1. Departments of Gastroenterology and Hepatology; University Hospital Essen; Essen; Germany
2. Institute for Transfusion Medicine, University Hospital Essen; Essen; Germany
3. Institute for Immunology, University Hospital Essen; Essen; Germany
4. Department of General, Visceral and Transplantation Surgery; University Hospital Essen; Essen; Germany
5. Fundeni Clinical Institute of Digestive Diseases and Liver Transplantation; Bucharest; Romania