1. The First Clinical Medical College, Lanzhou University, Lanzhou, Gansu, China;
2. Respiratory medicine department, Beijing Geriatric Hospital, Beijing, China;
3. Department of Hematology, Shanxi Provincial People’s Hospital, Xian, Shanxi, China;
4. People’s Hospital of Jingyuan County, Jingyuan, Baiyin, Gansu, China;
5. Department of Hematology, The First Affiliated Hospital, Lanzhou University, Lanzhou, Gansu, China;
6. Department of Anatomy and Histology, Lanzhou University, School of Basic Medical Sciences, Lanzhou, China