Presenter: Brandy Hill
Paper: Particle Depletion Does Not Remediate Acute Effects of Traffic-related Air Pollution and Allergen. A Randomized, Double-Blind Crossover Study
Authors: Denise J. Wooding, Min Hyung Ryu, Anke Huls, Andrew D. Lee, David T. S. Lin, Christopher F. Rider, Agnes C. Y. Yuen, and Chris Carlsten
Rationale: Diesel exhaust (DE), an established model of trafficrelated
air pollution, contributes significantly to the global burden of
asthma and may augment the effects of allergen inhalation. Newer
diesel particulate-filtering technologies may increaseNO2 emissions,
raising questions regarding their effectiveness in reducing harm from
associated engine output.
Objectives: To assess the effects of DE and allergen coexposure on
lung function, airway responsiveness, and circulating leukocytes, and
determine whether DE particle depletion remediates these effects.
Methods: In this randomized, double-blind crossover study, 14
allergen-sensitized participants (9 with airway hyperresponsiveness)
underwent inhaled allergen challenge after 2-hour exposures to DE,
particle-depleted DE (PDDE), or filtered air. The control condition
was inhaled saline after filtered air. Blood sampling and spirometry
were performed before and up to 48 hours after exposures. Airway
responsiveness was evaluated at 24 hours.
Measurements and Main Results: PDDE plus allergen
coexposure impaired lung function more than DE plus allergen,
particularly in those genetically at risk. DE plus allergen and PDDE
plus allergen each increased airway responsiveness in normally
responsive participants.DEplus allergen increased blood neutrophils
and was associated with persistent eosinophilia at 48 hours. DE and
PDDE each increased total peripheral leukocyte counts in a manner
affected by participant genotypes. Changes in peripheral leukocytes
correlated with lung function decline.
Conclusions: Coexposure to DE and allergen impaired lung
function, which was worse after particle depletion (which increased
NO2). Thus, particulates are not necessarily the sole or main
culprit responsible for all harmful effects of DE. Policies and
technologies aimed at protecting public health should be scrutinized
in that regard.
Clinical trial registered with www.clinicaltrials.gov (NCT02017431).
Keywords: diesel exhaust; asthma; filter; genetic susceptibility