Colony stimulating factors and hemopoiesis.

Work in the past twenty years has led to the discovery of multiple families of hemopoietic growth factors that regulate the production and functional activity of the various subsets of blood cells. For granulocyte-monocyte populations, four such regulators (the colony stimulating factors GM-CSF, G-CSF, M-CSF and Multi-CSF) have been shown to interact to regulate these populations. Each has been purified, cDNA's for each have been cloned and mass-produced recombinant CSF's are becoming available for clinical use. Initial trials indicate that the CSF's will be valuable agents in stimulating hemopoiesis either following chemotherapy or marrow transplants or in stimulating resistance to life-threatening infections. CSF's play an important role in the development of myeloid leukemia but curiously can suppress myeloid leukemic populations because of their differentiation-inducing actions. However, it is still unclear whether the CSF's will prove of value in the management of particular myeloid leukemias.