THE EFFECT OF GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR (RGM-CSF) ON MACROPHAGE FUNCTION IN MICROBIAL DISEASE

The haematopoietic growth factor, GM-CSF, has well-documented stimulat ory effects on monocyte and macrophage functions. These effects includ e enhanced proliferation of their progenitor cells, increased endocyto sis and metabolism of mature cells, increased function as antigen-pres enting cells, and increased inhibition or killing of intracellular fun gi, bacteria, protozoa and viruses. The major effect of GM-CSF on mono cytes and macrophages is to enhance phagocytic and metabolic functions , including increased synthesis of molecules toxic to microbes, and to release other proinflammatory cytokines. This results in inhibition a nd/or killing of Candida albicans, Aspergillus, Cryptococcus, Pneumocy stis, Leishmania, Mycobacteria, as well as other intracellular pathoge ns. GM-CSF also enhances the intracellular effectiveness of antiviral and antibacterial drugs. Viral replication may be increased in activat ed cells, therefore, when GM-CSF is used, a combination with appropria te antiviral drugs is recommended. Several reports in patients of succ essful management of microbial diseases which depend on macrophage fun ction are now reviewed. These reports support the clinical value of GM -CSF in the management of patients with cancer and chemotherapy relate d monocyte/macrophage dysfunction and presumed or documented microbial disease.