Linrong Lu1,2,3. 1. Institute of Immunology, and Department of Rheumatology in Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, P. R. China. lu_linrong@zju.edu.cn. 2. Zhejiang University-University of Edinburgh Institute, Zhejiang University School of Medicine, Haining, P. R. China. lu_linrong@zju.edu.cn. 3. Dr. Li Dak Sum and Yip Yio Chin Center for Stem Cells and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, P. R. China. lu_linrong@zju.edu.cn.