Cytokines in juvenile rheumatoid arthritis (JRA).

Juvenile rheumatoid arthritis (JRA), unlike rheumatoid arthritis of adulthood (RA), is a heterogenous disease comprising at least five subtypes that differ in clinical course and prognosis, and require different therapeutical approaches. As compared to RA, the production of local and systemic cytokines in JRA have not yet been as extensively investigated. In this article we review the available literature on cytokine expression in serum and synovial fluid in all five different subtypes of JRA. Even though the data are still fragmentary, the evidence so far suggests that the determination of serum cytokines yields relevant information as to clinical subtype and inflammatory activity of the disease. Furthermore, the cytokine data suggest that the pathogenesis of JRA may even by more heterogenous than defined by the clinical subtypes. Finally, future directions of research in this area are proposed, and-based on the latest results-arguments for (anti)cytokine therapies in JRA are critically discussed.