IL17A and chronic obstructive pulmonary disease: Bafadel et al. investigated the expression of inflammatory biomarkers in patients`sputum during COPD exacerbation and found that IL-1β levels correlate significantly with COPD exacerbation due to bacterial infection [8], and recently, in a small cohort of COPD patients, levels of serum IL-1β and IL-17 were found elevated in COPD exacerbation compared to stable COPD and healthy controls [24].