RT Journal Article
SR Electronic
T1 Expression of interferon β in synovial tissue from patients with rheumatoid arthritis: comparison with patients with osteoarthritis and reactive arthritis
JF Annals of the Rheumatic Diseases
JO Ann Rheum Dis
FD BMJ Publishing Group Ltd and European League Against Rheumatism
SP 1780
OP 1782
DO 10.1136/ard.2005.040477
VO 64
IS 12
A1 J van Holten
A1 T J M Smeets
A1 P Blankert
A1 P P Tak
YR 2005
UL http://ard.bmj.com/content/64/12/1780.abstract
AB Background: IFNβ may have immunomodulatory effects in rheumatoid arthritis (RA) and its increased production in RA synovium may be a reactive attempt to inhibit inflammation.Objective: To determine the expression of IFNβ in the synovial tissue of patients with RA, osteoarthritis, and reactive arthritis.Methods: Synovial biopsy specimens were obtained by arthroscopy from patients with RA and disease controls for immunohistological analysis using a monoclonal antibody specific for IFNβ. Bound antibody was detected by an immunoperoxidase method. Stained sections were evaluated by computer assisted image analysis. Double stainings were performed with antibodies to detect CD55 positive fibroblast-like synoviocytes (FLS), CD68 positive macrophages, and CD83 positive dendritic cells (DCs) coexpressing IFNβ.Results: IFNβ protein was abundantly expressed in the synovium of patients with RA. Digital image analysis showed a significant increase in the mean integrated optical density for IFNβ expression in RA synovial tissue compared with disease controls. Specific up regulation of IFNβ expression was also seen when the results were controlled for cell numbers. Phenotypic analysis showed that FLS, especially, but also macrophages and DCs may express IFNβ in RA synovial tissue.Conclusions: The increased expression of IFNβ in RA synovium suggests activation of an immunomodulatory mechanism that could inhibit synovial inflammation.