Human neutrophil defensins and secretory leukocyte proteinase inhibitor in squamous metaplastic epithelium of bronchial airways

Objective:The aim of this study was to analyze a possible contribution of human neutrophil defensins and secretory leukocyte proteinase inhibitor (SLPI) to the induction of airway epithelial changes such as squamous cell metaplasia. Materials and methods:The presence of these molecules and the number of proliferating (Ki-67-positive) epithelial cells was analyzed by immunohistochemistry in bronchial epithelium from subjects with (n=15) or without (n=14) chronic obstructive pulmonary disease (COPD). Results:Our data demonstrate higher numbers of defensin-positive (p=0.0001), elastase-positive (p=0.0001) and Ki-67-positive (p=0.0001) cells in areas with squamous cell metaplasia as compared to areas with intact or damaged epithelium, while the reverse was observed for SLPI expression (p=0.002). No differences were observed between subjects with or without COPD, nor between current smokers and those that had stopped smoking. Conclusions:These data are in line with a role of defensins in the hyperproliferative phenotype of squamous metaplastic lesions in the airways. This role does not seem to be restricted to patients with COPD.