection from those in whom we were unable to confirm HCV infection according to the current testing algorithms of JRC, which do not perform anti-HCV confirmatory tests., (© 2015 International Society of Blood Transfusion.)

Background: The Jr(a-) phenotype is rare in European and North American populations but is not so rare in Japanese and other Asian populations. Recently, two groups have established the connection between the Jr(a-) phenotype and the ATP-binding cassette, member G2 (ABCG2) gene and concluded that ABCG2-null alleles encode the Jr(a-) phenotype. In Japanese Red Cross Blood Centers, the Jr(a-) phenotype is found with a prevalence of 0.05% among blood donors, and we applied DNA-based genotyping to investigate the molecular basis of the Jr(a-) phenotype in Japan, in addition to serologic typing., Study Design and Methods: Purified genomic DNA extracts of Japanese donor samples [500 Jr(a+) and 85 Jr(a-) phenotypes] were amplified using specific amplification primers for the c.376C>T mutation, which is the most common mutation in the Asian JRnull allele. Polymerase chain reaction products were examined by high-resolution melt techniques and DNA sequence analyses., Results: Seventy-nine of 85 Jr(a-) samples were homozygous for the single-nucleotide polymorphism c.376C>T (Gln126Stop) change. In other samples, two novel null alleles were detected: c.2T>C and c.421C>A: c.1515delC., Conclusion: In this study, more than 90% of the Japanese Jr(a-) phenotypes had c.376C>T (Gln126Stop) nucleotide change. In the other Jr(a-), a new mutation (c.2T>C) in the start codon encoding Thr instead of Met, c.1515delC encoding Ala505AlafsStop and heterozygous for c.337C/T and c.736C/T were detected. DNA-based genotyping is accurate and useful for Jr(a-) donor typing., (© 2013 American Association of Blood Banks.)

Background: The Japanese Red Cross (JRC) conducted a prospective study to evaluate the frequency of transfusion-transmitted HBV, HCV and HIV infections to assess the risk of transfusion of blood components routinely supplied to hospitals., Study Design and Methods: Post-transfusion specimens from patients at eight medical institutes were examined for evidence of infection with HBV (2139 cases), HCV (2091) and HIV (2040) using individual nucleic acid amplification testing (NAT). If these specimens were reactive, pre-transfusion specimens were also examined for the virus concerned by individual NAT. In the event that the pre-transfusion specimen was non-reactive, then all repository specimens from implicated donors were tested for the viruses by individual donation NAT. In addition, a further study was carried out to evaluate the risk of transfusion of components from donors with low anti-HBc titres or high anti-HBc with high anti-HBs titres., Results: Transfusion-transmitted HCV and HIV infections were not observed. One case of post-transfusion HBV infection was identified (rate, 0·0004675; 95% CI for the risk of transmission, 1 in 451-41,841). The background rates of HBV, HCV and HIV infections in patients prior to transfusion were 3·4% (72/2139), 7·2% (150/2091) and 0% (0/2040), respectively. Sixty-four anti-HBc- and/or anti-HBs-reactive blood components were transfused to 52 patients non-reactive for anti-HBc or anti-HBs before and after transfusion (rate, 0; 95% CI for the risk of transmission, <1 in 22)., Conclusion: This study demonstrated that the current criteria employed by JRC have a low risk, but the background rates of HBV and HCV infections in Japanese patients are significant., (© 2011 The Author(s). Vox Sanguinis © 2011 International Society of Blood Transfusion.)

Objectives: The aim of this study was to evaluate the applicability of genotyping of the ABCG2 gene using MALDI‐TOF MS and to estimate the allele frequency in the Japanese population. Background: Jr (a−) phenotype has a prevalence of approximately 0·05% among Japanese blood donors; DNA‐based genotyping was conducted to investigate the molecular basis of the Jr (a−) phenotype along with serological typing. To detect all SNPs of the ABCG2 gene, a high‐throughput SNP genotyping platform is needed. Methods: Overall, 1004 Jr (a−) blood samples were collected from blood donors in Japan and pre‐genotyped. To detect the SNPs of the ABCG2 gene using MALDI‐TOF MS, polymerase chain reaction and unextend primer were designed. In total, 205 Jr (a−) samples were genotyped using MALDI‐TOF MS analysis. Results: The SNPs of 1004 Jr (a−) samples were identified using the HRM analysis and DNA sequencing, and 799 of 1004 (80%) Jr (a−) samples had the homozygous for c.376 T. The designed primers for MALDI‐TOF MS perfectly detected the SNPs of the ABCG2 gene. A total of 205 Jr (a−) samples were genotyped using MALDI‐TOF MS. Calling failures occurred in only two samples with the mutations c.736CT to c.376C and c.421C to c.421CA. The concordance rate between the pre‐genotyped and MALDI‐TOF MS‐based genotyping results was very high (99·02%) for all ABCG2 alleles. Conclusions: Jr (a‐) Japanese donors had almost the homozygous for c.376 T. However, detections of more than 20 SNPs of the ABCG2 gene for the JR blood group genotyping are needed. MALDI‐TOF MS‐based genotyping was highly concordant with the pre‐genotyped results for all ABCG2 alleles. [ABSTRACT FROM AUTHOR]

The article discusses an international forum from the journal "Vox Sanguinis" about donor notification and counselling techniques for transfusion-transmissible infections markers. Topics include notifying donors on positive screening test on the blood that has been donated, the role of counselling and donor notification in both blood safety and donor care, and the important elements for a notification message.

Rare blood is generally defined as one that occurs at a frequency of 1:100~1000 individuals or less, and it is sometimes difficult to provide such blood types to patients because of their rarities. The Japanese Red Cross ( JRC) Society lists 46 rare blood phenotypes that are divided into two categories. The rare blood types listed in Category I occur much less frequently than those listed in Category II. We screen for rare blood cells using monoclonal antibodies (MoAbs). Since 1987, our blood centre has established 93 MoAbs (32 human and 61 murine) and has provided them to the other blood centres. Many of IgG MoAbs are available on the machine by saline or bromelin method by cross-linking with anti-human or anti-mouse IgG. Thus, more than 10 000 donors with rare blood phenotypes (Category I, 748; Category II, 9314) are registered in Japan. We freeze rare blood, particularly Category I types. Since 1977, a total of 576 units of rare blood with phenotypes Di(b−), D−−, Jr(a−), Ko and Lan-, etc. have been supplied to 23 international countries. Thus, the JRC contributes to the International Panel of Donors of Rare Blood Type ( IDP) which is maintained by the International Blood Group Reference Laboratory ( IBGRL) in Bristol, UK. The IDP provides information on the location of rare blood donors when they cannot be found in their respective countries. We also joined the ISBT Working Party on Rare Donors which handles all matters related to rare blood. Our rare blood donor programme is successful because of international co-operation. [ABSTRACT FROM AUTHOR]