Role of IL‐5 and IL‐8 in the Pathogenesis of Nasal Polyps

Abstract

Objectives: (1) Evaluate the histopathological and immunohistochemical characteristics of different types of nasal polyps. (2) Quantify the expression of IL-5 and IL-8 in 2 different histotypes of nasal polyps in order to evaluate the role of these cytokines in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP) . Methods: This retrospective study was conducted on 44 specimens collected from nasal cavities of 44 patients with nasal polyposis who underwent functional endoscopic sinus surgery at the ENT University Unit of the A. Fiorini Hospital, Sapienza University of Rome, from January 2009 to January 2011. The specimens were analyzed at the histopathology unit of the university and divided into 2 groups according to their dominant histological features: Group A (polypoid mucosa and eosinophilia, 34 subjects) and Group B (polypoid mucosa associated with glandular hyperplasia, 10 subjects). Expression of IL-5 and IL-8 were analyzed on the specimens using immunohistochemical techniques. The same tests were run on nasal mucosa specimens drawn from 10 patients without sinusitis (control group). Results: IL-5 expression was significantly more expressed in Group A than in Group B ( P < .05). Both IL-5 and IL-8 expressions were significantly more expressed in Groups A and B compared to the control group ( P < .05). No significant difference was found in the expression of IL-8 between the 2 groups. Conclusions: The outcomes of this preliminary study suggest that IL-8 may play a role in the pathogenesis of both histological subtypes of nasal polyps, whereas IL-5 predominates in the eosinophilic subtype.