Stool test: At inclusion (day 0), stools will be collected with a kit for to remove to 5 mg for each patient.
Blood test: Blood sample taken during inclusion (day 0) will be collected. There is between 19 and 26 mL for each patient.
Induced sputum: At inclusion (day 0), bronchial aspiration after inhalation induction of 4 mL of 6% salt serum administered (after 200 μg of salbutamol via an inhalation chamber during a bronchial drainage session).
nasale virology: At inclusion (Day 0), patients will be taken nasal swab for virology with swab adapted for nasal swab or with suction trap when blowing the child's nose (depending on center practice)and multiplex PCR.
Study summary
The prevalence of asthma in preschool children is between 11 and12%. Inhaled corticosteroid therapy is the main therapy used, however this treatment seems insufficiently effective in some children.
Recent research in cystic fibrosis has made it possible to highlight pulmotypes corresponding to the different stages of pulmonary dysbiosis, and a predictive microbiological signature of an increased risk of early primocolonization to P. aeruginosa. These pulmotypes are the result of the so-called "enterotyping" analysis, a biostatistical method that makes it possible to stratify individuals according to the analysis of the microbiota. In the light of these data, it seems interesting to transcribe the concept of using a biomarker of the microbiota in the monitoring of a chronic lung disease such as asthma.
The hypothesis is that there is respiratory dysbiosis causing corticosteroid resistance to treatment in children under 3 years of age with severe asthma.
Eligibility
Sex
ALL
Min age
1 Year
Max age
3 Years
Healthy volunteers
No
Inclusion Criteria:
* Age greater than 1 year and less than 3 years
* Diagnosis of asthma by a pediatrician
* Parental consent
* Affiliation to the social security system
Exclusion Criteria:
* Chronic pathologies: congenital heart disease, immune deficiency, cystic fibrosis, bronchopulmonary dysplasia, encephalopathy, primary ciliary dyskinesia, laryngomalacia, digestive pathology requiring digestive surgery
* Premature \< 34 SA
* Recent antibiotic therapy (\< 7 days)
* Treatment with oral corticosteroid therapy within the previous 10 days.
* Patient whose parent(s) is (are) minor(s)
Primary outcome measure(s)
Number of species in the microbial Community — Day 0 The main evaluation is the comparison of respiratory biodiversity assessed using quantitative indices such as alpha diversity. Alpha diversity calculates the richness (number of species or OTU) by samples and how these OTUs are distributed (equitability). Richness will be measured with the Chao1 and equity with the Simpson index. The Shannon index is a composite measurethat allows us to have both information together, richness and equity in the same index.
Index of microbial similarity of samples — Day 0 The main evaluation is the comparison of respiratory biodiversity assessed using quantitative indices such beta diversity. Beta diversity analysis allows samples to be compared with each other. It calculates a matrix of distances between samples with the Bray Curtis/ Unifrac methods, weighted or not/ Jaccard by presence/absence. Next, the Principal Coordinate Analysis (PCoA ) will be used, multidimensional scaling to reduce this matrix to 2/3 dimensions. The samples from similar groups look alike with this analysis will be used.
This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
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