Effects of Allergen Inhalation on Adenosine Receptor Expression in Sputum and Peripheral Blood

Asthmatic Subjects - Inclusion Criteria: * Clinical diagnosis of asthma * Steroid naive or subjects not using their inhaled steroids for the last 4 weeks, short-acting beta-agonist for rescue medication * FEV1 \> 70% of predicted * Positive skin prick test for house dust mite, cat or grass pollen * PC20 methacholine or histamine \< 8 mg/ml Asthmatic Subjects - Exclusion Criteria: * Use of systemic steroids in the previous 6 weeks * Asthma exacerbations in the previous 6 weeks * Current or ex-smokers with ≥ 10 pack-years (≥ 2 pipe pack-years), ex smokers who stopped less than 1 year ago Healthy Subjects - Inclusion Criteria: * No airway complaints * FEV1 \> 90% of predicted * Negative skin prick test * PC20 methacholine or histamine \> 8 mg/ml Healthy Subjects - Exclusion Criteria: * Use of steroids in the previous 6 weeks * Current or ex-smokers with ≥ 10 pack-years (≥ 2 pipe pack-years), ex smokers who stopped less than 1 year ago