Donor-derived myelodysplastic syndrome and acute leukaemia after allogeneic haematopoietic stem cell transplantation: incidence, natural history and treatment response.

Donor-derived myelodysplastic syndrome/acute leukaemia (DD-MDS/AL) is a rare life-threatening complication of allogeneic haematopoietic stem cell (HSC) transplantation. However, it is unknown whether the risk differs by HSC source. Therefore, we evaluated the incidence of DD-MDS/AL in 2390 engrafted patients. With a median follow-up of 7·1 years (1-20·8), the incidence of DD-MDS/AL was 0·53% (95% confidence interval (CI), 0·01-1·41%], 0·56% (95%CI, 0·01-1·36%) and 0·56% (95%CI, 0·01-1·10%) in recipients of bone marrow (n = 1117), peripheral blood (n = 489) and umbilical cord blood (UCB, n = 784), respectively. While follow-up is shorter in recipients of UCB and peripheral blood, incidence of DD-MDS/AL is, thus far, similar between HSC sources.