1. Paediatric Hepatology, Gastroenterology and Transplantation, Child Health Department, ASST Papa Giovanni XXIII, 24127 Bergamo, Italy
2. Infectious Diseases Unit, ASST Papa Giovanni XXII, 24127 Bergamo, Italy
3. Division of Gastroenterology, Hepatology and Transplantation, ASST Papa Giovanni XXIII, 24127 Bergamo, Italy
4. Department of Medicine and Surgery, University of Milano-Bicocca, 20126 Milano, Italy