[Hematopoietic growth factors and anti-infective respiratory defenses]

Colony-Stimulating Factors (CSFs) are a family of glycoproteins that are required for the proliferation and differentiation of hematopoietic progenitor cells. Among these factors, G-CSF and GM-CSF are principally involved in the production of neutrophils. They have been demonstrated to be effective in correcting neutropenia during cytotoxic chemotherapy or bone marrow transplantations. Beside their hematopoietic action, recent data indicate that G-CSF and GM-CSF also have stimulatory effects on mature neutrophils function. The functional properties of neutrophils that are enhanced by G-CSF and GM-CSF are those related primarily to the host's defense against microorganisms. For Gm-CSF those stimulatory effects also concern the macrophages. Investigations of several animal models of severe bacterial infection and specially pneumonia have indicated that exogenous recombinant G-CSF or GM-CSF can significantly enhance host defenses and improve rates of survival. Trials of recombinant G-CSF in combination with antibiotics for the treatment of severe pneumonia in noneutropenic patients have recently been initiated. First results confirm the good tolerance of recombinant G-CSF. Further prospective studies are required to determine the effectiveness and the conditions of administration of G-CSF and GM-CSF in this indication.