Supplementary Material for: Altered T Helper 17 Responses in Children with Food Allergy

Background: While a central role for the T helper (Th) 1/Th2 axis in food allergy has been established, the Th17 response in food-allergic humans has not been addressed. Methods: Th17 responses in 18 peanut-allergic children, who were also allergic to at least one additional food allergen, were assessed relative to 15 age-matched healthy controls. To account for the atopy background in the allergic children, 7 atopic, but not food-allergic, individuals and their age-matched controls were included in this study. PBMCs were analyzed by flow cytometry ex vivo or were stimulated in vitro with peanut allergens, gliadin, or tetanus toxoid followed by analysis of proliferation and cytokine production in antigen-responsive cells. Results: We observed a significantly lower interleukin (IL) 17 production in CD4+ T cells of food-allergic individuals ex vivo (p < 0.02). In vitro, we found that IL-17 production in CD4+ T cells in response to all antigens tested was significantly impaired in food-allergic subjects compared to healthy controls (Ara: p < 0.005; gliadin: p < 0.004; TT: p < 0.03). No significant differences were observed between atopic and nonatopic individuals with no food allergy. Conclusion: Our results thus reveal a systemic, non-allergen-specific defect in Th17 responses to antigen stimulation in food allergic individuals, suggesting a role for Th17 cells in the control of food allergy and implicating IL-17 as a potential biomarker for tolerance to food antigens.