Severe Eosinophilic Asthma Phenotypes During Childhood Have Various Origins

Multiple sensitizations but also blood eosinophilia are associated with the persistence of exacerbations during childhood. The pivotal role of eosinophilia in the pathophysiology of allergic asthma and more generally of severe asthma in the pediatric population has made it an important research topic for many years. The indirect demonstration of bronchial inflammation by analyzing blood eosinophilia is common practice, especially when monitoring the effectiveness of biotherapies. However, blood eosinophilia is not always clearly related to bronchial eosinophilia.

On the other hand, several teams have recently sought to highlight the recurrence of allergen sensitization profiles associated with severe asthma, in order to identify predictive factors of clinical evolution.

Finally, recent studies have shown that the nasal microbiota plays an important role in the onset, development and severity of asthma.

Our study will allow us to study the clinical evolution at 10 years of the children from the SAMP cohort (severe asthma, eosinophilic or not, allergic or not) in order to understand the different possible evolutions of these phenotypes at different ages. These phenotypic trajectories have an important therapeutic implication, leading to the prescription of personalized treatments, in particular biologics (monoclonal antibodies).

Primary objective To evaluate, in children with moderate to severe asthma, the control of asthma according to the therapeutic load, atopic pathologies during childhood and initial serum levels of blood eosinophils and biomarkers of eosinophil activation Secondary objective Evaluate the evolution of asthma phenotypes according to the associated atopic pathologies (allergic rhinitis, atopic dermatitis and food allergy), according to the number of atopic comorbidities and their severity.

Study of the microbiota in children followed for moderate to severe asthma.

Practical procedure The investigator record the new tests prescribed as part of the routine care of these patients (respiratory function tests, blood tests) and ask them to complete a questionnaire (no travel required specifically for the study). In the event of a blood test prescribed and carried out in the department, the investigator will take an additional 2 ml, and perform a nasal and skin swab.

Inclusion criteria

• absence of opposition from the legal representative of the patient and if possible from the patient himself.
• patient with moderate to severe asthma at preschool or school age, previously included in SAMP Cohort

Exclusion criteria

• Patient included in another clinical study.
• Lack of coverage by social security.