Selective downregulation of IL-10 expression in intestinal IFN-γ+ Tr1 cells, but not Th cells or CD25+ Treg cells, was observed in patients with IBD; possible regulation by pro-inflammatory cytokines, IL-1β and IL-23 suggested a critical role of IFN-γ+ Tr1 cells in control of intestinal inflammation [99]. This evidence concerns the gene IL10 and inflammatory bowel disease.