IDENTIFICATION OF ANTILEUCOPROTEASE IN REMODELED HUMAN ADULT NASAL SURFACE EPITHELIUM

Antileucoprotease (ALP) is generally considered as a specific marker f or glandular serous cells, and plays a major role in the defence of th e respiratory tract against proteolytic damage, Nevertheless, several studies have identified ALP in bronchial and bronchiolar surface epith elial cells, and also an increased number of ALP-containing cells in b ronchiolar tissue during the development of pulmonary diseases, In ord er to define more clearly whether the surface epithelium might be invo lved in the defence of the respiratory mucose, we have investigated th e expression of ATE by cells of the nasal surface epithelium. Indirect immunocytochemistry and in situ hybridization for ALP were performed on human nasal polyp sections, The height of the surface epithelium, i ts morphology, and the degree of local inflammation were assessed in p arallel. Surface epithelium morphology was highly heterogeneous, ALP-c ontaining cells were identified, but only in remodelled areas of the s urface epithelium (foldings, basal cell and/or mucous cell hyperplasia ), with no association to the degree of inflammation. These results de monstrate that the surface epithelial cells of the human adult nasal m ucosa can express ALP in remodelled surface epithelium, and may be act ively involved in the biochemical defence of the airways.