Effects of Co-Exposure to Air Pollution and Allergen
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ClinicalTrials.gov Identifier: NCT01792232 |
Recruitment Status
:
Completed
First Posted
: February 15, 2013
Last Update Posted
: September 29, 2017
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Condition or disease | Intervention/treatment | Phase |
---|---|---|
Allergies | Other: Allergen Other: Saline | Not Applicable |
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Purpose/Objective:
To study the effects of diesel exhaust particles on lung function and on allergic responses.
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Hypotheses:
Hypothesis 1: DE exposure augments systemic oxidative stress from allergen challenge in allergen-sensitized individuals.
Hypothesis 2: DE exposure augments allergen-specific immune response in allergen-challenged airways in sensitized individuals. These responses will be greater in asthmatic individuals than in non-asthmatics.
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Justification:
The use of diesel engines is increasing because they are more fuel-efficient than gasoline engines. However, diesel engines produce different emissions than gasoline engines. Diesel exhaust is emitted from the tailpipe of both "on-road" diesel engine vehicles (diesel cars, buses and trucks) and "non-road" diesel engines (locomotives, marine vessels and some construction equipment). Diesel exhaust consists of both gaseous and particulate air pollutants. Since people with asthma and allergic diseases appear to be sensitive to air pollution, we would like to know how diesel exhaust (DE) can affects your respiratory and immune systems. We are expecting that any responses that may occur will only be detectable through careful examination of cells and tissues (e.g., bronchoalveolar lavage (fluid from your lungs), blood, urine). Understanding these potentially subtle changes will help us prevent health problems associated with air pollution in the future.
- Research Method:
This is a blinded crossover experiment between two conditions (DE or filtered air, FA), randomized and counter-balanced to order. Data collection for each condition will be separated by a 4-week washout period.
Following each exposure, The investigators will use bronchoscopy (performed at the Vancouver General Hospital Endoscopy Suite) to deliver a diluent-controlled segmental allergen challenge (SAC). 24 h post-SAC, airway reactivity will be assessed with a methacholine challenge. 48 h post-SAC, bronchoalveolar lavage (BAL), airway brushes and tissue biopsies will be obtained in the same regions for analysis of immune activation. Nasal lavage samples will also be collected to examine responses in the upper airways and blood and urine will be studied to examine systemic responses. Spirometry and methacholine challenge will be used to assess effects on airway function
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 18 participants |
Allocation: | Randomized |
Intervention Model: | Crossover Assignment |
Masking: | Triple (Participant, Investigator, Outcomes Assessor) |
Primary Purpose: | Basic Science |
Official Title: | Effect of Exposure to Allergens and Air Pollution on Lung Function and Immunity |
Study Start Date : | October 2011 |
Actual Primary Completion Date : | November 2013 |
Actual Study Completion Date : | November 2013 |

Arm | Intervention/treatment |
---|---|
Active Comparator: Filtered air
Exposure for 2 hours to filtered air followed by subject specific allergen placed in lung
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Other: Allergen
Subject specific allergen is placed in the lungs on day 1 of each triad
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Experimental: Diesel exhaust
Exposure for 2 hours to diesel exhaust followed by subject specific allergen placed in lung
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Other: Allergen
Subject specific allergen is placed in the lungs on day 1 of each triad
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Active Comparator: Filtered air control
Exposure for 2 hours to filtered air followed by subject saline placed in lung
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Other: Saline
Saline will be placed in the lung on day 1 of each triad
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Active Comparator: Diesel exhaust control
Exposure for 2 hours to diesel exhaust followed by saline placed in lung
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Other: Saline
Saline will be placed in the lung on day 1 of each triad
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- Allergen-specific IgE [ Time Frame: 48 hours ]BAL IgE specific to the allergen used for allergen challenge will be assessed at 48 hrs, from the BAL, using immunocap assay
- Human immune response [ Time Frame: 48 hours ]Determine if allergen-induced eosinophilic activation (measured by flow cytometry) and a Th2-type cytokine pattern is augmented by DE (300 µg/m3 inhaled for two hours) exposure.
- Oxidative stress [ Time Frame: 48 hours ]Establish that bronchial segment allergen-induced oxidative stress (urine 8-isoprostane, measured by ELISA) is augmented by DE (300 µg/m3 inhaled for two hours) exposure.
- Airway reactivity [ Time Frame: 48 hours ]Determine if airway reactivity (measured by PC20 methacholine challenge) is augmented by DE (300 µg/m3 inhaled for two hours) exposure.

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Ages Eligible for Study: | 19 Years to 49 Years (Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- Age between 19 and 49 years.
- Non-smoking.
- Positive skin prick test for at least one of: birch, grass, or dust
Exclusion Criteria:
- Using inhaled corticosteroids
- Pregnant or planning to be pregnant in the next 12 months / Breastfeeding
- Usage of bronchodilators more than three times per week.
- Co-morbidities (as assessed by the primary investigator)
- Taking part in other studies
- Unwilling to withhold bronchodilator, aspirin, anti-coagulant, antihistamine or decongestant medications or caffeine prior to testing procedures.
- FEV1(Forced expiratory volume in one second) < 70% predicted.
- Allergy to lidocaine, fentanyl, midazolam or salbutamol.
- Unstable asthma (i.e exacerbation in 2 weeks preceding testing)

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01792232
Canada, British Columbia | |
University of British Columbia | |
Vancouver, British Columbia, Canada, V5Z 1M9 |
Principal Investigator: | Christopher Carlsten, MD, MPH | University of British Columbia |
Publications:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: | Christopher Carlsten, Principal Investigator, University of British Columbia |
ClinicalTrials.gov Identifier: | NCT01792232 History of Changes |
Other Study ID Numbers: |
H11-01831 |
First Posted: | February 15, 2013 Key Record Dates |
Last Update Posted: | September 29, 2017 |
Last Verified: | September 2017 |
Keywords provided by Christopher Carlsten, University of British Columbia:
Diesel exhaust Air pollution Airway responsiveness Allergies |