Effect of allergic rhinitis on the expression of human β-defensin 2 in tonsils.

BACKGROUND

Human β-defensins (HBDs) are a newly identified family of antimicrobial peptides that are expressed by epithelia on mucosal surfaces. Exposure of airway epithelial cells to TH2-type cytokines results in a significant decrease in the antimicrobial activity of the cells.

OBJECTIVE

To investigate the effect of allergic rhinitis on the expression of HBD-2 in tonsils and adenoids.

METHODS

Palatine tonsils and adenoids were obtained from 30 patients with no history of recurrent tonsillitis. The patients were divided into 2 groups: allergic rhinitis and nonallergic rhinitis groups. Real-time polymerase chain reaction analysis was used to measure messenger RNA (mRNA) levels of HBD-2 mRNA in tonsil and adenoid tissue samples from the 2 patient groups. Immunofluorescent staining and enzyme-linked immunosorbent assay (ELISA) were used to evaluate the expression of HBD-2 protein in tonsil and adenoid tissues. The concentration of the cytokines interleukin (IL) 4, IL-5, and interferon γ (IFN-γ) in tissue homogenates was measured by ELISA.

RESULTS

Immunofluorescent staining data demonstrated the expression of HBD-2 protein in the surface epithelia of tonsils, and a marked difference in the staining intensity was observed the between 2 groups. HBD-2 mRNA and protein levels in the tonsils were significantly lower in the allergic rhinitis group than that in the nonallergic rhinitis group (P = .03 and P = .04, respectively). IL-5 and IFN-γ were not detected, and no significant difference was found in IL-4 concentrations in tonsil homogenates between the 2 groups.

CONCLUSION

Allergic rhinitis suppresses HBD-2, an epithelial antimicrobial peptide, in the tonsils.