recruitement difficulty

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.

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.