Identification of autoimmune type 1 diabetes and multiple organ-specific autoantibodies in adult-onset non-insulin-requiring diabetes in China: A population-based multicentre nationwide survey

Type 1 diabetes presenting in adults: Trends, diagnostic challenges and unique features

Type 1 diabetes (T1D) has been historically regarded as a childhood-onset disease; however, recent epidemiological data indicate that adult-onset T1D accounts for a substantial proportion of cases worldwide. There is evidence that adult-onset T1D is associated with the classic T1D triad of elevated genetic risk, the presence of islet-specific autoantibodies and progression to severe insulin deficiency. In this article, we review our understanding of the commonalities and differences between childhood and adult-onset T1D, and we highlight significant knowledge gaps in our understanding of the diagnosis, incidence, trajectory and treatment of adult-onset T1D. Compared to children, adults presenting with T1D exhibit differences in genetic risk, immunologic profiles and metabolic outcomes, including differences in the type and number of autoantibodies present, genetic associations and total genetic burden, rates of C-peptide decline, the persistence of C-peptide in long-duration disease and glycaemic control. In addition, obesity and metabolic syndrome are increasingly common in adults, which not only blurs the clinical distinction of adult-onset T1D from type 2 diabetes (T2D) but also likely contributes to differences in metabolic outcomes and rates of progression. Because T2D is so prevalent in the adult population, adult-onset T1D is misclassified as T2D in at least one in three cases, leading to delays in appropriate treatment. Current diagnostic tools, including autoantibody testing and C-peptide measurement, are underutilised or lack specificity in distinguishing adult-onset T1D from atypical T2D. Additionally, the impact of different responses to disease-modifying therapy between adults and children is unclear. Addressing these knowledge gaps requires expanded epidemiological studies, diverse patient registries and refined classification criteria to improve early detection and treatment strategies. A deeper understanding of adult-onset T1D will be critical to reduce the burden of misdiagnosis, lead to earlier diagnosis and treatment and optimise population-based screening approaches in this under-recognised population. PLAIN LANGUAGE SUMMARY: Type 1 diabetes (T1D) is an autoimmune disease that causes metabolic and nutritional complications due to the destruction of insulin-producing pancreatic β cells. T1D was formerly known as "juvenile diabetes" because it was assumed that most cases occurred in childhood; however, recent epidemiological data show that nearly half of all T1D cases are diagnosed in adulthood. Despite the high prevalence of adult-onset T1D, there are challenges with correctly diagnosing T1D in adulthood, and significant knowledge gaps remain regarding the incidence, trajectory, and treatment of adult-onset T1D. In this article, we summarize the current understanding of commonalities and differences between childhood and adult-onset T1D. Particularly, we highlight age-related differences in genetic risk, immunologic profiles, and metabolic outcomes and complications. Finally, we highlight key gaps in our understanding of adult-onset T1D that need to be addressed to reduce the burden of misdiagnosis and allow for better screening and treatment of T1D in adulthood.

Associations Between Diabetes Mellitus and Neurodegenerative Diseases

Diabetes mellitus (DM) and neurodegenerative diseases/disturbances are worldwide health problems. The most common chronic conditions diagnosed in persons 60 years and older are type 2 diabetes mellitus (T2DM) and cognitive impairment. It was found that diabetes mellitus is a major risk for cognitive decline, dementia, Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS) and other neurodegenerative disorders. Different mechanisms of associations between these diseases and diabetes mellitus have been suggested. For example, it is postulated that an impaired intracellular insulin signaling pathway, together with hyperglycemia and hyperinsulinemia, may cause pathological changes, such as dysfunction of the mitochondria, oxidative stress inflammatory responses, etc. The association between diabetes mellitus and neurodegenerative diseases, as well as the mechanisms of these associations, needs further investigation. The aim of this review is to describe the associations between diabetes mellitus, especially type 1 (T1DM) and type 2 diabetes mellitus, and selected neurodegenerative diseases, i.e., Alzheimer's disease, Parkinson's disease, Huntington's disease and amyotrophic lateral sclerosis. Suggested mechanisms of these associations are also described.

Prognosis and outcome of latent autoimmune diabetes in adults: T1DM or T2DM?

Latent Autoimmune Diabetes in Adults (LADA) is a type of diabetes mellitus often overlooked in clinical practice for its dual resemblance to Type 1 Diabetes Mellitus (T1DM) in pathogenesis and to Type 2 Diabetes Mellitus (T2DM) in clinical presentation. To better understand LADA's distinctiveness from T1DM and T2DM, we conducted a comprehensive review encompassing etiology, pathology, clinical features, treatment modalities, and prognostic outcomes. With this comparative lens, we propose that LADA defies simple classification as either T1DM or T2DM. The specific treatments for the disease are limited and should be based on the therapies of T1DM or T2DM that address specific clinical issues at different stages of the disease. It is crucial to identify LADA cases potentially misdiagnosed as T2DM, warranting prompt screening for poor blood sugar control, short-term blood sugar deterioration, and other conditions. If the prognosis for LADA is similar to T2DM, it can be managed as T2DM. However, if the prognosis fundamentally differs, early LADA screening is crucial to optimize patient outcomes and enhance research on tailored treatments. The pathogenesis of LADA is clear, so the prognosis may be the key to determining whether it can be classified as T2DM, which is also the direction of future research. On the one hand, this paper aims to provide suggestions for the clinical screening and treatment of LADA based on the latest progress and provide worthy directions for future research on LADA.

