ACUTE REJECTION OF MARROW GRAFTS IN PATIENTS TRANSPLANTED FROM A PARTIALLY MISMATCHED RELATED DONOR - CLINICAL AND IMMUNOLOGICAL CHARACTERISTICS

Bone marrow transplantation (BMT) from a partially mismatched related donor (PMRD) provides a treatment option for patients lacking a matche d sibling donor. T lymphocyte depletion of the graft reduces the risk of severe graft-versus-host disease, but may increase the risk of graf t failure. We evaluated the pattern of acute graft rejection in eight patients receiving PMRD BMT with respect to the conditioning therapy, diagnosis, age and sex of donor and recipient, degree of HLA mismatch, and peripheral blood immunophenotype at the time of graft failure. Al l grafts were partially depleted of T lymphocytes. Marrow grafts infus ed into patients who experienced acute rejection did not differ signif icantly in nucleated cell dose, degree of T lymphocyte depletion, T ce ll dose, or CFU-GM/kg infused, from those received by 31 patients who showed durable engraftment. In three of four patients who rejected the ir grafts, and had sufficient peripheral blood cells for immunophenoty ping, a CD3(+)CD8(+) T lymphocyte phenotype was predominant at the tim e of acute rejection. In one patient rejection was associated with a p redominant population of CD3(+)CD4(+) T lymphocytes. Rejection was sig nificantly associated with chronic myelogeneous leukemia and in patien ts mismatched by more than two antigens.