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AllergiesNCT01792232

Effects of Co-Exposure to Air Pollution and Allergen

A study testing Allergen and Saline in people with Allergies, run by University of British Columbia at 1 site in Canada.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The investigators are investigating the effects of combined exposures to diesel exhaust and allergens on lung function and on the immune system. After exposing individuals to either filtered air or carefully controlled levels of diesel exhaust in our exposure chamber, The investigators will use a procedure called… Read more about this study

Who is it for?
Ages 19 to 49 yearsHealthy volunteers can take part
Conditions the study is for
Allergies
What is being tested?
Allergen and Saline
Could I receive a placebo?
No, everyone receives an active treatment
How many people
18 participants
Where
1 siteCanada
Study dates
Oct 2011to Nov 2013
Phase
Interventional
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 19 to 49 years
  • All sexes
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • Age between 19 and 49 years.
  • Non-smoking.
  • Positive skin prick test for at least one of: birch, grass, or dust

Who cannot join

  • 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.
Show all 9Show fewer
  • 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)

Trial locations and contacts

1 site in 1 country.

Canada1 site
  • University of British Columbia

    Vancouver, British Columbia, V5Z 1M9

Other trials in Canada

About this study

Official title: Effect of Exposure to Allergens and Air Pollution on Lung Function and Immunity

The investigators are investigating the effects of combined exposures to diesel exhaust and allergens on lung function and on the immune system. After exposing individuals to either filtered air or carefully controlled levels of diesel exhaust in our exposure chamber, The investigators will use a procedure called bronchoscopy (whereby a thin, flexible tube is passed down the throat and into the lungs) to place a small amount of allergen directly in the lung. 48h later, the bronchoscopy will be repeated so that samples can be collected from the lungs. After 1mo, the entire procedure will be repeated with the alternate exposure.

Read the detailed description
  1. Purpose/Objective: To study the effects of diesel exhaust particles on lung function and on allergic responses.
  2. 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.
  3. 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.
  4. 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

Conditions
Allergies
Being tested
Allergen, Saline
Keywords
Diesel exhaust, Air pollution, Airway responsiveness, Allergies
Medical subject headings
Hypersensitivity

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • AllergenOther

    Subject specific allergen is placed in the lungs on day 1 of each triad

  • SalineOther

    Saline will be placed in the lung on day 1 of each triad

Study groups in NCT01792232
Study groupRoleWhat they receive
Filtered airActive comparatorExposure for 2 hours to filtered air followed by subject specific allergen placed in lung
Receives: Other: Allergen
Diesel exhaustExperimentalExposure for 2 hours to diesel exhaust followed by subject specific allergen placed in lung
Receives: Other: Allergen
Filtered air controlActive comparatorExposure for 2 hours to filtered air followed by subject saline placed in lung
Receives: Other: Saline
Diesel exhaust controlActive comparatorExposure for 2 hours to diesel exhaust followed by saline placed in lung
Receives: Other: Saline

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Allergen-specific IgE

    BAL IgE specific to the allergen used for allergen challenge will be assessed at 48 hrs, from the BAL, using immunocap assay

    Measured: 48 hours

Secondary outcomes (3)
  1. Human immune response

    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.

    Measured: 48 hours

  2. Oxidative stress

    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.

    Measured: 48 hours

  3. Airway reactivity

    Determine if airway reactivity (measured by PC20 methacholine challenge) is augmented by DE (300 µg/m3 inhaled for two hours) exposure.

    Measured: 48 hours

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted15 Feb 2013 (estimated)
  2. Study startOct 2011
  3. Primary completionNov 2013
  4. Study completionNov 2013

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Basic science
Allocation
Randomised
Intervention model
Crossover
Masking
Triple blind
Who is masked
Participant, Investigator, Outcomes assessor
Enrolment
18 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT01792232
Sponsor's protocol ID
H11-01831
Status last verified
Sep 2017
First submitted
14 Nov 2012
Last updated
29 Sep 2017
Results posted
No
Data monitoring committee
No

Publications

  • Saxon A, Diaz-Sanchez D. Air pollution and allergy: you are what you breathe. Nat Immunol. 2005 Mar;6(3):223-6. doi: 10.1038/ni0305-223. No abstract available.

