MethodsFThe 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 to investigate correlation with ILC2s. Lineage negative cells from nasal polyps were cultured in vitro with IL-33 or/and IL-2 to investigate the amount of cytokine produced by ILC2s.
Results: EDN and Th2 cytokines are significantly higher in ECRS than non-eosinophilic CRS (NECRS). EDN had strongly correlated with the numbers of ILC2s in NPs. The counts of ILC2s in NPs were significantly higher in ECRS than NECRS. Immunostained ILC2 were showed accumulated in nasal polyps of ECRS, but not in NECRS or normal subjects. ILC2’s CD25 surface expression in PBMC was significantly higher in ECRS than NECRS. ILC2’s IL-17RB surface expression in NPs was significantly higher in NECRS than ECRS. Lineage negative cells from ECRS’ NP, but not from NECRS’, produced IL-5 and IL-13 in both IL-2 and IL-33 stimulation.
Conclusions: ILC2 are considered as candidate of the commander in ECRS, which strongly induce Th2 inflammation. There are possibility that ILC2s have several subtypes and the characteristic of ILC2s are differ from their environment.