Spondyloarthropathy and rheumatoid arthritis: two different diseases, a similar cytokine network

Introduction

The reasons for the phenotypic differences between spondyloarthritis (SpA) and rheumatoid arthritis (RA) are still unclear. Slight divergences in the cytokine networks might contribute to this and may be the key to new treatment approaches.

Aim

The main goal of this work was to compare serum and synovial cytokines and chemokines in established SpA and RA patients.

Patients and methods

IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12 (p70), IL-17A, IL-18, IL-21, IL-22, IL-23, IFN-γ, MCP-1, MIP-1α, OPG, sRANKL, TGF-β, TNF, APRIL and BAFF levels were measured in SpA (n=8) serum and compared with RA (n=10) and controls (n=24). Synovial fluid (SF) from SpA (n=8), RA (n=12) and osteoarthritis (OA) (n=10) patients were also analyzed.

Results

No significant differences were found between SpA and RA, with the exception of higher levels of IL-21 in the SF of RA patients.

Conclusions

Our results suggest that although SpA and RA are chronic inflammatory diseases with different clinical manifestations, both share a similar cytokine profile, including Th17-related cytokines.