Number of included patients is sufficient.

Asthma is a chronic inflammatory disease, affecting up to 10 % of the general population in developed countries. Corticosteroids are necessary to control symptoms, but induce adverse events sometimes intolerable. In severe asthma, which represent 5 to 10% of global asthma, corticosteroids frequently fail to prevent severe exacerbations, leading to emergency care, hospitalization and sometimes death. The aim of this study is to identify predictive factors specific for exacerbation outcome which will lead to a minor increase in treatment in order to prevent exacerbations, while minimizing drug adverse effects.

Inclusion criteria :

• Male or female adults aged ≥ 18 years, who have signed an Inform Consent Form prior to initiation of any study-related procedure
• Patients with severe asthma with at least 2 exacerbations during the last 12 months that necessitated oral cortico-therapy or increase in oral cortico-therapy

Exclusion criteria :

• Pregnant or nursing women
• Patients with other chronic inflammatory lung disease
• Current smoker or a smoking history of 10 pack years or more

Patients with severe asthma