[1] Tsinghua Univ, Sch Med, Beijing, Peoples R China
[2] Beijing Univ Chinese Med, Beijing, Peoples R China
[3] China Japan Friendship Hosp, Natl Clin Res Ctr Resp Dis, Ctr Resp Med, Dept Pulm & Crit Care Med, Beijing 100029, Peoples R China
[4] Chinese Acad Med Sci & Peking Union Med Coll, Inst Resp Med, Beijing, Peoples R China
[5] Tsinghua Univ Peking Univ Joint Ctr Life Sci, Beijing, Peoples R China
[6] Capital Med Univ, Dept Resp Med, Beijing, Peoples R China