TY - JOUR T1 - Antimicrobial peptides in the real world: implications for cystic fibrosis JF - European Respiratory Journal JO - Eur Respir J SP - 617 LP - 618 DO - 10.1183/09031936.00017007 VL - 29 IS - 4 AU - P. S. Hiemstra Y1 - 2007/04/01 UR - http://erj.ersjournals.com/content/29/4/617.abstract N2 - The continuous cycle of respiratory infections and lung inflammation is a hallmark of cystic fibrosis (CF) lung disease and plays a central role in respiratory failure that develops in end-stage disease. Effective mucociliary clearance is an essential mechanism in host defence against infection and requires a functional “two-layer” mucus clearance system composed of a periciliary liquid layer and an overlying mucus layer in which inhaled substances are trapped 1. Together these two separate layers constitute airway surface liquid (ASL). Adequate hydration is essential for an optimal function of the mucociliary clearance system. Dehydration of the mucosal surface in CF may not only hamper effective mucus clearance but also causes adhesion of mucus to the epithelial surface. This results in airway flow obstruction, inflammation and favouring infections. In addition to this defect in mucociliary clearance, an inadequate function of the secreted effector molecules of the innate immune system in the lung has been suggested to contribute to increased susceptibility to infection in CF 2. Antimicrobial peptides and proteins are an essential element of this innate immune system, and the airway epithelium forms a range of these compounds 3. The main classes of antimicrobial peptides produced by airway epithelial cells are the β-defensins and the cathelicidins (LL-37 in humans). The antimicrobial activity of most of these peptides is markedly restricted in isotonic and hypertonic conditions, and optimal activity under laboratory conditions is … ER -