Clinical pilot study of a cytotoxic antiserum in myeloblastic leukemia

A large dose of equine antilymphocytic globulin (ALG, 120 mg/kg/day) was given intravenously to four patients with myeloblastic leukemia. Leukemic myeloblasts from each patient were lysed by the ALG in vitro, in the presence of the same patient's serum complement. In each patient, ALG infusion was followed by a reduction in the count of circulating leukemic myeloblasts, and a fall in the serum levels of C3 and C4 complement. It is likely that complement-mediated lysis of circulating leukemic myeloblasts occurred in these patients, as a result of ALG administration.