This study is designed to test the hypothesis that salmeterol use, and not fluticasone use or the combination treatment with fluticasone and salmeterol, is associated with a greater number of sputum eosinophils following antigen challenge and, under these circumstances, the migrating peripheral blood eosinophils are less adherent.

An antigen challenge is when a participant inhales either cat, ragweed, or dust dander in increasing concentrations until their lung function drops 15 or 20 percent.

Inclusion Criteria:

• 18-55 years of age
• history of asthma symptoms for the previous 6 months
• Forced Expiratory Value (FEV1) >75% of predicted
• positive prick skin test to cat, house dust mite or ragweed

Exclusion Criteria:

• history of life threatening asthma or anaphylaxis
• current smoker
• pregnant or breast-feeding
• evidence of an upper respiratory infection within 4 weeks of screening

This is a randomized/double-blinded/placebo-controlled/four-phase/crossover trial in subjects with a history of mild allergic asthma. Treatment arms included placebo, fluticasone 44 µg twice daily, salmeterol 50 µµg twice daily and combined FT and SA treatment, all given by inhalers. The order of these treatments was randomized for each subject.

2.5 years

Subject interview at visit

36 subjects were screened, identifying subjects with both a peripheral eosinophil count >0.200x106 cells/ml and a LPR >15% was more difficult than expected. Of the subjects screened, only 12 met criteria and 6 subjects completed.