Consensus guidance for monitoring individuals with islet autoantibody-positive pre-stage 3 type 1 diabetes

Given the proven benefits of screening to reduce diabetic ketoacidosis (DKA) likelihood at the time of stage 3 type 1 diabetes diagnosis, and emerging availability of therapy to delay disease progression, type 1 diabetes screening programmes are being increasingly emphasised. Once broadly implemented, screening initiatives will identify significant numbers of islet autoantibody-positive (IAb+) children and adults who are at risk of (confirmed single IAb+) or living with (multiple IAb+) early-stage (stage 1 and stage 2) type 1 diabetes. These individuals will need monitoring for disease progression; much of this care will happen in non-specialised settings. To inform this monitoring, JDRF in conjunction with international experts and societies developed consensus guidance. Broad advice from this guidance includes the following: (1) partnerships should be fostered between endocrinologists and primary-care providers to care for people who are IAb+; (2) when people who are IAb+ are initially identified there is a need for confirmation using a second sample; (3) single IAb+ individuals are at lower risk of progression than multiple IAb+ individuals; (4) individuals with early-stage type 1 diabetes should have periodic medical monitoring, including regular assessments of glucose levels, regular education about symptoms of diabetes and DKA, and psychosocial support; (5) interested people with stage 2 type 1 diabetes should be offered trial participation or approved therapies; and (6) all health professionals involved in monitoring and care of individuals with type 1 diabetes have a responsibility to provide education. The guidance also emphasises significant unmet needs for further research on early-stage type 1 diabetes to increase the rigour of future recommendations and inform clinical care.

The association of islet autoantibodies with the neural retinal thickness and microcirculation in type 1 diabetes mellitus with no clinical evidence of diabetic retinopathy

OBJECTIVE

To examine the association between islet autoantibodies (IAbs) and the retinal neurovascular changes in type 1 diabetes mellitus (T1DM) with no diabetic retinopathy (NDR).

METHODS

This cross-sectional study measured the neural retinal structure and microvascular density of 118 NDR eyes using spectral-domain optical coherence tomography angiography. Retinal structure parameters included retinal thickness (RT), inner retinal thickness (iRT), retina never fibral layer thickness (RNFL thickness), ganglion cell complex thickness (GCC thickness), and loss volume of GCC. Microvascular parameters included vessel density of superficial capillary plexus (sVD), vessel density of deep capillary plexus, and vessel density of choroid capillary plexus. Comparison and correlation analyses of these OCTA parameters were made with various IAbs, including glutamic acid decarboxylase antibody (GADA), tyrosine phosphatase-related islet antigen 2 antibody (IA2A), and zinc transporter 8 antibody (ZnT8A). A general linear model was used to understand the association of IAbs with the retina parameters.

RESULTS

The IAb positive (IAbs +) group, which included 85 patients, had thinner RT (235.20 ± 18.10 mm vs. 244.40 ± 19.90 mm at fovea, P = 0.021) and thinner iRT (120.10 ± 9.00 mm vs. 124.70 ± 6.90 mm at parafovea, P = 0.015), compared with the IAb negative (IAbs-) group comprising 33 patients. Furthermore, a more severe reduction of RT was demonstrated in the presence of multiple IAbs. Among the three IAbs, GADA was the most significant independent risk factor of all-round RT decrease (β = -0.20 vs. -0.27 at fovea and parafovea, respectively, P < 0.05), while titers of IA2A negatively affect sVD in the parafovea (β = -0.316, P = 0.003).

CONCLUSIONS

IAbs are associated with neural retinal thinning and microcirculation reduction in T1DM patients before the clinical onset of diabetic retinopathy.

Recovery of intracellular glucose uptake in T cells during partial remission of type 1 diabetes

AIMS/HYPOTHESIS

Notwithstanding the irreversible beta cell failure seen in type 1 diabetes, some individuals may experience a special phase named 'partial remission' or 'the honeymoon period', in which there is a transient recovery of beta cell function. Importantly, this stage of partial remission shows spontaneous immune downregulation, although the exact mechanisms are unclear. Intracellular energy metabolism is crucial for the differentiation and function of T cells, and provides promising targets for immunometabolic intervention strategies, but its role during partial remission is unknown. In this study, we aim to investigate the association between T cell intracellular glucose and fatty acid metabolism and the partial remission phase.

METHODS

This is a cross-sectional study with a follow-up component. Intracellular uptake of glucose and fatty acids by T cells was detected in participants with either new-onset type 1 diabetes or type 1 diabetes that was already in partial remission, and compared with heathy individuals and participants with type 2 diabetes. Subsequently, the participants with new-onset type 1 diabetes were followed up to determine whether they experienced a partial remission (remitters) or not (non-remitters). The trajectory of changes in T cell glucose metabolism was observed in remitters and non-remitters. Expression of programmed cell death-1 (PD-1) was also analysed to investigate possible mechanisms driving altered glucose metabolism. Partial remission was defined when patients had convalescent fasting or 2 h postprandial C-peptide >300 pmol/l after insulin treatment.

