1. Department of Gastroenterology and Hepatology; University Hospital Essen; University of Duisburg-Essen; Duisburg Germany
2. Department of General, Visceral and Transplantation Surgery; University Hospital Essen; University of Duisburg-Essen; Duisburg Germany
3. Institute for Transfusion Medicine; University Hospital Essen; University of Duisburg-Essen; Duisburg Germany