IL33 and chronic obstructive pulmonary disease: Because the release of mtROS and the presence of 8-OH-dG are able to induce the activation of NLRP3 inflammasome and because we found that NLRP3 protein levels are higher in unstable COPD patients, we went on by analyzing the molecular mechanism underlying the release of IL-18 and IL-33 from unstable COPD-derived PBMCs after combustion-generated UFP exposure.