The expression of IFN-β in synovial tissue from rheumatoid arthritis patients compared to osteoarthritis and reactive arthritis patients
© BioMed Central Ltd 2002
Received: 15 January 2002
Published: 4 February 2002
IFN-β may have anti-inflammatory effects in rheumatoid arthritis (RA) patients through inhibition of the production of proinflammatory cytokines like TNF-α. Increased IFN-β production in RA synovium could represent a reactive attempt to inhibit the inflammatory cascade. The aim of this study was to determine the expression of IFN-β in synovial tissue of patients with RA, osteoarthritis (OA), and reactive arthritis (ReA).
Synovial biopsy specimens were obtained by needle arthroscopy from 15 RA patients, 10 patients with inflammatory osteoarthritis (OA), and 5 patients with reactive arthritis (ReA). Immunohistologic analysis was performed using a monoclonal antibody specific for IFN-β (PBL). Bound antibody was detected according to a 3-step immunoperoxidase method. Stained sections were evaluated by computer-assisted image analysis.
IFN-β was abundantly expressed in the synovial tissue of RA patients, especially by fibroblast-like synoviocytes. Digital image analysis using a standardized program revealed a statistically significant increase in the mean integrated optical density for IFN-β expression in RA synovial tissue compared with controls (RA 1900 ± 514 vs. OA 447 ± 171, and ReA 358 ± 195) (P < 0.04). The specific upregulation of IFN-β expression was also observed when the results were controlled for cell numbers (P < 0.02).
The increased expression of IFN-β in RA synovium suggests activation of an immunomodulatory mechanism that could inhibit synovial inflammation.