1. Department of Spinal Surgery, Tianjin Hospital, Tianjin, P. R. China
2. Department of Immunology, Tianjin Key Laboratory of Cellular and Molecular Immunology, Key Laboratory of Educational Ministry of China, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, P. R. China
3. Department of Medical Laboratory, Tianjin Hospital, Tianjin, P. R. China