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

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).

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.

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.

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.