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 1beta (IL-1beta), 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 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 1% 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.