Risks of developing Epstein-Barr virus-related lymphoproliferative disorders after T-cell-depleted marrow...

T-cell depletion of bone marrow for allogeneic transplantation is known to increase the risks of Epstein-Barr virus-driven lymphoproliferative disorders that may result in fatal lymphoma, especially with transplants from unrelated or mismatched donors. Over the past 15 years, we have monitored the outcome of 2,582 transplants using CAMPATH-1 (CD52) antibodies to deplete lymphocytes from donor and/or recipient to prevent graft-versus-host disease or rejection. Unlike many other methods of T-cell depletion, CAMPATH-1 antibodies also deplete B lymphocytes. The actuarial risk of lymphoproliferative disease using CAMPATH-1 for depletion of donor lymphocytes was up to 1.3%, hardly different from reported figures for conventional nondepleted transplants. In contrast, the risk in a small group of patients transplanted from unrelated donors using E-rosette depletion was as high as 29%, comparable to other reports of specific T-cell depletion. We conclude that the additional depletion of B cells is beneficial, possibly because it reduces either the virus load or the virus target until the time when T cells begin to regenerate.