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BioMed Research International
Volume 2013 (2013), Article ID 607137, 9 pages
Clinical Study

Serum Proteome Analysis in Patients with Rheumatoid Arthritis Receiving Therapy with Tocilizumab: An Anti-Interleukin-6 Receptor Antibody

1Institute for Environmental and Gender Specific Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Tomioka, Urayasu-shi, Chiba 279-0021, Japan
2Department of Internal Medicine, Juntendo University Urayasu Hospital, 2-1-1 Tomioka, Urayasu-shi, Chiba 279-0021, Japan
3Department of Internal Medicine and Rheumatology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
4Department of Rheumatology, Kohnodai Hospital, National Center for Global Health and Medicine, 1-7-1 Kohnodai, Ichikawa-shi, Chiba 272-8516, Japan

Received 26 April 2013; Accepted 17 July 2013

Academic Editor: Vinod Chandran

Copyright © 2013 Mitsuaki Yanagida et al. 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.


Rheumatoid arthritis (RA) is a chronic inflammatory disorder of the synovial membrane that results in the destruction of bone and cartilage in affected joints. Tocilizumab is a biological agent and an anti-interleukin-6 (IL-6) receptor monoclonal antibody that blocks IL-6-mediated inflammatory processes in RA patients. In order to identify novel disease-related proteins and candidate biomarkers, we analyzed the changes in the serum proteome profiles of patients with RA who were treated with tocilizumab. Serum samples were collected from the RA patients before and after tocilizumab treatment. Following immunodepletion of major proteins, the proteins were digested and labeled with isobaric tag, iTRAQ reagent. The proteins were identified and quantified using liquid chromatography-tandem mass spectrometry. Among a total of 311 proteins identified, seven were decreased and 16 were increased by tocilizumab treatment. Although some of the proteins are known to be related to RA, several are currently unknown with respect to their relationship to RA and may be involved in the development of this disease. This study is the first to perform a comparative serum proteomic analysis of RA patients treated with tocilizumab. Our results may contribute to the identification of novel disease-related proteins and enhance the understanding of the pathogenesis of RA.