Immunological mechanisms associated with long-term remission of human type 1 diabetes

Impact of the initiation of isCGM soon after type 1 diabetes mellitus diagnosis in adults on glycemic indices and fear of hypoglycemia: a randomized controlled trial

Background

Continuous glucose monitoring (CGM) improves glycemic control and quality of life. Data on glycemic indices and fear of hypoglycemia (FoH) in newly diagnosed T1DM patients are limited.

Aim

To assess the impact of initiating intermittently scanned CGM (isCGM) within 1-6 months of diagnosis on glycemic control and FoH in adults with T1DM.

Subjects and methods

After wearing a blinded sensor for 14 days, participants were randomized (1:1) to either isCGM (intervention) or self-monitoring blood glucose (SMBG) with glucometers and blinded CGM (control). Primary outcomes were changes in time below 70 mg/dl (TB70) and FoH, assessed in the Hypoglycemia Fear Survey (HFS). Main secondary outcomes included changes in mean glucose and time in range (TIR) from baseline to 4 weeks after randomization.

Results

The full analysis set included 23 patients (12 from the intervention group and 11 from the control group), aged 25.6 ± 5.1 years (14 men, 9 women). All participants were on multiple daily insulin injections. TB70 changed from 2.42% to 2.25% in the intervention, and from 2.81% to 1.82% in the control group, and the between-therapy difference of 0.83% was insignificant. No difference between intervention and control groups in change in HFS-worry and HFS-behavior subscales between baseline and after 4 weeks was found (-1.6 ± 3.2 and 1.0 ± 2.2, respectively). The mean glucose levels changed from 7.03 mmol/l to 6.73 mmol/l and from 7.07 mmol/l to 7.43 mmol/l, in the intervention and control groups, respectively, which resulted in a between-therapy significant glucose difference of -0.66 mmol/l. The mean TIR changed from 88.0% to 90.0% in the intervention group and from 85.2 to 84.1% in the control group-the between-therapy difference was insignificant (3,1%). The study ended early due to CGM reimbursement policy changes, after which most patients eligible for the study could have isCGM reimbursed.

Conclusions

In newly diagnosed T1DM adults, TIR is high and hypoglycemia risk is low. The study group was small; however, the data suggest that the use of isCGM soon after T1DM diagnosis could result in mean glucose decrease, but not in change in TB70 and FoH.

Immunometabolic biomarkers for partial remission in type 1 diabetes mellitus

Shortly after diagnosis of type 1 diabetes mellitus (T1DM) and initiation of insulin therapy, many patients experience a transient partial remission (PR) phase, also known as the honeymoon phase. This phase presents a potential therapeutic opportunity due to its association with immunoregulatory and β cell-protective mechanisms. However, the lack of biomarkers makes its characterization difficult. In this review, we cover the current literature addressing the discovery of new predictive and monitoring biomarkers that contribute to the understanding of the metabolic, epigenetic, and immunological mechanisms underlying PR. We further discuss how these peripheral biomarkers reflect attempts to arrest β cell autoimmunity and how these can be applied in clinical practice.

Selected Serum Markers Associated with Pathogenesis and Clinical Course of Type 1 Diabetes in Pediatric Patients-The Effect of Disease Duration

Biochemical abnormalities in the course of type 1 diabetes (T1D) may cause the production/activation of various proteins and peptides influencing treatment and causing a risk of complications. The aim of this study was to assess concentrations of selected serum substances involved in the pathogenesis and course of T1D and to correlate their concentrations with the duration of T1D. The study included patients with T1D (n = 156) at the age of 3-17, who were divided according to the duration of the disease into those newly diagnosed (n = 30), diagnosed after 3-5 (n = 77), 6-7 (n = 25), and over 7 (n = 24) years from the onset of T1D, and age-matched healthy controls (n = 30). Concentrations of amylin (IAPP), proamylin (proIAPP), catestatin (CST), chromogranin A (ChgA), nerve growth factor (NFG), platelet-activating factor (PAF), uromodulin (UMOD), and intestinal fatty acid binding protein (I-FABP) were measured in sera using immunoenzymatic tests. There were significant differences in concentrations of all the substances except UMOD and NGF between T1D patients and healthy children. The duration of the disease affected concentrations of CST, ChgA, PAF, and NGF, i.e., proteins/peptides which could have an impact on the course of T1D and the development of complications. In long-term patients, a decrease in concentrations of CST and ChgA, and an increase in PAF concentrations were found. In the case of NGF, a decrease was observed after the initial high values, followed by an increase over 7 years after T1D diagnosis. Concluding, the results show that concentrations of selected serum indicators may change in the course of T1D. Further studies are needed to establish whether these indicators could be used in the context of predicting long-term complications.

