Zhang Qiurui Q Department of respiratory medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, - - 2014 Viral infection is a significant cause of chronic obstructive pulmonary disease (COPD) and acute exacerbation of COPD. RIG-I-like receptors (RLRs), including RIG-I and MDA-5, are important pattern recognition receptors for viral elimination.