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Logo of annrheumdAnnals of the Rheumatic DiseasesVisit this articleSubmit a manuscriptReceive email alertsContact usBMJ
Ann Rheum Dis. 2005 December; 64(12): 1780–1782.
Published online 2005 May 5. doi:  10.1136/ard.2005.040477
PMCID: PMC1755294

Expression of interferon ß in synovial tissue from patients with rheumatoid arthritis: comparison with patients with osteoarthritis and reactive arthritis


Objective: To determine the expression of IFNß 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 IFNß. 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 IFNß.

Results: IFNß 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 IFNß expression in RA synovial tissue compared with disease controls. Specific up regulation of IFNß 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 IFNß in RA synovial tissue.

Conclusions: The increased expression of IFNß in RA synovium suggests activation of an immunomodulatory mechanism that could inhibit synovial inflammation.

Figure 1
 IFNß expression in synovium from 17 patients with RA, nine with inflammatory OA, and six with ReA, detected by immunohistochemistry and evaluated by digital image analysis.
Figure 2
 Double staining of RA synovial tissue with (A) CD83 positive dendritic cells (blue) and IFNß (red); (B) CD68 positive macrophages (blue) and IFNß (red); and (C) CD55 positive fibroblasts like synoviocytes (blue) and IFNß ...

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