Erythropoietin and myeloid colony stimulating factors.

The production of blood cells in the body is controlled by at least 20 polypeptide growth factors. Most of these factors have been cloned and many expressed in bacterial and eukaryotic systems to give biologically active proteins. Currently, these recombinant human proteins are undergoing intensive evaluation for their use in treating primary haemopoietic diseases, or stimulating normal haemopoiesis following drug-, radiation- or virus-induced trauma of the bone marrow. Erythropoietin (EPO) and the myeloid colony stimulating factors (IL-3, G-CSF, GM-CSF and M-CSF) were among the first to be cloned and expressed.