    PubMed 15716966
  • Rudell B, Ledin MC, Hammarstrom U, Stjernberg N, Lundback B, Sandstrom T. Effects on symptoms and lung function in humans experimentally exposed to diesel exhaust. Occup Environ Med. 1996 Oct;53(10):658-62. doi: 10.1136/oem.53.10.658.

    PubMed 8943829
  • Diaz-Sanchez D, Tsien A, Fleming J, Saxon A. Combined diesel exhaust particulate and ragweed allergen challenge markedly enhances human in vivo nasal ragweed-specific IgE and skews cytokine production to a T helper cell 2-type pattern. J Immunol. 1997 Mar 1;158(5):2406-13.

    PubMed 9036991
  • Fujieda S, Diaz-Sanchez D, Saxon A. Combined nasal challenge with diesel exhaust particles and allergen induces In vivo IgE isotype switching. Am J Respir Cell Mol Biol. 1998 Sep;19(3):507-12. doi: 10.1165/ajrcmb.19.3.3143.

    PubMed 9730879
  • Hashimoto K, Ishii Y, Uchida Y, Kimura T, Masuyama K, Morishima Y, Hirano K, Nomura A, Sakamoto T, Takano H, Sagai M, Sekizawa K. Exposure to diesel exhaust exacerbates allergen-induced airway responses in guinea pigs. Am J Respir Crit Care Med. 2001 Nov 15;164(10 Pt 1):1957-63. doi: 10.1164/ajrccm.164.10.2011070.

    PubMed 11734452
  • Carlsten, C., et al., Symptoms and perceptions in response to a controlled diesel exhaust exposure in healthy adults. Environmental Research, In Review

  • Riedl MA, Diaz-Sanchez D, Linn WS, Gong H Jr, Clark KW, Effros RM, Miller JW, Cocker DR, Berhane KT; HEI Health Review Committee. Allergic inflammation in the human lower respiratory tract affected by exposure to diesel exhaust. Res Rep Health Eff Inst. 2012 Feb;(165):5-43; discussion 45-64.

    PubMed 22852485
  • Carlsten C, Melen E. Air pollution, genetics, and allergy: an update. Curr Opin Allergy Clin Immunol. 2012 Oct;12(5):455-60. doi: 10.1097/ACI.0b013e328357cc55.

    PubMed 22885891
  • Kramer MM, Hirota JA, Sood A, Teschke K, Carlsten C. Airway and serum adipokines after allergen and diesel exposure in a controlled human crossover study of atopic adults. Transl Res. 2017 Apr;182:49-60. doi: 10.1016/j.trsl.2016.11.001. Epub 2016 Nov 9.

    PubMed 27886976
  • Hosseini A, Hirota JA, Hackett TL, McNagny KM, Wilson SJ, Carlsten C. Morphometric analysis of inflammation in bronchial biopsies following exposure to inhaled diesel exhaust and allergen challenge in atopic subjects. Part Fibre Toxicol. 2016 Jan 13;13:2. doi: 10.1186/s12989-016-0114-z.

    PubMed 26758251
  • Carlsten C, Blomberg A, Pui M, Sandstrom T, Wong SW, Alexis N, Hirota J. Diesel exhaust augments allergen-induced lower airway inflammation in allergic individuals: a controlled human exposure study. Thorax. 2016 Jan;71(1):35-44. doi: 10.1136/thoraxjnl-2015-207399. Epub 2015 Nov 16.

    PubMed 26574583

Questions about this trial

What is this clinical trial studying?

A study testing Allergen and Saline in people with Allergies, run by University of British Columbia at 1 site in Canada.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 3 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 29 Sep 2017. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Allergen-specific IgE (time frame: 48 hours). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT01792232, which also lists 11 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Sep 2017.

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