Clinical evaluation of high mobility group box 1 protein in Legionella pneumophila pneumonia

High mobility group box 1 (HMGB-1) protein is involved in acute lung injury due to various etiologies. We evaluated HMGB-1 levels in sera and bronchoalveolar fluids in patients with pneumonia caused by Legionella pneumophila. Levels of HMGB-1 in the sera of patients with L. pneumophila pneumonia (32 cases) and control subjects (24 cases) were determined. Serum HMGB-1 levels in Legionella pneumonia were similar to those of the control subjects. No significant correlation between HMGB-1 levels and other biomarkers and the outcome of cases was observed. In contrast, HMGB-1 levels, as well as interferon-γ, in bronchoalveolar (BA) fluids from severe L. pneumophila pneumonia (7 cases) were significantly higher than those in the sera of identical patients. HMGB-1 levels in BA fluids were relatively higher in pneumonia cases with ALI than those without ALI. Our findings suggest that intra-pulmonary HMGB-1 may be involved in the pathophysiology of pneumonia caused by L. pneumophila.