NASAL POLYPOSIS PATHOGENESIS - A FLOW CYTOMETRIC AND IMMUNOHISTOCHEMICAL STUDY OF EPITHELIAL-CELL PROLIFERATION

In nasal polyps, constantly associated with chronic inflammation, freq uent epithelial morphological changes (squamous metaplasia, secretory hyperplasia) suggest a dysregulation of epithelial cell proliferation. Cell proliferation in nasal respiratory epithelium was therefore eval uated in nasal polyposis. In 20 patients, we compared cell proliferati on in mucosa from the inferior turbinate to these in nasal polyps usin g two methods: Flow cytometry analyzing first the ploidy and the perce ntage of S-phase cells (propidium iodide DNA labeling), secondly the p ercentage of Ki-67-labeled cells and the green fluoresent index (fluor escein-conjugated anti-human Ki-67 antigen labeling), and thirdly the percentage of Ki-67-labeled cells being in S-phase. Immunohistochemist ry, quantifying the expression of Ki-67 antigen in the epithelium perm itting to calculate a Ki-67 index. All cell-populations studied were d iploid. Percentages of S-phase cells, Ki-67-labeled cells, Ki-67 label ed cells being in the S-phase and green fluorescence index was signifi cantly higher in nasal polyps than in mucosa. Ki-67 index were signifi cantly higher in nasal polyps than in mucosa in the epithelium. Epithe lial cell proliferation which is therefore increased in nasal polyp co uld play an important role in nasal polyposis pathogenesis and its rel ationships with inflammation can be suggested.