Identification of Serum Biomarkers for CD15+ Hypodense Neutrophils in Severe Asthma

Inclusion Criteria: * Physician diagnosis of severe persistent asthma; * Positive skin test or radioallergosorbent test (RAST) for an aeroallergen; * Male or female age 12-65 years; * Non-smoker. Exclusion Criteria: * Asthma exacerbation requiring treatment with or increase in oral corticosteroids within 30 days prior to the study; * Respiratory infection within 30 days prior to the study; * Starting or requiring a change in allergen immunotherapy within 30 days prior to the study; * Having been treated with Xolair within the past year; * Requiring chronic immunosuppressive therapy; * Having taken methotrexate, gold salts, cyclosporine, or macrolide antibiotics within 3 months prior to study; * Having taken an investigational drug within 30 days prior to the study; * Have a history of drug or alcohol abuse; * Pregnancy