INTERLEUKIN-5, INTERLEUKIN-5, AND GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR EXPRESSION IN NASAL POLYPS

Purpose: Nasal polyps (NP) are grape-like clusters of chronically infl amed tissue. Little is known about the underlying cells and cytokines involved in nasal polyposis. For the present study, we hypothesize tha t elevated tissue levels of interleukin-3 (IL-3), interleukin-5 (IL-5) , and granulocyte-macrophage colony-stimulation factor (GM-CSF) contri bute to eosinophil recruitment and activation in NP. Materials and Met hods: To begin to test this hypothesis, we evaluated IL-3, IL-5, and G M-CSF levels and distributions in nasal polyp specimens obtained intra operatively from 13 patients and two normal controls. For these studie s, nasal polyp levels were determined by enzyme-linked immunosorbent a ssay (ELISA), and IL-3, IL-5, and GM-CSF distribution was determined b y immunohistochemistry.Results: Immunohistochemical staining of the NP indicated that in all 13 patient samples, IL-3, IL-5, and GM-CSF were associated with infiltrating cells, primarily eosinophils, in the NP. Quantitation of IL-3, IL-5, and GM-CSF in NP tissue homogenates indic ated that IL-3, IL-5, and GM-CSF levels were elevated in the NP tissue s when compared with control tissues. Additionally, elevation of indiv idual cytokines correlated with previous polypectomy (IL-3), steroid u se (IL-3, IL-5, and GM-CSF), asthma (IL-5), and age (GM-CSF). Conclusi on: These data support our hypothesis that IL-3, IL-5, and GM-CSF are likely to play a key role in eosinophil recruitment/activation and NP formation and support recently advanced theories that cytokines play a key role in the pathogenesis of this disease. Copyright (C) 1997 by W .B. Saunders Company.