Dose dependent and additive effects of IL-1β and tumour necrosis factor (TNF)-α on IL-1 receptor antagonist (IL-1Ra) secretion in the presence of A77 1726 in human synovial fibroblasts

<p><b>Copyright information:</b></p><p>Taken from "The active metabolite of leflunomide, A77 1726, increases the production of IL-1 receptor antagonist in human synovial fibroblasts and articular chondrocytes"</p><p>Arthritis Research & Therapy 2004;6(3):R181-R189.</p><p>Published online 19 Feb 2004</p><p>PMCID:PMC416438.</p><p>Copyright © 2004 Palmer et al., licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL.</p> Human osteoarthritis (OA) synovial fibroblasts (passage 4) were stimulated with various doses of IL-1β, or various doses of TNF-α or with 0.25 ng/ml IL-1β and 1 ng/ml TNF-α together, in the absence (open symbols) or presence (closed symbols) of 100 μmol/l A77 1726, for 48 hours. A77 1726 was added 2 hours before stimulation with IL-1β. IL-1Ra concentrations in culture supernatants were measured using ELISA. Results are represented as means ± SEM of three determinations in a representative experiment. Similar results were obtained with cells from three different donors (three OA samples). *< 0.05 versus control; < 0.05 versus cytokines without A77 1726.