GMCSF: More an Inflammatory Immune 'Cytokine' Than a Growth Factor

GMCSF, discovered in 1977, was one of the first growth factors for myelopoiesis. However, over time, it has been found to be redundant for basal myelopoiesis. Rather, its important function seems to be its effect on mature myeloid cells and the immune system. It is produced by a variety of cells, including macrophages, endothelial cells, T-cells etc. and works on the GMCSF receptor, which is mainly expressed by mature myeloid cells such as neutrophils, monocytes and macrophages. It has been found to be an important mediator of at least two autoimmune diseases: rheumatoid arthritis and multiple sclerosis. Animal models prove that GMCSF produced from T-cells play a crucial role in their pathogenesis of both these autoimmune diseases. This has led to the development of therapeutics which target GMCSF or its receptor. Clinical trials have been carried out in rheumatoid arthritis, which have shown modest efficacy. In addition, anti-GMCSF therapy has shown promise in giant cell arteritis.