Abstract

Nasal polyposis is a result of a chronic inflammatory disorder in the upper airways. In vitro studies have revealed that extravasation of leucocytes requires interactions between several sets of adhesion molecules expressed on the circulating leucocytes and the vascular endothelium. Therefore, the endothelial expression of intercellular adhesion molecule-1 (ICAM-1) in biopsies from polyps and inferior turbinates was investigated by the use of immunohistochemical staining. Biopsies were obtained from 11 patients suffering from nasal polyposis before, during and after treatment with 100 microg budesonide (Rhinocort Turbuhaler) in each nostril twice daily. Before, during and after treatment, ICAM-1 was expressed in the majority of vessels in polyps and mucosa of inferior turbinates. The intensity of endothelial ICAM-1 expression in polyps was significantly reduced during topical glucocorticoid treatment compared with the pretreatment and posttreatment levels (p < 0.005). In biopsies from the inferior turbinates, the intensity of the endothelial ICAM-1 expression was lower during treatment than after discontinuation of medical treatment (p < 0.005). In conclusion, topical budesonide treatment seems to downregulate ICAM-1 expression on the vascular endothelium in nasal polyps. Such an effect may interfere with leucocyte extravasation and partially account for the anti-inflammatory effect of local glucocorticoid treatment in human nasal polyposis.