1. Institute of Digestive Endoscopy and Medical Center for Digestive Disease, The Second Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu 210011, P.R. China
2. Department of Gastroenterology, The Affiliated Huai'an No.�1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, P.R. China
3. Department of Biotherapy, The Second Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu 210011, P.R. China