The use of unrelated donors (UD) for allogeneic bone marrow transplantation (BMT): a pilot study of the Canadian BMT Group.

Thirty-five patients underwent allogeneic bone marrow transplantation (BMT) from unrelated donors (UD), in a pilot study of the Canadian Bone Marrow Transplant Group with techniques routinely used in BMT from HLA-identical related donors. Thirty-two of the patients had hematologic malignancies and 3 had aplastic anemia. Donors and patients were matched at all HLA loci tested serologically in 29 cases; 19 of these patients had mutually non-reactive mixed leukocyte cultures (MLC's). Six patients had some degree of serologic mismatch. Stable engraftment occurred in all but 3 evaluable patients. Acute graft-versus-host disease (GVHD) developed in greater than 80% and fatal BMT-related deaths occurred in a total of 55% of all patients. Conversely, only two relapses have occurred, and the 1-year actuarial event-free survival for all patients is 40% (95% confidence intervals [CI], 24-55%) with a follow-up of 0.8 to 2.7 years. All survivors are out of the hospital and all save 1 have a normal performance status. Our study has confirmed the utility of unrelated donors for allogeneic BMT. Although more complications are seen than with HLA-matched sibling donors, these patients did not have such donors available and virtually all were incurable without transplants. Further studies, especially those using new methods to prevent transplant-related complications, are needed.