1. Department of Gastroenterology and Hepatology; University Hospital Essen, University Duisburg-Essen; Germany
2. Department of Biliary-Pancreatic Surgery; Sun Yat-sen Memorial Hospital, Sun Yat-sen University; Guangzhou China
3. Department of Pathology and Neuropathology; University Hospital Essen, University Duisburg-Essen; Germany
4. Institute of Virology, University Hospital Essen, University Duisburg-Essen; Germany