Lijuan Wang1, Tingting Hu2, Xiaobo Zhu3. 1. Institute of Pathogen Biology and Immunology, North University of Hebei, No 11, Zuanshi South Road, 075000, Zhangjiakou, Hebei Province, People's Republic of China. 2. The First Affiliated Hospital, North University of Hebei, 075000, Zhangjiakou, People's Republic of China. 3. Institute of Pathogen Biology and Immunology, North University of Hebei, No 11, Zuanshi South Road, 075000, Zhangjiakou, Hebei Province, People's Republic of China. zjkzxb@163.com.