Transfusion-transmitted bacterial infection risk due to the proliferation of psychrotrophic bacterial species in RBCs and their difficulty in detection.

Background: Reports of cases of bacterial infection due to transfusion of red blood cell (RBC) components (RBC-TTBI) are relatively rare. Hence, the possibility of undetectable bacterial contamination in RBCs, especially by psychrotrophic bacteria, must be clarified.

Study Design And Methods: We assessed nine psychrotrophic bacterial species, including those implicated in bacteremia or RBC-TTBIs.

Risk of transfusion-transmitted infection with severe acute respiratory syndrome coronavirus 2 from blood donors in Japan.

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) essentially affects respiratory organs and tissues. SARS-CoV-2 RNAemia is often associated with more severe cases of coronavirus disease 2019 (COVID-19) compared to cases without RNAemia. To determine the impact of the pandemic on transfusion medicine, particularly transfusion-related infection, we examined the frequency of blood donation with RNAemia, the viral RNA (vRNA) concentration, and any possibility of transfusion-transmitted infection (TTI) among transfusion recipients.

Two cases of Streptococcus dysgalactiae subspecies equisimilis infection transmitted through transfusion of platelet concentrate derived from separate blood donations by the same donor.

Background: Transfusion-transmitted bacterial infections (TTBIs) in Japan have been largely prevented due to a short shelf life of 3.5 days after blood collection for platelet concentrate (PC) and washed PCs (WPCs; PC in which 95% plasma is replaced by platelet additive solution).

Case Presentation: Case 1: In January 2018, a woman in her 50s with aplastic anaemia who received WPC transfusion and developed a fever the next day and Streptococcus dysgalactiae subspecies equisimilis (SDSE) was detected in the residual WPC.

Transfusion-transmitted HBV infection with isolated anti-HBs-positive blood.

Background: Hepatitis B virus (HBV)-positive individuals with isolated anti-HBs are found among HBV vaccine recipients and healthy blood donors with no vaccination history. HBV infectivity from blood transfusions derived from such individuals remains unclear.

Case Presentation: A male patient who received transfusion with blood negative for individual donation-NAT, HBsAg and anti-HBc but weakly positive for anti-HBs developed typical transfusion-transmitted (TT)-HBV with anti-HBc response.

Development of a recombinant hepatitis B immunoglobulin derived from B cells collected from healthy individuals administered with hepatitis B virus vaccines: A feasibility study.

Background: In Japan, plasma with a high concentration of Hepatitis B Virus (HBV) antibodies for hepatitis B immunoglobulin (HBIG) is almost entirely imported. We aimed to produce recombinant HBIG by isolating immunoglobulin cDNAs against the HBV surface antigen (HBsAg).

Study Design And Methods: B cells expressing HBsAg antibodies were obtained from blood center personnel who had been administered HB vaccine booster and then isolated by either an Epstein-Barr virus hybridoma or an antigen-specific memory B cell sorting method.

No evidence of bovine leukemia virus proviral DNA and antibodies in human specimens from Japan.

Background: The potential risk and association of bovine leukemia virus (BLV) with human remains controversial as it has been reported to be both positive and negative in human breast cancer and blood samples. Therefore, establishing the presence of BLV in comprehensive human clinical samples in different geographical locations is essential.

Result: In this study, we examined the presence of BLV proviral DNA in human blood and breast cancer tissue specimens from Japan.

Association of Staphylococcus aureus in platelet concentrates with skin diseases in blood donors: Limitations of cultural bacterial screening.

Background: Bacterial contamination in platelet concentrates (PCs) is a major problem in transfusion medicine. Contamination with Staphylococcus aureus is occasionally missed, even with cultural screening.

Study Design And Methods: Donors implicated in S.

Novel neutralizing human monoclonal antibodies against tetanus neurotoxin.

Tetanus is a fatal disease caused by tetanus neurotoxin (TeNT). TeNT is composed of a light chain (Lc) and a heavy chain, the latter of which is classified into two domains, N-terminus Hn and C-terminus Hc. Several TeNT-neutralizing antibodies have been reported, but it remains unclear which TeNT domains are involved in neutralization.

