In celiac disease (CD), gliadin-specific cells have been identified as IFN-γ-producing TH1 cells [45, 46], but inflammatory bystander CD4+ T cells have been reported to secrete high amounts of IL-17 during active inflammation [45] and at more severe disease stages, due to the loss of villous architecture and intestinal barrier integrity, allowing for increased bacterial translocation [47–49]. This evidence concerns the gene CD4 and celiac disease.