Comparison of immune reconstitution after unrelated and related T-cell-depleted bone marrow transplantation: Effect of patient age and donor leukocyte infusions

Unrelated bone marrow transplantation (BMT) is often complicated by fatal o pportunistic infections. To evaluate features unique to immune reconstituti on after unrelated BMT, the lymphoid phenotype. in vitro function, and life -threatening opportunistic infections after unrelated and related T-cell-de pleted (TCD) BMT were analyzed longitudinally and compared. The effects of posttransplant donor leukocyte infusions to treat or prevent cytomegaloviru s (CMV) or Epstein-Barr virus (EBV) infections on immune reconstitution wer e also analyzed. This study demonstrates that adult recipients of TCD unrel ated BMTs experience prolonged and profound deficiencies of CD3(+), CD4(+), and CD8(+) T-cell populations when compared with pediatric recipients of u nrelated BMT and adults after related BMT (P < .01). that these adults have a significantly increased risk of life-threatening opportunistic infection s, and that the rate of recovery of CD4 T cells correlates with the risk of developing these infections. Recovery of normal numbers of CD3(+), CD8(+), and CD4(+) T-cell populations is similar in children after related or unre lated BMT. This study also demonstrates that adoptive immunotherapy with sm all numbers of unirradiated donor leukocytes can be associated with rapid r estoration of CD3(+), CD4(+), and CD8(+) T-cell numbers, antigen-specific T -cell responses, and resolution of CMV- and EBV-associated disease after un related TCD BMT. (C) 1999 by The American Society of Hematology.