Cytokines, small secreted proteins, have a specific effect on the interactions and communications between cells. They play a pivotal role in the pathogenesis of autoimmune diseases. Factors in the breakdown of self-tolerance and the subsequent events leading to the induction of pathogenic responses remain unclear for most of the autoimmune diseases. Large numbers of studies have revealed a general scheme in which pro-inflammatory cytokines contribute to the initiation and propagation of autoimmune inflammation, whereas anti-inflammatory cytokines facilitate the regression of inflammation and thereby recovery from the disease. The interleukin (IL)-17/IL-23 axis that emerged as the new paradigm has compelled us to critically re-examine the cytokine-driven immune events in the pathogenesis and treatment of autoimmunity. T-helper 17 cells and Regulatory T cells are two lymphocyte subsets with opposing action. In this review, we discuss the mechanism that promotes development of these cells from common precursors and specific factors that impact their cell numbers and function. Also presented are findings that suggest how the equilibrium between pre-inflammatory T helper and regulatory T-cell subsets might be pharmacologically restored for therapeutic benefit, emphasising type-1 diabetes and rheumatoid arthritis. Furthermore, the emerging clinical data showing anti-IL-17 and anti-IL-23 treatments for their efficacy in treating immune-mediated inflammatory diseases are presented.
Keywords: Autoimmune; IL-17; IL-23; NF-κB; cytokines; immunomodulatory.