1 Royal Free Unit for Endoscopy, The Royal Free Hospital and University College London Institute for Liver and Digestive Health, Hampstead; Department of Gastroenterology, Cleveland Clinic London, London, United Kingdom.
2 Royal Free Unit for Endoscopy, The Royal Free Hospital and University College London Institute for Liver and Digestive Health, Hampstead; Department of Gastroenterology, Cleveland Clinic London, London, United Kingdom; Department of Pathophysiology and Transplantation, University of Milan, Italy, Milan, Italy; Center for Prevention and Diagnosis of Celiac Disease and Division of Gastroenterology and Endoscopy, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.