Severe Donor Events after Allogeneic Hematopoietic Stem Cell Donation.

The risk for donors of allogeneic hematopoietic stem cells (HSC) by bone marrow (BM) or by peripheral blood (PB) harvest is generally considered negligible. Scattered reports of severe to life-threatening complications and a recent controversy on hematopoietic malignancies after GCSF administration for peripheral stem cell donation have challenged this opinion. Previous studies were limited by small numbers. In two consecutive retrospective surveys conducted in 2003 and 2006 amongst 338 allogeneic transplant centres from 38 European countries participating in the annual EBMT activity surveys, centres were asked to report all donor deaths, all severe adverse events (SAE’s), defined as occurring within 30 days and any hematological malignancy in a donor occurring after HSC donation. 262/338 teams (77.5%) responded to the first survey (1993–2002) and 169/262 (65%) centres replied to the second survey (2003–2005). The responding teams performed a total of 51’024 first allogeneic HSCT, 27’770 BM and 23’254 PB HSCT, which corresponds to 69% of all 73’947 first allogeneic HSCT reported during this time to EBMT. There were 5 donor deaths, 1 after BM and 4 after PB donation, an incidence of 0.98 per 10’000 donations (95% CI 0.32–2.29), 37 SAE’s (incidence 7.25/10’000 donations; 95% CI 5.11–9.99), 12 in BM (incidence 4.32/10000 donations; 95% CI 2.24–7.75) and 25 in PB donors (incidence 10.76/10’000 donations; 95% CI 6.97–15.85; p<0.02). In absolute numbers, there were 20 hematological malignancies occurring in donors (3.92/10’000 donations; 95% CI 2.39–6.05), 8 after BM (2.88/10’000 donations; 95% CI 1.24–5.68) and 12 after PB donation (5.16/10’000 donations; 95% CI 2.67–9.02; p = 0.3). Based on the different observation times, the incidence rates for developing hematological malignancies are 0.398 per 10’000 person-years for BM and 1.20 per 10’000 person-years for PB donation, resulting in a relative risk of 3.02 (95% CI 1.11–6.87, p=0.027). These data document a definitive risk for death, SAE’s and hematological malignancies with HSC donation. Deaths occur with similar frequency in both groups. SAE’s were more frequently reported after PB donation. The incidence rate for developing hematopoietic malignancies is higher after PB donation. These data clarify the recent controversy on HSC donation. They form a basis for donor counselling and underline the need for standardised donor follow up and international cooperation in order to define risk factors and to build up preventive measures.