ABSTRACT
Objective To investigated the difference in induced sputum concentrations of mucin between the patients with eosinophilic bronchitis (EB) and classic asthma, and found out the difference in mechanism. Methods 20 patients with eosinophilic bronchitis (EB), 20 patients with classic asthma and 10 healthy controls were enrolled. Induced sputum levels of MUC5AC, MUC5B, LTC4 and PGE2 were measured by enzyme immunoassay in patients and healthy control. Results In patients with asthma, sputum MUC5A (26.8 ± 8.5)μg/mL and LTC4 (700.8 ± 172.3)pg/mL were significantly elevated whereas MUC5B levels (1.1 ± 0.5)μg/mL were reduced compared with patients with EB MUC5AC:( 17 . 6 ± 7 . 0 )μg/mL , LTC4:( 320 . 9 ± 89 . 4 ) pg/mL , MUC5B:(2.6 ± 0.5)μg/mL and healthy controls MUC5AC:(12.5 ± 4.3)μg/mL, LTC4:(91.2 ± 16.1)pg/mL, MUC5B:(2.6 ± 0.4)μg/mL (P < 0.01). PGE2 levels were higher in patients with EB (433.8 ± 118.1)pg/mL than in asthma(172.7 ± 74.5)pg/mL and controls(113.3 ± 18.3)pg/mL(P < 0.01), but results did not differ between asthma and controls. The LTC4 showed a significant positive correlation with MUC5AC (r = 0.785,P < 0.01), and a significant negative correlation with MUC5B (r = -0.703,P < 0.01). Conclusion A significant difference in MUC5AC/MUC5B ratio was founded in proximal airway between EB and asthma. The unbalance level between LTC4 and PGE2 would be involved in the pathogenesis of airway mucus hypersecretion.