Prominent expression of mRNA for proinflammatory cytokines in synovium in patients with juvenile rheumatoid arthritis or chronic Lyme arthritis.

Objective. To examine the cytokine profiles in synovium of patients with juvenile rheumatoid arthritis (JRA) or Lyme arthritis, 2 chronic inflammatory arthritides that affect children. Methods. We used in situ hybridization with specific riboprobes to determine the expression of mRNA for proinflammatory or antiinflammatory cytokines in synovial samples from 5 patients with early. untreated JRA, 15 patients with late, treated JRA, and 9 patients with chronic Lyme arthritis. For comparison, synovia were examined from 6 patients with rheumatoid or psoriatic arthritis, and from 9 patients with various orthopedic conditions. Results. Among the children with early, untreated JRA, a median of 3 to 8% of inflammatory cells in synovial samples expressed mRNA for the proinflammatory cytokines interleukin 1β (IL-1β), tumor necrosis factor-α (TNF-α), or interferon-γ (IFN-γ). Although a median of 3.9% of the cells expressed mRNA for the antiinflammatory cytokine IL-10, none had IL-4 mRNA. Most of the patients with late, treated JRA, chronic Lyme arthritis, rheumatoid, or psoriatic arthritis had mRNA for each of these proinflammatory cytokines in about 1% of the cells, whereas mRNA for the antiinflammatory cytokines was less frequent. The inflammatory cell density was much less in the synovium of patients with various orthopedic conditions, but about I % of the infiltrating cells expressed mRNA for at least one of the proinflammatory cytokines. Conclusion. Patients with early or late JRA or chronic Lyme arthritis have expression of mRNA in synovial tissue primarily for proinflammatory cytokines, with less expression of antiinflammatory cytokines.