Interleukin-8 expression in human nasal polyps

The cytokine interleukin 8 (IL-8) has been shown to be a potent mediator of leukocyte recruitment and neovascularization in inflammatory and neoplastic diseases. In this study we hypothesize that IL-8 produced in the nasal polyp microenvironment is responsible for the leukocyte recruitment seen in nasal polyposis. To test this hypothesis we evaluated nasal polyps for distribution and content of IL-8 antigen with immunohistochemical techniques and radioimmunoassay to determine tissue levels of IL-8. The immunohistochemical results demonstrated that IL-8 antigen staining occurred predominantly within inflammatory cells and epithelium. IL-8 was detected in all nasal polyp tissue homogenates (a mean value of 1767 +/- 1633 pg/mg total protein (TP) with a range of 134 to 3668 pg/mg TP vs control specimens with a mean value of 77 pg/mg TP with a range of 0.09 to 255 pg/mg TP). These data demonstrate the presence and distribution and levels of IL-8 antigen in nasal polyps in vivo, supporting our hypothesis that local production of IL-8 could be an important factor in the sustained recruitment of leukocytes in nasal polyposis. Thus IL-8 likely plays a significant role in the pathogenesis of this disease process and therefore is a potential target for therapeutic intervention.