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2628797 
Journal Article 
Abstract 
Effect of inhaled dust-mite antigen on regional particle deposition and mucociliary clearance in allergic asthmatics 
Bennett, WD; Zeman, KL; Wu, J; Herbst, M; Hernandez, M; Peden, DB 
2010 
Yes 
American Journal of Respiratory and Critical Care Medicine
ISSN: 1073-449X
EISSN: 1535-4970 
181 
A2534 
English 
WOS:000208771001448 
is part of a larger document 3452678 Proceedings of the American Thoracic Society 2010 International Conference, May 14-19, 2010, New Orleans
Acute exacerbations in allergic asthmatics may lead to impaired ability to clear mucus from their airways. We have been measuring mucociliary clearance (MCC) in allergic asthmatics following inhaled dust mite allergen extract (Dermatophagoides farinae) challenge (increasing doses of extract until > 15% reduction in FEV1 or maximum dose). At 4 hours post allergen challenge, regional particle deposition and clearance (central-peripheral ratio (C/P), skew of #pixels vs. counts/pixel histogram, MCC, and clearance through 24 hours (%24hr) as an index of airway vs. alveolar deposition), were measured by gamma scintigraphy following controlled inhalation of Tc99m-labeled particles for comparison to that on a baseline study day. Of the 12 patients studied, nine responded to inhaled allergen challenge with >10% reduction in FEV1. In all cases lung function had returned to pre challenge values by 4 hours post-challenge. In these responders, C/P tended to increase (1.85 vs. 2.20, p = 0.12), skew increased (2.00 vs. 2.53, p = 0.01), and %24hr increased (52 vs. 66, p = 0.01) at 4 hrs post challenge compared to baseline, all indicating enhanced bronchial airway deposition of inhaled particles. Tracheobronchial MCC (i.e. corrected for differences in %24hr) tended to slow at 4 hr post challenge compared to basal conditions (average clearance through 2 hours post radio-particle inhalation = 28 vs 34% respectively). Non-responders had no change in regional deposition or MCC post challenge vs. baseline. These data suggest that 1) regional deposition of inhaled particles is especially sensitive at detecting mild airway obstruction not found by spirometry and 2) antigen-induced accumulation of airway mucus is still evident up to 4 hours post allergen challenge. The application of therapies designed to prevent reductions in or restore MCC after an acute antigen-induced exacerbation should be considered. Supported by NIH/NHLBI RO1 HL080337 and NIH/NIAID U19AI077437. 
American Thoracic Society 2010 International Conference 
New Orleans, LA 
May 14-19, 2010