In this study, we verified whether measuring the number of CD34+ cells in the intermediate collection bag (hereinafter referred to as intermediate value) to determine the blood processing volume of the peripheral blood stem cell harvest contributes to appropriate collection and reduces patient burden. The study was conducted using 75 autologous peripheral blood stem cell harvests performed from January 2019 to December 2020. We confirmed the correlation between intermediate value and the number of CD34+ cells in the collection bag after harvest (hereinafter referred to as final value) (r=0.953) and checked the ratio of final values to the predicted value obtained from a regression equation substituting the intermediate values. The results showed that 59 cases (79%) were more than 80%, confirming the reliability of the intermediate values. The reduction in harvest time was analyzed in 59 cases in which collection was completed in one day. A median time reduction of 95 minutes was observed in 53 cases (90%) compared to those in which 250 ml/kg of blood was collected for processing. These results suggest that measurement of the intermediate value can efficiently and accurately ensure the target cell count and reduce patient burden.

The actual use of blood products in Japan in fiscal year 2021 was surveyed. Responses were received from 51% of the institutions that received blood products from the Japanese Red Cross Society. Eighty-one percent of the blood products received were registered. Compared with the period before the coronavirus pandemic, the number of institutions involved in blood transfusion, especially smaller institutions, decreased. In autologous blood transfusions, the number of patients, institutions, and units used per year all showed a decreasing trend. The numbers of institutions using diluted autologous blood transfusion showed an increasing trend. There were no significant changes in units of blood products used per bed per year. Large facilities showed a trend toward increasing amounts of globulin products used per bed per year. Blood product wastage rates showed a decrease in red blood cell and plasma products. Establishing a transfusion management system in smaller facilities, assigning clinical transfusion nurses, and involving the transfusion department in globulin products and retrievable autologous blood transfusions were challenges. Few facilities evaluated or recognized the appropriate use of blood products as part of their regular practice.

Bacterial infections resulting from platelet concentrate (PC) transfusion have been a longstanding issue in ensuring transfusion safety. In an attempt to reduce the adverse effects of transfusion caused by bacterial-contaminated PCs, development of methods to detect contaminating bacteria and techniques to inactivate bacteria have been promoted. Although these methods are effective in eliminating bacteria or bacteria-contaminated preparations, many of them have drawbacks such as requiring a number of days to determine the presence of bacteria, complicated operations, and special equipment. Gram-negative bacteria are the causative organisms in a high percentage of fatal cases of post-transfusion bacterial infection. Endotoxin is detected as a causative agent in multiple organ failure and shock in Gram-negative bacterial infection. We focused on the relationship between gram-negative bacteria and endotoxin and developed a rapid method to detect Gram-negative bacteria contamination in PCs by measuring endotoxin using the gel-clot technique of the Limulus test. This method is simple and quick to perform, and by performing the endotoxin test immediately before platelet transfusion, it is possible to detect and eliminate Gram-negative bacteria-contaminated PC that may cause serious symptoms with high probability.