1. Department of Gastroenterology, Hepatology and Infectious Diseases, Research Center Immunology/Institute of Experimental Internal Medicine, and Pathology, Otto-von-Guericke University, Magdeburg, Germany; Department of Medicine & Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong; and Department of Gastroenterology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China