RESULTS

Compared with participants with new-onset type 1 diabetes, intracellular glucose uptake by T cells decreased significantly in individuals with partial remission. The trajectory of these changes during follow-up showed that intracelluar glucose uptake in T cells fluctuated during different disease stages, with a decreased uptake during partial remission that rebounded after remission. This dynamic in T cell glucose uptake was only detected in remitters and not in non-remitters. Further analysis demonstrated that changes of intracellular glucose uptake were found in subsets of CD4+ and CD8+ T cells, including Th17, Th1, CD8+ naive T cells (Tn) and CD8+ terminally differentiated effector memory T cells (Temra). Moreover, glucose uptake in CD8+ T cells was negatively related to PD-1 expression. The intracellular metabolism of fatty acids was not found to be different between new-onset participants and those in partial remission.

CONCLUSIONS/INTERPRETATION

Intracellular glucose uptake in T cells was specifically decreased during partial remission in type 1 diabetes and may be related to PD-1 upregulation, which may be involved in the down-modulation of immune responses during partial remission. This study suggests that altered immune metabolism could be a target for interventions at the point of diagnosis of type 1 diabetes.

Adult-onset type 1 diabetes: A changing perspective

Type 1 diabetes most commonly presents in adulthood, contrary to the widely held view that it is a disease of childhood. Furthermore, a substantial proportion of cases of adult-onset type 1 diabetes does not require insulin therapy at clinical onset. Recent studies have emphasised the evidence that adult-onset type 1 diabetes is prevalent but often misclassified initially as type 2 diabetes (1, 2). In this review, we discuss that recent literature, highlighting the similarities and differences between adult-onset and childhood-onset type 1 diabetes, exploring recent debates surrounding its epidemiology and genetics, as well as expanding on important issues of diagnostic criteria for individuals presenting with adult-onset diabetes and the subsequent management once identified as having an autoimmune basis. In addition, this review looks at the psychosocial challenges faced by T1D patients and their possible management.

Adult-onset autoimmune diabetes

Adult-onset autoimmune (AOA) diabetes pathophysiology starts with immune changes, followed by dysglycaemia and overt disease. AOA diabetes can occur as classic type 1 diabetes when associated with severe loss of insulin secretion. More frequently, it is diagnosed as latent autoimmune diabetes in adults, a slowly progressing form with late onset, a long period not requiring insulin, and it is often misdiagnosed as type 2 diabetes. As its clinical presentation varies remarkably and immune markers often lack specificity, it is challenging to classify each case ad hoc, especially when insulin treatment is not required at diagnosis. Proper care of AOA diabetes aims to prevent complications and to improve quality of life and life expectancy. To achieve these goals, attention should be paid to lifestyle factors, with the aid of pharmacological therapies properly tailored to each individual clinical setting. Given the heterogeneity of the disease, choosing the right therapy for AOA diabetes is challenging. Most of the trials testing disease-modifying therapies for autoimmune diabetes are conducted in people with childhood onset, whereas non-insulin diabetes therapies have mostly been studied in the larger population with type 2 diabetes. More randomized controlled trials of therapeutic agents in AOA diabetes are needed.

Latent autoimmune diabetes in adults in China

Latent autoimmune diabetes in adults (LADA) is a type of diabetes caused by slow progression of autoimmune damage to pancreatic beta cells. According to the etiological classification, LADA should belong to the autoimmune subtype of type 1 diabetes (T1D). Previous studies have found general immune genetic effects associated with LADA, but there are also some racial differences. Multicenter studies have been conducted in different countries worldwide, but it is still unclear how the Chinese and Caucasian populations differ. The epidemiology and phenotypic characteristics of LADA may vary between Caucasian and Chinese diabetic patients as lifestyle, food habits, and body mass index differ between these two populations. The prevalence of LADA in China has reached a high level compared to other countries. The prevalence of LADA in China has reached a high level compared to other countries, and the number of patients with LADA ranks first in the world. Previous studies have found general immune genetic effects associated with LADA, but some racial differences also exist. The prevalence of LADA among newly diagnosed type 2 diabetes patients over the age of 30 years in China is 5.9%, and LADA patients account for 65% of the newly diagnosed T1D patients in the country. As a country with a large population, China has many people with LADA. A summary and analysis of these studies will enhance further understanding of LADA in China. In addition, comparing the similarities and differences between the Chinese and the Caucasian population from the perspectives of epidemiology, clinical, immunology and genetics will help to improve the understanding of LADA, and then promote LADA studies in individual populations.

Diabetic ketoacidosis as first presentation of latent autoimmune diabetes in adults in a patient with hashitoxicosis as first presentation of Hashimoto's thyroiditis: a case report

Background

Latent autoimmune diabetes in adults is an infrequent form of autoimmune diabetes mellitus, while Hashimoto’s thyroiditis, the most common thyroid disease in adults, rarely manifests as thyrotoxicosis. The concurrent initial presentation of these two autoimmune disorders is extremely rare.

