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Int J Clin Exp Pathol 2013;6(7):1375-1379

Original Article
Pathologic finding of increased expression of interleukin-17 in the synovial tissue of
rheumatoid arthritis patients

Ning Li, Jun C Wang, Tong H Liang, Ming H Zhu, Jia Y Wang, Xue L Fu, Jie R Zhou, Song G Zheng, Paul Chan, Jie Han

Department of Rheumatology, Shanghai East Hospital, Tongji University, Shanghai, China; Department of Pathology, Shanghai East Hospital,
Tongji University, Shanghai, China; Division of Rheumatology and Clinical Immunology, Department of Medicine, Taipei City Hospital-Heping
Fuyoo Branch, Taipei, Taiwan; Department of Pathology, Shanghai Chang Hai Hospital, The Second Army Medical College, Shanghai, China;
Division of Rheumatology & Immunology, Department of Medicine, University of Southern California, California, USA; Department of Medicine,
Wan Fang Hospital, Taipei Medical University, Taipei City, Taiwan. Equal contributors.

Received April 24, 2013; Accepted May 21, 2013; Epub June 15, 2013; Published July 1, 2013

Abstract: Rheumatoid arthritis (RA) is a common autoimmune disease of chronic systemic inflammatory disorder that will affect multiple
tissues and organs such as skin, heart or lungs; but it principally attacks the joints, producing a nonsuppurative inflammatory and proliferative
synovitis that often progresses to major damaging of articular cartilage and joint ankylosis. Although the definite etiology is still unknown, recent
studies suggest that T-helper cells (Th17) may play a pivotal role in the pathogenesis of RA. And interleukin-17 (IL-17), which is a cytokine of
Th17 cells, may be a key factor in the occurrence of RA. The binding of IL-17 to specific receptor results in the expression of fibroblasts,
endothelial and epithelial cells and also synthesis of several major factors such as tumor necrosis factor alpha (TNF-α), IL-1β that result in the
structural damage of RA joints. Though some previous studies have shown that IL-17 exists in the synovium of RA, few has definite proof
quantitatively by pathology about its existence in synovial membrane. This study comprised of 30 RA patients and 10 healthy control, pathologic
study of the synovial membrane showed increased expression of IL-17 in the synovial tissue of RA patients, the intensity is compatible with
clinical severity of disease as validated by DAS28 score and disease duration. Northern blot study also confirmed the increased expression of
IL-17 in the synovial tissues. This study sheds further light that IL-17 may be a key factor in the pathogenesis of RA and a determinant of
disease severity. (IJCEP1304032).

Keywords: Rheumatoid arthritis, interleukin-17, synovitis

Address correspondence to: Dr. Jie Han, Department of Rheumatology, Shanghai East Hospital, Tongji University, 150, Ji Mo Road,
Shanghai, China 200120. E-mail: hjgj85528@163.com; Dr. Paul Chan, Department of Medicine, Wan Fang Hospital, Taipei Medical University,
111, Hsing-Lung Road, Section 3, Wen-Shan District, Taipei City, Taiwan 116. E-mail: chanpaul@w.tmu.edu.tw