AIRWAY INFLAMMATION IN NONASTHMATIC SUBJECTS WITH CHRONIC COUGH

The physiopathology of chronic cough remains obscure. We evaluated the possibility that chronic cough in nonasthmatic subjects is associated with airway inflammation, and if this is so, what the relationship be tween this inflammation and the possible etiology of cough might be, a s well as its response to inhaled steroids. Nineteen nonsmoking, nonas thmatic subjects referred for a persistent cough (mean: 3.8 yr) were e valuated and compared with 10 normal subjects. The evaluation included a respiratory questionnaire, a physical examination, allergy skin-pri ck tests, chest and sinus radiographs, esophageal pH monitoring, measu rements of expiratory flows, methacholine and citric acid challenges, and flexible bronchoscopy for bronchoalveolar lavage (BAL) and bronchi al biopsies. Fourteen subjects further accepted participation in a ran domized, double-blind crossover trial of inhaled beclomethasone (500 m u g four times daily) and a placebo for 1 mo each. Four groups of subj ects were identified according to the presence of postnasal discharge (n = 4), gastroesophageal reflux (n = 6), both conditions (n = 5), or neither (n = 4). Subjects with chronic cough had an increased number o f inflammatory cells in their bronchoalveolar lavage fluid (BALF), but there was no significant difference between the four subgroups of cou ghers. As compared with control subjects, the bronchial biopsies of su bjects with chronic cough showed increased epithelial desquamation (p = 0.004) and inflammatory cells (p = 0.005), particularly mononuclear cells (p < 0.01), in addition to submucosal fibrosis, squamous-cell me taplasia, and loss of cilia. These findings were not significantly dif ferent between the different etiologic groups. In subjects with chroni c cough, basement-membrane thickness was normal and not different from that of control subjects. In the two groups, six and two subjects, re spectively, had a 50% or greater reduction in cough symptoms after bec lomethasone or placebo, although overall mean daily cough scores were not significantly different for the two treatments. Pretreatment bronc hial biopsies of steroid-responsive patients were similar to those of nonresponders. In conclusion, subjects with chronic cough show evidenc e of airway inflammation with a predominantly mononuclear-cell infiltr ate and epithelial damage. However, no correlation was found between t he intensity of this inflammation and the short-term response to high doses of inhaled steroids.