Differences in Airway Inflammation in Cystic Fibrosis and Primary Ciliary Dyskinesia

Abstract

Cystic fibrosis (CF) and primary ciliary dyskinesia (PCD) patients both have chronic lung infection and neutrophilic inflammation, but there is a milder clinical phenotype in PCD. To understand the detailed inflammatory mechanisms in these two conditions in order to identify potential therapeutic targets and useful biomarkers of disease severity, spontaneously expectorated sputum was collected from CF and PCD patients with similar spirometry. Sputum was homogenized in phosphate-buffered saline, centrifuged, and the supernatants analyzed. Surprisingly, the level of neutrophil-stimulating activity was similar in CF and PCD patients, with a trend for lower amounts of CXC chemokines in CF patients. In an exploratory, hypothesis generating study, we found that levels of neutrophil elastase, cathepsin G, and elastin degradation products were significantly elevated in CF patients in exacerbation compared to stable PCD patients, despite similar spirometry in both groups. Neutrophil chemoattractants are similar or...