Severe short-term adverse events in related bone marrow or peripheral blood stem cell donors

The incidence of severe adverse events (SAEs) and associated risk factors in hematopoietic cell transplantation donors needs to be clarified for related donors (relatives of the transplant recipient), whose criteria for donation are more lenient than for unrelated donors. Data from related donors registered in the Japanese national data registry database between 2005 and 2021 were evaluated to determine the association of short-term SAE incidence with donor characteristics at registration.Fourteen of 4339 bone marrow (BM) donors (0.32%) and 54 of 10,684 peripheral blood stem cell (PBSC) donors (0.51%) experienced confirmed SAEs during the short donation period. No deaths were observed. Past medical history was a common risk factor for SAEs in both BM and PBSC donors. Age of 60 years or older and female sex were identified as risk factors for SAEs in PBSC donors. Female sex was also a risk factor for poor mobilization, which resulted in discontinuation of PBSC collection.Although donors should be selected carefully, a certain level of safety is ensured for related donors in Japan. Donor safety should be further increased by improving the selection method for related donors and extending the follow-up period.