Application of immortalized human erythroid progenitor cell line in serologic tests to detect red blood cell alloantibodies.

BACKGROUND: Antibody screening in pretransfusion tests is necessary to avoid critical complications of blood transfusion. Although red blood cells (RBCs) expressing relevant alloantigen(s) have been used for serologic antibody screening, little attention has been given to the use of cell lines, in which blood group antigen gene(s) are transduced, as reagent RBCs for antibody screening. STUDY DESIGN AND METHODS: The use of an erythroid progenitor cell line for serologic tests was studied. The expression of blood group antigens of erythroid progenitor cells was analyzed by genotyping and flow cytometry. Serologic analysis including hemagglutination was performed using erythroid progenitor cells to evaluate their sensitivity for antibody detection. Overexpression of exogenous erythroid antigen by lentiviral transduction was carried out and investigated for antibody detection sensitivity. RESULTS: Erythroid progenitor cells contained a substantial amount of hemoglobin and expressed sufficient levels of blood group antigens to detect corresponding monoclonal antibodies. Furthermore, the cell line could acquire an exogenous RBC antigen after lentiviral transduction and detected corresponding monoclonal and alloantibodies with equal sensitivity to antigen-positive RBCs. CONCLUSION: Application of erythroid progenitor cell lines for screening for unexpected antibodies could be helpful in solving issues such as reagent availability associated with the conventional RBC-based assay. The genetic expandability of erythroid progenitor cell lines by gene modification techniques could lead to the development of more convenient reagent RBCs.

Analysis of HTLV-1 proviral load (PVL) and antibody detected with various kinds of tests in Japanese blood donors to understand the relationship between PVL and antibody level and to gain insights toward better antibody testing.

Adult T-cell leukemia/lymphoma (ATL) occurs in approximately 5% of individuals infected with human T-cell leukemia virus type 1 (HTLV-1). A high proviral load (PVL; more than four copies per 100 peripheral blood mononuclear cells (PBMCs) or 1.6 copies per 100 blood leukocytes) and being male are risk factors for ATL development. Whether anti-HTLV-1 antibody level is related to such risk is unknown. Here, PVL and antibody levels were examined using real-time PCR and other tests in 600 HTLV-1 positive screened Japanese blood donors to understand the relationship between PVL and antibody level in asymptomatic carriers and to gain insights toward better antibody testing for HTLV-1 infection. The 430 donors in whom proviral DNA was detected were considered as true positives for HTLV-1 infection. Among donors aged 40 years or older, more males than females had a PVL corresponding to more than 1.6% infected leukocytes, and an antibody titer below the median (P = 0.0018). In antibody tests using an HTLV-1 positive cell line or Env antigens there was a large discrepancy in antibody titer among 13 provirus-positive samples, probably suggesting that antibody-based screening tests should incorporate multiple HTLV-1 antigens, such as Gag and Env antigens.

Pulsed xenon flash treatment inactivates bacteria in apheresis platelet concentrates while preserving in vitro quality and functionality.

BACKGROUND: Pulsed xenon (Xe) flash without any photoreactive compounds has been shown to inactivate a type of bacteria spiked into platelet (PLT) suspension in plasma, but enhanced the PLT storage lesion (PSL). Predicting reduction of PSL with increasing bactericidal ability, pulsed Xe flash was filtered through a band-stop filter, which excluded ultraviolet (UV)A, UVB, and visible light. STUDY DESIGN AND METHODS: Apheresis PLT concentrates (PCs) inoculated with bacteria were irradiated with filtered Xe flash (fXe treatment). For in vitro functional quality assessment, PLT aggregation and thrombin generation together with other assays that monitor the PSL were investigated. RESULTS: Staphylococcus aureus and Streptococcus dysgalactiae could be inactivated without regrowth during 6 days of storage. PC variables, such as PLT count, concentrations of soluble CD40 ligand, and ratio of aggregated PLTs, were not significantly different between fXe-treated and untreated PCs after 6 days of storage, while PAC-1 binding increased in the fXe-treated PLTs. Responsiveness of fXe-treated PLTs to ADP was maintained over a 6-day storage period as shown by the up regulation of P-selectin expression and induction of both integrin αIIbß3 conformational change and PLT aggregation. The fXe-treated PLTs showed a sustained aggregation curve in response to ADP, whereas untreated PLTs transiently aggregated and then subsequently dissociated. Thrombin-generating kinetics of fXe-treated PLTs via PLT membrane surface were equivalent to those of untreated PLTs. CONCLUSIONS: The fXe treatment inactivated bacteria in apheresis PCs in plasma without additional chemical compounds. The fXe-treated PCs retained acceptable in vitro properties of PC quality and PLT functionality.

