Increased plasma levels of high mobility group box 1 protein in patients with bipolar disorder: A pilot study.

High mobility group box 1 (HMGB1) is a pro-inflammatory cytokine that emerges as a promising peripheral marker of inflammation. HMGB1 and C-reactive protein levels were assessed in plasma of control subjects and remitted patients with bipolar disorder (BD). HMGB1 levels were significantly higher in patients with BD as compared to control subjects whereas C-reactive protein levels did not differ between the two groups. No significant effect of potential covariates was identified. The results of this pilot study suggest that HMGB1 might be a specific peripheral marker of inflammation in BD.