1. Department of Pulmonary and Critical Care Medicine, The First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan 610500, P.R. China
2. Department of Pathology, The First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan 610500, P.R. China
3. School of Laboratory Medicine, Chengdu Medical College, Chengdu, Sichuan 610500, P.R. China