IFNG and inflammatory bowel disease: This occurs through actions on immune cells (e.g., macrophages, natural killer cells, and T cells), epithelial cells and stem cells.28,55,56 For many years, IFN-γ has been known to directly impact pathological mechanisms in IBD and in mouse models through promoting gut barrier dysfunction and intestinal inflammation.27,28,57,58 IFN-γ is one of the core cytokines secreted by immune cells in the lamina propria during active IBD, although a more pronounced IFN-γ phenotype is likely to be detected in active CD, compared to UC.59–62