Type 1 Diabetes
Conditions
Keywords
Type 1 Diabetes, Regulatory T cells, Pathophysiology of T1DM
Brief summary
Type 1 diabetes (T1D) is caused by an autoimmune response leading to the destruction of pancreatic beta cells. The disease association with particular HLA class II alleles, particularly HLA-DQ8, indicates the implication of CD4 T cells in its aetiology. The hypothesis is therefore that T1D starts by the loss of tolerance in autoreactive CD4 T cells. This might result from alterations in conventional autoreactive CD4 T cells (Tcons), which drive disease, or autoreactive regulatory CD4 T cells expressing the transcription factor FOXP3 (Tregs), which normally maintain immune tolerance. The investigators expect that the characterization of HLA-DQ8-restricted Tcons and Tregs in recent onset HLA-DQ8+ T1D patients shall shed light on the molecular mechanisms underpinning T1D development. This knowledge will guide the development of novel cell therapies harnessing the power of genetically engineered Tregs expressing the relevant antigen receptor to restore immune homeostasis upon cell transfer. The ultimate goal is to reach a curative effect
Detailed description
During the development of type 1 diabetes (T1DM), regulatory T cells (Treg) are modified and their protective role is no longer optimal, particularly against pathology-specific autoreactive antigens. The hypothesis is that in patients with T1DM, the function and phenotype of Treg cells, as well as their receptor repertoire for the antigen to which they are specific (TCR), no longer allow them to control tolerance. The in-depth study of these cells, at both genetic and molecular levels, will enable a major breakthrough in our understanding of the pathophysiology of T1DM, and in the development of targeted cell therapy. The investigators expect major/important differences between patient Tregs and those of the control population in this study, at the molecular, phenotypic and functional levels. These differences will highlight the TCRs recognizing the target self-antigens. In this way, investigators expect to be able to select a limited number of Treg TCRs that could ultimately be used in cell therapy to restore the protective role of Tregs in these patients. Thus, this knowledge will enable to propose in the future a more effective immunotherapy with a long-term effect, in order to improve the management of patients with autoimmune diabetes and potentially cure them. Accordingly, yhe investigators will study insulin-specific Tregs in T1DM patients and control individuals, as well as conventional T cells directed against the same antigen, which in patients are implicated in the disease. This will include a study of their functional status, their transcriptomic profile, as well as their TCRs and their fine recognition properties of the major diabetes self-antigen, insulin.
Interventions
BIOLOGICALFrequency of Treg and Teffs
additionnal blood sampling at inclusion
BIOLOGICALPhenotype of Treg and Teffs
additionnal blood sampling at inclusion
BIOLOGICALRNA seq analysis
additionnal blood sampling at inclusion
BIOLOGICALHLA typing
additionnal blood sampling at inclusion
BIOLOGICALbeta-cell autoantibody dosage
additionnal blood sampling at inclusion
BIOLOGICALGlycated haemoglobin (HbA1C) dosage
additionnal blood sampling at inclusion
BIOLOGICALblood glucose dosage
additionnal blood sampling at inclusion
BIOLOGICALC-peptide dosage
additionnal blood sampling at inclusion
Sponsors
URC-CIC Paris Descartes Necker Cochin
Assistance Publique - Hôpitaux de Paris
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
6 Years to 18 Years
Healthy volunteers
No
Inclusion criteria
Newly diagnosed T1DM group: * Age ≥ 2 years and \< 18 years on day of inclusion; * Weight ≥ 12 kg; * Newly diagnosed T1DM, diagnosis defined according to International Society of Pediatric and Adolescent Diabetes (ISPAD) criteria by: hyperglycemia \> 2g/L and/or ketonemia and/or polyuro-polydipsia and/or weight loss ; * Absence of other associated inflammatory or autoimmune diseases; * Affiliation with a health insurance scheme or beneficiary (excluding AME); * Written consent of parental guardians; * Ability to understand and read French. Control group : * Age ≥ 2 years and \< 18 years on the day of inclusion; * Weight ≥ 12 kg; * No personal history of T1DM; * Affiliation with a health insurance scheme or entitled person (excluding AME); * Written consent from parental guardians; * Ability to understand and read French.
Exclusion criteria
Newly diagnosed T1DM group: * Use of oral or intravenous corticosteriods in the month prior to blood sampling * Contraindication to the use of anaesthetic cream for blood sampling. Control group : * History of autoimmune or inflammatory disease * Use of oral or intravenous corticosteriods in the month prior to blood sampling * Contraindication to the use of anaesthetic cream for blood sampling
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Frequency and phenotype of Tregs | Within 4 weeks of T1DM diagnosis | study the frequency and phenotype of insulin-specific autoreactive Tregs lymphocytes among CD4+ T lymphocytes in children with T1DM and compare these values with those of controls. These parameters will be analyzed by flow cytometry using immune cells from blood samples taken from the T1DM and control groups. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| HLA testing | Within 4 weeks of T1DM diagnosis | Description : the HLA of T1DM and controls will be analyzed by qPCR. This will make it possible to associate the results obtained during the analysis of the main criteria with the HLA of each individual. |
| Isolate insulin-specific Tregs and Teffs cells | Within 4 weeks of T1DM diagnosis | Insulin-specific Tregs and Teffs cells will be isolated by flow cytometry |
| Treg and Teffs transcriptome | Within 4 weeks of T1DM diagnosis | their transcriptome and TCR will be determined by single-cell transcriptomics analysis (scRNAseq). |
| Full TCR repertoire of Tregs and Teffs | Within 4 weeks of T1DM diagnosis | Following flow cytometry, the different repertoires will be compared between the DT1 and control groups. |
| Machine learning analysis | Within 4 weeks of T1DM diagnosis | Machine learning analysis of the data obtained (TCR, transcriptome, frequency and phenotype of insulin-specific Tregs and Teffs) to predict the relationship between TCR and functional properties of Tregs and Teffs in patients and controls |
Countries
France
Contacts
Primary ContactJacques BELTRAND, MD, PhD
Backup ContactSarah BOUCHARD
Outcome results
None listed