Research article

Early rheumatoid arthritis is characterized by a distinct and transient synovial fluid cytokine profile of T cell and stromal cell origin

Karim Raza^1,2 , Francesco Falciani³ , S John Curnow¹ , Emma J Ross¹ , Chi-Yeung Lee⁴ , Arne N Akbar⁵ , Janet M Lord¹ , Caroline Gordon^1,2 , Christopher D Buckley^1,2 and Mike Salmon¹

¹MRC Centre for Immune Regulation, Division of Immunity and Infection, The University of Birmingham, Birmingham, UK

²Department of Rheumatology, City Hospital, Sandwell and West Birmingham Hospitals NHS Trust, Birmingham, UK

³School of Biosciences, The University of Birmingham, Birmingham, UK

⁴Department of Radiology, City Hospital, Sandwell and West Birmingham Hospitals NHS Trust, Birmingham, UK

⁵Department of Immunology and Molecular Pathology, Royal Free and University College Medical School, London, UK

author email corresponding author email

Arthritis Research & Therapy 2005, 7:R784-R795doi:10.1186/ar1733

Published:	7 April 2005

Abstract

Pathological processes involved in the initiation of rheumatoid synovitis remain unclear. We undertook the present study to identify immune and stromal processes that are present soon after the clinical onset of rheumatoid arthritis (RA) by assessing a panel of T cell, macrophage, and stromal cell related cytokines and chemokines in the synovial fluid of patients with early synovitis. Synovial fluid was aspirated from inflamed joints of patients with inflammatory arthritis of duration 3 months or less, whose outcomes were subsequently determined by follow up. For comparison, synovial fluid was aspirated from patients with acute crystal arthritis, established RA and osteoarthritis. Rheumatoid factor activity was blocked in the synovial fluid samples, and a panel of 23 cytokines and chemokines measured using a multiplex based system. Patients with early inflammatory arthritis who subsequently developed RA had a distinct but transient synovial fluid cytokine profile. The levels of a range of T cell, macrophage and stromal cell related cytokines (e.g. IL-2, IL-4, IL-13, IL-17, IL-15, basic fibroblast growth factor and epidermal growth factor) were significantly elevated in these patients within 3 months after symptom onset, as compared with early arthritis patients who did not develop RA. In addition, this profile was no longer present in established RA. In contrast, patients with non-rheumatoid persistent synovitis exhibited elevated levels of interferon-γ at initiation. Early synovitis destined to develop into RA is thus characterized by a distinct and transient synovial fluid cytokine profile. The cytokines present in the early rheumatoid lesion suggest that this response is likely to influence the microenvironment required for persistent RA.