1 Department of Respiratory and Critical Care Medicine, Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, China.
2 Xinxiang Medical University, Xinxiang, Henan 453003, China.
3 Department of Pneumology and Respiratory Care Medicine, Thoraxklinik and Translational Lung Research Center, University of Heidelberg, Heidelberg D-69126, Germany.