Abstract: Objective: To study the pathological characters of the bronchial mucus membrane in mild and moderately persistent asthmatic patients and to explore the possible functions of neutrophils. Methods: Bronchial biopsy specimens and bronchial alveolar lavage fluids(BALF) were obtained from 12 patients with intermittent asthma(group A), 16 patients with mild or moderately persistent asthma(group B) and 14 patients with peripheral lung cancer in an early stage (group C). The pathological characters were observed by light microscopy using HE staining. Expression of MPO in the bronchial mucus membrane was determined by immunohistochemical staining. The cell count and MPO, ECP, IL8 contents in BALF were determined at the same time. Results: The Eos count in BALF of the A, B and C groups（×106/ml）was （7.58±4.42）,（8.89±4.25） and（4.32±2.13）respectively, which was significantly higher in groups A and B than in group C(P＜0.05）. The neutrophil count was （4.04±2.14）,（15.03±6.79） and（4.15±1.09）respectively, which was significantly higher in group B than in groups A and C（P＜0.05）. The ECP content was （72.50±28.27）(mg/ml),（76.88±22.85）(mg/ml) and（42.67±24.00）(mg/ml) respectively, which was significantly higher in groups A and B than in group C（P＜0.05）. The MPO content was（11.35±5.87）(u), （25.31±15.71）(u) and（12.67±6.44）(u)respectively, which was significantly higher in group B than in groups A and C（P＜0.05）. The IL8 content was （3.43±1.46）(ng/ml), （14.12±11.41）(ng/ml) and （2.93±0.93）(ng/ml)respectively, which was significantly higher in group B than in groups A and C（P＜0.05）. The MPO positive cells under the mucus membrane in group B were significantly higher than in group A（P＜0.05）. Conclusion: Both neutrophils and Eos participate in the inflammatory reaction of mild and moderately persistent asthma and neutrophils play a more important role in it.

Key words: Neutrophil, Persistent asthma, Biopsy, BALF