NK Cell Subsets Changes in Partial Remission and Early Stages of Pediatric Type 1 Diabetes

Abstract

Type 1 diabetes (T1D) is a chronic metabolic disease characterized by the autoimmune destruction of β-cells in the pancreatic islets. T1D is preceded by islet-specific inflammation led by several immune cells. Among them, natural killer (NK) cells are emerging as important players in T1D development. Human NK cells are characterized by CD56 and CD16 expression, which allows classifying NK cells into four subsets: 1) CD56dimCD16+ or effector NK cells (NKeff); 2) CD56brightCD16− or regulatory NK cells (NKreg); 3) intermediate CD56brightCD16+ NK cells; and 4) CD56dimCD16− NK cells, whose function is not well determined. Since many studies have shown that T1D progression is associated with changes in various immune cell types, we hypothesize that the kinetics of NK cell subsets in the blood could correlate with different stages of T1D. To that aim, pediatric patients newly diagnosed with T1D were recruited, and peripheral NK cell subsets were analyzed by flow cytometry at several disease checkpoints: disease onset, partial remission (PR), 8 months (for non-remitters), and 12 months of progression. Our results showed that total NK cells and their four subsets are altered at the early stages of T1D. A decrease in the counts and percentage of total NK cells and NKeff cells at the different disease stages was found when compared to controls. These results suggest the extravasation of these cells into the islets at disease onset, which is maintained throughout the follow-up. By contrast, NKreg cells increased during the early stages after T1D onset, and both intermediate NK cells and CD56dimCD16- NK cells diminished at the PR stage, which might reflect the immunoregulatory attempts and could be candidate biomarkers for this stage. Also, CD56dimCD16- NK cells increased during T1D progression. Finally, changes in CD16 expression were identified in the different T1D stages, highlighting a CD16 expression reduction in total NK cells and NKeff cells 1 year after diagnosis. That may reflect a state of exhaustion after multiple cell-to-cell interactions. Altogether, our preliminary data provide a longitudinal picture of peripheral NK cell subpopulations during the different T1D stages, which could be potential candidate biomarkers indicators of disease progression.

Candidate Biomarkers for the Prediction and Monitoring of Partial Remission in Pediatric Type 1 Diabetes

“…Furthermore, mechanisms of immune regulation are non-linear along the natural history of T1D—matching well with the proposed relapsing-remitting character of the disease course—and the PR phase is associated with these immunomodulatory changes ( 15 , 16 ). Consistent with this idea, studies investigating changes in immune parameters have reported that patients with the highest frequency of CD4 + CD25 + CD127 hi lymphocytes at disease onset experience the longest PR ( 17 , 18 ), that increased levels of regulatory T, B, and NK cells can be found during T1D progression (which could reflect attempts at restoring self-tolerance) ( 19 , 20 ), and that the absence of IL-4, TNF-α, IL-10, and IL-13 in sera correlates with the length of the remission period ( 21 ). Interestingly, peripheral antigen-specific regulatory T cells (T REG ) diminish during the honeymoon phase in comparison to the time of diagnosis ( 22 ).…”

“…Blood samples from patients with T1D were acquired for centralized measurement of HbA1c, fasting basal and stimulated C-peptide, genetics, and immunology; and insulin requirements were recorded. At the time of T1D diagnosis, HLA typing of DRB1 alleles and islet autoantibodies to IA-2, GAD65, and ZnT8 were determined as previously reported ( 20 ). HbA1c was determined by high-performance liquid chromatography (ADAMS A1c HA-8180V, Arkray, MN, USA) in all patients at each time-point.…”

Intralymphatic GAD-alum Injection Modulates B Cell Response and Induces Follicular Helper T Cells and PD-1+ CD8+ T Cells in Patients With Recent-Onset Type 1 Diabetes

“…Other variations observed during the treatment included the reduction of cells commonly associated with cytotoxic activity such as DN NKT cells and CD56+CD16+ NK cell subsets. However, it is difficult to assure whether the decline was a result of the treatment, as variations in cytotoxic NK cell subsets might also be related to dynamic changes during the disease ( 37 ).…”

Single-Cell RNA Sequencing of Peripheral Blood Mononuclear Cells From Pediatric Coeliac Disease Patients Suggests Potential Pre-Seroconversion Markers

“…In multiple sclerosis, genetic risk loci have been found to be more enriched in open chromatin regions of NK cells ( 58 ). For type 1 diabetes, it was reported that specific peripheral NK cell subsets may serve as potential candidate biomarkers of disease progression ( 59 ). In the context of CeD, Type 1 innate lymphoid cells, which share a similar cytotoxic profile and several markers with conventional NK cells, have been demonstrated to be altered in active CeD ( 60 , 61 ).…”