Preliminary clinical trial of autologous bone marrow transplantation after in vitro monoclonal antibody and complement treatments in null cell-type acute lymphocytic leukemia.

Autologous bone marrow transplantation (BMT) in null cell-type acute lymphocytic leukemia (Null-ALL) was carried out after depletion of leukemia cells from transplanted bone marrow. Patients' autologous bone marrow cells were harvested during remission and treated in vitro with complement and three monoclonal antibodies (NL-1, NL-22 and HL-47) reactive to Null-ALL cells, and then cryopreserved. Three patients were transplanted with the antibody-treated bone marrow cells during the first remission period after preconditioning with intensive chemotherapy and total body irradiation, while transplantations in two other patients, who were in poor clinical condition, were done during the fourth remission period and the third relapse, respectively. Good preservation of hematopoietic stem cells after antibody treatment and cryopreservation of bone marrow cells was demonstrated in all five cases studied. Clinically, prompt recovery of white blood cells and platelets was observed in the three patients who received BMT during the first remission period; two of them have continued remission (2 and 15 months), while the other relapsed after 7 months of remission. these results suggested that autologous BMT with these three antibodies may be an effective mode of therapy for Null-ALL patients.