Mucus properties in children with primary ciliary dyskinesia: comparison with cystic fibrosis.
OBJECTIVE
It has been assumed that cystic fibrosis (CF) lung disease is due in part to abnormal airway mucus. Primary ciliary dyskinesia (PCD) is a form of bronchiectasis that is similar to CF in many ways but is caused by congenital defects in mucociliary clearance. Our objective was to compare the biophysical and transport properties of CF and PCD sputa in subjects matched for age and degree of lung function impairment.


METHODS
PCD patients (n = 19; mean age, 9.5 +/- 3.0 years [+/- SD]; FEV1, 65.0 +/- 7.8 L) were recruited from the clinic at the Royal Brompton Hospital. Patients with CF (n = 30, mean age, 10.8 +/- 2.6 years; FEV1, 61.8 +/- 22.8 L) were identified from the Wake Forest University School of Medicine CF Center. Pulmonary function testing and sputum collection were performed as part of routine, scheduled clinic visits.


METHODS
Pulmonary function was measured by spirometry, and sputum was collected during the pulmonary function test maneuver. Some patients were longitudinally assessed at visits during the course of 3 years. Sputum properties measured were dynamic viscoelasticity, wettability, cohesivity, interfacial (surface) tension, solids composition, DNA and interleukin (IL)-8 concentration, in vitro mucociliary transportability, and cough transportability.


RESULTS
Inflammation as measured by IL-8 concentration was three times greater in the PCD sputa (p < 0.0001). There were no significant differences in the sputum biophysical or transport properties comparing CF with PCD sputum.


CONCLUSIONS
It is unlikely that established CF lung disease is principally due to abnormal sputum properties, and it is more likely that the biophysical and transport properties reflect disease severity regardless of whether bronchiectasis is due to CF or PCD.
Bush
Andrew
A
Pediatric Pulmonology, Imperial School of Medicine at National Heart and Lung Institute, London, UK.
Payne
Donald
D
Pike
Sarah
S
Jenkins
Gavin
G
Henke
Markus O
MO
Rubin
Bruce K
BK
D015415:Biomarkers / Q000378:metabolism; D002648:Child; D003550:Cystic Fibrosis / Q000378:metabolism* / Q000503:physiopathology; D004548:Elasticity; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism; D007619:Kartagener Syndrome / Q000378:metabolism* / Q000503:physiopathology; D009093:Mucus / Q000378:metabolism*; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D013147:Spirometry; D013183:Sputum / Q000378:metabolism; D014783:Viscosity
D015415:Biomarkers; D016209:Interleukin-8