New-onset type 1 diabetes and severe acute respiratory syndrome coronavirus 2 infection

Type 1 diabetes (T1D) is a condition characterized by an absolute deficiency of insulin. Loss of insulin-producing pancreatic islet β cells is one of the many causes of T1D. Viral infections have long been associated with new-onset T1D and the balance between virulence and host immunity determines whether the viral infection would lead to T1D. Herein, we detail the dynamic interaction of pancreatic β cells with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the host immune system with respect to new-onset T1D. Importantly, β cells express the crucial entry receptors and multiple studies confirmed that β cells are infected by SARS-CoV-2. Innate immune system effectors, such as natural killer cells, can eliminate such infected β cells. Although CD4⁺ CD25⁺ FoxP3⁺ regulatory T (T_REG ) cells provide immune tolerance to prevent the destruction of the islet β-cell population by autoantigen-specific CD8⁺ T cells, it can be speculated that SARS-CoV-2 infection may compromise self-tolerance by depleting T_REG -cell numbers or diminishing T_REG -cell functions by repressing Forkhead box P3 (FoxP3) expression. However, the expansion of β cells by self-duplication, and regeneration from progenitor cells, could effectively replace lost β cells. Appearance of islet autoantibodies following SARS-CoV-2 infection was reported in a few cases, which could imply a breakdown of immune tolerance in the pancreatic islets. However, many of the cases with newly diagnosed autoimmune response following SARS-CoV-2 infection also presented with significantly high HbA_1c (glycated hemoglobin) levels that indicated progression of an already set diabetes, rather than new-onset T1D. Here we review the potential underlying mechanisms behind loss of functional β-cell mass as a result of SARS-CoV-2 infection that can trigger new-onset T1D.

Immunoregulatory Biomarkers of the Remission Phase in Type 1 Diabetes: miR-30d-5p Modulates PD-1 Expression and Regulatory T Cell Expansion

The partial remission (PR) phase of type 1 diabetes (T1D) is an underexplored period characterized by endogenous insulin production and downmodulated autoimmunity. To comprehend the mechanisms behind this transitory phase and develop precision medicine strategies, biomarker discovery and patient stratification are unmet needs. MicroRNAs (miRNAs) are small RNA molecules that negatively regulate gene expression and modulate several biological processes, functioning as biomarkers for many diseases. Here, we identify and validate a unique miRNA signature during PR in pediatric patients with T1D by employing small RNA sequencing and RT-qPCR. These miRNAs were mainly related to the immune system, metabolism, stress, and apoptosis pathways. The implication in autoimmunity of the most dysregulated miRNA, miR-30d-5p, was evaluated in vivo in the non-obese diabetic mouse. MiR-30d-5p inhibition resulted in increased regulatory T cell percentages in the pancreatic lymph nodes together with a higher expression of CD200. In the spleen, a decrease in PD-1⁺ T lymphocytes and reduced PDCD1 expression were observed. Moreover, miR-30d-5p inhibition led to an increased islet leukocytic infiltrate and changes in both effector and memory T lymphocytes. In conclusion, the miRNA signature found during PR shows new putative biomarkers and highlights the immunomodulatory role of miR-30d-5p, elucidating the processes driving this phase.

