Research article

Synovial fluid leukocyte apoptosis is inhibited in patients with very early rheumatoid arthritis

Karim Raza^1,2 , Dagmar Scheel-Toellner¹ , Chi-Yeung Lee³ , Darrell Pilling⁴ , S John Curnow¹ , Francesco Falciani⁵ , Victor Trevino⁵ , Kanta Kumar^1,2 , Lakhvir K Assi¹ , 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

³Department of Radiology, City Hospital, Sandwell and West Birmingham Hospitals NHS Trust, Birmingham, UK

⁴Department of Biochemistry and Cell Biology, Rice University, Houston, Texas, USA

⁵School of Biosciences, The University of Birmingham, Birmingham, UK

author email corresponding author email

Arthritis Research & Therapy 2006, 8:R120doi:10.1186/ar2009

Published:	19 July 2006

Abstract

Synovial leukocyte apoptosis is inhibited in established rheumatoid arthritis (RA). In contrast, high levels of leukocyte apoptosis are seen in self-limiting crystal arthritis. The phase in the development of RA at which the inhibition of leukocyte apoptosis is first apparent, and the relationship between leukocyte apoptosis in early RA and other early arthritides, has not been defined. We measured synovial fluid leukocyte apoptosis in very early arthritis and related this to clinical outcome. Synovial fluid was obtained at presentation from 81 patients with synovitis of ≤ 3 months duration. The percentages of apoptotic neutrophils and lymphocytes were assessed on cytospin preparations. Patients were assigned to diagnostic groups after 18 months follow-up. The relationship between leukocyte apoptosis and patient outcome was assessed. Patients with early RA had significantly lower levels of neutrophil apoptosis than patients who developed non-RA persistent arthritis and those with a resolving disease course. Similarly, lymphocyte apoptosis was absent in patients with early RA whereas it was seen in patients with other early arthritides. The inhibition of synovial fluid leukocyte apoptosis in the earliest clinically apparent phase of RA distinguishes this from other early arthritides. The mechanisms for this inhibition may relate to the high levels of anti-apoptotic cytokines found in the early rheumatoid joint (e.g. IL-2, IL-4, IL-15 GMCSF, GCSF). It is likely that this process contributes to an accumulation of leukocytes in the early rheumatoid lesion and is involved in the development of the microenvironment required for persistent RA.