*Corresponding to
Xuebing Feng, M.D. and Ph.D., Department of Rheumatology and Immunology, the affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008, P.R.China (email: fengxuebing@hotmail.com)
Xiaojun Tang, Ph.D., Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210008, China (email: xjtang09@163.com)