RESUMEN
Bone marrow granulocytic-macrophagal precursors (GMP) and fibroblastic precursors (FP) were measured in 235 children with acute lymphoblastic leukemia (ALL) receiving polychemotherapy (PCT) in progression of the disease. A total of 408 culture investigations were conducted. PCT proved to exert different effects on hemopoiesis during the first acute ALL period and remission. In the former period the target for PCT were blast cells, the course of induction therapy increased the number of GMP, FP and early granulocytic cells. In recurrent ALL the sensitivity of GMP to PCT grew, while FP remained intact. PCT performed in remission resulted in gradual suppression of granulocytopoiesis, GMP beginning from the second remission year. The treatment discontinuation on remission year 3-5 produced enhancement of granulocytosis by all parameters.