Evangelisches Krankenhaus Kalk, University of Cologne, Germany. Apheresis Center Rostock (ACR), Rostock, Germany. Department of Medicine I, Agaplesion Markus Hospital and Crohn Colitis Clinical Research Center Rhein-Main, Frankfurt/Main, Germany. Department of Internal Medicine IV (Gastroenterology, Hepatology, Infectious Diseases), University Hospital of Jena, Jena, Germany. Department of Pathology, University of Cologne, Germany.