e., thymus-derived Treg originating from the thymus (tTregs)] and induced peripheral Treg that derive from the neoconversion of T cells in the periphery (pTregs) depending on the environmental conditions, especially in the gut, as demonstrated for “naïve” CD4+ T cells upon exposure to TGFβ (9) in vitro or in mouse models of colitis as we recently demonstrated in vivo using Foxp3 transgenic reporter mice and dextran sulfate colitis or CD4+ T cell models (10). This evidence concerns the gene CD4 and colitis.