Initial neutrophil/lymphocyte and lymphocyte/monocyte ratios can predict future insulin need in newly diagnosed type 1 diabetes mellitus

OBJECTIVES

The exact mechanism of partial clinical remission in type 1 diabetes mellitus (T1DM) has not been elucidated yet. The severity of the inflammation at the time of diagnosis may affect the occurrence or duration of this phase. We aimed to investigate the relationship between hematological inflammatory parameters at the time of diagnosis in T1DM and (i) daily insulin requirement during the follow-up and (ii) the presence of partial clinical remission period, which was determined according to insulin dose-adjusted HbA_1c levels.

METHODS

A single-center retrospective study was conducted, including children who were diagnosed with T1DM, were positive for at least one autoantibody, and were followed up for one year in our clinic between 2010 and 2020.

RESULTS

Sixty-eight patients (55.9% female, 64.7% prepubertal) were included in the study, whose mean age was 8.4 ± 4.2 years. A total of 38 patients (55.9%) had partial clinical remission. None of the initial hematological indices were associated with the occurrence of partial remission. Initial neutrophil/lymphocyte ratio (NLR) and derived-NLR (d-NLR) levels were significantly lower (p=0.011 and 0.033, respectively) and lymphocyte/monocyte ratio (LMR) levels were significantly higher (p=0.005) in patients who showed an insulin requirement of <0.5 IU/kg/day at the 3rd month after diagnosis.

CONCLUSIONS

Initial hematological parameters were not found as a predictor of partial clinical remission period in T1DM in children. However, a lower NLR and d-NLR, or a higher LMR at the time of diagnosis can be used as an indicator of a low daily insulin need at the 3rd month of T1DM.

Identification of Sorafenib as a Treatment for Type 1 Diabetes

Th1 cell activation is considered a key mediator of the pathogenesis of type 1 diabetes. Targeting IL-12-induced Th1 cell differentiation seems to be an effective way to block the development of type 1 diabetes. However, given the critical function of Th1 in the immune system, the potential side effects hinder the application of anti-Th1 therapy in the treatment of type 1 diabetes. To identify safe anti-Th1 treatment(s), we screened the FDA-approved tyrosine kinase inhibitor (TKI) drug library using an IL-12-induced Th1 differentiation cell model. We found that among the TKIs with little effect on T cell viability, sorafenib is the top contender for the inhibition of Th1 differentiation. Treatment of NOD mice with sorafenib significantly impeded the development of type 1 diabetes and ameliorated insulitis, which coincided with a specifically decreased accumulation of Th1 cell population in the pancreas but not in peripheral immune organs. Mechanistically, sorafenib indirectly inhibited janus kinase 2 (JAK2) activity and blocked IL-12-induced phosphorylations of JAK2 and signal transducer and activator of transcription 4 (STAT4). Since sorafenib is classified as an FDA-approved drug, it serves as a preliminary lead point for additional experimentation and may be a promising therapy for type 1 diabetes in humans.

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

The partial remission (PR) phase, a period experienced by most patients with type 1 diabetes (T1D) soon after diagnosis, is characterized by low insulin requirements and improved glycemic control. Given the great potential of this phase as a therapeutic window for immunotherapies because of its association with immunoregulatory mechanisms and β-cell protection, our objective was to find peripheral immunological biomarkers for its better characterization, monitoring, and prediction. The longitudinal follow-up of 17 pediatric patients with new-onset T1D over one year revealed that, during the PR phase, remitter patients show increased percentages of effector memory (EM) T lymphocytes, terminally differentiated EM T lymphocytes, and neutrophils in comparison to non-remitter patients. On the contrary, remitter patients showed lower percentages of naïve T lymphocytes, regulatory T cells (TREG), and dendritic cells (DCs). After a year of follow-up, these patients also presented increased levels of regulatory B cells and transitional T1 B lymphocytes. On the other hand, although none of the analyzed cytokines (IL-2, IL-6, TGF-β1, IL-17A, and IL-10) could distinguish or predict remission, IL-17A was increased at T1D diagnosis in comparison to control subjects, and remitter patients tended to maintain lower levels of this cytokine than non-remitters. Therefore, these potential monitoring immunological biomarkers of PR support that this stage is governed by both metabolic and immunological factors and suggest immunoregulatory attempts during this phase. Furthermore, since the percentage of TREG, monocytes, and DCs, and the total daily insulin dose at diagnosis were found to be predictors of the PR phase, we next created an index-based predictive model comprising those immune cell percentages that could potentially predict remission at T1D onset. Although our preliminary study needs further validation, these candidate biomarkers could be useful for the immunological characterization of the PR phase, the stratification of patients with better disease prognosis, and a more personalized therapeutic management.

