IL-21 expression during sublingual immunotherapy for allergic rhinitis.

BACKGROUND

Allergic rhinitis (AR) is an inflammatory disorder involving immunoglobulin E (IgE)-mediated immune response. Interleukin (IL)-21 IL-21 can regulate immune cell functions and IgE production. We aimed to explore the modulation of IL-21 expression before and after sublingual immunotherapy (SLIT) in AR patients and its correlation with IgE and Th2 cytokines.

METHODS

Fifty AR patients were enrolled and treated with HDM allergen extract via SLIT. Serum levels of IL-21 and Th2 cytokines as well as IgE were determined using enzyme-linked immunosorbent assay (ELISA). Statistical analysis was performed to compare changes in cytokine levels and assess correlations.

RESULTS

After 3 years of SLIT, serum levels of IL-21, Th2 cytokines and IgE were significantly reduced. Greater decreases were found in the effective treatment group compared to the ineffective group. The expression of IL-21 was correlated to IL-4 and IgE levels.

CONCLUSION

SLIT downregulates the expression of IL-21 and other Th2 cytokines, with IL-21 potentially serving as a biomarker for SLIT efficacy in AR patients.