Unique clinical courses of transfusion-transmitted hepatitis E in patients with immunosuppression.

BACKGROUND: The high prevalence of specific immunoglobulin G for hepatitis E virus (HEV) in Japanese people raises the possibility of a high incidence of HEV-viremic blood donors and therefore frequent transfusion-transmitted HEV (TT-HEV). STUDY DESIGN AND METHODS: TT-HEV cases established in Japan through hemovigilance and those published in the literature were collected. Infectivity of HEV-contaminated blood components and disease severity in relation to immunosuppression were investigated. RESULTS: Twenty established TT-HEV cases were recorded over the past 17 years. A lookback study verified that five of 10 patients transfused with known HEV-contaminated blood components acquired HEV infection. The minimal infectious dose of HEV through transfusion was 3.6 × 104 IU. Nine of the 19 TT-HEV cases analyzed had hematologic diseases. Only two cases showed the maximal alanine aminotransferase level of more than 1000 U/L. Two patients with hematologic malignancy and two liver transplant recipients had chronic liver injury of moderate severity. CONCLUSION: The infectivity of HEV-contaminated components was 50%. Immunosuppression likely causes the moderate illness of TT-HEV, but it may lead to the establishment of chronic sequelae. Transfusion recipients, a population that is variably immunosuppressed, are more vulnerable to chronic liver injury as a result of TT-HEV than the general population is as a result of food-borne infection.

Comparison between in vitro properties of washed platelet concentrates suspended in M-sol and those in BRS-A, both of which were prepared with an automated cell processor.

BACKGROUND: Washed platelet concentrate (WPC) is prepared manually in general, but automated preparation is desirable to minimize variation in the WPC quality and enhance WPC production. Recently, the software was improved for an automated cell processor (ACP) to control all processes of WPC preparation. M-sol and BRS-A, which are mixtures of medical solutions, are widely used for WPC preparation with a manual method in Japan. In this study, we prepared WPC suspended in M-sol (WPC-M) or BRS-A (WPC-B) with the ACP, and compared their in vitro properties during 7-day storage. STUDY DESIGN AND METHODS: PC was divided into two equal aliquots for WPC-M and WPC-B. A divided PC, medical solutions and disposable materials were set in the ACP, and it was started to prepare WPC-M or WPC-B on Day 0. Prepared WPC was stored on a flatbed shaker until Day 7. RESULTS: The pH of WPC-M and WPC-B was maintained above 6.8 during the 7-day storage. The differences in aggregation (%), HSR (%), P-selectin expression, GPIbα expression, and phosphatidylserine expression between WPC-M and WPC-B were minimal until Day 3. CONCLUSION: The in vitro properties of WPC-B are not markedly different from those of WPC-M until Day 3.

Real-time measurement of platelet shape change by light scattering under riboflavin and ultraviolet light treatment.

