1. Department of Basic Medicine, Haihe Clinical College of Tianjin Medical University, Tianjin 300350, P.R. China
2. Key Research Laboratory for Infectious Disease Prevention for State Administration of Traditional Chinese Medicine, Tianjin Institute of Respiratory Diseases, Tianjin 300350, P.R. China
3. Department of Pathology, Tianjin University Haihe Hospital, Tianjin 300350, P.R. China
4. Department of Respiratory Medicine, Tianjin University Haihe Hospital, Tianjin 300350, P.R. China