PLACEBO-CONTROLLED IMMUNOPATHOLOGIC STUDY OF 4 MONTHS OF INHALED CORTICOSTEROIDS IN ASTHMA

The effect of prolonged inhaled corticosteroid treatment on bronchial immunopathology was assessed in 25 nonsmoking mildly asthmatic subject s previously receiving intermittent inhaled beta(2)-agonist alone. Inh aled beclomethasone dipropionate (BDP), 500 mu g twice per day or plac ebo was administered for 4 mo in a double-blind parallel group study. Histamine bronchial provocation, fiberoptic bronchoscopic biopsy, and bronchoalveolar ravage (BAL) were performed before and after treatment . There was no difference in bronchial responsiveness or lung function between groups. In patients treated with BDP compared with placebo, t here was a significant reduction in toluidine blue-staining mast cells (p = 0.028) and total (p = 0.005) and activated eosinophils (p = 0.05 ) in biopsies but no difference in eosinophils or eosinophil cationic protein in BAL. Granulocyte-macrophage colony-stimulating factor expre ssion was significantly reduced in the bronchial epithelium, and the t hickness of Type III collagen deposition in the bronchial lamina retic ularis reduced from 29.7 +/- 4.4 to 19.8 +/- 3.4 mu m (mean +/- 95% co nfidence interval)(p = 0.04). No change in helper or activated helper T cells occurred. Prolonged BDP treatment reduces inflammatory infiltr ation, proinflammatory cytokine expression, and subepithelial collagen deposition, a recognized abnormality in asthma.