BACKGROUND: The adoption of pathogen reduction technologies (PRTs) is considered for the implementation of safer platelet (PLT) transfusion. However, the effects of PRT treatment including irradiation with ultraviolet (UV) light on PLT shape have not yet been fully clarified. STUDY DESIGN AND METHODS: Leukoreduced PLT concentrates (PCs) were treated with riboflavin and UV light (Mirasol PRT, TerumoBCT). PLT shape and adenosine diphosphate (ADP)-induced shape change were evaluated by a light scattering method where the amplitude of the scattered signal intensity was measured as the indicator of the proportion of discoid PLTs. Using a modified fluorometer, the real-time effects of different wavelengths of UV light on PLT shape were examined over the range of 300 to 360 nm at the same dose. RESULTS: The proportion of discoid PLTs in the Mirasol PRT-treated PCs decreased immediately after treatment. The difference in the proportion between PRT-treated and untreated PLTs became larger with storage. Although this modification correlated significantly with the pH decrease and P-selectin expression, the Mirasol PRT-treated PLTs retained sufficient ability to undergo an ADP-induced shape change. In the study using the modified fluorometer, the proportion of discoid PLTs significantly decreased with the wavelength (< 320 nm) of irradiated UV light. CONCLUSION: Mirasol PRT treatment of PCs decreases the proportion of discoid PLTs, which seemed to be caused by the irradiation with UV light of short wavelengths (< 320 nm), not that of long wavelengths (≥ 320 nm) in the Mirasol PRT system. Modification of UV light wavelength may improve the quality of PRT-treated PCs.

Reduction of bacteria and human immunodeficiency virus Type 1 infectivity of platelet suspension in plasma using xenon flash-pulse light in a bench-scale trial.

BACKGROUND: Current pathogen reduction systems for platelet concentrates (PCs) require addition of chemical compounds and/or reduction of plasma content in PCs. We have investigated a new method using xenon (Xe) flash-pulse light without additional compounds or plasma replacement. STUDY DESIGN AND METHODS: An aliquot of apheresis platelets (PLTs) in plasma inoculated with bacteria or human immunodeficiency virus Type 1 (HIV-1) was irradiated with Xe flash-pulse light (Xe flash phototreatment). Bacterial growth was monitored up to 6 days of storage, whereas HIV-1 infectivity was assayed just after treatment. Pairs of Xe flash-phototreated and untreated PCs were examined for PLT lesion during the storage period. RESULTS: Under the current conditions, a low titer (1.8 colony-forming units [CFUs]/mL) of Staphylococcus aureus did not proliferate during the 6-day storage period, but grew in some cases at high-titer (24.0 CFUs/mL) inoculation. HIV-1 infectivity was reduced by 1.8 log. PLT recovery of the treated PCs was lower than untreated ones. An increase of mean PLT volume and glucose consumption, together with a decrease of hypotonic shock response and pH, were enhanced by the treatment. CD62P- and PAC-1-positive PLTs increased after the treatment, indicating the induction of PLT activation. Among biologic response modifiers, soluble CD40 ligand was significantly increased in the treated PCs on Day 6. CONCLUSIONS: Xe flash phototreatment could prevent bacterial proliferation and reduce HIV-1 infectivity in 100% plasma PCs without any additional compounds, but enhanced PLT storage lesions. Further improvement is required to increase the potency of pathogen inactivation with reducing PLT damage.

First report of the isolation of Lactococcus garvieae from a platelet concentrate in Japan.

BACKGROUND: Bacterial contamination of platelet concentrates (PCs) remains a serious problem in transfusion. We have been conducting sterility tests on all PCs rejected by blood centers or hospitals due to abnormal appearances. We recently experienced a case in which discrepant results were obtained between the methods used to identify a bacterial species isolated from a PC, requiring further analyses. STUDY DESIGN AND METHODS: Bacteria were isolated from a PC using the BacT/ALERT system and plate culture. The species was identified using biochemical tests and molecular analysis. Phylogenetic trees were constructed using sequences of the 16S ribosomal RNA (rRNA) and superoxide dismutase (sodA) genes from the bacterial isolate and related species. In addition, the isolate was cultured at temperatures of 10°C and below to determine its growth activity at low temperatures. RESULTS: Biochemical tests determined that the isolate was Streptococcus alactolyticus, whereas molecular analysis determined that it was Lactococcus garvieae. These two species belonged to different clusters on the phylogenetic tree. Similar to L. garvieae, the isolate could grow at 10°C. CONCLUSIONS: We conclude that the isolate was L. garvieae according to molecular identification and its growth characteristic at 10°C. Molecular analysis enabled the identification of this species, which was difficult to classify by biochemical tests. Blood facilities need to be prepared with multiple techniques, including genetic analysis techniques, for identifying contaminating bacterial species. L. garvieae can grow at 10°C and can contaminate both red blood cell concentrates and PCs; thus, this species should be listed as a cryophilic bacterium that could threaten blood safety.