UV light-emitting diode (UV-LED) at 265 nm as a potential light source for disinfecting human platelet concentrates.

The risk of sepsis through bacterial transmission is one of the most serious problems in platelet transfusion. In processing platelet concentrates (PCs), several methods have been put into practice to minimize the risk of bacterial transmission, such as stringent monitoring by cultivation assays and inactivation treatment by photoirradiation with or without chemical agents. As another potential option, we applied a light-emitting diode (LED) with a peak emission wavelength of 265 nm, which has been shown to be effective for water, to disinfect PCs.

Clinical utility of a passive immune basophil activation test for the analysis of allergic transfusion reactions.

Background: In previous studies, we demonstrated that the basophil activation test, which is performed using patient blood and the supernatants from transfused blood components, was able to elucidate not only the causative relationship between allergic transfusion reactions and the transfusion but also the mechanisms behind allergic transfusion reactions. However, for a large number of allergic transfusion reactions, patients are in a state of myelosuppression, and the basophil activation test cannot be performed for these patients because there are insufficient numbers of peripheral blood basophils.

Study Design And Methods: To overcome this obstacle, we developed a passive immune basophil activation test, in which patient plasma and residually transfused blood are used as the patient's sources of immunoglobulin E and allergen, respectively, whereas healthy volunteer basophils serve as the responder cell source.

Mitochondrial damage-associated molecular patterns as potential proinflammatory mediators in post-platelet transfusion adverse effects.

Background: Platelet concentrates (PCs) are the most common blood components eliciting nonhemolytic transfusion reactions (NHTRs), such as allergic transfusion reactions and febrile reactions. However, the precise mechanisms of NHTRs in PC transfusion remain largely unknown. Previous studies reported that mitochondria-derived damage-associated molecular patterns (DAMPs) could be important mediators of innate cell inflammation.

High-resolution melting analysis as an alternative method for human neutrophil antigen genotyping.

Human neutrophil antigen (HNA)-typed granulocyte panels are widely used to screen for the presence of HNA antibodies and to determine antibody specificity. Many laboratories screen donors for HNA genotypes using low-throughput methods such as allele-specific polymerase chain reaction (PCR), PCR-restriction fragment-length polymorphism, and multiplex PCR. In the present study, we used a high-resolution melting (HRM) analysis to determine HNA genotypes.

The IgE-dependent pathway in allergic transfusion reactions: involvement of donor blood allergens other than plasma proteins.

On transfusion, several plasma proteins can cause anaphylaxis in patients deficient in the corresponding plasma proteins. However, little is known about other allergens, which are encountered much more infrequently. Although it has been speculated that an allergen-independent pathway underlying allergic transfusion reactions (ATRs) is elicited by biological response modifiers accumulated in blood components during storage, the exact mechanisms remain unresolved.

Metagenomic profiling of the viromes of plasma collected from blood donors with elevated serum alanine aminotransferase levels.

Background: In Japanese Red Cross (JRC) blood centers, blood collected from donors with serum alanine aminotransferase (ALT) levels of more than 60 U/L are disqualified even if serologically negative for transfusion-transmitted infections (TTIs). To assess potential risks of TTIs in plasma with elevated serum ALT levels in the current donor screening program of the JRC, we conducted a metagenomic analysis (MGA) of virome profiles in the plasma of blood donors with or without elevated serum ALT levels.

Study Design And Methods: Based on serum ALT levels, donors were classified into three groups: "high," more than 79 U/L; "middle," 61 to 79 U/L; and "low," less than 61 U/L.

Reevaluation of confirmatory tests for human T-cell leukemia virus Type 1 using a luciferase immunoprecipitation system in blood donors.

Background: Recently, Japanese Red Cross blood centers have changed the confirmatory test method from an indirect immunofluorescence (IF) technique to Western blotting (WB) for antibodies against human T-cell leukemia virus Type 1 (HTLV-1). In this study, these HTLV-1 tests were assessed using another sensitive method, that is, a luciferase immunoprecipitation system (LIPS), to identify a better confirmatory test for HTLV-1 infection.

