Fourteen patients with T-cell-derived leukemia and lymphoma underwent high-dose chemoradiotherapy and anti-T-cell monoclonal antibody-treated autologous bone marrow transplantation (ABMT). All patients were either in sensitive relapse or had adverse prognostic features, and five patients had a history of bone marrow involvement with disease. Patients received a median of 2 (1 to 3) prior chemotherapy regimens; 10 patients received local radiotherapy. After high-dose ablative therapy, greater than 500/mm3 granulocytes and greater than 20,000 untransfused platelets/mm3 were noted at a median of 23 (13 to 48) and 26 (15 to 43) days post-ABMT, respectively. Natural killer (NK) cells, T cells (predominantly T8+), and monocytes were noted within the first 1 to 2 months post-AMBT, as seen in other series. Disease-free survival was a median of 10.1 months, 5.9 months for patients with T acute lymphoblastic leukemia or lymphoblastic lymphoma and 25.6 months for patients with T non-Hodgkin's lymphoma (NHL). Toxicities were common and severe. Thirty-six percent of patients developed bacteremias early post-BMT. Late complications included a skin rash consistent with graft versus host disease; infections with Herpes zoster, hepatitis, and Pneumocystis carinii; and the development of Epstein-Barr virus associated lymphoproliferative syndrome. Our findings suggest that patients who have undergone T-depleted ABMT have a profound immunodeficiency not reflected in the phenotypic reconstitution of the T and NK cells. Characterization of the functional deficiency may facilitate the development of methods to reduce the long-term toxicity of AMBT in these patients.