1. Department of Human Anatomy, Chengde Medical University, Chengde, Hebei 067000, P.R. China
2. Department of Immunology, Chengde Medical University, Chengde, Hebei 067000, P.R. China
3. Department of Clinical Laboratory, Affiliated Hospital of Chengde Medical University, Chengde, Hebei 067000, P.R. China