To determine the pattern of expression of Type 1 and Type 2 cytokines in synovial tissues and fluids (SF) of patients with different forms of juvenile rheumatoid arthritis (JRA) and juvenile spondyloarthropathy (JSpA), and to contrast these with findings in adult patients with RA.
Sixty-three SF mononuclear cell preparations and synovial tissue samples from 50 patients with JRA or JSpA and 7 synovial tissues from patients with adult onset RA were analyzed by reverse transcription polymerase chain reaction for the presence or absence of interleukin 2 (IL-2), tumor necrosis factor-beta (TNF-beta), interferon-gamma (IFN-gamma), and IL-10 and IL-4 mRNA.
IL-4 mRNA was identified significantly more often in the synovial compartment of patients with pauciarticular onset disease (JRA or JSpA) compared with polyarticular onset JRA (58 vs 14%; p < 0.01) or RA (29%). Similarly, IL-4 mRNA was detected more often in those with a persistently pauciarticular disease course compared to those with a polyarticular course (68 vs 30%; p < 0.01). Furthermore, the combination of IL-4 and IL-10 mRNA was found more frequently in nonerosive compared with erosive disease (38 vs 15%; p < 0.05). IL-2 and TNF-beta mRNA were found in all groups. IFN-gamma mRNA was detected in 33% of those with systemic onset JRA compared with 85% of other types of JRA (p < 0.01).
This study provides further evidence of immunopathological differences between chronic forms of arthritis with childhood onset, and highlights similarities with and differences from adult RA. Our findings suggest that IL-4, possibly in combination with IL-10, has an antiinflammatory or disease restricting role.