Objective: Neutrophils have been shown to produce interleukin-8 (IL-8) and interleukin-1 receptor antagonist (IL-1ra) in large amounts compared with other cytokines. Since IL-8 has a proinflammatory action whereas IL-1ra is antiinflammatory, our objective was to examine the relative levels of production of these cytokines by synovial fluid (SF) neutrophils isolated from patients with rheumatoid arthritis (RA).
Methods: We measured cytokine production using an enzyme-linked immunosorbent assay and analyzed messenger RNA accumulation in cells by Northern blot.
Results: SF neutrophils produced significantly more IL-8 and IL-1 beta, but significantly less IL-1ra, than peripheral blood neutrophils.
Conclusion: These observations provide new information on the production of pro- and antiinflammatory molecules by neutrophils in the SF environment, and their possible role in RA.