NLRP3 and chronic obstructive pulmonary disease: In peripheral blood mononuclear cells (PBMCs) and bronchial tissues, the mRNA levels of NLRP3, Caspase-1, apoptosis-associated spec-like protein containing CARD (ASC), IL-18, and IL-1b were elevated in AECOPD comparing with smokers; however, the mRNA levels of these gene were decreased in COPD patients in stable stage (Wang H. et al., 2018), suggesting that NLRP3 inflammasome is associated with AECOPD.