IL-33 Expression Is Lower in Current Smokers at both Transcriptomic and Protein Levels.

IL-33 is a proinflammatory cytokine thought to play a role in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD). A recent clinical trial using an anti-IL-33 antibody showed a reduction in exacerbation and improved lung function in ex-smokers but not current smokers with COPD. This study aimed to understand the effects of smoking status on IL-33.