2026 Volume 63 Issue 1 Pages 27-32
Background: In response to the coronavirus disease 2019 (COVID-19) pandemic, the Japan Marrow Donor Program allowed cryopreservation of bone marrow and peripheral blood stem cell (PBSC) products from April 2020 as a special measure. Although allogeneic hematopoietic cell transplantation (HCT) using cryopreserved donor cells has been implemented, its impact on pediatric patients remains unclear.
Methods: We conducted a survey among institutions participating in the Japan Pediatric Leukemia/Lymphoma Study Group, a hematologic oncology division of the Japan Children’s Cancer Group, that had registered pediatric HCT cases.
Results: The response rate was 77% (53/69 institutions). Variations were observed in storage methods, including storage solutions, among the institutions. Following the onset of the COVID-19 pandemic, cryopreservation rates increased for unrelated bone marrow transplantation (BMT) (36/185, 19%), unrelated PBSC transplantation (5/11, 45%), and related BMT (12/141, 9%). In unrelated BMT, the engraftment rates on day 28 did not differ significantly between the cryopreserved and fresh grafts (89% vs. 93%, p = 0.50).
Conclusion: Owing to the COVID-19 pandemic, the number of cryopreserved grafts has increased; however, cryopreservation did not significantly affect the engraftment rates and, therefore, may be a viable option for future donor cell management. Further standardization and improvement of cryopreservation techniques remain important challenges.
