COLONY-STIMULATING FACTORS AND RESPIRATOR Y DEFENSES AGAINST INFECTION

Colony-Stimulating Factors (CSFs) are a family of glycoproteins that a re required for the proliferation and differentiation of hematopoietic progenitor cells. Among these factors, G-CSF and GM-CSF are principal ly involved in the production of neutrophils. They have been demonstra ted to be effective in correcting neutropenia during cytotoxic chemoth erapy or bone marrow transplantations. Beside their hematopoietic acti on, recent data indicate that G-CSF and GM-CSF also have stimulatory e ffects on mature neutrophils function. The functional properties of ne utrophils that are enhanced by G-CSF and GM-CSF are those related prim arily to the host's defense against microorganisms. For Gm-CSF those s timulatory effects also concern the macrophages. Investigations of sev eral animal models of severe bacterial infection and specially pneumon ia have indicated that exogenous recombinant G-CSF or GM-CSF can signi ficantly enhance host defenses and improve rates of survival. Trials o f recombinant G-CSF in combination with antibiotics for the traitement of severe pneumonia in nonneutropenic patients have recently been ini tiated. First results confirm the good tolerance of recombinant G-CSF. Further prospective studies are required to determine the effectivene ss and the conditions of administration of G-CSF and GM-CSF in this in dication.