Role of BAFF in pediatric patients with allergic rhinitis during sublingual immunotherapy

Sublingual immunotherapy (SLIT) is the only therapeutic option for allergic rhinitis (AR) that modifies the immunological process to an allergen, rather than treating symptoms simply. However, its regulatory mechanisms are largely unknown. B-cell-activating factor of the TNF family (BAFF) plays very important roles in the development, differentiation, and proliferation of B cells and T cells. The aim of this study was to identify the role of BAFF during SLIT in pediatric patients with AR. Seventy-two house dust mite (HDM)-sensitized pediatric patients with AR were enrolled in this study. Thirty-six pediatric patients received HDM allergen extract for SLIT and 36 pediatric patients received placebo. Serum and nasal aspirate of different time points during treatment was collected and used for enzyme-linked immunosorbent assay (ELISA) of BAFF and related cytokines, respectively. Peripheral blood mononuclear cells were collected and stimulated by HDM allergen with or without rhBAFF after 12 months of treatment. Our results showed that the expression of BAFF protein decreased during the SLIT treatment compared with that in the placebo group after 6 months of therapy, and this trend lasted for 12 months. The decreased BAFF expression was positively related to Th2 cytokines and increased IL-10 expression. BAFF was also related to local production of IgA. In vitro experiments showed that BAFF can promote Th2 cytokines and inhibit IL-10 expression by PBMCs. Conclusion: During SLIT, BAFF expression was decreased and related to low Th2 cytokine expression and enhanced IL-10 expression. Besides, BAFF may contribute to local production of IgA. Our results suggested that BAFF may be an important biomarker during SLIT. Authors’ summary. Sublingual immunotherapy (SLIT) is the only therapeutic option for allergic rhinitis (AR) that modifies the immunological process to an allergen, rather than simply treating symptoms. However, its regulatory mechanisms are largely unknown. B-cell-activating factor of the TNF family (BAFF) plays very important roles in the development, differentiation, and proliferation of B cells and T cells. Our results showed that during SLIT, BAFF expression was decreased and related to low Th2 cytokine expression and enhanced IL-10 expression. Besides, BAFF may contribute to local production of IgA. Our results suggested that BAFF may be an important biomarker during SLIT.