Case presentation

A 29-year-old male of Albanian descent presented after being hospitalized owing to diabetic ketoacidosis. The diagnosis of type 1 diabetes mellitus was placed, and intensified insulin therapy was initiated. Medical history was not of significance except a 5 kg weight loss within 2 months. The patient presented with recurrent episodes of hypoglycemia, and the doses of preprandial and basal insulin were reduced. The differential diagnosis included type 1 diabetes mellitus “honeymoon” period or another type of diabetes mellitus. His serological tests only revealed positive autoantibodies against glutamic acid decarboxylase 65 and C-peptide. The diagnosis leaned toward latent autoimmune diabetes in adults, and the therapeutic approach involved cessation of preprandial insulin therapy, regulation, and subsequent discontinuation of basal insulin and introduction of metformin. Two years later, basal insulin was reintroduced along with a glucagon-like peptide-receptor agonist and metformin. Further physical examination during the initial visit disclosed upper limb tremor, lid lag, excessive sweating, increased sensitivity to heat, and tachycardia. Laboratory tests were indicative of hashitoxicosis (suppressed level of thyroid-stimulating hormone, high levels of total and free thyroid hormones, positive anti-thyroglobulin and anti-thyroid peroxidase, and negative anti-thyroid-stimulating hormone receptor). Thyroid-stimulating hormone level was spontaneously restored, but an increase was observed during follow-up. Levothyroxine was administrated for 2 years until the patient had normal thyroid function.

Conclusions

The prevalence of thyroid autoantibodies in patients with latent autoimmune diabetes in adults ranges from 20% to 30%. This correlation can be attributed to genetic involvement as well as disorders of immune tolerance to autoantigens. Hence, this report gives prominence to the holistic approach and consideration of comorbidities in patients with diabetes mellitus.

Enhanced T Cell Glucose Uptake Is Associated With Progression of Beta-Cell Function in Type 1 Diabetes

Background

Abnormal intracellular glucose/fatty acid metabolism of T cells has tremendous effects on their immuno-modulatory function, which is related to the pathogenesis of autoimmune diseases. However, the association between the status of intracellular metabolism of T cells and type 1 diabetes is unclear. This study aimed to investigate the uptake of glucose and fatty acids in T cells and its relationship with disease progression in type 1 diabetes.

Methods

A total of 86 individuals with type 1 diabetes were recruited to detect the uptake of glucose and fatty acids in T cells. 2-NBDG uptake and expression of glucose transporter 1 (GLUT1); or BODIPY uptake and expression of carnitine palmitoyltransferase 1A(CPT1A) were used to assess the status of glucose or fatty acid uptake in T cells. Patients with type 1 diabetes were followed up every 3-6 months for 36 months, the progression of beta-cell function was assessed using generalized estimating equations, and survival analysis was performed to determine the status of beta-cell function preservation (defined as 2-hour postprandial C-peptide >200 pmol/L).

Results

Patients with type 1 diabetes demonstrated enhanced intracellular glucose uptake of T cells as indicated by higher 2NBDG uptake and GLUT1 expression, while no significant differences in fatty acid uptake were observed. The increased T cells glucose uptake is associated with lower C-peptide and higher hemoglobin A1c levels. Notably, patients with low T cell glucose uptake at onset maintained high levels of C-peptide within 36 months of the disease course [fasting C-petite and 2-hour postprandial C-peptide are 60.6 (95%CI: 21.1-99.8) pmol/L and 146.3 (95%CI: 14.1-278.5) pmol/L higher respectively], And they also have a higher proportion of beta-cell function preservation during this follow-up period (P<0.001).

Conclusions

Intracellular glucose uptake of T cells is abnormally enhanced in type 1 diabetes and is associated with beta-cell function and its progression.

Latent Autoimmune Diabetes in Adults (LADA): From Immunopathogenesis to Immunotherapy

Latent autoimmune diabetes in adults (LADA) is a type of diabetes characterized by slow autoimmune damage of pancreatic β cells without insulin treatment in the early clinical stage. There are differences between LADA and classical type 1 diabetes (T1D) and type 2 diabetes (T2D) in genetic background, autoimmune response, rate of islet function decline, clinical metabolic characteristics, and so on. The disease progression and drug response of patients with LADA are closely related to the level of islet autoimmunity, thus exploring the pathogenesis of LADA is of great significance for its prevention and treatment. Previous studies reported that adaptive immunity and innate immunity play a critical role in the etiology of LADA. Recent studies have shown that the intestinal microbiota which impacts host immunity hugely, participates in the pathogenesis of LADA. In addition, the progression of autoimmune pancreatic β cell destruction in LADA is slower than in classical T1D, providing a wider window of opportunities for intervention. Therefore, therapies including antidiabetic drugs with immune-regulation effects and immunomodulators could contribute to promising interventions for LADA. We also shed light on potential interventions targeting the gut microbiota and gut-associated immunity, which may be envisaged to halt or delay the process of autoimmunity in LADA.

Serum Bile Acid Profiles in Latent Autoimmune Diabetes in Adults and Type 2 Diabetes Patients

BACKGROUND

Impaired bile acid (BA) metabolism has been associated with the progression of type 2 diabetes (T2D). However, the contribution of BAs to the pathogenesis of latent autoimmune diabetes in adults (LADA) remains unclear. This study was aimed at investigating the association of serum BAs with different diabetes types and analyzing its correlation with main clinical and laboratory parameters.

