Lymphocyte function after autologous bone marrow transplantation (BMT): a comparison with patients treated with allogeneic BMT and with chemotherapy only.

T- and B-cell function after autologous bone marrow transplantation (ABMT) was assessed and compared with that found after allogeneic BMT and after chemotherapy only. In all 16 patients with acute leukaemia in remission treated with high-dose chemotherapy and single or double ABMT, T-helper numbers and function in an assay measuring PWM-induced Ig synthesis were grossly defective and closely resembled the defects observed after allo-BMT involving chemoradiotherapy (six patients). T-helper activity was more variable after chemotherapy only (eight patients), but in individual patients the defect was as great as that observed after BMT. In contrast, suppressor activity was comparably increased in all patient groups and increased numbers of Leu 15+ Dr+ Tac- suppressor T cells were consistently observed, suggesting chronic activation of suppressor T cells, the cause of which remains unknown. B-cell function was also uniformly impaired in all patients tested. It is therefore concluded that defective immune function after BMT is not due to alloimmune or radiotherapy-mediated effects. Furthermore, since many patients were studied a prolonged period after BMT and had no T cells with a thymic phenotype and no evidence of infection, it is unlikely that the defects are secondary to cellular immaturity following marrow regeneration or to superadded infection. The gross immune defects observed after various forms of BMT are likely, therefore, to be directly attributable to the chemotherapy involved.