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

Abstract

<b><i>Introduction:</i></b> 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). <b><i>Methods:</i></b> 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)-γ, IL-1β, and tumor necrosis factor (TNF)-α were assessed in the tissue cultures. <b><i>Results:</i></b> 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-γ, IL-1β, and TNF-α 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. <b><i>Conclusion:</i></b> 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.