Original article

Oxidative stress in nonallergic nasal polyps associated with bronchial hyperresponsiveness1 Nasal polyposis (NP) is an inflammatory chronic disease of the upper respiratory tract with unknown etiology. Inflammation is one of the most important factors involved in the development of NP (1–5). Clinical as well as experimental studies suggest that nasal polyp forma-tion and growth may be initiated and perpetuated by both infectious and noninfectious inflammation (3). In several studies, inflammatory cells, including eosinophils, neu-trophils, macrophages, and lymphocytes were found in high concentrations in NP tissue compared with normal tissue (1–4). Many studies have pointed out that histo-pathologic abnormities of NP, such as edema and inflammation, were closely related to the infiltration o