CD4+CD25+CD127hi cell frequency predicts disease progression in type 1 diabetes

Transient partial remission, a period of low insulin requirement experienced by most patients soon after diagnosis, has been associated with mechanisms of immune regulation. A better understanding of such natural mechanisms of immune regulation might identify new targets for immunotherapies that reverse type 1 diabetes (T1D). In this study, using Cox model multivariate analysis, we validated our previous findings that patients with the highest frequency of CD4⁺CD25⁺CD127^hi (127-hi) cells at diagnosis experience the longest partial remission, and we showed that the 127-hi cell population is a mix of Th1- and Th2-type cells, with a significant bias toward antiinflammatory Th2-type cells. In addition, we extended these findings to show that patients with the highest frequency of 127-hi cells at diagnosis were significantly more likely to maintain β cell function. Moreover, in patients treated with alefacept in the T1DAL clinical trial, the probability of responding favorably to the antiinflammatory drug was significantly higher in those with a higher frequency of 127-hi cells at diagnosis than those with a lower 127-hi cell frequency. These data are consistent with the hypothesis that 127-hi cells maintain an antiinflammatory environment that is permissive for partial remission, β cell survival, and response to antiinflammatory immunotherapy.

Regenerative medicine of pancreatic islets

The pancreas became one of the first objects of regenerative medicine, since other possibilities of dealing with the pancreatic endocrine insufficiency were clearly exhausted. The number of people living with diabetes mellitus is currently approaching half a billion, hence the crucial relevance of new methods to stimulate regeneration of the insulin-secreting β-cells of the islets of Langerhans. Natural restrictions on the islet regeneration are very tight; nevertheless, the islets are capable of physiological regeneration via β-cell self-replication, direct differentiation of multipotent progenitor cells and spontaneous α- to β- or δ- to β-cell conversion (trans-differentiation). The existing preclinical models of β-cell dysfunction or ablation (induced surgically, chemically or genetically) have significantly expanded our understanding of reparative regeneration of the islets and possible ways of its stimulation. The ultimate goal, sufficient level of functional activity of β-cells or their substitutes can be achieved by two prospective broad strategies: β-cell replacement and β-cell regeneration. The "regeneration" strategy aims to maintain a preserved population of β-cells through in situ exposure to biologically active substances that improve β-cell survival, replication and insulin secretion, or to evoke the intrinsic adaptive mechanisms triggering the spontaneous non-β- to β-cell conversion. The "replacement" strategy implies transplantation of β-cells (as non-disintegrated pancreatic material or isolated donor islets) or β-like cells obtained ex vivo from progenitors or mature somatic cells (for example, hepatocytes or α-cells) under the action of small-molecule inducers or by genetic modification. We believe that the huge volume of experimental and clinical studies will finally allow a safe and effective solution to a seemingly simple goal-restoration of the functionally active β-cells, the innermost hope of millions of people globally.

Partial remission in Brazilian children and adolescents with type 1 diabetes. Association with a haplotype of class II human leukocyte antigen and synthesis of autoantibodies

OBJECTIVE

Characterization of partial remission using the insulin dose-adjusted HbA1c (IDAA1c) ≤ 9 definition in a multiethnic Brazilian population of children and adolescents with type 1 diabetes (T1D), in addition with the determination of both Class II HLA genotype and autoantibodies.

METHODS

We analyzed the prevalence of partial remission in 51 new-onset T1D patients with a median time follow-up of 13 months from diagnosis. For this study, anti-GAD65, anti-IA2 and HLA class II genotyping were considered.

