Natural killing and antibody-dependent cytotoxicity by T leukaemic blasts from acute lymphoblastic leukaemia

Bone marrow T leukaemic blasts from four patients with T-cell acute lymphoblastic leukaemia (ALL) were examined as effectors in natural killing (NK) and antibody-dependent cytotoxicity (ADCC). T leukaemic blasts demonstrated both Nk (against K-562 cells as targets) and ADCC (against chicken erythrocytes (CRBC) and cells of SB cell line as targets). NK activity and ADCC (against SB cells) were comparable to NK and ADCC (against SB cells) of peripheral blood T cells from healthy controls. ADCC against CRBC by leukaemic blasts was lower than that of peripheral T cells from normal controls. Of leukaemic blasts 20-42% possessed IgG Fc receptors. This study demonstrates that T leukaemic blasts are effectors in NK and ADCC assays.