NLRP3 inflammasome is activated during infectious exacerbations of chronic obstructive pulmonary disease (ECOPD). a) Protein concentration of caspase-1, interleukin (IL)-1β and IL-18 in sputum of COPD patients studied during an ECOPD (V1) and at recovery (V2). Data are presented as mean±sem of n=41 (V1) and n=41 (V2). b) Sputum concentrations of caspase-1, IL-1β and IL-18 in COPD patients studied during an episode of ECOPD of infectious or noninfectious origin. Data are presented as mean±sem of n=17 infectious V1 (during ECOPD), n=14 infectious V2 (recovery), n=30 noninfectious V1 and n=21 noninfectious V2 individuals. *: p<0.05; **: p<0.01. c) Representative Western blot for ASC sputum samples from ECOPD patients, denoting oligomeric ASC complexes, a hallmark of inflammasome activation. ASC oligomeric complexes were not detected when samples were run under reduced conditions. MK: marker.