HMGB1 and RAGE levels in induced sputum correlate with asthma severity and neutrophil percentage.
Previous work indicated that high mobility group box-1 (HMGB1) protein may be involved in neutrophilic asthma. Here, we sought to investigate the correlation between HMGB1 and one of its receptors, receptor for advanced glycosylation end products (RAGE), with the severity of bronchial asthma. Compared to the control group (30 healthy individuals), patients in the asthma group (n=72) exhibited a higher percentage of neutrophils and higher HMGB1 and RAGE levels in induced sputum samples (P<0.05). Concurrently, FEV(1)% was significantly lower in the asthma group (P<0.05). Further, compared to mild and moderate asthma, in patients with severe asthma ACQ scores, the percentage of neutrophils, and HMGB1 levels were significantly higher, while FEV(1)% was significantly lower (P<0.05). The percentage of neutrophils and HMGB1 and RAGE levels were lower after treatment than before treatment (P<0.05). Finally, negative correlations were observed between HMGB1 or RAGE levels and FEV(1)% (r=-0.777 and r=-0.291, P<0.05), and positive correlations were detected between HMGB1 or RAGE levels and percentage of neutrophils (r=0.803 and r=0.326, P<0.05). Additionally, positive correlations were observed between HMGB1 and RAGE levels within the asthma group (r=0.306, P<0.05). Therefore, HMGB1 protein levels correlate with the severity of asthma, and HMGB1 may contribute to the inflammatory process of asthma.