Using biology of disease to understand and guide therapy of JIA.

Juvenile idiopathic arthritis (JIA) is a heterogeneous, multi-factorial disease. The ability to distinguish various subtypes of JIA has enabled more directed and uniform clinical care. Possible triggers of the disease include genetic and environmental factors such as infections and vaccinations. Autoreactive T cells responding to unknown antigens are among the mechanisms that perpetuate the cycle of autoimmune inflammation once established. There are two groups of candidate auto-antigens that are thought to play a role in induction or modulation of T-cell responses. The first group is derived from cartilage and other joint-related tissue and the second group is derived from stress proteins. Several molecules have been implicated in the quest to restore immune homeostasis and tolerance, such as regulatory T cells, FoxP3, heat shock proteins, cytokines, chemokines and other key mediators of inflammation. Treatment strategies might focus on the induction of regulation in a more specific fashion.