1. The Institute of Transplantation Science, Organ Transplantation Center, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
2. Beijing Institute of Hepatology, Beijing Youan Hospital, Capital Medical University, Beijing 100069, P.R. China
3. Department of Clinical Laboratory, Haidian Maternal and Child Health Hospital, Beijing 100080, P.R. China