T-cell depletion of bone marrow transplants for leukemia from donors otherthan HLA-identical siblings: advantage of T-cell antibodies with narrow specificities

T-cell depletion of donor marrow decreases graft-versus-host disease result ing from transplants from unrelated and human leukocyte antigen (HLA)-mis-m atched related donors. However, there are diverse strategies for T-cell-dep leted transplantation, and it is uncertain whether any improve leukemia-fre e survival (LFS), To compare strategies for T-cell-depleted alternative don or transplants and to compare T-cell depleted with non-T-cell-depleted tran splants, we studied 870 patients with leukemia who received T-cell-depleted transplants from unrelated or HLA-mismatched related donors from 1982 to 1 994, Outcomes were compared with those of 998 non-T-cell-depleted transplan ts. We compared LFS using different strategies for T-cell-depleted transpla ntation considering T-cell depletion technique, intensity of pretransplant conditioning, and posttransplant immune suppression using proportional haza rds regression to adjust for other prognostic variables. Five categories of T-cell depletion techniques were considered: narrow-specificity antibodies , broad-specificity antibodies, Campath antibodies, elutriation, and lectin s, Strategies resulting in similar LFS were pooled to compare T-cell-deplet ed with non-T-cell-depleted transplants. Recipients of transplants T-cell d epleted by narrow-specificity antibodies had lower treatment failure risk ( higher LFS) than recipients of transplants T-cell depleted by other techniq ues. Compared with nonT-cell-depleted transplants (5-year probability +/- 9 5% confidence interval [CI] of LFS, 31% +/- 4%), 5-year LFS was 29% +/- 5% (P = NS) after transplants T-cell depleted by narrow-specificity antibodies and 16% +/- 4% (P < .0001) after transplants T cell depleted by other tech niques. After alternative donor transplantation, T-cell depletion of donor marrow by narrow-specificity antibodies resulted in LFS rates that were hig her than those for transplants T-cell depleted using other techniques but s imilar to those for non-T-cell-depleted transplants. (C) 2000 by The Americ an Society of Hematology.