The Role Of IL-5 And IL-8 In The Pathogenesis Of Bronchial Asthma And Chronic Bronchitis

Bronchial asthma is an inflammatory disorder of the airways characterized by the infiltration of eosinophils and mast cells. To investigate the mechanism of eosinophil activation in the pathogenesis of asthma, we measured eosinophil-activating cytokines ,eosinophil survival as well as chemotactic assay in sera and sputum extracts, obtained from 33 asthmatic patients. Eosinophil viabilities in the sera and sputum extracts were significantly higher in asthmatic patients than that in control group (p<0.001). IL-5 induced an increase in eosinophil activity in a dose-dependent way. Ten ug/ml of anti-IL-5 antibody inhibited EVEA induced by IL-5 in concentration as great as 1000pg/ml. Also, eosinophil chemotactic activities in the sputum extracts were significantly higher in patients with chronic asthmatic bronchitis than that in control group (p<0.05). The concentration of IL-8 in sera of patients with chronic asthmatic bronchitis was significantly higher than that of asthmatic patients. These findings suggest that different mechanism might play a role in the pathogenesis of chronic asthmatic bronchitis and bronchial asthma. IL-8 measurement might be helpful in the differential diagnosis between bronchial asthma and chronic asthmatic bronchitis.Chronic bronchitis is also a airway disease characterized by infiltration of neutrophils and other inflammatory cells. Neutrophil chematactic and survival activities in sera and sputum extracts were significantly higher in chronic bronchitis than that in other subjects (p<0.001). Anti-IL-8 antibody inhibited NVEA induced by IL-8. Neutrophil survival rate was significantly decreased when cultured with anti-IL-8 antibody as well as with the sera or sputum extracts derived from patients with chronic bronchitis (p<0.05). These results indicate that neutrophil and IL-8 may play an important role in the pathogenesis of chronic bronchitis.Bronchial asthma and chronic bronchitis are common in that both are systemic diseases mainly involved in the inflammatory cells...