Persistence of Airway Inflammation and Remodeling in Subjects With Symptomatic or Complete Asthma Remission

Primary Outcome Measures :

• Airway inflammation (% induced sputum eosinophils)

Secondary Outcome Measures:

• Perception of induced respiratory symptoms
• Airway response to methacholine and AMP, and perception scores
• Diurnal variation in Peak Expiratory Flows
• Profile of regulatory T cells in the peripheral blood
• Changes in these parameters over time (baseline, 6 months, 1 and 2 years)

Inclusion criteria

• In remission of their asthma: absence of respiratory symptoms, no rescue asthma medication need and (for complete remission) an optimal pulmonary function (FEV1 > 90%) and normal PC20 methacholine for more than two years (with no current treatment).
• With a proven past history of asthma from medical files (reversible airway obstruction (> 12% FEV1 after bronchodilator or 20% by other means) proven by spirometry, PEF measures or methacholine challenge according to current criteria + previous symptoms and asthma medication use), having no more asthma symptoms and not having used asthma medication for more than 2 years.
• Agree to sign the consent form.
• No other condition that could interfere with the study measurements.

Exclusion criteria

• Unable to adhere to the protocol requirements.
• Other current respiratory disease.
• Upper or lower respiratory tract infection or use of antibiotics < 1 month.
• Use of oral corticosteroids within the last 3 months.
• Signs or symptoms of progressive or uncontrolled renal, hepatic, hematologic, endocrine, pulmonary, cardiac, neurologic, or cerebral disease.