Interleukin-6 as a therapeutic target in candidate inflammatory diseases.

Interleukin (IL)-6 is a multifunctional cytokine that regulates immune response, inflammation, and hematopoiesis. Although IL-6 plays several important physiological roles, deregulated overproduction of IL-6 causes various clinical symptoms and abnormalities in laboratory test results. Overproduction of IL-6 has been shown to underlie a number of autoimmune and inflammatory diseases, including rheumatoid arthritis (RA), systemic-onset juvenile idiopathic arthritis (soJIA), and Castleman's disease, as well as malignancies such as multiple myeloma and mesothelioma. Blocking of IL-6 signaling may be therapeutic in diseases characterized by pathological IL-6 overproduction. This review provides an overview of IL-6 as a therapeutic target in candidate inflammatory diseases.