Association of Dysbiosis and Immune Response in Bronchiolitis in Under 12 Months -Old Infants

Study Overview
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Brief Summary
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Acute bronchiolitis is a common disease in children under the age of two, caused mainly by the respiratory syncytial virus (RSV). Furthermore, given the same medical history, it is still very difficult to predict the course and severity of the infection at the onset of symptoms, Some studies have highlighted the importance of the microbiota (intestinal, oral or nasopharyngeal) and of the immune response to RSV in children, We will include 80 children under 2 years old with hospitalized bronchiolitis and non-hospitalized bronchiolitis. Oral, nasal and stool samples will be taken to study the various microbiota in search of dysbiosis. A capillary blood sample will be taken for immune studies.

Official Title
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Association of Dysbiosis and Immune Response in Bronchiolitis in Under 12 Months -Old Infants

Conditions
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Bronchiolitis

Intervention / Treatment
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* Other: Sampling


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Infants <12 months With bronchiolitis during RSV epidemic season No chronic illness No bronchiolitis medical history Signed consent from parents or legal guardians Exclusion Criteria: Chronic respiratory illness Medical history of bronchiolitis or newborn asthma Treatment with immunosuppressants Patient with no social security affiliation

Ages Eligible for Study
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Minimum Age: 1 Day
Maximum Age: 12 Months

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Severe bronchiolitis<br>venous blood samples. Buccal, nasopharyngeal and rectal swabs | Other: Sampling<br>* Single-time sampling of respiratory virus-infected children<br>|
| Other: Non-hospitalized bronchiolitis<br>Capillary blood samples. Buccal, nasopharyngeal and rectal swabs | Other: Sampling<br>* Single-time sampling of respiratory virus-infected children<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Dysbiosis | comparison of the quantitative and qualitative composition of bacteria (alpha diversity, beta diversity, Shannon and Simpson index) in the digestive and nasopharyngeal microbiota | Inclusion | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Measurement of innate and adaptive responses by quantification of cytokines and chemokines in plasma | Inflammatory/regulatory cytokines (IL1->17, IL-10, TGF-b, EGF, FGF-2, IFN-alpha, IFN-gamma, IFN-beta, MCRP-1 MCP-3, TNF-alpha...), cytokines of adaptative response (Th1, Th17, Th2 and/or Treg), markers of inflammatory response (interferon, TNFa, …), quantified by Luminex | inclusion | 
| Identifying the mRNA profile in blood samples and nasal swabs | mRNA will be identified by using RNA-Seq (Illumina) | inclusion | 
| Sequencing viral strains for mutation | Typing of respiratory syncytial virus-A (RSV-A) and B (RSV-B) and sequencing of strains (Amplicons) | Inclusion | 
| Comparison of respiratory syncytial virus (RSV) antibodies levels on newborn screening specimen and on capillary swab during infection | Levels of RSV antibodies will be measured and compared between newborn screening specimen and capillary swab during infection | Birth, Inclusion | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Newborns, Dysbiosis, respiratory syncytial virus (RSV)