Severe Asthma Research Program

Asthmatic Patients: Inclusion Criteria: 1. Physician diagnosis of asthma, 2. Age 6 years and older 3. Evidence of historical reversibility, including either: * FEV1 bronchodilator reversibility ≥ 12%, or * Airway hyperresponsiveness reflected by a methacholine PC20 ≤16 mg/mL. Exclusion Criteria: 1. Pregnancy during the characterization phase, 2. Current smoking, 3. Smoking history \> 10 pack years if ≥30 years of age, or smoking history \> 5 pack years if \<30 years of age (Note: if a subject has a smoking history, no smoking within the past year), 4. Other chronic pulmonary disorders associated with asthma-like symptoms, including (but not limited to) cystic fibrosis, chronic obstructive pulmonary disease, chronic bronchitis, vocal cord dysfunction (that is the sole cause of respiratory symptoms and at the PI's discretion), severe scoliosis or chest wall deformities that affect lung function, or congenital disorders of the lungs or airways, 5. History of premature birth before 35 weeks gestation, 6. Unwillingness to receive an intramuscular triamcinolone acetonide injection, 7. Evidence that the participant or family may be unreliable or poorly adherent to their asthma treatment or study procedures, 8. Planning to relocate from the clinical center area before study completion, 9. Any other criteria that place the subject at unnecessary risk according to the judgment of the Principal Investigator and/or attending physician(s) of record, or 10. Currently participating in an investigational drug trial for asthma therapies. Healthy Controls: Inclusion criteria: Healthy subjects between the age of 18 and 65 years. Exclusion criteria 1. History of chronic diseases that affect the lungs, 2. A history suggestive of allergic rhinitis, eczema or chronic sinusitis, 3. An improvement in FEV1 of more than 12% following 4 puffs of albuterol, 4. Smoking history \> 10 pack years if ≥30 years of age, or smoking history \> 5 pack years if \<30 years of age, or any smoking within the past year, 5. Respiratory tract infection within the past 4 weeks, 6. Pregnancy, 7. History of premature birth (\<35 weeks).