The upper airway response to pollen is enhanced by exposure to combustion particulates: a pilot human experimental challenge study.
Hauser-R; Rice-TM; Krishna Murthy-GG; Wand-MP; Lewis-D; Bledsoe-T; Paulauskis-J
Environ Health Perspect 2003 Apr; 111(4):472-477
Although human experimental studies have shown that gaseous pollutants enhance the inflammatory response to allergens, human data on whether combustion particulates enhance the inflammatory response to allergen are limited. Therefore, we conducted a human experimental study to investigate whether combustion particulates enhance the inflammatory response to aeroallergens. "Enhancement" refers to a greater-than-additive response when combustion particulates are delivered with allergen, compared with the responses when particulates and allergen are delivered alone. Eight subjects, five atopic and three nonatopic, participated in three randomized exposure-challenge sessions at least 2 weeks apart (i.e., clean air followed by allergen, particles followed by no allergen, or particles followed by allergen). Each session consisted of nasal exposure to combustion particles (target concentration of 1.0 mg/m3) or clean air for 1 hr, followed 3 hr later by challenge with whole pollen grains or placebo. Nasal lavage was performed immediately before particle or clean air exposure, immediately after exposure, and 4, 18 and 42 hr after pollen challenge. Cell counts, differentials, and measurement of cytokines were performed on each nasal lavage. In atopic but not in nonatopic subjects, when allergen was preceded by particulates, there was a significant enhancement immediately after pollen challenge in nasal lavage leukocytes and neutrophils (29.7 × 10(3) cells/mL and 25.4 ×10(3) cells/mL, respectively). This represents a 143% and 130% enhancement, respectively. The enhanced response for interleukin-4 was 3.23 pg/mL (p = 0.06), a 395% enhancement. In atopic subjects there was evidence of an enhanced response when particulates, as compared to clean air, preceded the allergen challenge
Airborne-particles; Airway-obstruction; Allergens; Combustibility; Cellular-reactions; Respiratory-hypersensitivity; Respiratory-system-disorders; Particulates; Exposure-methods; Humans; Pollutants; Nasal-cavity; Combustion-products; Combustion-gases
R. Hauser, Department of Environmental Health, Occupational Health Program, Harvard School of Public Health, Building I, Room 1405, 665 Huntington Avenue, Boston, Massachusetts 02115 USA.
Disease and Injury: Asthma and Chronic Obstructive Pulmonary Disease
Environmental Health Perspectives