1 School of Medicine, Tsinghua University, Beijing, China.
2 Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA, USA.
3 Center for Medicine and the Microbiome, University of Pittsburgh, Pittsburgh, PA, USA.
4 Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine and University of Pittsburgh Medical Center, Pittsburgh, PA, USA.