Depletion of T-lymphocytes in donor marrow with pan-T monoclonal antibodies and complement for prevention of acute graft-versus-host disease: a pilot study on 29 patients.

A cooperative study was done on ex vivo treatment of bone marrow for the prevention of acute graft-versus-host disease (GvHD), in which either CD2-CD5-CD7 (14 patients) or CD2-CD3 (15 patients) monoclonal antibody cocktail and complement were used. In this study, 29 patients (12 female, 17 male; average age, 22-1/2 yr) received T-cell-depleted allograft through complement cytolysis, 26 from HLA-identical donors and 3 from HLA-mismatched donors. All of the patients had malignant disease with poor prognosis; 21 had acute leukemia, 7 had chronic granulocytic leukemia, and 1 had multiple myeloma. After bone marrow transplantation (BMT), GvHD prophylaxis was maintained in 12 patients (group 1), was stopped at day 11 in 6 patients (group 2), and was not administered to 11 patients (group 3). The treatment removed 92.65 +/- 5.36% of donor bone marrow T-cells with one round of complement lysis. Of 3 patients who received mismatched transplant, 2 did not achieve engraftment. Engraftment was achieved in all of the patients who had matched BMT. Two patients had acute GvHD, 1 with grade 2 in group 1, and 1 with grade 3 in group 3. No patient has developed chronic GvHD; for 9 patients, the follow-up is longer than 6 months. Five patients relapsed within 6 months after BMT. Eighteen patients are alive and well in complete remission, with an average follow-up of 7.5, 10.6, and 2.7 months for patients in groups 1, 2, and 3, respectively.