1. Inflammatory Bowel Disease Program, Section of Gastroenterology. Digestive Disease Center, University of the Andes Clinic, Santiago, Chile
2. Department of Internal Medicine, São Paulo State University (UNESP), Medical School, Botucatu, SP, Brazil
3. Departament of Pathological Anatomy, University of the Andes Clinic, Santiago, Chile
4. Department of Pediatrics, Faculty of Medicine, Pontifical Catholic University of Chile, Santiago, Chile