Jelušić M et al. (2007) Interleukin-18 as a mediator of systemic juvenile idiopathic arthritis. Clin Rheumatol 26: 1332–1334

Juvenile idiopathic arthritis (JIA) is associated with abnormal production of cytokines. Interleukin (IL)-18 levels are elevated in children with systemic JIA and this cytokine is known to mediate articular damage in patients with rheumatoid arthritis. New data indicates that IL-18 is not involved in the pathogenesis of oligoarticular or polyarticular JIA, but could be a good therapeutic target for systemic JIA.

Jelušic´ et al. analyzed sera obtained from 17 children with systemic JIA, 31 children with oligoarticular JIA, 33 children with polyarticular JIA and 18 randomly selected children who did not suffer from inflammatory diseases. Blood was obtained from patients with JIA during the active phase of the disease and at least 6 months after the onset of clinical remission. Synovial fluid samples were also obtained from the inflamed joints of 16 children with oligoarticular JIA.

Children with systemic JIA had significantly higher levels of serum IL-18 than children with oligoarticular and polyarticular JIA, and than control patients. Serum levels of IL-18 decreased in patients with systemic JIA when the children entered clinical remission, but were still significantly higher than levels detected in those patients suffering from the other forms of this disease. IL-18 was present at comparable levels in synovial fluid and sera collected from patients with oligoarticular JIA, and neither oligoarticular nor polyarticular JIA were associated with higher-than-normal levels of serum IL-18. The authors conclude that IL-18 might be a good target for treatment of systemic JIA.