Eosinophil-derived neurotoxin, elastase, and cytokine profile in effusion from eosinophilic otitis media.

Background: Eosinophilic otitis media (EOM) is an intractable disease characterized by a remarkably viscous effusion and accumulation of numerous eosinophils in both the middle ear effusion and the mucosa. The key factors in EOM pathogenesis remain unclear. The purpose of this study is to identify the important factors involved in EOM pathogenesis.
Methods: Middle ear effusion samples were collected from 12 patients with EOM and 9 patients with secretory otitis media (SOM), as controls. Multiple cytokines in the effusion were measured using a Bio-Plex™ Human Cytokine 27-Plex panel. Eosinophil-derived neurotoxin (EDN) and elastase were measured by ELISA. The concentrations of EDN, elastase, and each cytokine were compared between the EOM and SOM groups. Furthermore, in the EOM group, each cytokine was examined for correlation with EDN and elastase.
Results: EDN and elastase concentrations were significantly higher in the EOM group than in the SOM group (p < 0.05). IL-5, IL-1β, MIP-1α, G-CSF, IL-1ra, IL-4, IFN-γ, MIP-1β, IL-10, TNF-α, VEGF, and IL-2 concentration was significantly higher in the EOM group than in the SOM group (p < 0.05). Significant positive correlations were found between EDN and IL-1ra, IL-2, IL-5, IL-9, IL-13, eotaxin, MIP-1α, PDGF-BB, and RANTES in the EOM group (p < 0.05).
Conclusions: Our study showed that IL-5, IL-2, MIP-1α, and IL-1ra are the important factors involved in EOM pathogenesis. Furthermore, not only eosinophil, but also neutrophil are involved in middle ear inflammation of EOM.
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