Food-allergic children have decreased peripheral regulatory B cells and altered B cell responses to IL-10

Increases in IL-10-producing cells and allergen-specific IgG4 are associated with allergic tolerance, including tolerance to foods; however, B cell responses to IL-10 and the role of regulatory, IL-10-producing B cells have not been well-explored in the context of food allergy. Blood samples were collected from food-allergic (FA) and non-food-allergic (NFA) children between 2 and 6 years of age. Flow cytometry was performed to determine the frequency of IL-10 receptor (IL-10R)+ and IL-10+ B cells. Peripheral blood mononuclear cells (PBMCs) and purified B cells were cultured with combinations of anti-CD40, IL-4, and IL-10. Immunoglobulins were quantified from culture supernatants using multiplexed immunoassays. With data collection and analysis ongoing, preliminary results show decreased IL-10R expression on memory B cells in FA children compared to NFA children (p < 0.02). Both FA and NFA children display low frequencies of IL-10+ B cells in the periphery. IL-10+ cells are decreased among CD38+ CD27+ B cells in FA compared to NFA children (p < 0.03), with emerging trends in other B cell subsets. IL-10 decreased IL-4-induced IgG4 production from PBMCs in FA children (p < 0.01), but not NFA children. IL-10 also increased IL-4-induced IgE production from purified B cells in FA children (p = 0.05). These results suggest that, in comparison to NFA children, B cells from FA children show a decreased ability to bind IL-10, as well as an altered response to IL-10 with respect to IL-4-induced IgG4 and IgE production. FA children also have decreased frequencies of peripheral regulatory B cells.