RESULTS

Partial remission occurred in 41.2% of T1D patients until 3 months after diagnosis, mainly in those aged 5-15 years. We have demonstrated a significant increase in the haplotypes of class II HLA DRB1*0301-DQB1*0201 in children and adolescents with a partial remission phase of the disease (42.9% vs 21.7% in non-remitters, P = .0291). This haplotype was also associated with the reduction of anti-IA2 antibodies production. Homozygote DRB1*03-DQB1*0201/DRB1*03-DQB1*0201 children had the lowest prevalence of IA-2A antibodies (P = .0402). However, this association does not correlate with the time of the remission phase.

CONCLUSION

Although the number of patients studied was reduced, our data suggested that the association between genetics and decrease in antibody production to certain islet auto-antigen may contribute, at least in part, to the remission phase of T1D.

The remission phase in type 1 diabetes: Changing epidemiology, definitions, and emerging immuno-metabolic mechanisms

Type 1 diabetes mellitus (T1DM) is characterized by irreversible islet β cell destruction. During the progression of this disease, some patients with T1DM experience a phase of remission known as honeymoon or partial remission (PR) that is mainly characterized by satisfactory glycemic control and the transient recovery of islet β cell function. This special phase is a good model for studying the mechanism of β cell protection, might serve as a proper intervention period for immunotherapy, and may be related to disease prognosis. This special stage is highly valuable for studies aiming to identify possible targets that may be used to cure T1DM. An in-depth understanding of the diagnosis, epidemiology, and possible mechanisms of the PR phase is highly needed. In general, patients enter the PR phase approximately 3 months after starting insulin therapy, and this phase could be sustained for 6 to 9 months. Current research increasingly focuses on the metabolic and immunological aspects to constantly update our understanding of this phase. This review concentrates on the PR phase of T1DM to provide a comprehensive outlook of its epidemiology, diagnostic criteria, and underlying immune metabolic mechanisms.

The Remission Phase in Type 1 Diabetes: Role of Hyperglycemia Rectification in Immune Modulation

The remission phase (or honeymoon period) is a spontaneous "temporary cure stage" in type 1 diabetes course, which provides a good human model for studying β-cell protection. The exact mechanisms are still uncertain, but one of the generally recognized mechanisms is that correction of "glucotoxicity" by exogenous insulin therapy leads to "β-cell rest" and β-cell recovery. Beyond this, the remission phase is accompanied by changes in various immune cells and immune molecules, indicating downregulation of immune response, and induction of immune tolerance. The role of hyperglycemia rectification in the regulation of immune response should be emphasized because glucose metabolism is critical to maintain the normal function of immune system. Here, recent evidence of immune modulation based on the rectification of hyperglycemia from multiple aspects such as immune cells, inflammatory cytokines, biomolecules, and cell antigenicity was reviewed. It should be noteworthy that the interaction between glucose metabolism and immune plays an important role in the pathogenesis of the remission phase. The best intervention strategy may be the combination of strict glycemic control and immune modulation to protect β-cell function as early as possible.

Remission Phase in Paediatric Type 1 Diabetes: New Understanding and Emerging Biomarkers

Type 1 diabetes (T1D) is a metabolic disease of unknown aetiology that results from the autoimmune destruction of the β-cells. Clinical onset with classic hyperglycaemic symptoms occurs much more frequently in children and young adults, when less than 30% of β-cells remain. Exogenous insulin administration is the only treatment for patients. However, due to glucose dysregulation, severe complications develop gradually. Recently, an increase in T1D incidence has been reported worldwide, especially in children. Shortly after diagnosis, T1D patients often experience partial remission called "honeymoon phase," which lasts a few months, with minor requirements of exogenous insulin. In this stage, the remaining β-cells are still able to produce enough insulin to reduce the administration of exogenous insulin. A recovery of immunological tolerance to β-cell autoantigens could explain the regeneration attempt in this remission phase. This mini-review focuses on the remission phase in childhood T1D. Understanding this period and finding those peripheral biomarkers that are signs of immunoregulation or islet regeneration could contribute to the identification of patients with a better glycaemic prognosis and a lower risk of secondary complications. This remission phase could be a good checkpoint for the administration of future immunotherapies.

