Eotaxin, a CC chemokine specific for eosinophils, is implicated in the pathogenesis of asthma recruiting eosinophils into the airways. Theophylline has been used for the treatment of asthma and rece was proposed to have an anti-inflammatory action. The aim of this study is to examine whether theophylline may inhibit the eosinophilic airway inflammation by reducing the expression of eotaxin.

The expression of eotaxin mRNA was assessed by Northern analysis in A549 cells 4 h after stimulation with TNF-α or IL-1β And then, theophylline was added to A549 cells stimulated with 0.1 ng/ml IL-1β.

Eotaxin mRNA expression rates induced by 0.1, 1, 10 ng/mL TNF-α as compared with β-action were 7%, 22%, 28%, respectively. Eotaxin mRNA expression rates induced by 0.01, 0.1, 1, 10 ng/ml IL-1β as compared with β-action, were 10%, 42%, 63%, 72%, respectively. Eotaxin mRNA expression rates after addition of 0, 0.001, 0.01, 0.1 µM dexamethasone induced by 10 ng/mL TNF-α, as compared with β-action were 27%, 18%, 8%, respectively. Eotaxin mRNA expression rates after the addition of 0.001, 0.01, 0.1 mM dexamethasone induced by 0.1 ng/mL IL-1β, as compared with β -action, were 43%, 47%, 12%, 8%, respectively. Eotaxin mRNA expression rates after the addition of 0, 0.001, 0.01, 0.1, 1, 10 mM theophylline induced by 0.1 ng/mL IL-1β, as compared with β-action, were 48%, 40%, 33%, 22%, 16%, 14%, respectively.

These results suggest that theophylline may reduce eosinophil infiltration of the airway at least in part by reducing the expression of eotaxin under the conditions of these experiments.