The "Guidelines for the Implementation of Transfusion Therapy" by the Ministry of Health, Labour, and Welfare clearly state that forward group typing alone is adequate for ABO blood group typing in infants aged < 4 months due to the presence of acquired maternal antibodies and insufficient production of anti-A and anti-B. However, the guidelines make no clear description of reverse group typing after ≥ 4 months of age. We analyzed the results of ABO blood group typing in 1,068 infants aged < 3 years who underwent ABO blood group typing in our hospital between January 2010 and April 2017. The concordance rate between forward and reverse group typing was compared between infants aged < 1 month and those aged ≥ 1 month - < 4 months, but no difference was observed (p = 0.638). In addition, evaluation of the concordance rate at 2-month intervals in infants aged ≥ 4 months - < 1 year showed that the concordance rate increased with age. Comparison of the concordance rate between infants aged < 4 months (56.6%) and those aged ≥ 4 months - < 1 year (76.5%) showed a significant difference (p < 0.001). The concordance rate was about 90% in infants aged ≥ 1 year. These results suggest that the appropriate timing of ABO blood group typing using forward and reverse group typing is ≥ 1 year after birth.

Nationwide questionnaire survey on transfusion medicine has been conducted over a period of 10 years or more as a project commissioned by the Japanese government. When the survey was initiated, the goals of the project were to establish a blood transfusion management system and to reduce the usage of albumin preparations and fresh-frozen plasma (FFP). The blood transfusion management system has been improved by the measures taken by the national government, including the introduction of a blood transfusion management fee, as well as by an accreditation system established by academic societies. As a result, the waste rate of blood products has decreased. Regarding usage, the use of albumin preparations and FFP has rapidly decreased to the internationally agreed level through the development of criteria for the appropriate use of blood products, and through the publication of evidence-based guidelines on the use of blood products by academic societies. The results of the present survey clearly showed that blood products are used appropriately and safely in transfusion medicine in Japan. However, newly identified issues are the need to evaluate the actual use of immunoglobulin preparations, which has rapidly increased in recent years, and to ascertain the use of individual blood products by medical specialty and blood transfusion site.

Hepatitis B is caused by hepatitis B virus (HBV) infection. Hepatitis B vaccine has been given to infants of HBV carriers to prevent mother-to-child transmission in Japan. In 2016, Hepatitis B vaccine was introduced into universal vaccination. An anti-HBs titer of 10 mIU/ml or higher after vaccination is considered to indicate the acquisition of protective immunity against HBV. Many in vitro diagnostics kits for anti-HBs are available to measure anti-HBs titer but observed titers may differ among kits. In 2008, anti-HBs quantification kits were evaluated using the Japanese National Standard for anti-HBs immunoglobulin. Results suggested greater than three-fold differences in observed titers among kits. Some kits were subsequently improved, and new anti-HBs kits have been introduced into the market. In this study, we re-evaluated anti-HBs quantification kits using two reference materials. The differences in observed titers among kits has decreased, to 2.1 times or less.

To clarify the actual status of countermeasures against the shortage of supply of blood products for blood transfusion and plasma fractionated products for disasters at hospitals, we conducted a survey on the operations of blood product supply and crisis management of transfusion therapy at disaster base hospitals nationwide.

Responses were obtained from 373 of the 730 target facilities (response rate: 51.1%). Among the hospitals that have prepared manuals for disaster prevention management, the rate of preparation of items related to blood product operation and testing systems was 130/356 facilities (36.5%). Furthermore, few medical institutions have established procedures such as a risk assessment system for the supply of blood products and in-hospital demand control based thereon. Only 44/102 facilities (43.1%) clarified the authority of the specified staff and departments that would likely be the key groups in developing such measures.

In order to establish a crisis management system for medical institutions in the event of a crisis related to the supply of blood products, a standard Business Continuity Plan (BCP) must be developed. Further, there is an urgent need to develop cooperative relationships and training protocols among the relevant hospitals, blood centers, blood plasma product suppliers, and administrative agencies.

Immune-mediated hemolytic anemia including Evans syndrome, is a known to be a complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). We recently experienced a 28-year-old female patient with chronic myelogenous leukemia (CML) in blastic crisis who developed Evans syndrome after allogeneic bone marrow transplantation from an unrelated male donor (blood type A, Rh+). She developed acute graft-versus-host disease (GVHD) and organizing pneumonia, which was treated with steroid therapy. One year after allo-HSCT, anti-E appeared during a regular checkup for irregular antibody following withdrawal of the steroid. One month later, she developed severe hemolytic anemia and thrombocytopenia. The Rh blood types of the donor and recipient were DCcEe and DCCee, respectively. At the onset of hemolysis, recipient-derived B cells remained in her peripheral blood. These observations led us to speculate that allo-antibody production by the remaining recipient-derived B cells triggered the generation of autologous antibodies against red blood cells and platelets, resulting in Evans syndrome. We suggest that an irregular antibody screening test might be helpful in predicting hemolytic events after allo-HSCT.

Daratumumab (DARA), an anti-CD38 antibody drug for multiple myeloma (MM), is known to cause false-positive results in the indirect antiglobulin test (IAT), which may continue for about 6 months after the last dose.

Here, we report 2 cases of IAT negativity early after DARA administration. Case 1 was a woman in her 70s with IgG-type MM who was administered DARA, bortezomib and dexamethasone (DBd) therapy. IAT became positive after the start of treatment, but became negative 12 days after the third dose and 8 days after the fifth dose. Case 2 was a woman in her 50s with IgG-type MM who was administered DBd therapy. IAT became positive after the start of treatment. DARA was ineffective and was terminated after the sixth dose. IAT became negative 14 days after the last dose.

Early IAT negativity after DARA administration suggests that tumor burden in the bone marrow is sufficiently large to consume DARA, and may be clinically informative.