Gastroenterologist, former head of the digestive diseases and nutrition department at the Huriez hospital in Lille (France). Current director of the Center for Inflammatory Bowel Diseases, Gastroenterology Department of Icahn school of medicine at Mount Sinai, New York. Member of the learned society IOIBD (International Organization of Inflammatory Bowel disease) since 2009. Scientific advisor for the "Immunology, Microbiology and Inflammatory Bowel Disease" (IMIBD) section of the AGA (American Gastroenterological Association) since 2006. He has been president of several learned societies, including ECCO and GETAID.