Thus, adoptive immunotherapy for inflammatory bowel disease (IBD) could become clinically relevant since DC that prevent and reverse T1DM exhibit features similar to gut tolerogenic CD103+ DC; they are stably immature, co-stimulation-impaired, and express the RA-metabolizing enzyme ALDH1A2 which together convert immunosuppressive progenitors of Foxp3+ Tregs into highly suppressive Foxp3+ Tregs. Here, ALDH1A2 is linked to inflammatory bowel disease.