Pathogenesis of lung disease in cystic fibrosis

Lung disease in cystic fibrosis is primarily due to a defect in the cystic fibrosis transmembrane regulating protein (CFTR). This results in abnormal chloride transfer across epithelial membranes causing an excessively viscid mucus lining of the airways. Bacterial invasion particularly with Staphylococcus aureus, Haemophilus influenzae and Pseudomonas aeruginosa stimulates a vigorous and excessive primarily neutrophil-driven inflammatory response throughout the lungs. Products of this inflammation not only damage incoming bacteria but also the host tissue itself. Over a period of years this chronic suppurative process results in permanent ongoing lung destruction principally manifested as bilateral bronchiectasis.