Regeneration of pancreatic insulin-producing cells by in situ adaptive cell conversion

The impaired ability to produce or respond to insulin, a hormone synthetized by the pancreatic β-cells, leads to diabetes. There is an excruciating need of finding new approaches to protect or restore these cells once they are lost. Replacement and ex vivo directed reprogramming methods have an undeniable therapeutic potential, yet they exhibit crucial flaws. The in vivo conversion of adult cells to functional insulin-producing cells is a promising alternative for regenerative treatments in diabetes. The stunning natural transdifferentiation potential of the adult endocrine pancreas was recently uncovered. Modulating molecular targets involved in β-cell fate maintenance or in general differentiation mechanisms can further potentiate this intrinsic cell plasticity, which leads to insulin production reconstitution.

Diabetes recovery by age-dependent conversion of pancreatic δ-cells into insulin producers

Total or near-total loss of insulin-producing β-cells occurs in type 1 diabetes. Restoration of insulin production in type 1 diabetes is thus a major medical challenge. We previously observed in mice in which β-cells are completely ablated that the pancreas reconstitutes new insulin-producing cells in the absence of autoimmunity. The process involves the contribution of islet non-β-cells; specifically, glucagon-producing α-cells begin producing insulin by a process of reprogramming (transdifferentiation) without proliferation. Here we show the influence of age on β-cell reconstitution from heterologous islet cells after near-total β-cell loss in mice. We found that senescence does not alter α-cell plasticity: α-cells can reprogram to produce insulin from puberty through to adulthood, and also in aged individuals, even a long time after β-cell loss. In contrast, before puberty there is no detectable α-cell conversion, although β-cell reconstitution after injury is more efficient, always leading to diabetes recovery. This process occurs through a newly discovered mechanism: the spontaneous en masse reprogramming of somatostatin-producing δ-cells. The juveniles display 'somatostatin-to-insulin' δ-cell conversion, involving dedifferentiation, proliferation and re-expression of islet developmental regulators. This juvenile adaptability relies, at least in part, upon the combined action of FoxO1 and downstream effectors. Restoration of insulin producing-cells from non-β-cell origins is thus enabled throughout life via δ- or α-cell spontaneous reprogramming. A landscape with multiple intra-islet cell interconversion events is emerging, offering new perspectives for therapy.

Low frequency of regulatory T cells in the peripheral blood of children with type 1 diabetes diagnosed under the age of five

The highest annual increase in the incidence of type 1 diabetes (T1D) in children under the age of 5 years and aggressive process of β-cell destruction in this age group indicate the need to assess the immune system. The aim of this study was to evaluate regulatory T cells (Tregs) frequency in the peripheral blood of children <5 years of age with newly diagnosed T1D in comparison with diabetic children diagnosed at a later age and healthy controls. 40 children with newly diagnosed T1D (20 children <5 years of age and 20 older patients) and 40 age-matched controls were included in this study. Flow cytometric analysis of Tregs was performed using the following markers: CD4, CD25, CD127, FoxP3, IL-10, and TGF-β. Apoptosis was measured using anti-active caspase 3 monoclonal antibody. Fasting C-peptide and HbA1c were monitored as well. We showed that T1D children <5 years had lower C-peptide concentration than diabetic children ≥5 years of age (0.32 vs. 0.80 ng/ml, respectively, p = 0.0005). There was lower frequency of CD4(+)CD25(high)CD127(low)FoxP3(+) Tregs in T1D children <5 years than ≥5 years of age (0.87 vs. 1.56 %, respectively, p = 0.017). Diabetic children <5 years had lower CD4(+)CD25(high)CD127(low)FoxP3(+), CD4(+)CD25(high)IL-10, and CD4(+)CD25(high)TGF-β Tregs compared to age-matched controls. There was no difference in Tregs apoptosis between the examined groups. This study highlights the distinctiveness of diabetes in children <5 years of age. Understanding the differences of immune system activity in the young diabetic children would open the way to identify children at risk for T1D and enables the use of novel forms of intervention.

