Importantly, our analysis of blood-derived effector CD4+ T cells from IBD patients revealed defects in Notch/STAT3-induced IL-10 production, which were associated with reduced Blimp-1 and c-Maf expression, suggesting that dysregulation of the Notch/STAT3-IL-10 axis in effector CD4+ T cells might contribute to disease development and/or progression. Here, IL10 is linked to inflammatory bowel disease.