Extracellular high-mobility group box 1 is increased in patients with Behçet's disease with intestinal involvement.

High-mobility group box 1 (HMGB1) protein has been demonstrated to play an important role in chronic inflammatory diseases including rheumatoid arthritis, and systemic lupus erythematosus. This study investigated the association between extracellular HMGB1 expression and disease activity, and clinical features of Behçet's disease (BD). Extracellular HMGB1 expression in the sera of 42 BD patients was measured and was compared to that of 22 age- and sex-matched healthy controls. HMGB1 expression was significantly increased in BD patients compared to healthy controls (78.70 ± 20.22 vs 10.79 ± 1.90 ng/mL, P = 0.002). In addition, HMGB1 expression was significantly elevated in BD patients with intestinal involvement compared to those without (179.61 ± 67.95 vs 61.89 ± 19.81 ng/mL, P = 0.04). No significant association was observed between HMGB1 concentration and other clinical manifestations, or disease activity. It is suggested that extracellular HMGB1 may play an important role in the pathogenesis of BD.