DIFFERENCES IN SYNOVIAL-FLUID CYTOKINE LEVELS BETWEEN JUVENILE AND ADULT RHEUMATOID-ARTHRITIS

Objective. To evaluate quantitative or qualitative differences in syno vial fluid (SF) cytokine levels among patients with systemic juvenile rheumatoid arthritis (JRA), antinuclear antibody positive pauciarticul ar JRA, or adult RA. Methods. SF levels of interleukin 1 alpha(IL-1 al pha), IL-1 beta, IL-1 receptor antagonist (IL-1Ra) IL-11, tumor necros is factor-alpha (TNF-alpha), soluble TNF receptor 1 (sTNFR1), leukemia inhibitory factor (LIF), all measured by immunoassays, and of IL-6, m easured with a bioassay using B9 cells, were evaluated in 11 patients with systemic JRA, 24 with pauciarticular TRA, and 22 adult patients w ith RA. Results. SF IL-6 levels were significantly higher in patients with systemic JRA than patients with pauciarticular JRA (p = 0.003) or RA(p = 0.002). IL-1 alpha was detectable in 12/24 SF samples from pau ciarticular JRA, in 2/22 SF from RA, and in no sample from systemic JR A (p = 0.004 vs RA; p = 0.005 vs systemic JRA). SF IL-11 levels were s ignificantly higher in patients with RA than patients with systemic JR A (p = 0.012) or pauciarticular JRA (p = 0.005). We found no significa nt differences in SF levels of IL-1 beta, IL-1Ra, TNF-alpha, sTNFR1, o r LIF. Conclusion. In systemic JRA, SF levels of IL-6 are significantl y higher than in pauciarticular JRA or in RA; IL-1 alpha is present in a significant proportion of patients with pauciarticular JRA, but not in those with RA or systemic JRA.