The purpose of this study is to study the effects of Xolair using non-invasive techniques from the expired gas of patients with moderate to severe allergic asthma.

Traditional methods of sampling secretions from the lower respiratory tract include sputum collection, sputum induction, and bronchoscopy with bronchoalveolar lavage. They cannot be repeated within a short period of time because of their invasiveness, and because the procedures themselves may include an inflammatory response. The need to monitor inflammation in the lungs has led to the exploration of exhaled gases and condensates. Noninvasive monitoring may assist in differential diagnosis of pulmonary diseases, assessment of disease severity and response to treatment.

Inclusion Criteria:

• On medium to high dose inhaled corticosteroids either with or without a long acting beta agonist
• Baseline IgE 30-700 IU/mL
• Exhaled nitric oxide greater than 13 ppb
• Positive skin test to at least one of the following perennial allergens: cat, dog, dust mite, cockroach
• Stable asthma at the time of enrollment

Exclusion Criteria:

• Concurrent diseases/conditions, history of other diseases/conditions, with clinically significant uncontrolled systemic disease or a history of such disease (eg, infection, hematological, renal, hepatic, coronary heart disease or other cardiovascular disease, endocrinological, or gastrointestinal disease) within previous 3 months
• Upper or lower respiratory tract infection within 6 weeks of screening visit
• Elevated IgE level other than atopy
• Known sensitivity to Xolair
• < 3 months of stable immunotherapy
• Smokers
• Pregnant/nursing women
• Women of childbearing potential who are not practicing medically approved contraceptive methods (eg, oral, subcutaneous, mechanical, or surgical contraception) including abstinence
• Patients who currently hav diagnosed cancer, are currently being investigated for possible cancer or who have any history of cancer
• Known sensitivity to study drug or class of study drugs
• Patients with severe medical condition(s) that in the view of the investigator prohibits participation in the study
• Use of any other investigational agent in the last 30 days.