INTERLEUKIN-1 RECEPTOR ANTAGONIST IN NEONATES, CHILDREN AND ADULTS, AND IN PATIENTS WITH PAUCI-ARTICULAR AND POLYARTICULAR ONSET JUVENILE CHRONIC ARTHRITIS

Objective. The production of interleukin (IL)-1 alpha IL-1 beta and IL -1 receptor antagonist (IL-1ra) by blood mononuclear cells (MNC), as w ell as the corresponding serum levels of IL-1ra were examined in blood samples from umbilical colds (n = 11), children (n = 40) and adults ( n = 20), and in 42 patients with juvenile chronic arthritis (JCA) of t he pauci- or polyarticular onset type. Results. IL-1ra serum levels we re found to differ significantly between the three age groups, being h igher in neonates (569 pg/ml) than in children (70 pg/ml) and adults ( 177 pg/ml). IL-1ra production in E. coli lipopolysacharide (LPS) stimu lated-cultures of MNC was also significantly higher in neonates (media n 2451 pg/ml) that in children (1526 pg/ml), but similar to that in ad ults (2107 pg/ml). IL-1ra levels in the sera of both subgroups of JCA patients were significantly elevated (median 257 pg/ml), but did not r eflect paraclinical or clinical disease parameters. In samples of syno vial fluid the IL-1ra levels tended to be fairly high, up to approxima tely 2 ng/ml, brat they did not reflect the serum levels of IL-1ra. Co nclusion. These findings suggests that the upregulation of IL-1ra prod uction forms part of the immunoregulatory response in JCA patients, an d that the insufficient production of IL-1ra is unlikely to contribute to the pathogenesis of JCA.