Background: Granulocyte-macrophage colony stimulating factor (GM-CSF) can affect the treatment of acute non-lymphocytic leukaemia (ANLL) by supporting normal haemopoiesis and by enhancing the proliferation and the maturation of leukaemic cells.
Methods: A human recombinant E. Coli synthesized GM-CSF was administered to 7 patients with ANLL at a dose of 5 or 10 micrograms/kg/day for 7 days, prior to antileukaemic treatment. Peripheral blood neutrophil and blast cell count was monitored daily. Changes in marrow blast cell morphologic features, mitotic index, and the reactivity to a panel of monoclonal antibodies were assessed after 3 and 7 days of treatment.
Results: Peripheral blood neutrophil and blast cell count increased in 6/7 cases. The mitotic index of marrow cells increased in 6/7 cases. A significant maturation occurred along the granulocytic line (2 cases) and the monocytic line (1 case). Mild to moderate eosinophilia developed in 3/7 cases. Early stem cell markers (CD 34 and HLA-DR) were not lost, or actually increased. Myelomonocytic markers (CD 33, CD 13, and CD 14) rose and fell. Expression of the multidrug resistance-associated 170 kd glycoprotein remained stable.
Conclusions: These data showed that in vivo GM-CSF more consistently enhanced the proliferation than the maturation of leukaemic cells.