[The role of type 2 innate lymphoid cells in the pathogenesis of eosinophilic chronic rhinosinusitis with nasal polyps].

Objective: To investigate the type 2 innate lymphoid cells (ILC2s) in eosinophilic nasal polyps, non-eosinophilic nasal polyps and controls, and to compare the characteristics of ILC2s indifferent types of nasal polyp. Methods: Flow cytometric analysis was used to quantify the ILC2s and Th2 cells in tissues from 19 patients with chronic rhinosinusitis with nasal polyp (CRSwNP) and 6 controls. The patients were classified into two groups as eosinophilic chronic rhinosinusitis with nasal polyps (ECRSwNP) and non-eosinophilic chronic rhinosinusitis with nasal polyps (non-ECRSwNP) based on eosinophil counts under hematoxylin-eosin staining. ILC2 and Th2 cell frenquencies, measured as a percentage of CD45(+) cells, were compared among ECRSwNP group (n=9), non-ECRSwNP group (n=10) and control group (n=6) using Mann-Whitney U test .The correlation between ILC2, Th2 cell frequencies and eosinophil count in tissues was analyzed using Pearson correlation coefficient. Results: ILC2 frequencies in ECRSwNP group were significantly higher than non-ECRSwNP group and controls ((0.051±0.025) vs (0.011±0.017), (0.051±0.025) vs (0.004±0.004), Z value was -3.185, -3.186, respectively, both P<0.05). There was no significant difference between ILC2 frequencies in non-ECRSwNP and controls ((0.011±0.017) vs (0.004±0.004), Z=-0.712, P=0.492). Th2 cell frequencies in ECRSwNP and non-ECRSwNP group were significantly higher than controls ((0.500±0.437) vs (0.106±0.102), (0.275±0.170) vs (0.106±0.102), Z value was -2.946, -2.278, respectively, both P<0.05). There was no significant difference between Th2 frequencies in non-ECRSwNP group and ECRSwNP group ((0.275±0.170) vs (0.500±0.437), Z=-1.306, P=0.211). ILC2 frequencies significantly correlated with Th2 cell frequencies (r=0.571, P=0.011) and tissue eosinophilia (r=0.579, P=0.009). Th2 cell frequencies significantly correlated with tissue eosinophilia (r=0.844, P=0.001). There was no significant association between ILC2 and allergic status. Conclusion: ILC2s are elevated in ECRSwNP, and not influenced by allergic status, suggesting that ILC2s play an important role in ECRSwNP without allergic diseases.