The shelf life of red blood cell components (RBCs) in Japan was extended from 21 days to 28 days in March 2023, but still remains shorter than the 36 to 43 days in other countries. It is expected that extension of RBC shelf life will reduce wastage. However, irradiation of RBCs to avoid graft-versus-host disease may cause storage lesions. Here, we investigated whether the later irradiation of RBCs reduces the deterioration of RBC quality and contributes to the extension of shelf life.

We irradiated RBCs on either day 2, 7, 14, or 21 post-collection during 42-day storage. We set the in vitro quality of RBCs irradiated on day 2 and stored until day 28 as the control. We compared the quality of RBCs irradiated later (days 7, 14, or 21) on days 28, 35, and 42, respectively, with the control. Late irradiation did not reduce the increased hemolysis or decreased ATP concentration on days 35 and 42. Only RBCs irradiated on day 21 and stored until day 35 had supernatant potassium concentrations equal to control values. RBCs irradiated on day 14 and stored until day 35, and those irradiated on day 21 and stored until day 42 showed deformability equal to control values.

These results suggest that late irradiation is less effective in maintaining the quality of RBCs after 35 days storage and less useful for extension of the shelf life of RBCs.

We retrospectively examined whether adjusting the amount of apheresis using the number of CD34-positive cells in the product during peripheral blood stem cell collection (PBSCH) led to optimal collection. A total of 52 subjects, including 28 allogeneic and 24 autologous PBSCH, were analyzed. We observed a correlation between the number of CD34-positive cells in the product during PBSCH (mid-apheresis) and after PBSCH (final product): total (R = 0.986), allogeneic (R = 0.973), autologous (R = 0.996).

Additionally, the median value was 101% (range 79-129) in the allogeneic group and 123% (85-192) in the autologous group. The autologous group showed a significantly higher intermediate value. For events that occurred during collection, the value was significantly higher in the case group which waited 11 min or longer to start MNC collection. Although more appropriate PBSCH could be performed using the intermediate value, the final value was higher than the intermediate value with autologous PBSCH, and waiting 11 min or longer before starting MNC collection.

Peripheral blood stem cell harvesting (PBSCH) is an established general practice; however, recent medical advances have led to diversification in hematopoietic stem cell transplantation and collection. A questionnaire survey on cell therapy and blood cell apheresis was conducted to understand the current situation and identify issues in Japan. A total of 159 facilities/departments responded to the survey. The annual number of autologous PBSCH was "11-25" in 48% and "1-10" in 37% of the centers, while the annual number of allogeneic PBSCH for related transplantation was "1-10" in 60% of the centers and "1-10" in 50% for unrelated transplantation. Collection sites were in the wards (40%), transfusion department (36%), and dialysis unit (26%). The apheresis system was staffed mainly by clinical engineers (67%) and doctors (23%). Primarily, doctors (96%) performed peripheral vascular punctures and were present at all times during collection in 37% of the centers. The Spectra Optia was the equipment most commonly used for apheresis. To freeze the product, 89% of the centers used "CP-1" without a controlled rate freezer. This survey revealed the diversification of collection methods in Japan, with "task shift" emerging as a significant concern.

Dysfibrinogenemia is characterized by the presence of functional abnormalities despite the maintenance of normal levels of fibrinogen antigen. Plasma fibrinogen level is commonly measured by Clauss fibrinogen assay (CFA). Although CFA may underestimate the true antigen level in patients with dysfibrinogenemia, the clot waveform helps distinguish between true low fibrinogen values and those caused by qualitative abnormalities. Case 1 was a woman in her 50s with persistent proteinuria and no history of bleeding disorders who showed a low fibrinogen level before renal biopsy. Based on the CFA clot waveform, dysfibrinogenemia was diagnosed. The renal biopsy was performed without significant bleeding complications, and replacement therapy was not required. Case 2 was a pregnant woman in her 30s with no history of bleeding disorders who showed a low fibrinogen level prior to her second childbirth. The CFA clot waveform indicated a preserved antigen level, leading to a diagnosis of dysfibrinogenemia. She had a successful delivery without any replacement therapy. In both cases, the presence of a heterozygous missense mutation in the fibrinogen γ chain (γArg301His) was confirmed. The CFA clot waveform is useful in diagnosing dysfibrinogenemia and determining treatment strategies in patients with low levels of fibrinogen without bleeding symptoms.

Mimicking antibody is a specific antibody that is adsorbed on both antigen-positive and -negative erythrocytes. Mimicking antibodies can be classified into two categories: alloantibody-like mimicking antibodies and autoantibody-like mimicking antibodies. Since alloantibody-like mimicking antibodies induce the same reaction as alloantibodies, it is necessary to accurately understand the history of blood transfusion and pregnancy. Meanwhile, autoantibody-like mimicking antibodies show specificity for antigens possessed by the patient, facilitating identification. However, blood selection in RBC transfusion is hampered by the risk of alloantibody production, and the clinical significance of autoantibody-like mimicking antibodies must be considered.

Here, we report the case of a patient with an alloantibody-like mimicking anti-c identified after long-term transfusion of R₁R₁ RBC due to possession of anti-E, and of a second patient with an autoantibody-like mimicking anti-E by first testing in the absence of a history of transfusion and pregnancy.