[1] Univ Duisburg Essen, Univ Clin Essen, Dept Gastroenterol & Hepatol, D-45122 Essen, Germany
[2] Elisabeth Hosp, Dept Gastroenterol & Hepatol, D-58638 Iserlohn, Germany
[3] Univ Duisburg Essen, Univ Clin Essen, Inst Pharmacogenet, D-45122 Essen, Germany
[4] Univ Duisburg Essen, Univ Clin Essen, Inst Pathol, D-45122 Essen, Germany
[5] Helios Clin, Dept Gastroenterol & Hepatol, D-42549 Velbert, Germany
[6] Max Grundig Clin, Dept Gastroenterol & Hepatol, D-77815 Buhl, Germany