Bronchial biopsy and sequential bronchoalveolar lavage in atopic cough: In view of the effect of histamine H1-receptor antagonists

Abstract

We have shown that some patients presenting with chronic bronchodilator-resistant non-productive cough have global atopic tendency, airway cough hyper-sensitivity without non-specific bronchial hyperresponsiveness and eosinophilic inflammation of the trachea and bronchi, abbreviated as atopic cough (AC). Histamine H1 receptor antagonists are effective in relieving the cough in some patients with AC but not in others in whom corticosteroids are needed to improve the cough. The aim of the present study was to compare the intensity of eosinophil infiltration in biopsied bronchial submucosa and sequential bronchoalveolar lavage (SBAL) fluids between two subgroups of patients with AC: (i) group A, successfully treated with histamine H1 receptor antagonists; and (ii) group B, requiring corticosteroids. Sequential BAL was performed using three 50 mL aliquots of physiologic saline solution and then bronchoscopic bronchial biopsy was performed in group A (n = 9) and B (n = 9) patients. Sequential BAL was also performed in normal controls (NC; n = 13). The first SBAL fraction was analyzed as bronchial lavage fluid (BLF) and the mixed fluid of the second and third SBAL fractions as bronchoalveolar lavage fluid (BALF). The number of eosinophils in the bronchial subepithelium was significantly (P = 0.0134) greater in group B patients (median 8.3 cells/mm2; range 3.6–21.9 cells/mm2) compared with group A (median 3.6 cells/mm2; range 0–10.0 cells/mm2). However, There were no significant differences in the number or percentage of eosinophils in BLF or BALF between group A, group B and NC subjects. These findings confirm that eosinophils do not infiltrate the peripheral airways of AC and suggest that corticosteroids are required to relieve the cough in more severe illness of AC, in which submucosal eosinophilic inflammation of the central bronchi is more intensive compared with the milder illness successfully treated with histamine H receptor antagonists.