HMGB1 Levels Are Increased in Patients with Juvenile Idiopathic Arthritis, Correlate with Early Onset of Disease, and Are Independent of Disease Duration

Levels of extracellular HMGB1 are increased in the inflamed joints of patients with JIA. This warrants further studies of HMGB1 as a mediator of JIA pathogenesis as well as a biomarker for inflammatory activity and as a target for therapy. The variation in levels of HMGB1 and S100 proteins in relation to disease onset indicates a difference in inflammatory phenotype during disease progression.