Sequence analysis of two variable cytomegalovirus genes for distinction between transfusion- and breast milk-transmitted infections in a very-low-birthweight infant.

BACKGROUND: Cytomegalovirus (CMV) infections in very-low-birthweight infants can lead to serious clinical consequences. When CMV-related symptoms occur after transfusion, CMV transmission is often attributed to the transfusion products rather than to breast milk. However, it is sometimes difficult to distinguish between transfusion-transmitted and breast milk-transmitted CMV infections. PATIENT AND METHODS: A patient was born at 27 gestational weeks with a weight of 689 g. He was transfused with leukoreduced red blood cells (LR-RBCs), which were later found to be CMV seropositive and CMV DNA positive. He was also fed with CMV DNA-positive breast milk. Thereafter, he developed CMV disease with thrombocytopenia and jaundice. To determine the route of transmission, we analyzed the sequences of two variable CMV genes, UL139 and UL146, by direct sequence analysis. We also performed deep sequence analysis to determine whether there were polyclonal CMV strains in the LR-RBCs transfused. RESULTS: CMV DNA sequence-matching rates for the LR-RBCs and the patient's blood were 64.6% for the UL139 gene and 68.6% for the UL146 gene. In contrast, the sequences of these genes in the patient's blood were 100% matched with those in the breast milk. Furthermore, by deep sequence analysis, the CMV strain found in the patient's blood was not detected in the LR-RBCs transfused. CONCLUSION: The results indicate that the pathogenic CMV strain was transmitted through breast milk, which is consistent with the claims that transfusion-transmitted CMV infection due to leukoreduced blood products is uncommon.

A new ABCG2 null allele with a 27-kb deletion including the promoter region causing the Jr(a-) phenotype.

BACKGROUND: The high-prevalence antigen Jr(a) is carried on the ATP-binding cassette transporter ABCG2. The ABCG2 gene consists of 16 exons and its translation start codon is located on the second exon. Although the occurrence of the Jr(a-) phenotype is rare, several ABCG2 null alleles have been reported. We report a new ABCG2 null allele having a large deletion in this study. STUDY DESIGN AND METHODS: The Jr(a) status was determined by standard serologic tests and genomic DNA was isolated from whole blood. Exons 1 to 16 and the 5'-untranslated region of the ABCG2 gene were analyzed by polymerase chain reaction and sequencing. Expression of the ABCG2 protein on red blood cells was examined by immunoblotting. RESULTS: A Jr(a-) blood donor had a novel allele having a 27-kb deletion including noncoding Exon 1 and the promoter region of ABCG2, and the donor was apparently homozygous for the allele. In addition, we found three more individuals having heterozygosity for the same allele, with ABCG2*01N.01 having c.376C>T (p.Q126X), but did not find the allele having the 27-kb deletion in 3000 Jr(a+) individuals. Immunoblotting revealed that the ABCG2 protein was not found to be expressed in the individual with homozygosity for the ABCG2 27-kb deleted and in two individuals with an ABCG2 27-kb deleted/ABCG2*01N.01 genotype, which indirectly allows to conclude that the 27-kb deletion is responsible for a null ABCG2 allele. CONCLUSION: We first identified an ABCG2 null allele (provisional ISBT allele number ABCG2*01N.23) having a large deletion including the promoter region.