METHODS

Patients with LADA, patients with T2D, and healthy controls (HCs) were enrolled. Serum BA profiles and inflammatory cytokines were measured. The correlation of BA species with different indicators was assessed by Spearman's correlation method.

RESULTS

Patients with diabetes (LADA and T2D) had significantly higher serum BAs, especially conjugated BAs, compared with those in HCs. Nevertheless, serum BA profiles had no special role in the progression of LADA, because no significant differences in BAs were observed between LADA and T2D patients. Interestingly, HbA1c levels and HOMA-β were found to be correlated with a series of BA species. Proinflammatory cytokines (IL-1β, IL-6, and TNF-α) and anti-inflammatory cytokine (IL-10) were all positively associated with several BA species, especially the conjugated secondary BAs.

CONCLUSION

Serum BAs regulate glucose homeostasis, but have no special value in the pathogenesis of LADA patients. Our study adds further information about the potential value of serum BAs in different types of diabetes.

Adult-Onset Type 1 Diabetes: Current Understanding and Challenges

Recent epidemiological data have shown that more than half of all new cases of type 1 diabetes occur in adults. Key genetic, immune, and metabolic differences exist between adult- and childhood-onset type 1 diabetes, many of which are not well understood. A substantial risk of misclassification of diabetes type can result. Notably, some adults with type 1 diabetes may not require insulin at diagnosis, their clinical disease can masquerade as type 2 diabetes, and the consequent misclassification may result in inappropriate treatment. In response to this important issue, JDRF convened a workshop of international experts in November 2019. Here, we summarize the current understanding and unanswered questions in the field based on those discussions, highlighting epidemiology and immunogenetic and metabolic characteristics of adult-onset type 1 diabetes as well as disease-associated comorbidities and psychosocial challenges. In adult-onset, as compared with childhood-onset, type 1 diabetes, HLA-associated risk is lower, with more protective genotypes and lower genetic risk scores; multiple diabetes-associated autoantibodies are decreased, though GADA remains dominant. Before diagnosis, those with autoantibodies progress more slowly, and at diagnosis, serum C-peptide is higher in adults than children, with ketoacidosis being less frequent. Tools to distinguish types of diabetes are discussed, including body phenotype, clinical course, family history, autoantibodies, comorbidities, and C-peptide. By providing this perspective, we aim to improve the management of adults presenting with type 1 diabetes.

Accurate diagnosis and heterogeneity analysis of a 17q12 deletion syndrome family with adulthood diabetes onset and complex clinical phenotypes

PURPOSE

17q12 Deletion Syndrome is heterogeneous and the reasons remain unclear. We clarified the clinical characteristics of adulthood diabetes onset 17q12 deletion syndrome and investigated the unclear phenotype-genotype correlation.

METHODS

We collected the clinical history and laboratory results of a family with autosomal dominant inheritance diabetes and renopathy. Sanger sequencing of HNF1B and a panel of monogenic diabetic genes were performed to identify the monogenetic diabetes. Semiquantitative PCR and Chromosome 100 K sequence analysis were performed to analyze the copy numbers variation of diabetes related genes. Allelic specific quantitative PCR were used for TBC1D3 and paralogues diagnosis. The reported cases were reviewed and assessed to compare with patients in this study.

RESULTS

Differential variants in genomic DNA and clinical presentations among family members were explored to determine the probable phenotype-genotypes correlation. The four patients were diagnosed with 17q12 deletion syndrome with 1.47-1.76 Mb heterogeneous deletion, which led to the haploinsufficiency of HNF1B, ACACA, LHX1, PIGW, miRNA2909 and other genes. The patients had different amount of genes deletion in TBC1D3 and paralogues, which might associate with the heterogeneous clinical phenotypes.

CONCLUSIONS

We first reported an adulthood diabetes onset 17q12 deletion syndrome family with the largest number of patients. The heterogeneous clinical phenotypes might be related to the haploinsufficiency of TBC1D3 and its paralogues.

Diagnostic value of combined islet antigen-reactive T cells and autoantibodies assays for type 1 diabetes mellitus

AIMS/INTRODUCTION

Type 1 diabetes mellitus is a T cell-mediated autoimmune disease. However, the determination of the autoimmune status of type 1 diabetes mellitus relies on islet autoantibodies (Abs), as T-cell assay is not routinely carried out. This study aimed to investigate the diagnostic value of combined assay of islet antigen-specific T cells and Abs in type 1 diabetes mellitus patients.

MATERIALS AND METHODS

A total of 54 patients with type 1 diabetes mellitus and 56 healthy controls were enrolled. Abs against glutamic acid decarboxylase (GAD), islet antigen-2 and zinc transporter 8 were detected by radioligand assay. Interferon-γ-secreting T cells responding to glutamic acid decarboxylase 65 and C-peptide (CP) were measured by enzyme-linked immunospot.

RESULTS

The positive rate for T-cell responses was significantly higher in patients with type 1 diabetes mellitus than that in controls (P < 0.001). The combined positive rate of Abs and T-cell assay was significantly higher than that of Abs assay alone (85.2% vs 64.8%, P = 0.015). A significant difference in fasting CP level was found between the T+ and T- groups (0.07 ± 0.05 vs 0.11 ± 0.09 nmol/L, P = 0.033). Furthermore, levels of fasting CP and postprandial CP were both lower in the Ab- T+ group than the Ab- T- group (fasting CP 0.06 ± 0.05 vs 0.16 ± 0.12 nmol/L, P = 0.041; postprandial CP 0.12 ± 0.13 vs 0.27 ± 0.12 nmol/L, P = 0.024).

