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 ju venile rheumatoid arthritis (JRA) or Lyme arthritis, 2 chronic inflammatory arthritides that affect children. Methods. We used in situ hybridization with specific riboprobes to determin e chi: 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 co mparison, synovia were examined from 6 patients with rheumatoid or psoriati c 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 proinflamm atory cytokines interleukin 1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF alpha), or interferon-gamma (IFN-gamma). 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 arthr itis, rheumatoid, or psoriatic arthritis had mRNA for each of these proinfl ammatory cytokines in about 1% of the cells, whereas mRNA for the antiinfla mmatory cytokines was less frequent. The inflammatory cell density was much less in the synovium of patients with various orthopedic conditions, but a bout 1% of the infiltrating cells expressed mRNA for at least one of the pr oinflammatory cytokines. Conclusion. Patients with early or late JRA or chronic Lyme arthritis have expression of mRNA in synovial tissue primarily for proinflammatory cytokin es, with less expression of antiinflammatory cytokines.