Antibody-dependent cellular cytotoxicity of leukaemic blast cells and neutrophils from patients with acute myelogenous leukaemia.

The antibody-dependent cellular cytotoxicity against ox erythrocytes by blast cells and neutrophils from six patients with acute myelogenous leukaemia and one patient with blast crisis of chronic myelogenous leukaemia was studied. Leukaemic myeloblastic and monocytic cells behaved like potent killer cells toward ox erythrocytes and their activity was comparable with that of neutrophils from leukaemic and normal subjects. The target cell destruction was positively related to the effector cell: target cell ratio and was clearly antibody-dependent since the cytotoxic effect did not involve antibody-unsensitized erythrocytes. We suggest that this experimental system, which involves the use of ox erythrocytes sensitized by purified rabbit anti-ox IgG, provides a new and sensitive method for studying antibody-dependent cellular cytotoxicity by myeloid cells.