80949
document
Effect of six-hour exposure to nitrogen dioxide on early-phase nasal response to allergen challenge in patients with a history of seasonal allergic rhinitis . BACKGROUND Recent studies have suggested that exposure to air pollutants may enhance the airway responsiveness of susceptible individuals to inhaled allergen . METHODS To investigate the effect of exposure to nitrogen dioxide ( NO2 ) on nasal airways resistance ( NAR ) and inflammatory mediators in nasal lavage fluid , eight subjects with a history of seasonal allergic rhinitis , who were tested out of season , were exposed in a randomized single-blind , crossover study to either air or 400 ppb NO2 for 6 hours . The changes in NAR and eosinophil cationic protein ( ECP ) , mast cell tryptase ( MCT ) , neutrophil myeloperoxidase ( MPO ) , and interleukin-8 ( IL-8 ) in nasal lavage fluid before and after exposure were evaluated . Another group of eight subjects with a history of seasonal allergic rhinitis were also randomized to exposure to air or 400 ppb NO2 for 6 hours and then challenged with allergen , before evaluation for changes in NAR and changes in ECP , MCT , MPO , and IL-8 in nasal lavage fluid . RESULTS Exposure to air or NO2 did not alter either NAR or the levels of ECP , MCT , MPO , or IL-8 in nasal lavage fluid . Allergen challenge after exposure to both air and NO2 significantly ( p < 0.05 ) increased levels of MCT , but not MPO and IL-8 in the nasal lavage fluid . In addition , allergen challenge after exposure to NO2 but not air , significantly increased levels of only ECP in nasal lavage fluid ( p < 0.05 ) . CONCLUSIONS These results suggest that acute exposure to NO2 at concentrations found at the curbside in heavy traffic during episodes of pollution , may " prime " eosinophils for subsequent activation by allergen in individuals with a history of seasonal allergic rhinitis .
80950
Intervention_Pharmacological
nitrogen dioxide
80951
Intervention_Pharmacological
nitrogen dioxide ( NO2 )
80952
Intervention_Control
air
80953
Intervention_Pharmacological
NO2
80954
Intervention_Pharmacological
NO2
80955
Intervention_Pharmacological
NO2
80956
Intervention_Pharmacological
NO2
80957
Intervention_Pharmacological
NO2
80958
Intervention_Pharmacological
NO2
80959
Outcome_Physical
nasal response
80960
Outcome_Physical
changes in NAR and eosinophil cationic protein ( ECP ) , mast cell tryptase ( MCT ) , neutrophil myeloperoxidase ( MPO ) , and interleukin-8 ( IL-8 ) in nasal lavage fluid
80961
Outcome_Physical
changes in NAR
80962
Outcome_Physical
changes in ECP
80963
Outcome_Physical
MCT
80964
Outcome_Physical
MPO
80965
Outcome_Physical
IL-8 in nasal lavage fluid
80966
Outcome_Physical
NAR
80967
Outcome_Physical
levels of ECP , MCT , MPO , or IL-8
80968
Outcome_Physical
MCT
80969
Outcome_Physical
MPO
80970
Outcome_Physical
IL-8
80971
Outcome_Physical
ECP in nasal lavage
80972
Participant_Condition
patients with a history of seasonal allergic rhinitis
80973
Participant_Condition
susceptible individuals
80974
Participant_Sample-size
eight subjects
80975
Participant_Sample-size
Another group of eight