Severe events in donors after allogeneic hematopoietic stem cell donation

Background The risk for donors of allogeneic hematopoietic stem cells transplants is generally considered negligible. Scattered reports of severe complications and a recent controversy on hematopoietic malignancies after granulocyte colony-stimulating factor administration have challenged this opinion. Design and Methods Three hundred and thirty-eight allogeneic transplant teams from 35 primarily European countries were asked to report numbers of fatalities, severe adverse events and hematologic malignancies occurring among their hematopoietic stem cell donors. Results Two hundred and sixty-two of the 338 teams (77.5%) responded to a first survey (19932002) and 169 of the 262 responder teams (65%) to a second survey (2003-2005). They had performed a total of 51,024 first allogeneic hematopoietic stem cell transplantations, of which 27,770 were bone marrow and 23,254 peripheral blood. They observed five donor fatalities, one after a bone marrow donation and four after peripheral blood donation (incidence 0.98 per 10,000 donations; 95% CI 0.32-2.29), 37 severe adverse events (7.25/10,000; 95% Cl 5.11-9.99), of which 12 in bone marrow donors (4.32/10,000; 95% Cl 2.24-7.75) and 25 in peripheral blood donors (10.76/10,000; 95% CI 6.97-15.85; p<0.05) and 20 hematologic malignancies (3.92/10,000; 95% CI 2.39-6.05), of which 8 after donating bone marrow and 12 after donating peripheral blood stem cells. The observed incidence rate of hematologic malignancies did not exceed the expected incidence in an age- and sex-adjusted general population. Conclusions Hematopoietic stem cell donation is associated with a small but definite risk of fatalities and serious adverse events. True incidences might be higher, due to potential underreporting by study design. A continuous, standardized donor follow-up is needed to define donor risk groups and to monitor intermediate and long-term sequelae.