Sibila O, et al. - Among adults with bronchiectasis (n=135), researchers investigated pulmonary and systemic levels of antimicrobial peptide (AMP) as well as their link with disease severity and future risk of exacerbations. The participants were prospectively enrolled at three European centres. They used ELISA to determine baseline levels of cathelicidin LL-37, lactoferrin, lysozyme and secretory leucocyte protease inhibitor (SLPI) in serum and sputum samples. For 12 months, they observed the patients. Among participants, dysregulated sputum AMP levels were evident, with the frequent exacerbator phenotype characterized by elevated LL-37 and decreased SLPI levels. Findings revealed the association of elevated LL-37 and reduced SLPI levels with Pseudomonas aeruginosa infection. Future risk of exacerbations in bronchiectasis could be predicted by elevated LL-37 and reduced SLPI levels.