FRIDAY, April 28 (HealthDay News) -- Inhalation of elemental carbon ultrafine particles (EC-UFP), a major component of urban air pollution, causes a significant increase in airway inflammation in sensitized mice when given 24 hours before an allergen challenge, according to a study in the April issue of the Journal of Allergy and Clinical Immunology.
Francesca Alessandrini, Ph.D., of the ZAUM Center for Allergy and Environment in Munich, Germany, and colleagues studied ovalbumin-sensitized mice and non-sensitized controls. The mice were exposed to ultrafine carbon particles 24, 96 or 168 hours before an ovalbumin aerosol challenge, or 24 or 72 hours after the challenge. Allergic inflammation was determined using a bronchoalveolar lavage cell count, cytokine/total protein assays, lung histology and measurement of airway hyperresponsiveness.
Sensitized mice that inhaled the EC-UFP 24 hours before receiving an allergen challenge showed significant increase in bronchoalveolar lavage inflammatory cell infiltrate, protein, IL-4, IL-5 and IL-13, compared with controls. However, sensitized mice that were exposed to the particles after the allergen challenge showed only moderate negative responses.
"To the best of our knowledge, our study is the first to demonstrate that in sensitized animals, inhalation of relatively inert EC-UFP has strong adjuvant activity when inhaled before allergen challenge, whereas EC-UFP inhalation during an ongoing allergic inflammation does not," the authors write. "Thus the sequence of events seems to be critical and should be considered when studying in vivo effects of particulate matter exposure."
Abstract
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