Center for Prevention and Diagnosis of Celiac Disease-Gastroenterology and Endoscopy Unit, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy. Luca.elli@policlinico.mi.it. Celiac Center, Beth Israel Deaconess Medical Center (BIDMC), Harvard Medical School, Boston, MA, USA. Department of Gastroenterology and Endoscopy, CELAC network, AP-HP Centre, Hôpital Européen Georges Pompidou, Université de Paris, Cité and Institut National du Cancer, Paris, France. Celiac Disease Center, Department of Medicine, Columbia University Irving Medical Center, Columbia University, New York, NY, USA. Center for Celiac Disease, Gastrointestinal Unit, AOU San Giovanni di Dio e Ruggi D'Aragona and Department of Medicine Surgery Dentistry, Scuola Medica Salernitana, University of Salerno, Salerno, Italy. Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Medizinische Klinik für Gastroenterologie, Infektiologie und Rheumatologie, Berlin, Germany. K.G. Jebsen Coeliac Disease Research Centre, University of Oslo, Oslo, Norway. Department of Gastroenterology, Rikshospitalet, Oslo University Hospital, Oslo, Norway. Department of Medicine, Division of Gastroenterology, Mater Dei Hospital, Msida, Malta. Department of Infection, Immunity and Cardiovascular Diseases, Royal Hallamshire Hospital, University of Sheffield, Sheffield, UK. Center for Prevention and Diagnosis of Celiac Disease-Gastroenterology and Endoscopy Unit, Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy. Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy. Department of Medicine, Dr. C. Bonorino Udaondo Gastroenterology Hospital, Buenos Aires, Argentina. Department of Pathology and Medicine, Yale University School of Medicine, New Haven, CT, USA. Department of Gastroenterology, Palmerston North District Health Board (DHB), Palmerston North, New Zealand. Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, Seville, Spain. Biomedal S.L., Seville, Spain. Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada. Program in Nutrition, Department of Health Studies & Applied Educational Psychology, Teachers College, Columbia University, New York, NY, USA. IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy. Department of Surgery, Oncology and Gastroenterology, University of Padua, Padua, Italy. Gastroenterology Unit, Azienda Ospedale-Università Padova, Padua, Italy.