Conversion of adult pancreatic alpha-cells to beta-cells after extreme beta-cell loss

Pancreatic insulin-producing beta-cells have a long lifespan, such that in healthy conditions they replicate little during a lifetime. Nevertheless, they show increased self-duplication after increased metabolic demand or after injury (that is, beta-cell loss). It is not known whether adult mammals can differentiate (regenerate) new beta-cells after extreme, total beta-cell loss, as in diabetes. This would indicate differentiation from precursors or another heterologous (non-beta-cell) source. Here we show beta-cell regeneration in a transgenic model of diphtheria-toxin-induced acute selective near-total beta-cell ablation. If given insulin, the mice survived and showed beta-cell mass augmentation with time. Lineage-tracing to label the glucagon-producing alpha-cells before beta-cell ablation tracked large fractions of regenerated beta-cells as deriving from alpha-cells, revealing a previously disregarded degree of pancreatic cell plasticity. Such inter-endocrine spontaneous adult cell conversion could be harnessed towards methods of producing beta-cells for diabetes therapies, either in differentiation settings in vitro or in induced regeneration.

Distinct clinical courses in type 1 diabetes mellitus induced by peg-interferon-alpha treatment for chronic hepatitis C

We report two cases of type 1 diabetes mellitus (T1DM) which developed after interferon (IFN) therapy for chronic hepatitis C. The patients had experienced abrupt hyperglycemia with positive anti-glutamic acid decarboxylase antibodies, resulting in initiation of insulin therapy. In one case, insulin therapy could be discontinued because endogenous insulin secretion was preserved at the onset and pancreatic beta cell function was recovered thereafter. In the other case with Hashimoto's thyroiditis and Sjögren's syndrome, continuation of insulin therapy was necessary because blood glucose levels were unstably controlled. Lasting autoimmunity superior to immunosuppressive mechanism may be associated with distinct clinical courses in these cases.

The honeymoon phase: intersection of metabolism and immunology

PURPOSE OF REVIEW

Even though the honeymoon phase in type 1 diabetes mellitus has been well known, its underlying pathogenic mechanisms remain poorly described. The common explanation that it occurs due to 'beta-cell rest' on initiation of insulin therapy seems inadequate based on recent observations and studies and its underlying immunological aspects overlooked.

RECENT FINDINGS

In this article, we will review the metabolic and immunological aspects of the honeymoon phase and we will present our current model of the pathophysiology of this phase. Our view is that it is one of many phases of remission occurring basically due to development of adaptive immune tolerance along the course of type 1 diabetes. We will also review new findings of the interplay between metabolic factors (ambient glucose level) and immune function.

SUMMARY

The honeymoon phase provides a unique model to understand the pathogenesis of type 1 diabetes. Research to unravel its immune pathogenesis is needed. It may turn out that the optimum form of intervention in type 1 diabetes is one that combines enhancement of antigen-specific adaptive immune tolerance with optimized metabolic control in order to keep cytotoxic T cells anergic.

Rehabilitation of adaptive immunity and regeneration of beta cells

Type 1 Diabetes (T1D) is an autoimmune disease resulting from the destruction of pancreatic insulin-producing beta cells that most frequently occurs in genetically predisposed children. Recent observations illustrating the regenerative capability of the endocrine pancreas in addition to advances in stem cell and gene therapy technologies enable the exploration of alternatives to allogeneic islet transplantation. Living-cell-mediated approaches can abrogate autoimmunity and the consequent destruction of beta cells without the need for immunosuppressive drugs. Such approaches can be used as a foundation for new protocols that more easily translate to the clinical setting. The twin goals of controlling autoimmune disease and promoting stable regeneration of insulin-producing beta cells should be considered the cornerstones of the successful development of a cure for this chronic disease.