1 Department of Gastroenterology and Hepatology, University Hospital Essen, Hufelandstr. 55, D-45147 Essen, Germany.
2 Institute of Virology, University Hospital Essen, Hufelandstr. 55, D-45147 Essen, Germany.
3 Department of Gastroenterology and Hepatology, University Hospital Essen, Hufelandstr. 55, D-45147 Essen, Germany. Electronic address: Christian.Lange@uk-essen.de.