The Roles of Type 2 Innate Lymphoid Cells (ILC2) in Chronic Rhinosinusitis (CRS)

Abstract

FEBRUARY 2015 AB54 Abstracts S A T U R D A Y 171 The Roles of Type 2 Innate Lymphoid Cells (ILC2) in Chronic Rhinosinusitis (CRS) Keisuke Uno, Yoshinori Matsuwaki, MD, PhD, Kazuhiro Omura, Eika Hayashi, Hirohito Kita, MD, Nobuyoshi Otori, MD, Hiromi Kojima, MD; Department of Otorhinolaryngology, The Jikei University School of Medicine, Tokyo, Japan, Departments of Immunology and Internal Medicine, Mayo Clinic, Rochester, MN. RATIONALE: Chronic rhinosinusitis (CRS) is one of the most frequent chronic diseases, and little is understood about its pathogenesis. Eosinophils are considered to play a major role in its pathology, but we still know little which is causing chronic immune activation and persistent eosinophilic inflammation in CRS. Recently, type 2 innate lymphoid cells (ILC2s, lineage (-), CD45 (+), CD127 (+), CD294 (+)) were identified as a candidate, which produce highly levels of Th2 cytokines such as IL-5 and IL-13, which activates eosinophils. We hypothesized that ILC2s are enriched in blood and nasal polyps in patients with eosinophilic CRS (ECRS) and are associated with its pathology. METHODS: The patients with CRS or pituitary adenoma (normal sinus) who underwent endoscopic sinus surgery (ESS) in Jikei University Hospital were enrolled. We used PBMC and nasal polyps (NPs) from patients with CRS or normal subjects, and analyzed the amount of ILC2 by flow cytometry. We also investigated the distribution of ILC2s in NPs by immunohistochemistry. EDN and cytokines in NPs were measured by ELISA. RESULTS: EDN and Th2 cytokines are significantly higher in ECRS than non-eosinophilic CRS (NECRS). The counts of ILC2s were significantly higher in ECRS than NECRS. Immunostained ILC2 were showed in nasal polyps of ECRS, but not in NECRS or normal subjects. The distribution of ILC2 in NPs was observed as chain-like. ILC2’s CD25 surface expression in PBMC was significantly higher in ECRS than NECRS. CONCLUSIONS: ILC2 are considered as candidate of the commander in ECRS, which strongly induce Th2 inflammation.