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

Characteristics of Symptomatic Asthma Remissions

This study aims at determining the patterns of asthma remission, the prevalence of these different patterns, the various factors associated with such remissions and possible recurrences of asthma, in order to determine the mechanisms involved in these processes.

The investigators therefore want to document these specificities in subjects in complete remission of their asthma, and those in only symptomatic remission of their asthma, in comparison with mildly symptomatic asthmatic subjects and healthy controls.

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.