IL-6 and inflammatory diseases

Abstract

Interleukin-6 (IL-6) is a multifunctional cytokine that plays key roles not only in the immune system but also in a variety of biological processes. It is a primary regulator of both acute and chronic inflammations. Moreover, it has proven an excellent target for clinical treatment, as the anti-IL-6 receptor antibody has been successfully used against autoimmune disorders such as rheumatoid arthritis, juvenile idiopathic arthritis, and Castleman’s disease. In fact, it could be argued that IL-6 is the best example of basic cytokine research extending into clinical application. Here, we summarize IL-6 and its biological functions, with particular emphasis on inflammation and chronic inflammatory diseases, and a recently discovered inflammation control mechanism, the inflammation amplifier (formerly known as the IL-6 amplifier). We also describe a recent finding that indicates neural stimulations can modulate the activation of the inflammation amplifier at local blood vessels, creating a gate for the influx of immune cells into the central nervous system, which suggests the entry of immune cells into target organs can be artificially manipulated by local neural stimulation.