Figure 1.

The pleiotropic effects of IL-6

IL-6, which consists of a four-helix bundle, is a master cytokine that exerts various biological effects. In addition to driving inflammation, fever, cytokinaemia, and tumorigenesis, IL-6 regulates metabolism, bone turnover, and haematopoiesis, and is essential for innate and adaptive immunity. In the liver, IL-6 contributes to tissue regeneration, lipid balance, and induction of the acute-phase response. This cytokine also promotes macrophage polarisation from the pro-inflammatory M1 state to an anti-inflammatory M2 phenotype and is required for the proliferation of the intestinal epithelium. IL-6=interleukin-6. RANKL=receptor activator of nuclear factor-κB ligand. VEGF=vascular endothelial growth factor.