Asthma is one of the most common diseases affecting about 2.5 million Canadians, and can result in reduced quality of life and difficulties with work and school. Once the disease has become established with irreversible changes in the lungs it can be very difficult to treat. Severe asthma although less common than mild asthma uses more healthcare resources.

The objective of this project is to find out how the changes in the lung develop in severe asthma. Once this is known then new treatments can be developed to prevent irreversible damage to the lungs.

Volunteers will have substances sprayed up their nose and then samples collected from their nose. Levels of proteins and cells can be measured in these samples. This will give an indication of the type of inflammation that occurs.

The usual method of investigating the changes that occur in asthma is to challenge the lungs. Samples have to then be collected from the lungs. This can be in the form of sputum which must be treated to break it down to a liquid or washed out during a camera test. These methods cause problems with measuring proteins and they are broken down or diluted. Because the nose is easily accessible samples can be obtained at many time points. Because the samples can be collected directly from the nose the problems with obtaining samples from the lung are avoided.

Inclusion Criteria:

• 1 Subjects over the age of 18 2 Subjects able to give written informed consent 3 Subjects able to comply with study procedures and protocol 4 Subjects with a history of allergic asthma 5 Subjects with a positive skin prick test to a common aeroallergen 6 Subjects who are otherwise healthy with no other health problems

Exclusion Criteria:

1. Subjects with a viral URTI within 2 weeks prior to screening.

2. Subjects with a TNSS> 2 at screening

3. Subjects with a structural nasal abnormality or nasal polyps on examination, a history of frequent nose bleeding, nasal surgery within the previous 3 months.

4. Subjects who are a current smoker or have a history of smoking within the previous 3 months.

5. Subjects who have used a medication that could affect responses to nasal challenge (eg corticosteroids, decongestants, anti-histamines) or any other nasally applied medication within 2 weeks prior to screening.

6. Subjects who have participated in any other clinical trials within the previous 3 months.

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