Effect of Local Corticosteroid Administration on CD8(+)CD25(+)Foxp3(+) Tregs in Neutrophilic CRSwNP

Introduction: CD8(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) play an important role in human's immune tolerance. The study was aimed to assess the influence of budesonide nasal spray on CD8(+)CD25(+)Foxp3(+) Tregs and to evaluate their cellular functions in neutrophilic chronic rhinosinusitis with nasal polyps (CRSwNPs). Methods: Fifteen patients with neutrophilic CRSwNPs were enrolled and received physiological saline or budesonide nasal spray treatment (Saline or Budesonide group) for 3 months. Nasal tissue samples were obtained from normal subjects or those patients and cultured in vitro. CD8(+)CD25(+)Foxp3(+) Tregs were separated from normal or NP tissues and also cultured in vitro. Then interleukin (IL)-10 and its mRNA were evaluated in the above cell cultures. The cells were applied into NP cultures. Finally, myeloperoxidase (MPO), interferon (IFN)-gamma, IL-1 beta, and tumor necrosis factor (TNF)-alpha were assessed in the tissue cultures. Results: CD8(+)CD25(+)Foxp3(+) Tregs decreased in NP tissues. Budesonide administration did not enhance the percentage of these cells in polypoid tissues. IL-10 and its mRNA were increased in the above cell cultures from NPs. However, there were no statistical differences between the two treatments in the IL-10 expression. Additionally, levels of MPO, IFN-gamma, IL-1 beta, and TNF-alpha were totally elevated in NP tissue cultures and reduced after the administration of CD8(+)CD25(+)Foxp3(+) Tregs. However, there were no significant differences in concentrations of these mediators between these two groups of the CD8(+)CD25(+)Foxp3(+) Tregs treatment in vitro. Conclusion: The findings indicate that CD8(+)CD25(+)Foxp3(+) Tregs might regulate the neutrophilic inflammation, and budesonide nasal spray therapy could not ameliorate the inflammation in neutrophilic CRSwNPs.