RESUMEN
Numbers, proliferative potential, and differentiative capacity of bone marrow granulocyte-macrophage precursor cells were studied in 130 children with acute lymphoblastic leukemia [ALL], including 77 children in an acute phase of the disease and 53 in remission. Bone marrow samples from 65 children without hematopoietic abnormalities were used as controls. The numbers of clonogenic precursors were found to be below normal in all phases of ALL, particularly during the acute period when the bone marrow was heavily infiltrated with leukemic cells. It is shown that the decreases in the numbers and proliferative potential of the precursor cells during the acute phases were associated with the effects of leukemic blast cells, but that in remission the observed reduction in the precursor cell pool was due to the cytostatic effect of therapy. The differentiative capacity of clonogenic granulocyte and macrophage precursors was not altered in children with ALL