ABSTRACT
BACKGROUND AND OBJECTIVES: Fas and Fas ligand (Fas-L) interactions mediate apoptosis of eosinophils. It is possible that reduction of Fas/Fas-L or Fas-L expression on eosinophils could induce the eosinophilia seen in Samter's triad. The purpose of this study was to analyse the release of LT and Fas/Fas-L expression pattern following exposure to varying concentrations of aspirin in aspirin sensitive nasal polyp (ASP) and non-aspirin sensitive nasal polyp (NASP) patients. MATERIALS AND METHODS: Twenty NASP patients and 16 ASP patients were recruited. Nine healthy subjects served as normal controls. LT levels and Fas/Fas ligand expressions were analysed by ELISA and flow cytometry. RESULTS: Both NASP and ASP patients showed increased release of LT on aspirin exposure in blood and nasal polyps. But ASP patients showed an even greater release of LT on aspirin exposure in blood as compared to NASP patients (p<0.05). LT release from peripheral blood elements do not necessarily coincide with those results obtained from nasal polyps. Eosinophils in ASP patients have significantly decreased Fas expression when compared to NASP patients (p<0.0001). CONCLUSION: These results suggested the role of LT and eosinophils in aspirin intolerance mechanisms in both blood and nasal polyp tissues. The decreased expression of the Fas receptor or defect of Fas/Fas-L interaction could be an important role in pathogenesis of nasal polyp regardless of their association with aspirin sensitivity.