IL‐6: Regulator of Treg/Th17 balance

IL-6 is a pleiotropic cytokine involved in the physiology of virtually every organ system. Recent studies have demonstrated that IL-6 has a very important role in regulating the balance between IL-17-producing Th17 cells and regulatory T cells (Treg). The two T-cell subsets play prominent roles in immune functions: Th17 cell is a key player in the pathogenesis of autoimmune diseases and protection against bacterial infections, while Treg functions to restrain excessive effector T-cell responses. IL-6 induces the development of Th17 cells from naïve T cells together with TGF-beta; in contrast, IL-6 inhibits TGF-beta-induced Treg differentiation. Dysregulation or overproduction of IL-6 leads to autoimmune…