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Background@#Sterility and safety assurance of hematopoietic stem cell (HSC) products is critical in transplantation. Microbial contamination can lead to product disposal and increases the risk of unsuccessful clinical outcomes. Therefore, it is important to implement and maintain good practice guidelines and regulations for the HSC collection and processing unit in each hospital. We aimed to share our experiences and suggest strategies to improve the quality assurance of HSC processing. @*Methods@#We retrospectively analyzed microbial culture results of 11,743 HSC products processed over a 25-year period (January 1996 to May 2021). Because of reorganization of the HSC management system in 2008, the 25-year period was divided into periods 1 (January 1996 to December 2007) and 2 (January 2008 to May 2021). We reviewed all culture results of the HSC products and stored aliquot samples and collected culture results for peripheral blood and catheter samples. @*Results@#Of the 11,743 products in total, 35 (0.3%) were contaminated by microorganisms, including 19 (0.5%) of 3,861 products during period 1 and 16 (0.2%) of 7,882 products during period 2. Penicillium was the most commonly identified microorganism (15.8%) during period 1 and coagulase-negative Staphylococcus was the most commonly identified (31.3%) during period 2. HSC product contamination occurred most often during HSC collection and processing. @*Conclusions@#The contamination rate decreased significantly during period 2, when the HSC management system was reorganized. Our results imply that handling HSC products by trained personnel and adopting established protocols, including quality assurance programs, aid in decreasing the contamination risk.
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Immune-related adverse events, including immune hemolytic anemia, have been reported in patients treated with immune checkpoint inhibitors. In particular, RBC autoantibodies are important because they can cause hemolytic anemia and interfere with pre-transfusion tests. On the other hand, there are few reports on the characteristics of RBC autoantibodies induced by immune checkpoint inhibitors in Korea. The medical history and laboratory results, including pretransfusion tests of ten patients treated with immune checkpoint inhibitors, were reviewed retrospectively. The median interval from the first administration of immune checkpoint inhibitors to the development of autoantibodies was 12 weeks. In eight patients, only cold autoantibodies were developed. Both warm and cold autoantibodies developed in one patient, and warm autoantibodies alone were detected in one patient.Of seven patients tested by a direct antiglobulin test, two were negative, and the remaining five were positive for IgG and negative for C3d. In conclusion, this study presented ten cases of autoantibody developments in patients treated with immune checkpoint inhibitors and the possible relationship between the immune checkpoint inhibitors and RBC autoantibody development. Further comprehensive studies will be needed to elucidate this relationship.