In 1985, Popovsky reported that Transfusion-Associated Circulatory Overload (TACO) occurred more frequently than expected in red blood cell (RBC) transfusions. From 2012, the Japanese Red Cross (JRC) started analyzing data on TACO cases. Here, we highlight a newly identified risk. The JRC diagnosed and classified 162 cases of TACO according to the day of the week of onset. The number of cases with TACO onset from Monday to Sunday was 17, 26, 28, 27, 32, 22, and 10, respectively. Because the supply of RBC units decreases towards the weekend, the TACO/RBC ratio was 3.5 times higher on Saturdays than on Mondays (p<0.01). In this report, we first focused on this apparent trend of "weekend TACO". Second, during transfusions, clinicians generally focus on incremental changes in patients' hemoglobin levels, while the increase in fluid infused with the blood components rarely receives as much attention. Because transfusion is a fluid infusion, it is directly correlated with the intravenous fluid load. We therefore recommend the proactive use of diuretics to maintain fluid balance before and after transfusion and emphasize the concept of "isovolemic transfusion".

The guidelines for proper use of blood products and albumin are widely used in Japan. However, there is currently no standard guideline for intravenous immunoglobulins (IVIGs). Total supply of IVIGs is increasing with each year in Japan. Recently, the average consumption of IVIGs in Tokyo Women's Medical University Hospital was about 24 kg/year. The Departments of Neurology, Urology and Gastroenterology used approximately 38%, 12%, and 8% of the hospital's total IVIG supply, respectively. According to the survey, the recent change in the amount of IVIGs used varied for different diseases: use for humoral immunodeficiency decreased dramatically, while use for autoimmune diseases increased. In addition, IVIGs were used for desensitization therapy for renal transplantation in the Department of Urology. As the number of patients with autoimmune diseases increases, along with the availability and convenience of IVIGs, demands for IVIGs will also rise. Furthermore, demonstrated usefulness of IVIGs in organ transplantation will also increase demand. To maintain the demand-supply balance of IVIGs and to effectively use blood donation-derived plasma in Japan, we propose that the Japanese Association of Blood Transfusion and Cell Therapy and related associations cooperate to ensure the proper use of IVIG products.

Anti-Jk^a and anti-Jk^b against the Kidd antigen cause delayed hemolytic transfusion reactions. Detection of the antibodies by crossmatching is difficult and represents a clinical problem. A JK*A allele (JK*01W.01) with c.130G>A in exon 4 of the JK gene encoding an amino acid substitution (p.Glu44Lys) was reported in 2011. This single nucleotide polymorphism (SNP) reduces the expression level of Jk^a and Jk3 antigens. In this study, we examined the prevalence of the c.130A polymorphism and its effect on the expression of Jk^a and Jk3 in Japanese blood donors. The prevalence of c.130A was 38.5% in 2,017 Japanese donors, accounting for 82.6% of JK*01W.01 in JK*A. On the other hand, the prevalence of c.130A in JK*B was only 0.1%. The red blood cells (RBCs) of the individuals with c.130A showed low expression of Jk^a and Jk3 antigens by flow cytometry. As the prevalence of the Jk (a+b+) phenotype is approximately 50% in the Japanese population, more than 80% of Jk (a+b+) donors are expected to have weak expression of the Jk^a antigen on their RBCs. Therefore, it is important to note that weak expression of Jk^a antigen causes false negative crossmatching. If the patient has anti-Jk^a, blood for crossmatching must be confirmed Jk (a-) using an anti-Jk^a reagent with high potency.

A patient without a prior history of hepatitis B was found to be positive for antibodies to the hepatitis B e antigen (anti-HBe) after blood transfusion. Several subsequent studies revealed that the anti-HBe positivity was donor-derived. This experience prompted us to conduct a study on the anti-HBe positivity in blood products and the blood kinetics of donor-derived anti-HBe after transfusion. We studied the positivity rate of anti-HBe in 1,064 bags of residual plasma of either 240 ml of fresh frozen plasma (FFP) or 10 units of platelet concentrate (PC). Anti-HBe was detected in 24 bags (2.3%), which were transfused to 18 anti-HBe- negative patients. We studied the kinetics of donor-derived anti-HBe in these 18 patients after transfusion. Anti-HBe positivity in these patients lasted more than three months but was transient, and higher anti-HBe titer transfusions were associated with higher detection rates of anti-HBe. All 18 patients were negative for hepatitis B virus DNA (HBV DNA) using the TaqMan gene expression assay and antibodies against the hepatitis B core antigen, suggesting that there was no possibility of transfusion-transmitted HBV infection. Our results indicate that careful consideration is required when interpreting positive anti-HBe results after transfusion.