Study Design And Methods: Plasma samples from 54 qualified donors and 114 HTLV-1 screening-positive donors were tested by LIPS for antibodies against HTLV-1 Gag, Tax, Env, and HBZ recombinant proteins.

Degenerate polymerase chain reaction strategy with DNA microarray for detection of multiple and various subtypes of virus during blood screening.

Background: The risk of transferring blood-borne infections during transfusion is continually increasing because of newly emerging and reemerging viruses. Development of a rapid screening method for emerging viruses that might be transmitted by transfusion is required to eliminate such pathogens during blood donor screening. Owing to increased use of human materials in organ transplants and cell therapy, the risk of donor-transmitted viral infections is also increasing.

Detection of anti-human platelet antibodies against integrin α2β1 using cell lines.

Background: Antibodies against human platelet antigens (HPA) are a cause of thrombocytopenia. Detection of rare anti-HPA antibodies using platelet preparations is difficult and would be improved by an alternative method that does not require platelets. In the present study, we describe the establishment of cell lines that stably express specific HPA associated with integrin α2β1 and the application of these cell lines for detecting anti-HPA-5a and anti-HPA-5b antibodies.

Xenotropic murine leukemia virus-related virus proviral DNA not detected in blood samples donated in Japan.

The xenotropic murine leukemia virus-related virus (XMRV) was first described as a novel human gammaretrovirus in prostate tumor tissues and was reported to be found in blood, suggesting the possibility of XMRV transmission via blood transfusion. The gag and env regions of the XMRV proviral DNA that were detected 1,030 blood samples collected from the greater Tokyo area were examined by real-time PCR analysis. However, XMRV infection was not found in the samples; this suggested that the risk of XMRV transmission via transfusion is very low in Japan.

No association of xenotropic murine leukemia virus-related virus with prostate cancer or chronic fatigue syndrome in Japan.

Background: The involvement of xenotropic murine leukemia virus-related virus (XMRV) in prostate cancer (PC) and chronic fatigue syndrome (CFS) is disputed as its reported prevalence ranges from 0% to 25% in PC cases and from 0% to more than 80% in CFS cases. To evaluate the risk of XMRV infection during blood transfusion in Japan, we screened three populations--healthy donors (n = 500), patients with PC (n = 67), and patients with CFS (n = 100)--for antibodies against XMRV proteins in freshly collected blood samples. We also examined blood samples of viral antibody-positive patients with PC and all (both antibody-positive and antibody-negative) patients with CFS for XMRV DNA.

An endogenous murine leukemia viral genome contaminant in a commercial RT-PCR kit is amplified using standard primers for XMRV.

During pilot studies to investigate the presence of viral RNA of xenotropic murine leukemia virus (MLV)-related virus (XMRV) infection in sera from chronic fatigue syndrome (CFS) patients in Japan, a positive band was frequently detected at the expected product size in negative control samples when detecting a partial gag region of XMRV using a one-step RT-PCR kit. We suspected that the kit itself might have been contaminated with small traces of endogenous MLV genome or XMRV and attempted to evaluate the quality of the kit in two independent laboratories. We purchased four one-step RT-PCR kits from Invitrogen, TaKaRa, Promega and QIAGEN in Japan.

Neonatal alloimmune thrombocytopenia caused by an antibody specific for a newly identified allele of human platelet antigen-7.

Background: Neonatal alloimmune thrombocytopenia (NAIT) is a neonatal disorder characterized by maternal alloimmunization against fetal platelet (PLT) antigens inherited from the father. A healthy 30-year-old Japanese woman (Hit) gave birth to her second child after an uneventful pregnancy. Nine hours after birth, the infant presented with severe petechiae and a PLT count of 6 x 10(9)/L.

Thrombopoietic-mesenchymal interaction that may facilitate both endochondral ossification and platelet maturation via CCN2.

CCN2 plays a central role in the development and growth of mesenchymal tissue and promotes the regeneration of bone and cartilage in vivo. Of note, abundant CCN2 is contained in platelets, which is thought to play an important role in the tissue regeneration process. In this study, we initially pursued the possible origin of the CCN2 in platelets.