Figure 1. Pathogenic idea of CF lung disease (3),(4). In a healthy subject, the airway epithelium is lined by a mucus layer (ML) residing atop the so-called periciliary liquid layer (PCL); A. Due to the presence of the low-viscosity PCL, efficient mucociliary clearance is facilitated, whereby velocity of the mucus layer decreases from proximal to periphery lung generations. In CF airways, volume of both layers is successively depleted, leading to the complete removal of the PCL (B, C). The mucus layer becomes adherent to the epithelial surface and, as a consequence, mucociliary clearance slows down and stops.
