Expression of Granulocyte/Macrophage-Colony-Stimulating Factor, lnterleukin-8 and RANTES in the Bronchial Epithelium of Mild Asthmatics Is Down-Regulated by Inhaled Beclomethasone Dipropionate

Recent studies have demonstrated that bronchial epithelial cells of asthmatics are capable of expressing proinflam-matory cytokines, including granulocyte/macrophage-col-ony-stimulating factor (GM-CSF) interleukin (IL)-6 and IL-8, which may play a role in the aetiology of allergic airway disease, possibly by attracting and activating inflammatory cells [1, 2]. In this study, we have investigated the expression of GM-CSF, IL-8 and RANTES and activation of eosinophils in the bronchial epithelium of mild asthmatics and assessed their associations with bronchial responsiveness. We have also assessed the effects of inhaled beclomethasone diproprionate (BDP) on GM-CSF, IL-8 and RANTES and activated eosinophils in the bronchial epithelium, in a randomised, placebo-controlled double-blind manner. 25 mild-asthmatic volunteers were randomised to two parallel treatment groups to receive either BDP 500 μg twice daily or matched placebo for 4 months. The PC20 FEV, was determined and bronchial biopsies were collected from each subject prior to commencing treatment and at the end of the treatment period. All biopsies were processed immunocytochemically and analysed for the total number of EG2-staining cells (activated eosinophils), GM-CSF, IL-8 and RANTES. EG2-staining cells in the epithelium were counted and expressed as the number of cells/mm2. Expression of GM-CSF, IL-8 and RANTES was quantified by computerised colour image analysis [3] and the results expressed as the percentage of the total epithelial area staining for these cytokines.