Comparative Study of Pathophysiological Mechanisms and Bronchial Response in Occupational Asthma to Wheat Flour and Quaternary Ammonium Compounds During Standardized Bronchial Provocation Tests

Study Overview
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Brief Summary
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Occupational asthma (OA) caused by high molecular weight (HMW) substances have been shown to induce predominantly an eosinophilic inflammation. In contrast, OA caused by low molecular weight (LMW) substances results in a neutrophilic inflammation. In addition, data regarding phenotype of lymphocytes in OA caused by HMW and LMW substances are scarce. The use of a new equipment will allow the realization of specific standardized bronchial challenges (BC) to occupational agents. Thus, we propose to study in more detail the cellular mechanisms involved during BC to HMW and LMW occupational agents in a double-blind placebo controlled study.

Official Title
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Comparative Study of Pathophysiological Mechanisms and Bronchial Response in Occupational Asthma to Wheat Flour and Quaternary Ammonium Compounds During Standardized Bronchial Provocation Tests

Conditions
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Occupational Asthma

Intervention / Treatment
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* Other: standardized bronchial challenge test (SCL SCL • • GenaSOL ™ GenaSIC ™)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: For patients with occupational asthma to wheat flour: Clinical history, A positive skin test to wheat flour and / or specific IgE to wheat flour For patients with occupational asthma to quaternary ammonium compounds: -Clinical history, For two types of asthma: Patients must have a worsening of bronchial hyperreactivity during work compared to a rest period assessed by a metacholine challenge FEV before challenge (nonspecific and specific) must be> 70%. Exclusion Criteria: Asthmas: no occupational asthma: secondary to clinically relevant sensitization to an allergen domestic aggravated at work.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo<br> | Other: standardized bronchial challenge test (SCL SCL • • GenaSOL ™ GenaSIC ™)<br>* At Visit 1: Patients are selected and they will receive a metacholine challenge test during and outside of work. After randomization, patients undergo a standardized bronchial challenge test (SCL SCL • • GenaSOL ™ GenaSIC ™) to either an wheat flour allergen extract or didecyldimethylammonium chloride or placebo. Each bronchial challenge test is followed by blood sampling at different time points and induced sputum. The immediate bronchial response and late bronchial response will be recorded.<br>|
| Active Comparator: flour allergen extract or quaternary ammonium compound<br> | Other: standardized bronchial challenge test (SCL SCL • • GenaSOL ™ GenaSIC ™)<br>* At Visit 1: Patients are selected and they will receive a metacholine challenge test during and outside of work. After randomization, patients undergo a standardized bronchial challenge test (SCL SCL • • GenaSOL ™ GenaSIC ™) to either an wheat flour allergen extract or didecyldimethylammonium chloride or placebo. Each bronchial challenge test is followed by blood sampling at different time points and induced sputum. The immediate bronchial response and late bronchial response will be recorded.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Assessment of cellular inflammation in peripheral blood and induced sputum | Before and after bronchial challenge: assessment of cellular inflammation in peripheral blood and induced sputum, exhaled NO; assessment of peripheral T lymphocyte phenotype. | 33 months |