[Levels of HMGB1 in induced sputum from patients with asthma and chronic obstructive pulmonary disease].

OBJECTIVE: To explore the relationship between the sputum levels of high mobility group protein B1 (HMGB1) and airway inflammation in bronchial asthma and chronic obstructive pulmonary disease (COPD) patients.

METHODS: A total of 57 patients with persistent asthma [per Global Initiative for Asthma (GINA) guidelines], 30 patients with stable COPD [stratified by Global Initiative for COPD (GOLD) status] and 20 control subjects were recruited. After completing an asthma control questionnaire, spirometry was performed before sputum induction. The ratio of forced expiratory volume in the first second (FEV(1))/predictive value (FEV(1)%Pre) and neutrophil differential count in induced sputum were recorded. The concentrations of HMGB1 in the supernatant of sputum were measured by ELISA (enzyme-linked immunosorbent assay).

RESULTS: The sputum concentrations of HMGB1 in the asthmatics and COPD patients were significantly higher than those of the control subjects [(291 ± 55) and (511 ± 39) vs (61 ± 5) ng/L, all P < 0.01]. And they were significantly negatively correlated with FEV(1)%Pre in all subjects. The levels of HMGB1 in induced sputum of COPD patients were significantly higher than those of asthmatics and healthy controls (P < 0.01). No significant difference existed in the levels of HMGB1 between patients with eosinophilic and noneosinophilic asthma [(290 ± 55) vs (292 ± 54) ng/L, P > 0.05]. The HMGB1 levels with COPD stage II and stage III were significantly higher than those with stage I [(526 ± 29) and (541 ± 29) vs (471 ± 18) ng/L]. The differences of sputum neutrophil percentage were statistically significant in mild, moderate and severe asthma [(27 ± 2)%, (36 ± 4)%, (49 ± 4)%]. And the sputum levels of HMGB1 were significantly higher in the patients with moderate and severe asthma [(312 ± 14) vs (347 ± 11) ng/L]. And the levels of HMGB1 in asthmatic and COPD patients were positively correlated with neutrophil percentage. According to the multivariate analysis, neutrophil percentage and FEV(1)%Pre were independent predictors of sputum HMGB1, but not smoking, age, gender and eosinophilic percentage.

CONCLUSION: HMGB1 may contribute to airway inflammation through its higher expression in bronchial asthma and COPD patients.