Efficacy of Budesonide Nasal Spray on Neutrophilic Chronic Rhinosinusitis with Nasal Polyps: A Combined Clinical and Experimental Study

Abstract

Background: Neutrophilic chronic rhinosinusitis with nasal polyps (CRSwNP) occur predominantly in Asian subjects. Appropriate treatments for this endotype have not been elucidated. This study aimed to evaluate the efficacy of budesonide nasal spray on neutrophilic CRSwNP. Materials and Methods: Fifteen neutrophilic CRSwNP patients were included, and then they received budesonide nasal spray treatment for 3 months. Biopsies of nasal polyps (NPs) were obtained from these subjects. Their clinical indexes were scored using Visual Analog Scale (VAS), Sino-Nasal Outcome Test (SNOT)-22, and Endoscopic Appearances (EAs). Histological analyses were used to assess numbers of neutrophils, goblet cells, and submucosal gland cells in NPs. Percentages of CD8⁺ T cells and CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Tregs) were evaluated using flow cytometry. Mucin 5AC (MUC5AC), MUC5B, myeloperoxidase (MPO), interferon (IFN)-γ, and interleukin (IL)-1β and their mRNAs were also examined. After that, we cultured NP tissues in vitro and evaluated the abovementioned inflammatory parameters before and after the administration of budesonide. Results: Budesonide nasal spray did not improve clinical evaluations including VAS, SNOT-22, and EA scores. Numbers of neutrophils and goblet cells, the score of submucosal gland cells, percentages of CD8⁺ T cells and Tregs, MUC5AC, MUC5B, MPO, IFN-γ, and IL-1β and their mRNAs were not decreased in NPs after the budesonide treatment. Furthermore, the administration of budesonide into NP cultures also did not reduce their levels in comparison with those before the treatment. Conclusion: These findings demonstrate that budesonide treatment may not alleviate the inflammatory condition in neutrophilic CRSwNP.