Does matched unrelated donor transplantation have the same outcome as matched sibling transplantation in unselected patients?

Outcome differences by donor type for allogeneic hematopoietic stem cell transplantation vary based on disease and recipient age. The following paper summarizes analyses of transplant outcome among adults with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) who received transplants from HLA-identical siblings, fully (8/8) matched unrelated donors (MUD), or mismatched (7/8) unrelated donors. The paper also reviews transplantation outcomes for children with leukemia who had genotypically matched sibling donors, mismatched (7/8) or phenotypically matched related donors or matched (8/8) unrelated donors. Morbidity is higher after unrelated donor vs HLA-matched sibling transplants due to higher rates of acute graft-vs-host disease (GVHD). However, survival is similar or within 10%-15% with all studies donor type, with disease-specific differences probably reflecting differences in underlying population risk for treatment-related mortality.