IL-6: a cytokine at the crossroads of autoimmunity.

IL-6 is implicated in the development and progression of autoimmune diseases in part by influencing CD4 T cell lineage and regulation. Elevated IL-6 levels drive inflammation in a wide range of autoimmune diseases, some of which are also characterized by enhanced T cell responses to IL-6. Notably, the impact of IL-6 on inflammation is contextual in nature and dependent on the cell type, cytokine milieu and tissue. Targeting the IL-6/IL-6R axis in humans has been shown to successfully ameliorate a subset of autoimmune conditions. In this review, we discuss recent studies investigating how IL-6 regulates the CD4 T cell response in the context of autoimmune disease and highlight how blocking different aspects of the IL-6 pathway is advantageous in the treatment of disease.