CONCLUSIONS

Enzyme-linked immunospot assays in combination with Abs detection could improve the diagnostic sensitivity of autoimmune diabetes.

Islet Function and Insulin Sensitivity in Latent Autoimmune Diabetes in Adults Taking Sitagliptin: A Randomized Trial

CONTEXT

The long-term effects of dipeptidyl peptidase-4 inhibitors on β-cell function and insulin sensitivity in latent autoimmune diabetes in adults (LADA) are unclear.

OBJECTIVE

To investigate the effects of sitagliptin on β-cell function and insulin sensitivity in LADA patients receiving insulin.

DESIGN AND SETTING

A randomized controlled trial at the Second Xiangya Hospital.

METHODS

Fifty-one patients with LADA were randomized to sitagliptin + insulin (SITA) group or insulin alone (CONT) group for 24 months.

MAIN OUTCOME MEASURES

Fasting C-peptide (FCP), 2-hour postprandial C-peptide (2hCP) during mixed-meal tolerance test, △CP (2hCP - FCP), and updated homeostatic model assessment of β-cell function (HOMA2-B) were determined every 6 months. In 12 subjects, hyperglycemic clamp and hyperinsulinemic euglycemic clamp (HEC) tests were further conducted at 12-month intervals.

RESULTS

During the 24-month follow-up, there were no significant changes in β-cell function in the SITA group, whereas the levels of 2hCP and △CP in the CONT group were reduced at 24 months. Meanwhile, the changes in HOMA2-B from baseline were larger in the SITA group than in the CONT group. At 24 months, first-phase insulin secretion was improved in the SITA group by hyperglycemia clamp, which was higher than in the CONT group (P < .001), while glucose metabolized (M), insulin sensitivity index, and M over logarithmical insulin ratio in HEC were increased in the SITA group (all P < .01 vs baseline), which were higher than in the CONT group.

CONCLUSION

Compared with insulin intervention alone, sitagliptin plus insulin treatment appeared to maintain β-cell function and improve insulin sensitivity in LADA to some extent.

microRNA-143-3p contributes to inflammatory reactions by targeting FOSL2 in PBMCs from patients with autoimmune diabetes mellitus

AIM

Autoimmune diabetes mellitus (defined as ADM) comprises classical type 1 diabetes mellitus (T1DM) and latent autoimmune diabetes in adults (LADA). In this study, microRNAs (miRNAs) expression profiles and functions in peripheral blood mononuclear cells (PBMCs) of ADM patients were mapped and used to explore epigenetic regulation of the pathogenesis of ADM.

METHODS

PBMCs samples from T1DM patients, LADA patients, and type 2 diabetes mellitus (T2DM) patients, as well as age- and sex-matched healthy controls for T1DM and T2DM, respectively, were collected and were sequenced to screen the miRNAs expression profiles. The target genes were verified by dual-luciferase reporter assay. Silencing or overexpressing of the differentially expressed miRNAs, or simultaneously silencing the miRNAs and it's target gene, and then levels of the mRNAs, protein and cytokines were detected.

RESULTS

miR-143-3p expression was upregulated in ADM patients. The target gene of miR-143-3p was identified as Fos-related antigen 2 (FOSL2). Transfection of a miR-143-3p inhibitor into PBMCs upregulated FOSL2 expression, resulting in a downregulated expression of the IL-2, TNF-α, and IFN-γ, and an upregulated expression of IL-6. Transfection of a miR-143-3p mimic into PBMCs downregulated FOSL2 expression, leading to an upregulation of IL-2 and TNF-α expression and a downregulation of IL-6 expression. When silencing FOSL2 while inhibiting miR-143-3p in PBMCs, there was no significant change in expression of the FOSL2 mRNA, protein and cytokines.

CONCLUSION

The expression of miR-143-3p in PBMCs from ADM patients is upregulated. miR-143-3p could function in the pathogenesis of ADM by modulating the inflammatory reaction through FOSL2.

Frequency, clinical characteristics, and determinants of partial remission in type 1 diabetes: Different patterns in children and adults

BACKGROUND

Partial remission (PR) is a special stage in type 1 diabetes (T1D). The different patterns of PR frequency, characteristics, and determinants in juvenile and adult patients are unclear, and data on Chinese are lacking.

METHODS

A total of 186 children and 114 adults with T1D who were regularly followed up in a cohort were included for analysis. PR was defined according to C-peptide ≥300 pmol/L or index of insulin dose-adjusted hemoglobin A1c ≤9, as previously recommended. C-peptide and islet autoantibodies were determined with chemiluminescence and radioimmunoassay, respectively.

RESULTS

The frequency of PR in children was higher than that in adults, with the proportion being 69.9% and 58.8%, respectively (P < .05). For juvenile-onset T1D, the frequency of PR gradually decreased as the onset age decreased, from 87.5% in 13- to 18-year olds to 46.5% in under 6-year olds. Multivariable analyses showed that onset age and male sex were positively related with the frequency of PR in children, while the related factors in adults were initial glycosylated hemoglobin A1c and C-peptide levels. The median PR duration was similar in children (14.8 ± 1.2 months) and adults (16.4 ± 1.9 months). Older onset age was related with a longer PR duration in children, but no such associations were found in adult individuals.