Flow cytometric detection of anti-HLA antibodies has yet to be optimally standardized. There is no consensus on whether serum or plasma specimens should be used. We studied interspecimen differences in anti-HLA antibody levels between serum and plasma using the flow cytometric method FlowPRA^®. We simultaneously examined the serum and plasma of a total of 55 cases that were positive or negative for anti-HLA antibodies. The percentage of class I and class II beads that reacted with plasma was significantly correlated with those that reacted with serum (class I: r = 0.8570 p < 0.0001, class II: r = 0.7529 p < 0.0001). Plasma and serum, samples that were positive for anti-HLA antibodies were identical in all 55 cases for class I and in 54 cases for class II. In one case, class II anti-HLA antibodies were detected in plasma but not in serum. Mean fluorescence intensity in plasma samples was significantly higher than that in serum. Non-specific reaction due to high background intensity was seen in 2 plasma specimens out of 55 cases. Therefore, both serum and plasma specimens are useful for detecting anti-HLA antibodies using Flow PRA^®, although the features of each specimen should be considered.

Hematopoietic progenitor cell (HPC) counts can be rapidly performed at low cost, and are reportedly well correlated with CD34+ cell number. We investigated the correlation between HPC counts and CD34+ cell counts in patients (PTs) and healthy donors (HDs) to determine the usefulness of HPC counts in assessing the optimal timing for peripheral blood stem cell harvest (PBSCH) and optimal blood processing volume. HPC counts in peripheral blood were significantly correlated with that of CD34+ cells, particularly in HDs. Cut-off values of HPC counts for a target of 2×10⁶/kg CD34+ cells were 37 /μl for HDs and 23 /μl for PTs. In HDs, only HPC counts on the first day of PBSCH predicted the final CD34+ cell count/kg. In contrast, in PTs, the LD ratio of the first day of G-CSF to the first day of PBSCH, body weight, and HPC counts the day before the first day of PBSCH were significantly correlated with CD34+ cell count. Moreover, the regression equation generated using these values accurately predicted the final CD34+ cell count/kg (R=0.986). We conclude that HPC count is a rapid and low cost method for predicting the optimal timing of PBSCH both in PTs and HDs.

Recently, home transfusions (HT) have increased due to governmental promotion of home care service. The Yame hospital group, which includes general hospitals and home care hospitals, created a unique HT system.

Beginning in November 2014, preparatory meetings were held to discuss the indications for HT, acquisition of informed consent, available products, transfusion-related examinations and preparation, blood product transportation, transfusion procedure, treatment of adverse events, billing, and so on.

A total of 20 home transfusions were planned for 5 patients between May 2015 and February 2017. Eighteen (18) transfusions were completed. There were no adverse events and QOL improved in every patient. One scheduled transfusion was not performed due to the deterioration of the patient's condition. One patient died while the blood products were in transport. One of the five patients was tested for transfusion transmitted infection (negative result).

Although HT still faces challenges such as unexpected change in patient condition and increased burden on medical staff, cooperation between general hospitals and home care hospitals resolves some of the problems associated with blood safekeeping and transfusion-related examinations. This collaborative approach makes it possible to safely introduce HT.

The pre-transfusion test for patients with anti-John Milton Hagen (JMH), an antibody against high-frequency antigens, has been associated with difficulty in the identification of irregular antibodies as well as incompatibility with the cross-match test. Thus, establishing a transfusion for these patients can be problematic. Although anti-JMH usually exhibits IgG4 subclass, IgG4 appears to be of no clinical significance. We found that monoclonal anti-human IgG reagent, which had no reactivity to IgG4, provided useful information in compatibility testing in a patient with anti-JHM.

An 82-year-old male patient underwent a cross-match test via an indirect anti-globulin test, and was positive for the polyclonal anti-human IgG reagent but negative for the monoclonal version. Anti-JMH was identified in the test results at Japanese Red Cross Blood Center. An IgG subclass analysis using flow cytometry showed IgG4 positivity.

Based on the results of the monoclonal anti-human IgG reagent test, transfusion was performed. The expected outcome of the transfusion was achieved with no hemolytic side effects.

A monoclonal anti-human IgG reagent that does not react with IgG4 seems to be useful for checking alloantibody production after transfusion, and enables the reporting of cross-match test results that are valid for treatment, particularly in patients with anti-JMH.