Crosstalk Between Mucosal-Associated Invariant T (MAIT) Cells and the Gut Microbiota and Mucosa in the Development of Type 1 Diabetes in Children (MAIT-DT1)

  • End date
    Oct 1, 2025
  • participants needed
  • sponsor
    Institut National de la Santé Et de la Recherche Médicale, France
Updated on 4 October 2022
Accepts healthy volunteers


To investigate in a prospective way changes in Mucosal-Associated Invariant T (MAIT) cells frequency, phenotype and function in link with the gut microbiota, gut integrity and the presence of Coxsackie virus B in two cohorts of pediatric patients: patients with a high genetic risk of type 1 diabetes and pediatric patients with recently diagnosed T1D by comparison with control subjects

  1. To measure blood MAIT cells frequency, phenotype and function in the three cohorts
  2. To analyze gut microbiota and the presence of Coxsackie B enterovirus (CVB) and their impact on MAIT cell function
  3. To evaluate gut integrity and analyze the gut mucosa
  4. To integrate all the data obtained with T1D development and evolution


Subjects: Multi study. Subjects will be included in the pediatric diabetes and endocrinology unit in Necker Sick children hospital and in the pediatric unit of ANTONY hospital.

  • Recent-onset (RO) n=40: New onset patients will be included shortly after diagnosis.
  • At risk (AR) cohort n=70: Routinely screened siblings of T1D patients previously tested positive for HLA DR3 and DR4 will be asked to be a part of the study.
  • Control (C) cohort (n=50): Control subjects will be patients consulting at Necker Hospital for endocrine testing
  • Control for Endoscopy (CE) n= 20: patients consulting at Necker Hospital or at Antony hospital for UGI endoscopy

MAIT cell analysis: For FACS analysis, MAIT cells will be identified as CD3+ CD4- CD161high Vα7.2+ T cells. Surface markers will be analyzed to determine their activation status (CD25, CD69, CD44), their exhaustion (PD1, KLRG1, TIM3), their migration capacity (CCR6), and their proliferation and survival will be analyzed by Ki67 and BCL2 expression. Cytokine production will be assessed after PMA-ionomycin activation, followed by intracytoplasmic staining with antibodies against IL-2, IFN-γ TNF-α, IL-2, IL-4, IL-10, IL-13, IL-17 and granzyme B. To determine the capacity of MAIT cells to response to TCR stimulation (exhaustion), in vitro stimulation will be performed in the presence of specific bacterial ligands. Activation marker expression will be analyzed by FACS and cytokines released in the supernatant by Cytometry based assay.

Gut microbiota analysis: Stool samples are collected and directly kept under anaerobic condition. Within an hour the samples are processed: one fraction is aliquoted and frozen at -80°C and another fraction is used to prepared fecal supernatant for the bioassay of MAIT ligands, aliquoted and frozen. Bioassay to measure the presence of MAIT cell ligands by bioassays using WT3 cell line as well as plate bound MR117. 16S sequencing of all samples and according to the results obtained with the bioassay and 16S, 10 samples will be selected for metagenomic analysis.

Coxsackie virus B (CVB) infection status: Specific antibodies against coxsackie virus B and CVB specific-qPCR measurement in gut microbiota samples will be performed in all patients of the three cohorts, and analysis of the gut mucosa by q-PCR and immunochemistry will be performed on a subset of patients.

Gut integrity: the investigators will assess the permeability of the intestine using the Lactulose-Mannitol test in a sub sample of RO, RD and AR groups (> 5 years of age, n=20). In brief after an overnight fast, the patients will drink 50 ml solution of 5 g lactulose and 2 g mannitol. Urine will be collected during before and 5 hours after ingestion.

Gut mucosa analysis: In a subset of patients (without celiac disease as determined by the dosage of antibodies against transglutaminase), duodenal biopsies will be obtained during an IUG endoscopy . Duodenal biopsy will be performed in RD subjects older than 8 years of age and in CE subjects older than 4 years of age. These biopsies will be analyzed by qPCR for the expression of key epithelial molecules such as the fucosyl transferase 2 (fut2), tight junction proteins (occludin, claudin4), antimicrobial peptides (Reg3, LL37) and mucus component (mucin 2). Immune cells function will also be assessed by q-PCR for key cytokines/molecules such as IL-23, IL-17, IL-22, Foxp3, IL-10, TGFb and CVB.

Based on previous study, the sample size should allow statistical differences between AR, RO and C groups. The investigators anticipate to observe blood MAIT cell abnormalities in RO patients and some at risk children after seroconversion but before diabetes onset. This new data will strengthen our predictive model (see preliminary data). Since MAIT cells recognize bacterial ligand we hypothesize that MAIT cells alteration could occur in parallel with microbiota changes and/or CVB infection. The investigators anticipate observing gut mucosa abnormalities in RO children and the severity of these abnormalities may correlate with the level of MAIT cells defect and the presence of CVB infection. The investigators expect to demonstrate that MAIT cells represent a new biomarker of progression toward diabetes as well as a functional immune marker of the aggressiveness of the autoimmune disease. As such this study could determine the accurate therapeutic window for preventive strategies based on MAIT cells manipulation.

Condition Type1diabetes
Treatment MAIT cells analysis, MAIT cytokines production analysis, Lactulose/Mannitol Test, UGI Endoscopy, Coxsackie virus B infection status
Clinical Study IdentifierNCT05054361
SponsorInstitut National de la Santé Et de la Recherche Médicale, France
Last Modified on4 October 2022


Yes No Not Sure

Inclusion Criteria

Recent onset group
age > 12 months and < 15 years
recently diagnosed type 1 diabetes according ISPAD criteria
At risk subjects
age > 12 months and < 15 years
siblings of type 1 diabetic patient
HLA DR3 and DR4 positive
Control subjects
age > 12 months and < 15 years
no HLA associated with high risk type 1 diabetes
no antibodies against pancreas antigenes
Control subjects for UGI endoscopy
age > 12 months and < 15 years
suspicion of coeliac disease or gastritis

Exclusion Criteria

For all groups
no health care insurance
parents or tutors unable to sign the consent
personal history of autoimmune disease and/or inflammatory disease except from T1D for RD and CE groups
use of corticosteroids during the month before inclusion
pregnant subjects
medical contraindication of anesthetic topics
For control subjects for UGI endoscopy control and Recent onset-endoscopy
age below 8 years for Recent onset-endoscopy group
age below 4 for UGI endoscopy control group
cardiac or respiratory insufficiency, cardiac rhythm disorders, coagulation disease, patients treated with anticoagulant or antiaggregant drug
history of allergy to anesthetic drug
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