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Arthritis
Volume 2011 (2011), Article ID 765624, 8 pages
http://dx.doi.org/10.1155/2011/765624
Review Article

The Roles of Interleukin-6 in the Pathogenesis of Rheumatoid Arthritis

Product Research Department, Fuji-Gotemba Research Laboratories, Chugai Pharmaceutical Co., Ltd., 1-135 Komakado, Gotemba, Shizuoka 412-8513, Japan

Received 21 December 2010; Revised 15 February 2011; Accepted 22 March 2011

Academic Editor: Burkhard Leeb

Copyright © 2011 Misato Hashizume and Masahiko Mihara. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Several clinical studies have demonstrated that the humanized anti-interleukin-6 (IL-6) receptor antibody tocilizumab (TCZ) improves clinical symptoms and prevents progression of joint destruction in rheumatoid arthritis (RA). However, the precise mechanism by which IL-6 blockade leads to the improvement of RA is not well understood. IL-6 promotes synovitis by inducing neovascularization, infiltration of inflammatory cells, and synovial hyperplasia. IL-6 causes bone resorption by inducing osteoclast formation via the induction of RANKL in synovial cells, and cartilage degeneration by producing matrix metalloproteinases (MMPs) in synovial cells and chondrocytes. Moreover, IL-6 is involved in autoimmunity by altering the balance between Th17 cells and Treg. IL-6 also acts on changing lipid concentrations in blood and on inducing the production of hepcidin which causes iron-deficient anemia. In conclusion, IL-6 is a major player in the pathogenesis of RA, and current evidence indicates that the blockade of IL-6 is a beneficial therapy for RA patients.