Comparative evaluation of 11 commercialized rapid diagnostic tests for detecting Trypanosoma cruzi antibodies in serum banks in areas of endemicity and nonendemicity.

Chagas disease is one of the main public health issues in Latin America. Increasingly during the past few decades, Trypanosoma cruzi infection has been detected in North America, Europe, and the Western Pacific, mainly as a result of population movement. The limited availability of rapid serological diagnostic tests hinders rapid diagnosis and early treatment in areas of endemicity and nonendemicity. In collaboration with 11 national reference laboratories (NRLs) from different geographical areas, we evaluated the performances of commercialized serological rapid diagnostic tests (RDT) for T. cruzi infection. Eleven commercialized T. cruzi infection RDTs were evaluated on a total of 474 samples extensively tested with at least three different techniques for Chagas disease, maintained at controlled low temperatures, and stored in the serum banks of the 11 NRLs. We measured the sensitivity, specificity, and concordance of each RDT and provided an additional questionnaire to evaluate its ease of use. The selected RDTs in this study were performed under controlled laboratory conditions. Out of the 11 RDTs, we found 8 of them to be useful, with the cassette format favored over the strip. We did not observe significant differences in RDT performances in the different regions. Overall, the performance results were lower than those disclosed by the manufacturers. The results of this evaluation validate the possibility of using RDTs to diagnose Chagas disease, thereby decreasing the time to treatment at a primary health care facility for patients who are willing to be treated. Further studies should be conducted in the laboratory and in the field to confirm these data, expressly to evaluate reproducibility in resource-limited settings, or using whole blood in clinical settings in areas of endemicity and nonendemicity.

Effects of riboflavin and ultraviolet light treatment on platelet thrombus formation on collagen via integrin αIIbß3 activation.

BACKGROUND: The adoption of pathogen reduction technology (PRT) is considered for the implementation of safer platelet (PLT) transfusion. However, the effects of PRT treatment on PLT thrombus formation under blood flow have not yet been fully clarified. STUDY DESIGN AND METHODS: Leukoreduced PLT concentrates (PCs) obtained by plateletpheresis were treated with riboflavin and ultraviolet light (Mirasol PRT). PC samples were passed through a column filled with collagen-coated beads at a fixed shear rate after 1, 3, and 5 days of storage. The thrombus formation ability was evaluated by measuring collagen column retention rate. The change in the activation state of integrin αIIbß3 on PLTs during storage was examined by flow cytometry. RESULTS: The retention rate of the PRT-treated PLTs was significantly higher than that of the control PLTs on the day of treatment and decreased with storage but remained higher than those of the control during storage. This modification did not correlate with the total αIIbß3 or fibrinogen binding on the PLTs but correlated significantly with PAC-1 binding. Mn(2+) -induced αIIbß3 activation also fully restored the retention rate in the Day 5 PRT-treated PLTs along with the increase in PAC-1 binding. CONCLUSION: Riboflavin-based PRT treatment of PCs leads to the enhancement of thrombus formation on collagen, which is related to the activation status of αIIbß3, which does not bind to fibrinogen but binds to PAC-1. The impact of this finding on the hemostatic or even thrombogenic potential in vivo must await clinical evaluation.

Antibody against immunoglobulin E contained in blood components as causative factor for anaphylactic transfusion reactions.

