HMGB1 and systemic-onset juvenile idiopathic arthritis: As shown in Figure 1 the median serum HMGB1 levels in children with systemic-onset JIA (17402 pg/ml) were 15 fold higher than those in control group (1149 pg/ml) and were also significantly higher than those in children with oligoarticular (3552 pg/ml), polyarticular (4374 pg/ml) or SLE children (P < 0.05).