BDNF has been linked to the pathogenesis of airway hyperresponsiveness in asthma. In this trial, the impact of a treatment with salmeterol and salmeterol / fluticasone on BDNF concentrations will be assessed in patients with asthma. The investigators hypothesize that salmeterol impacts on BDNF concentrations in patients with asthma.

Inclusion Criteria:

• Age > 18 years, a physician's diagnosis of allergic asthma
• A documented sensitization to aero-allergens (pollen, animal hair, or house dust mite)
• A pre-bronchodilator forced expiratory volume in the first second (FEV1) > 80 % of the predicted value (% predicted), a provocative concentration of histamine causing a 20 % fall in FEV1 (PC20) of < 8 mg histamine / ml

Exclusion Criteria:

• No regular treatment (only short-acting inhalers on demand were allowed)
• No history of or evidence for any other chronic disease than asthma
• No history of smoking, absence of any signs or symptoms of an infection