However, NRLP3 inflammasome activation may be important during viral and bacterial infections.11, 13 Previous studies have shown elevated levels of IL-1β in exhaled breath condensate and sputum during COPD exacerbations, particularly when associated with bacterial infections.40 We observed a modest, albeit significant, reduction of IL-1RA in the BAL of patients with stable COPD compared with control smokers with normal lung function, which is in line with previous studies,41 but without significant differences in their IL-1β/IL-1RA ratio. This evidence concerns the gene IL1B and bacterial infectious disease.