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 (1993-2002) 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% CI 5.11-9.99), of which 12 in bone marrow donors (4.32/10,000; 95% CI 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.