1. Department of Rheumatology and Immunology, Peking University People's Hospital
2. Department of Rheumatology and Immunology, Beijing Friendship Hospital, Capital Medical University, Beijing
3. Department of Rheumatology and Immunology, People's Hospital of Hebei Province, Shijiazhuang
4. Department of Rheumatology and Immunology, Handan First Hospital, Handan
5. Department of Rheumatology and Immunology, Tengzhou Central People's Hospital, Tengzhou, China.