BACKGROUND: Determining the mechanism underlying the development of transfusion reactions is important in transfusion therapy. Two bags of fresh-frozen plasma obtained from a donor (index donor) were implicated in two cases of anaphylactic transfusion reactions. STUDY DESIGN AND METHODS: The serum prepared from the index donor plasma transfused into the second patient (Patient 2) was evaluated using cord blood-derived mast cells (CBMCs) incubated with Patient 2 plasma. The component in the serum required for the degranulation was determined and quantified by chromatography in combination with degranulation assay, Western blot analysis, and enzyme-linked immunosorbent assay. The component in the plasma required for CBMC sensitization was determined using human immunoglobulin (Ig)E or normal plasma in place of Patient 2 plasma in the assay. Sera collected from the index donor between 2001 and 2008 were examined for the CBMC degranulation factor. RESULTS: The donor serum activated CBMCs incubated with Patient 2 plasma. The IgG fraction of the donor serum induced degranulation of CBMCs sensitized with IgE or plasma containing a normal IgE concentration. The IgG anti-IgE at a concentration higher than 2200 ng/mL, which showed CBMC degranulation activity, was detected in the donor sera for at least 7 years. CONCLUSION: Transfusion of a high concentration of the anti-IgE in the donor plasma was suggested to induce mast cell degranulation in the patients leading to the development of anaphylactic transfusion reactions. Antibodies existing in not only the patient circulation but also the transfused blood might cause transfusion-induced anaphylaxis.

Establishment of culture systems for Genotypes 3 and 4 hepatitis E virus (HEV) obtained from human blood and application of HEV inactivation using a pathogen reduction technology system.

BACKGROUND: It has been demonstrated that the hepatitis E virus (HEV) can be transmitted via blood transfusion, and the risk of HEV transmission via transfusion has become a major global concern. An HEV culture system for blood-derived HEV has been sought to obtain valuable knowledge of the virus and the risk of HEV infection through blood products. STUDY DESIGN AND METHODS: We endeavored to establish an HEV culture system using RNA-positive blood specimens for Genotypes (G) 3 and 4 and applied this system to evaluate tissue culture infectious dose (TCID). We applied this method to investigate the potential of the Mirasol pathogen reduction technology (PRT) system (Terumo BCT) to inactivate live HEV in contaminated platelet samples (PLTs). PLTs were spiked with cultured HEV G3 or G4 and then treated with the Mirasol PRT system. PLTs were examined before and after the treatment for HEV load using TCID titration. RESULTS: We successfully established two strains for HEV production: the JRC-HE3 strain for G3 and the UA1 strain for G4. The Mirasol PRT system expressed more than 3 log inactivation for JRC-HE3 and more than 2 log inactivation for UA1. CONCLUSION: The Mirasol PRT system inactivated greater than 2 to 3 logs of live HEV in PLTs and can potentially be used to lower the possibility of blood-borne HEV transmission. The G3 and G4 HEV inocula identified in this study and the hepatoma cell culture system provide a new means to assess HEV infectious titer and to evaluate other pathogen reduction strategies.

Novel swine model of transfusion-related acute lung injury.

BACKGROUND: Transfusion-related acute lung injury (TRALI) is a life-threatening complication of blood transfusion. Antibodies against human leukocyte antigens in donors' plasma are the major causes of TRALI. Several animal models of TRALI have been developed, and the mechanism underlying TRALI development has been extensively investigated using rodent models. Although sheep models of nonimmune TRALI have been developed, large-animal models of antibody-mediated TRALI are not yet available. STUDY DESIGN AND METHODS: To develop a swine model of TRALI, male Clawn strain miniature pigs were used. A monoclonal antibody (MoAb) against swine leukocyte antigens (SLAs) Class I (4G8, 0.3 or 1.0 mg/kg body weight [BW]) and a control antibody (1.0 mg/kg BW) were injected into the peripheral vein after priming with or without 1 µg/kg BW lipopolysaccharide (LPS; n = 3 each). Lung injury was assessed using PaO2 /FiO2 (P/F) ratio and by chest X-ray imaging. Histopathologic analysis was also conducted. RESULTS: Lung injury could be induced by injecting 4G8 at an amount of 1.0 mg/kg BW, after LPS. The P/F ratio 90 minutes after the administration of 4G8 significantly decreased (p < 0.05). Bilateral infiltration was shown in chest X-ray imaging. Lung injury was confirmed by histopathologic analysis. CONCLUSION: Lung injury in pigs was successfully induced by anti-SLA MoAb. Priming with LPS is a prerequisite for inducing lung injury and the amount of the antibody is a critical condition.

