Epithelial-mesenchymal interaction in rhino-bronchial remodeling

ABSTRACT

The clinical phase and outcome of allergic diseases is related to the degree of bronchial and nasal remodeling. The present study aimed at assessing some features of both upper and lower airway remodeling in allergic patients as well as the role of epidermal growth factor and its receptor [EGFR] and transforming growth factor fi [TGF-fi] in this process.Twenty patients with mild persistent asthma according to G1NA guidelines and mild persistent allergic rhinitis [ARIA] were included in the present study. Fibreoptic bronchoscopy was done during stable disease. Forceps biopsy was taken from a segmental bronchus and from the nasal turbinates. The biopsies taken were stained by haematoxylin and eosin [H and E] for histopathologic evaluation and immunohistochemical detection of EGFR and TGF-ft was done.Abnormalities in nasal epithelium [ulceration, atypia, and basement membrane thickening] were detected in 50% of asthmatic patients and abnormalities in bronchial epithelium were detected in 40% of them. EGFR was expressed in all abnormal nasal and bronchial epithelium specimens. TGF-f$ was expressed in 90% of abnormal nasal epithelium and all abnormal bronchial epithelium. Both factors were expressed only in hypertrophied nasal and bronchial mucus glands and some inflammatory cells. They were positively correlated with both nasal and bronchial basement membrane thickness.Remodeling occurs even in mild allergic patients. Epithelial-mesenchymal interaction through EGFR and TGF-/3 release plays a major role in this process