Update on the pathogenesis and treatment of systemic idiopathic arthritis

Systemic juvenile idiopathic arthritis (SJIA) is an inflammatory condition characterized by fever, lymphadenopathy, rash, arthritis, and serositis. Although the ultimate cause of this disorder remains elusive, recent work defining cytokine effector mechanisms has led to a new treatment paradigm for this condition. In this review, we describe the recent immunological reclassification of SJIA as an autoinflammatory disorder as well as detailing the dramatic changes in its treatment.

SJIA is an autoinflammatory disorder in which defects of innate immune system pathways lead to significant inflammation. Recent studies of the pathophysiology, as well as successful treatment trials, have established interleukin-1β (IL-1β) and IL-6 as key cytokines in the pathogenesis of this condition. As a result, their inhibition has become the centerpiece of the current SJIA treatment paradigm.

There has been a major shift away from the traditional treatments of SJIA towards therapeutics that inhibit IL-1β and IL-6. In fact, the IL-1 blocker anakinra is now regarded as standard of care for SJIA patients with systemic symptoms, while the IL-6 inhibitor tocilizumab shows great potential. Future research holds promise for the development of more efficient cytokine inhibition as well a more comprehensive knowledge of the innate cytokine networks in this disease.