Cytomegalovirus (CMV) seroprevalence in Japanese blood donors and high detection frequency of CMV DNA in elderly donors.

BACKGROUND: The current prevalence of cytomegalovirus (CMV) in Japan and the risk of CMV transfusion transmission are unknown in the era of seronegative leukoreduced blood components. STUDY DESIGN AND METHODS: We measured CMV-specific immunoglobulin (Ig)M and IgG in 2400 samples of whole blood collected from 12 groups of blood donors categorized by sex and age at 10-year intervals from their teens to their 60s. We also tested for CMV DNA using polymerase chain reaction in the cellular fractions of all samples. RESULTS: We found that 76.6% of blood donors were CMV seropositive. The seroprevalences among donors in their 20s and 30s were 58.3 and 73.3%, respectively. We detected CMV DNA in the cellular fraction of 4.3% of samples from donors in their 60s and in 1.0% of samples from donors younger than 60 years. None of the 562 seronegative samples was DNA positive. Furthermore, 14% of DNA-positive samples also contained DNA in the plasma fraction, and two of five such samples were derived from donors in their 60s. Leukoreduced plasma components derived from donations with CMV DNA in plasma samples also contained a relevant amount of CMV DNA. CONCLUSION: The seroprevalence of CMV among Japanese blood donors of child-bearing age has not changed over the past 15 years. Latent CMV becomes reactivated more frequently among elderly donors than among younger donors. A proportion of them have free CMV DNA in their plasma fraction, which could not be diminished by leukoreduction. The risk of transfusion-transmitted CMV infection in blood with plasma CMV DNA should be determined.

Residual risk of transfusion-transmitted hepatitis B virus (HBV) infection caused by blood components derived from donors with occult HBV infection in Japan.

BACKGROUND: Nucleic acid amplification testing (NAT) for hepatitis B virus (HBV) during blood screening has helped to prevent transfusion-transmitted HBV infection (TT-HBV) in Japan. Nevertheless, 4 to 13 TT-HBV infections arise annually. STUDY DESIGN AND METHODS: The Japanese Red Cross (JRC) analyzed repository samples of donated blood for TT-HBV that was suspected through hemovigilance. Blood donations implicated in TT-HBV infections were categorized as either window period (WP) or occult HBV infection (OBI) related. In addition, we analyzed blood from 4742 donors with low antibody to hepatitis B core antigen (anti-HBc) and antibody to hepatitis B surface antigen (anti-HBs) titers using individual-donation NAT (ID-NAT) to investigate the relationship between anti-HBc titer and proportion of viremic donors. RESULTS: Introduction of a more sensitive NAT method for screening minipools of 20 donations increased the OBI detection rate from 3.9 to 15.2 per million, while also the confirmed OBI transmission rate increased from 0.67 to 1.49 per million. By contrast the WP transmission rate decreased from 0.92 to 0.46 per million. Testing repository samples of donations missed by minipools of 20 donations NAT showed that 75 and 85% of TT-HBV that arose from WP and OBI donations, respectively, would have been interdicted by ID-NAT. The ID-NAT trial revealed that 1.94% of donations with low anti-HBc and anti-HBs titers were viremic and that anti-HBc titers and the frequency of viremia did not correlate. CONCLUSIONS: The JRC has elected to achieve maximal safety by discarding all units with low anti-HBc and anti-HBs titers that account for 1.3% of the total donations.

Impact of chemiluminescent enzyme immunoassay screening for human parvovirus B19 antigen in Japanese blood donors.