CONCLUSIONS

Children and adults with T1D have different patterns on PR frequency, clinical characteristics, and determinants. For patients during this special phase, the relatively high C-peptide level and to reduce insulin dosage accordingly should be emphasized in clinical practice.

Management of Latent Autoimmune Diabetes in Adults: A Consensus Statement From an International Expert Panel

A substantial proportion of patients with adult-onset diabetes share features of both type 1 diabetes (T1D) and type 2 diabetes (T2D). These individuals, at diagnosis, clinically resemble T2D patients by not requiring insulin treatment, yet they have immunogenetic markers associated with T1D. Such a slowly evolving form of autoimmune diabetes, described as latent autoimmune diabetes of adults (LADA), accounts for 2-12% of all patients with adult-onset diabetes, though they show considerable variability according to their demographics and mode of ascertainment. While therapeutic strategies aim for metabolic control and preservation of residual insulin secretory capacity, endotype heterogeneity within LADA implies a personalized approach to treatment. Faced with a paucity of large-scale clinical trials in LADA, an expert panel reviewed data and delineated one therapeutic approach. Building on the 2020 American Diabetes Association (ADA)/European Association for the Study of Diabetes (EASD) consensus for T2D and heterogeneity within autoimmune diabetes, we propose "deviations" for LADA from those guidelines. Within LADA, C-peptide values, proxy for β-cell function, drive therapeutic decisions. Three broad categories of random C-peptide levels were introduced by the panel: 1) C-peptide levels <0.3 nmol/L: a multiple-insulin regimen recommended as for T1D; 2) C-peptide values ≥0.3 and ≤0.7 nmol/L: defined by the panel as a "gray area" in which a modified ADA/EASD algorithm for T2D is recommended; consider insulin in combination with other therapies to modulate β-cell failure and limit diabetic complications; 3) C-peptide values >0.7 nmol/L: suggests a modified ADA/EASD algorithm as for T2D but allowing for the potentially progressive nature of LADA by monitoring C-peptide to adjust treatment. The panel concluded by advising general screening for LADA in newly diagnosed non-insulin-requiring diabetes and, importantly, that large randomized clinical trials are warranted.

Organ-specific autoantibodies in Chinese patients newly diagnosed with type 1 diabetes mellitus

This study aims to investigate the prevalence of islet autoantibodies and other organ-specific autoantibodies in type 1 diabetes mellitus (T1DM) patients and characterize their clinical features. Glutamic acid decarboxylase antibody (GADA), insulinoma antigen 2 antibody (IA-2A), zinc transporter 8 antibody (ZnT8A) and tetraspanin7 antibody (TSPAN7A) were assayed by radioligand or luciferase immunoprecipitation system assays in 205 newly diagnosed acute-onset T1DM patients and 170 healthy controls. Other organ-specific autoantibodies, including thyroid peroxidase antibody (TPOA), thyroglobulin antibody (TGA), tissue transglutaminase antibody (tTGA) and 21-hydroxylase antibody (21-OHA), were also measured. The prevalence of GADA, IA-2A, ZnT8A, TSPAN7A, TPOA, TGA and 21-OHA was higher in T1DM patients than in healthy controls. The combinational assay of various islet autoantibodies could increase the frequency of autoantibody positivity in T1DM to 85.4%. GADA+ IA-2A+ T1DM patients preferentially had TPOA and TGA, while IA-2A+ patients often had tTGA. Patients positive for two or more islet autoantibodies often had TPOA and TGA. BMI of multiple islet autoantibody-positive patients was lower than that of patients with single or no islet autoantibodies, and there were no significant differences in C-peptide and glycated hemoglobin between patients positive for islet autoantibodies combined with other organ-specific antibodies and noncombined patients. Younger female patients who were islet autoantibody positive were more likely to have TPOA and TGA. The frequency of Graves' disease was much higher in T1DM patients than in healthy controls. T1DM usually occurs together with other organ-specific autoantibodies. Measuring of other organ-specific autoantibodies will be beneficial for T1DM patients.

PD-1 and PD-L1 Expression in Peripheral CD4/CD8+ T Cells Is Restored in the Partial Remission Phase in Type 1 Diabetes

CONTEXT

Partial remission (PR) in type 1 diabetes (T1D) is accompanied by downregulation of the immune response. Programmed cell death-1 (PD-1) and its ligand (PD-L1) are important immunosuppressive molecules, but their changes in the PR phase are unclear.

OBJECTIVE

We investigated the dynamic changes of PD-1/PD-L1 expression on T cells around the PR phase in T1D.

METHODS

Ninety-eight T1D patients were recruited cross-sectionally and grouped according to PR status into nonremitters (individuals who did not undergo PR during the disease course; n = 39), pre-PR (n = 15), mid-PR (n = 30), and post-PR (n = 14) subgroups. PR was defined according to C-peptide level ≥300 pmol/L or index of insulin-adjusted hemoglobin A1c ≤9 as recommended. Among all the 98 patients, 29 newly diagnosed individuals were prospectively followed up for 1 year. The dynamic changes of PD-1/PD-L1 expression, frequency of regulatory T cells (Tregs) and IL-35+ Tregs among peripheral CD4/CD8+ T cells were determined.

