[Changes of HMGB1 and RAGE in induced sputum from patients with bronchial asthma]

To explore the relationship between HMGB1 (high mobility group box-1) protein and receptor for advanced glycosylation end products (RAGE) and the nosogenesis and severity of bronchial asthma.

Based on the criteria, the asthma group included 64 acute-onset asthma patients while the control group had 20 healthy cases. The asthma group received a 4-week combination inhalation therapy of budesonide and formoterol. Lung functions and induced sputum examinations were conducted before and after treatment. The percentage of a second forced expiratory volume in the predicted value (FEV(1)%) was recorded. A differential count of neutrophilic leukocyte in reduced sputum was performed. And the sputum levels of HMGB1 and RAGE were detected by ELISA (enzyme linked immunosorbent assay).

Prior to treatment, the neutrophilic leukocyte percentage and the levels of HMGB1 and RAGE were all higher than those of control group (P < 0.01). The induced sputum of severe asthma patients had higher levels of neutrophilic leukocyte percentage and HMGB1 than those of mild cases (P < 0.01). But the level of RAGE showed no statistical significance among mild, moderate or severe asthma cases (P > 0.05). The post-treatment levels of neutrophilic leukocyte percentage, HMGB1 and RAGE were lower as compared with the pre-treatment ones (P < 0.01). These three parameters in uncontrolled cases were higher than those in completely controlled cases (P < 0.05); in asthma group, both HMGB1 and RAGE had a negative correlation with FEV(1)% (r = -0.830, r = -0.632, P < 0.01); in induced sputum, both HMGB1 and RAGE had a positive correlation with FEV(1)% (r = 0.820, r = 0.623, P < 0.01). The levels of HMGB1 and RAGE were positively correlated (r = 0.929, P < 0.01).

Both HMGB1 and RAGE participate in the inflammatory process of asthmatic airway. HMGB1 is correlated with the severity of asthma. And the levels of HMGB1 and RAGE in induced sputum may be employed as reference indices for the observation of therapeutic effects.