BACKGROUND: To reduce the risk of human parvovirus B19 (B19V) transmission through contaminated blood for transfusion and plasma-derived products, the Japanese Red Cross (JRC) Blood Centers introduced B19V antigen screening by chemiluminescent enzyme immunoassay (CLEIA-B19V) in 2008. STUDY DESIGN AND METHODS: Donor samples that were positive by CLEIA-B19V screening were tested for B19V DNA. The sensitivity of CLEIA-B19V was tested using samples of all three genotypes and B19V DNA-positive donations. B19V DNA-positive donations and pooled plasma were quantitatively assayed for B19V DNA. B19V DNA-positive donations were phylogenetically analyzed by polymerase chain reaction direct sequencing. RESULTS: The sensitivity of CLEIA-B19V was inferred to be approximately 6.3 log IU/mL with the genotype samples and 6.4 log IU/mL with B19V DNA-positive donor samples. Of 417 CLEIA-B19V-positive samples from 1,035,560 donations in Hokkaido, Japan, 101 were positive for B19V DNA. The 198 strains of B19V DNA-positive donations in Hokkaido over the past 15 years clustered exclusively with Genotype 1. After introduction of CLEIA-B19V, the viral load for B19V DNA in all 772 pooled plasma for fractionation from donors in nationwide Japan did not exceed 4 log IU/mL. CONCLUSION: CLEIA-B19V can detect all three genotypes of B19V (viral load >6.3 log IU/mL) and limit the viral load (<4 log IU/mL) in pooled plasma, and thus such screening has further reduced the risk of transfusion-transmitted B19V infection. These results show that CLEIA-B19V screening at the JRC Blood Centers can be an alternative approach to comply with recommendations regarding B19V in the United States and Europe.

Current prevalence of HTLV-1 in Japan as determined by screening of blood donors.

Human T-cell leukemia virus type-1 (HTLV-1), a major source of adult T-cell leukemia and related diseases, is endemic to southwestern Japan. Mother-to-infant transmission via breast milk is an important route of infection, and establishing programs to prevent such transmission requires exact figures on the HTLV-1 prevalence rate and the number of carriers. Therefore, the seroprevalence of HTLV-1 among 1,196,321 Japanese first-time blood donors from 2006 to 2007 was investigated. A total of 3,787 of such donors were confirmed to be positive for anti-HTLV-1 antibody. By applying a fitness curve to the age ranges outside the blood donor age range, the present number of HTLV-1 carriers covering ages from 0 to 99 years was estimated to be at least 1.08 million in Japan; this value was 10% lower than that reported in 1988. The adjusted overall prevalence rates were estimated to be 0.66% and 1.02% in men and women, respectively. The peak in carrier numbers was found among individuals in their 70s, which is a shift from the previous peak observed in the 1988 database among individuals in their 50s. Carriers were distributed not only in the endemic southwestern region of Japan, but throughout the country, particularly in the greater Tokyo metropolitan area. By applying population projections, it was calculated that the carrier number will decrease by half in the next two decades; however, the carrier population will age over that interval, meaning that the age of patients with adult T-cell leukemia will also be higher.

Prevalence of amino acid mutation in hepatitis C virus core region among Japanese volunteer blood donors.

It is not known whether there is a trend of increasing or decreasing incidence of new hepatitis C virus (HCV) infections in Japan. From the treatment point of view, it is important to verify HCV genotypes and the prevalence of treatment-resistant clones of HCV. At the Japanese Red Cross blood centers, all blood samples obtained from blood donation have been screened using serological methods and the minipool nucleic acid amplification testing. One hundred and fourteen donors have been identified over the past 10 years to be HCV RNA-only positive without detectable anti-HCV and were considered to be in the acute phase of HCV infection. There was a trend of decreasing incidence of such new infections among the blood donors. HCV RNA-only-positive samples were examined further for genotyping and HCV RNA quantitation. Genotype 2 (2a plus 2b) was predominant (78.2%) among them followed by genotype 1b (21.2%). Direct sequencing was carried out to detect the possible treatment-resistant mutant clones 70Q and 91M, clones with amino acid substitutions at positions 70 and 91 of the HCV core protein, respectively. 70Q and 91M were found regularly in donors with genotype 1b, but not in those with other genotypes. No particular endemic areas for the mutant clones were identified. There was no significant difference in the mean viral titer between the 70Q mutant type and the non-70Q wild-type. Even in newly infected people, the mutant clone 70Q was detected frequently.