Autologous bone-marrow transplantation in CALLA-positive acute lymphoblastic leukemia after in-vitro treatment with J5 monoclonal antibody and complement.

A monoclonal antibody (J5) specific for the common acute-lymphoblastic-leukaemia antigen (CALLA) was used for in-vitro pre-treatment of bone-marrow before autologous transplantation in four patients with CALLA-positive acute lymphoblastic leukaemia (ALL) in relapse, who did not have HLA-compatible donors. After remission induction and intensification, bone-marrow cells were harvested, treated with J5 antibody and rabbit complement, and cryopreserved in liquid nitrogen. Patients received ablative chemotherapy and total-body irradiation before reinfusion of autologous J5-treated bone marrow. The transplantation protocol was well tolerated, and engraftment of normal myeloid cells occurred in all for patients. Two patients have continued in unmaintained remission with complete haematopoietic reconstitution for more than 1 year after autologous transplantation.