Increased level of high mobility group box 1 in the serum and skin in patients with generalized pustular psoriasis.

High-mobility group box 1 (HMGB-1) is a highly abundant pro-inflammatory protein associated with the pathogenesis of inflammatory and autoimmune diseases. HMGB-1 expression level increases in patients with psoriasis vulgaris (PV). However, HMGB-1 expression in patients with generalized pustular psoriasis (GPP) is unknown. In this study, we investigated HMGB-1 expression in GPP. HMGB-1 expression levels were examined in the skin and serum of patients with GPP, PV, atopic dermatitis (AD) and healthy controls (HC) using enzyme-linked immunosorbent assay and immunohistochemistry. The elevation in HMGB-1 expression was significantly higher in GPP patients than in PV, AD and HC patients. In addition, patients with GPP had elevated serum HMGB-1 levels compared with those with AD and HC. Furthermore, serum HMGB-1 levels were significantly decreased after systemic treatment. In the correlation analysis, a significant positive correlation was detected between serum HMGB-1 levels and the Japanese severity score for GPP. HMGB-1 may be involved in the pathogenesis of GPP and can be useful to evaluate disease severity and the effectiveness of GPP treatment.