INTERLEUKIN-8 EXPRESSION IN HUMAN NASAL POLYPS

The cytokine interleukin 8 (IL-8) has been shown to be a potent mediat or 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 r ecruitment seen in nasal polyposis. To test this hypothesis we evaluat ed nasal polyps for distribution and content of IL-8 antigen with immu nohistochemical techniques and radioimmunoassay to determine tissue le vels of IL-8. The immunohistochemical results demonstrated that IL-8 a ntigen staining occurred predominantly within inflammatory cells and e pithelium. 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 1 34 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 i n vivo, supporting our hypothesis that local production of IL-8 could be an important factor in the sustained recruitment of leukocytes in n asal polyposis. Thus IL-8 likely plays a significant role in the patho genesis of this disease process and therefore is a potential target fo r therapeutic intervention.