Study of the Frequency and of the Regulatory Function of Positive T Lymphocytes Dual CD4CD8aa (DP8a) Specific to a Bacteria of the Intestinal Microbiota (Faecalibacterium Prausnitzii) in Atopic Dermatitis, Asthma and Allergic Rhinitis
Condition: Allergic Asthma; Allergic Rhinitis; Atopic Dermatitis
MeSH terms: Rhinitis; Asthma; Rhinitis, Allergic; Dermatitis, Atopic; Dermatitis; Eczema
Study type: Observational

Summary: 
      The prevalence of allergic diseases (atopic dermatitis, asthma, rhinitis, conjunctivitis and
      food allergy) has increased dramatically in industrialized countries over the last 20-30
      years.

      Allergic diseases are present especially in children and young adults, but all age groups are
      affected, with variations across countries and age. To propose new therapies, the
      investigators must first understand the physiopathology.

      Since their discovery the regulatory T cells have continued to be the subject of work to
      understand their role in maintaining immune homeostasis in the human body but also their
      involvement in autoimmune diseases, inflammatory diseases, transplants of solid organs or
      fluids and allergic diseases.

      It was identified two broad classes of regulatory T cells:

        -  T cells = natural regulators acquisition of a phenotype and a regulatory function right
           out of the thymus ( CD25 + / CD127 + low / FoxP3 +).

        -  T cells induced regulators = acquisition of a phenotype and a regulatory function on the
           periphery depending on the cytokine micro-environment.

      Phenotypic characterization of these is less obvious and even more so than during the last
      ten years several induced regulatory T cell populations have been described ( eg, Tr1 ).

      A new subpopulation of T cells induced in patients with inflammatory bowel disease recently
      identified have a particular phenotype as bearing the CD4 and CD8 double marking with a
      regulatory phenotype.

      These regulatory T cells are also induced a specific of a commensal intestinal bacterium
      (Faecalibacterium prausnitzii).

      Regarding allergies, it has been widely demonstrated a relationship between changes of the
      intestinal microbiota and the occurrence of allergic diseases.

      The investigators would therefore propose a cross-sectional study, single-center, controlled,
      single blinded to study the role of T cells called double positive induced regulators DP8 to
      compare the frequency and the regulatory function of specific DP8 of Faecalibacterium
      prausnitzii in atopic dermatitis, asthma and allergic rhinitis compared to control samples.
    

Detailed description: 
      The primary endpoint will be the highlight of a quantitative reduction of double positive T
      cells (CD4 + / CD8 +) the specific F prausnitzii peripheral blood in patients with allergic
      asthma, allergic rhinitis and atopic dermatitis compared to samples from a control sample
      collection made available by the laboratory BIOFORTIS® located near Nantes University of
      Nantes.
    

Intervention name(s): double positive T cells (CD4 + / CD8 +) to the specific peripheral blood of F prauznitzii analyse
Intervention type(s): Genetic
Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients undergoing a consultation with an allergist at the University Hospital of Nantes
        or city firm under a monitoring or an initial consultation for atopic dermatitis, allergic
        asthma or allergic rhinitis.
      
Biospecimen description: 
      PBMC
    
Keywords: Double positive lymphocyte T F prausnitzii