1. Department of Gastroenterology, Peking University Third Hospital , Beijing, China
2. Beijing Key Laboratory for Helicobacter Pylori Infection and Upper Gastrointestinal Diseases , Beijing, China
3. Department of Basic Medical Sciences, School of Medicine, Tsinghua University , Beijing, China
4. Institute for Immunology, Tsinghua University , Beijing, China
5. Department of Laboratory Medicine, Peking University Third Hospital , Beijing, China