RESULTS

PD-1/PD-L1 on CD4+/CD8+ T cells showed a dynamic change around the PR phase: lowest in pre-PR phase, restored in mid-PR phase, and declined again in post-PR phase. Conversely, this pattern did not occur for nonremitters. Notably, PD-1 expression on CD8+ T cells in mid-PR was positively correlated with the length of the PR phase. The percentages of circulating Tregs and IL-35+ Tregs showed no relation to PR.

CONCLUSIONS

The PR phase is associated with restoration of PD-1/PD-L1 on CD4+ and CD8+ T cells, suggesting that PD-1/PD-L1 may be a potential target for prolonging this phase in T1D.

Autoimmunity plays a role in the onset of diabetes after 40 years of age

AIMS/HYPOTHESIS

Type 1 and type 2 diabetes differ with respect to pathophysiological factors such as beta cell function, insulin resistance and phenotypic appearance, but there may be overlap between the two forms of diabetes. However, there are relatively few prospective studies that have characterised the relationship between autoimmunity and incident diabetes. We investigated associations of antibodies against the 65 kDa isoform of GAD (GAD65) with type 1 diabetes and type 2 diabetes genetic risk scores and incident diabetes in adults in European Prospective Investigation into Cancer and Nutrition (EPIC)-InterAct, a case-cohort study nested in the EPIC cohort.

METHODS

GAD65 antibodies were analysed in EPIC participants (over 40 years of age and free of known diabetes at baseline) by radioligand binding assay in a random subcohort (n = 15,802) and in incident diabetes cases (n = 11,981). Type 1 diabetes and type 2 diabetes genetic risk scores were calculated. Associations between GAD65 antibodies and incident diabetes were estimated using Prentice-weighted Cox regression.

RESULTS

GAD65 antibody positivity at baseline was associated with development of diabetes during a median follow-up time of 10.9 years (HR for GAD65 antibody positive vs negative 1.78; 95% CI 1.43, 2.20) after adjustment for sex, centre, physical activity, smoking status and education. The genetic risk score for type 1 diabetes but not type 2 diabetes was associated with GAD65 antibody positivity in both the subcohort (OR per SD genetic risk 1.24; 95% CI 1.03, 1.50) and incident cases (OR 1.97; 95% CI 1.72, 2.26) after adjusting for age and sex. The risk of incident diabetes in those in the top tertile of the type 1 diabetes genetic risk score who were also GAD65 antibody positive was 3.23 (95% CI 2.10, 4.97) compared with all other individuals, suggesting that 1.8% of incident diabetes in adults was attributable to this combination of risk factors.

CONCLUSIONS/INTERPRETATION

Our study indicates that incident diabetes in adults has an element of autoimmune aetiology. Thus, there might be a reason to re-evaluate the present subclassification of diabetes in adulthood.

Allostasis and the origins of adult-onset diabetes

Physiological plasticity enables homeostasis to be maintained in biological systems, but when such allostasis fails, then disease can develop. In a new population-based study by Rolandsson et al (https://doi.org/10.1007/s00125-019-05016-3), autoimmunity, defined by an immunogenotype, predicted adult-onset non-insulin requiring diabetes. Type 1 diabetes is no longer viewed as a disease confined to children, with a significant proportion, maybe the majority, presenting in adulthood. Such cases masquerade as type 2 diabetes and their identification has clinical utility. Nevertheless, in this study, autoimmunity had a limited effect on the overall risk of adults developing diabetes.

Latent Autoimmune Diabetes in Adults: A Review of Clinically Relevant Issues

Latent autoimmune diabetes in adults (LADA) is still a poorly characterized entity. However, its prevalence may be higher than that of classical type 1 diabetes. Patients with LADA are often misclassified as type 2 diabetes. The underlying autoimmune process against β-cell has important consequences for the prognosis, comorbidities, treatment choices and even patient-reported outcomes with this diabetes subtype. However, there is still an important gap of knowledge in many areas of clinical relevance. We are herein focusing on the state of knowledge of relevant clinical issues than may help in the diagnosis and management of subjects with LADA.

Genetic, Functional, and Immunological Study of ZnT8 in Diabetes

Zinc level in the body is finely regulated to maintain cellular function. Dysregulation of zinc metabolism may induce a variety of diseases, e.g., diabetes. Zinc participates in insulin synthesis, storage, and secretion by functioning as a "cellular second messenger" in the insulin signaling pathway and glucose homeostasis. The highest zinc concentration is in the pancreas islets. Zinc accumulation in cell granules is manipulated by ZnT8, a zinc transporter expressed predominately in pancreatic α and β cells. A common ZnT8 gene (SLC30A8) polymorphism increases the risk of type 2 diabetes mellitus (T2DM), and rare mutations may present protective effects. In type 1 diabetes mellitus (T1DM), autoantibodies show specificity for binding two variants of ZnT8 (R or W at amino acid 325) dictated by a polymorphism in SLC30A8. In this review, we summarize the structure, feature, functions, and polymorphisms of ZnT8 along with its association with diabetes and explore future study directions.