Effect of stem cell source on outcomes after unrelated donor transplantation in severe aplastic anemia

Outcome after unrelated donor bone marrow (BM) transplantation for severe aplastic anemia (SAA) has improved, with survival rates now approximately 75%. Increasing use of peripheral blood stem and progenitor cells (PBPCs) instead of BM as a graft source prompted us to compare outcomes of PBPC and BM transplantation for SAA. We studied 296 patients receiving either BM (n = 225) or PBPC (n = 71) from unrelated donors matched at human leukocyte antigen-A, -B, -C, -DRB1. Hematopoietic recovery was similar after PBPC and BM transplantation. Grade 2 to 4 acute graft-versus-host disease risks were higher after transplantation of PBPC compared with BM (hazard ratio = 1.68, P = .02; 48% vs 31%). Chronic graft-versus-host disease risks were not significantly different after adjusting for age at transplantation (hazard ratio = 1.39, P = .14). Mortality risks, independent of age, were higher after PBPC compared with BM transplantation (hazard ratio = 1.62, P = .04; 76% vs 61%). These data indicate that BM is the preferred graft source for unrelated donor transplantation in SAA.