Update on the pathogenesis and treatment of systemic onset juvenile rheumatoid arthritis.

PURPOSE OF REVIEW: Although systemic onset juvenile rheumatoid arthritis accounts for only about 20% of most reported series, children with systemic onset juvenile rheumatoid arthritis are often the most difficult to treat. Many children with persistent systemic onset juvenile rheumatoid arthritis have marked physical and emotional disability as a result of both disease and treatment-related morbidities. This review highlights recent studies that better elucidate the etiopathogenesis of systemic onset juvenile rheumatoid arthritis. New therapies derived from better understanding of cytokines, cytokine gene expression, and their complex interactions, which result in inflammation, are improving our ability to control active disease while reducing or reliance on corticosteroids.

RECENT FINDINGS: Recent advances in our understanding of the etiopathogenesis of systemic onset juvenile rheumatoid arthritis have led to therapies that specifically target the cytokines found in abnormal quantities in children with active disease. Biologic agents that directly target interleukin-1a, interleukin-6, and tumor necrosis factor alpha are currently in use, and additional agents that modulate interleukin-18, myeloid-related proteins 8 and 14, natural killer cell function, and macrophage migration inhibitory factor production are under investigation.

SUMMARY: Anakinra, monoclonal antibody to interleukin-6 receptor, and thalidomide each have led to significant clinical improvement with fewer side effects than resulted when corticosteroids were the mainstay of therapy.