Sublingual Immunotherapy Decreased the Serum Levels of Interleukin-36γ in Allergic Rhinitis.

Background: Allergy immunotherapy (AIT), a treatment approach for allergic rhinitis (AR), is recognized for its potential to modify the disease course beyond mere symptom relief. Interleukin-36γ (IL-36γ), a key player in immune responses, has been implicated in promoting eosinophilic inflammation in AR by activating eosinophils. We aimed to investigate the effect of IL-36γ on group II lymphoid cell (ILC2) in AR patients who underwent sublingual immunotherapy (SLIT). Methods: Twenty-four AR patients were enrolled and administered with SLIT. Serum proteins of IL-36γ, interleukin-5 (IL-5), and interleukin-13 (IL-13) during SLIT were quantitatively assessed using enzyme-linked immunosorbent assay (ELISA). The proportion of ILC2 was determined by flow cytometry. Sorted ILC2s were stimulated by IL-36γ and ILC2 cell differentiation, and type II cytokines expression were examined. Results: SLIT treatment decreased the serum protein levels of IL-36γ, IL-5, IL-13, and the proportion of ILC2 significantly. IL-36γ suppressed the proliferation of ILC2 by inhibiting the levels of ILC2 transcription factor. IL-36γ also inhibited IL-5 and IL-13 expression from ILC2. Conclusion: The changes of IL-36γ during SLIT were related to the inhibited function of ILC2, implying that IL-36γ may be used as a new biomarker for monitoring the efficacy of SLIT in AR.