Abstract:Objective Neutrophilic chronic rhinosinusitis with nasal polyps (CRSwNP) occur predominantly in Eastern Asian subjects. Appropriate treatments for this endotype have not been elucidated. This study aimed to evaluate the effect of local glucocorticoid budesonide nasal spray on neutrophilic CRSwNP. Methods Fifteen CRSwNP subjects were enrolled and received budesonide treatment for three months. Nasal samples were obtained from normal nasal mucosa and nasal polyps (NP) of CRSwNP patients, and their endotypes were identified using immunofluorescent staining. Then the infiltration of neutrophils (Neu) was examined with immunohistochemical staining before and after budesonide treatment. After that, we used Hematoxylin-Eosin and Periodic Acid–Schiff staining to assess goblet cells and submucosal gland cells before and after the therapy. Finally, we evaluated the effect of the treatment on inflammatory mediators including myeloperoxidase (MPO) and interferon-γ (IFN-γ) and mucin (MUC)5AC and MUC5B through enzyme linked immunosorbent assay. Results All the recruited patients (n = 15) belonged to the neutrophilic endotype. The number of Neu was increased in NP compared to normal nasal mucosa, and was not decreased significantly after budesonide treatment. Goblet cell numbers and submucosal gland cells scores were higher than normal tissues, and were not reduced significantly after the treatment. The contents of MPO, IFN-γ, MUC5AC and MUC5B were enhanced compared to normal mucosa. However, there were no statistical significances between pre and post treatments in above substances. Conclusion Budesonide can not treat neutrophilic NP effectively.