1. Department of Respiratory and Critical Care Medicine, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
2. Scottish Centre for Respiratory Medicine, University of Dundee, Dundee, United Kingdom
3. Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
4. Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom; and
5. Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania