Abstract
Aims/hypothesis Slow progressors to type 1 diabetes are individuals positive for multiple pancreatic islet autoantibodies who have remained diabetes-free for at least 10 years; regulation of the autoimmune response is understudied in this group. Here, we profile CD4+ regulatory T cells (Tregs) in a small but well-characterised cohort of extreme slow progressors with median age 43 (range 31-72 years), followed up for 18-32 years.
Methods Peripheral blood samples were obtained from slow progressors (n=8), age and sex-matched to healthy donors. One participant in this study was identified with a raised HbA1c at the time of assessment and subsequently diagnosed with diabetes; this donor was individually evaluated in the analysis of the data. Peripheral blood mononuclear cells (PBMCs) were isolated and, to assess frequency, phenotype and function of Tregs in donors, multi-parameter flow cytometry and T cell suppression assays were performed. Unsupervised clustering analysis, using FlowSOM and CITRUS (cluster identification, characterization, and regression), was used to evaluate Treg phenotypes.
Results Unsupervised clustering on memory CD4 T cells from slow progressors showed an increased frequency of activated memory CD4 Tregs, associated with increased expression of glucocorticoid-induced TNFR-related protein (GITR), compared with matched healthy donors. One participant with a raised HbA1c at the time of assessment had a different Treg profile compared with both slow progressors and matched controls. Functional assays demonstrated that Treg-mediated suppression of CD4+ effector T cells from slow progressors was significantly impaired, compared with healthy donors. However, effector CD4 T cells from slow progressors were more responsive to Treg suppression compared with healthy donors, demonstrated by increased suppression of CD25 and CD134 expression on effector CD4 T cells.
Conclusions/interpretations We conclude that activated memory CD4+ Tregs from slow progressors are expanded and enriched for GITR expression, highlighting the need for further study of Treg heterogeneity in individuals at risk of developing type 1 diabetes.
Methods Peripheral blood samples were obtained from slow progressors (n=8), age and sex-matched to healthy donors. One participant in this study was identified with a raised HbA1c at the time of assessment and subsequently diagnosed with diabetes; this donor was individually evaluated in the analysis of the data. Peripheral blood mononuclear cells (PBMCs) were isolated and, to assess frequency, phenotype and function of Tregs in donors, multi-parameter flow cytometry and T cell suppression assays were performed. Unsupervised clustering analysis, using FlowSOM and CITRUS (cluster identification, characterization, and regression), was used to evaluate Treg phenotypes.
Results Unsupervised clustering on memory CD4 T cells from slow progressors showed an increased frequency of activated memory CD4 Tregs, associated with increased expression of glucocorticoid-induced TNFR-related protein (GITR), compared with matched healthy donors. One participant with a raised HbA1c at the time of assessment had a different Treg profile compared with both slow progressors and matched controls. Functional assays demonstrated that Treg-mediated suppression of CD4+ effector T cells from slow progressors was significantly impaired, compared with healthy donors. However, effector CD4 T cells from slow progressors were more responsive to Treg suppression compared with healthy donors, demonstrated by increased suppression of CD25 and CD134 expression on effector CD4 T cells.
Conclusions/interpretations We conclude that activated memory CD4+ Tregs from slow progressors are expanded and enriched for GITR expression, highlighting the need for further study of Treg heterogeneity in individuals at risk of developing type 1 diabetes.
| Original language | English |
|---|---|
| Pages (from-to) | 343-355 |
| Number of pages | 13 |
| Journal | Diabetologia |
| Volume | 65 |
| Issue number | 2 |
| Early online date | 28 Oct 2021 |
| DOIs | |
| Publication status | Published - Feb 2022 |
Bibliographical note
Funding Information:The BOX study was funded by Diabetes UK (14/0004869). The SNAIL study was funded by a Strategic Research Agreement from the JDRF (17–2013-529). AEL was funded by a Diabetes UK/JDRF RD Lawrence Fellowship (18/0005778 and 3-APF-2018-591-A-N).
Publisher Copyright:
© 2021, The Author(s).
Keywords
- autoantibodies
- CD4+ T cells
- regulatory T cells
- Slow progression
- Type 1 diabetes
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