Sublingual Immunotherapy Decreases Expression of Interleukin-33 in Children with Allergic Rhinitis.

OBJECTIVES: To identify the expression of IL-33 during SLIT (Sublingual immunotherapy) in AR (Allergic rhinitis) children.

METHODS: Thirty children received house dust mite (HDM) allergen extract for SLIT and thirty children received placebo in this study. Serum and nasal lavage samples of cases and controls were collected at different time points during SLIT. Interleukin (IL)-33 and other cytokines were estimated in these samples by enzyme-linked immuno sorbent assay (ELISA). Peripheral blood mononuclear cells (PBMC) were prepared and stimulated with rhIL-33 (with or without other stimulators) at different time points during SLIT.

RESULTS: The present results showed that both serum and nasal lavage of IL-33 levels decreased significantly after 12 mo treatment and this trend maintained at least until 24 mo. The decreased nasal IL-33 level was positively correlated to local Th2 cytokines and increased IL-10 expression at 2 y post SLIT treatment. In vitro experiments showed that IL-33 promotes IL-4 and IL-5 and inhibits IL-10 expression by peripheral blood mononuclear cells (PBMCs) in AR.

CONCLUSIONS: Decreased IL-33 expression during SLIT may contribute to low Th2 response and enhanced Regulatory T cell cytokines expression. Thus, IL-33 maybe an important predictor during SLIT.