The pathogenesis, clinical course, and response to treatment in systemic juvenile idiopathic arthritis (SJIA) differ from other types of juvenile idiopathic arthritis and are similar to other interleukin-1 (IL-1)-mediated diseases.
Interleukin (IL)-1α and IL-1β are proinflammatory cytokines that play a role in many diseases such as rheumatoid arthritis, juvenile rheumatoid arthritis, gout, and periodic inflammatory syndromes, including familial Mediterranean fever and Muckle-Wells syndrome.