1. Department of Microbiology and Immunology, Basic Medical College, Shanxi Medical University, Jinzhong, Shanxi 030619, P.R. China
2. Department of Rheumatology, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
3. Third Hospital of Shanxi Medical University, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Taiyuan, Shanxi 030032, P.R. China
4. Department of Health Statistics, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
5. Department of Rheumatology, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China