Prediction of type 1 diabetes in the general population

Circulating non-coding RNA in type 1 diabetes mellitus as a source of potential biomarkers - An emerging role of sex difference

Non-coding RNAs (ncRNAs), such as microRNA, long non-coding RNA, and circular RNA, are considered essential regulatory molecules mediating many cellular processes. Moreover, an increasing number of studies have investigated the role of ncRNAs in cancers and various metabolic disorders, including diabetes mellitus. Interestingly, some circulating ncRNA detected in body fluids may serve as novel biomarkers. There is still a lack of conventional biomarkers that detect the early stage of type 1 diabetes mellitus. Many circulating microRNA, long non-coding RNA, and circular RNA show aberrant expression in type 1 diabetes patients compared to healthy individuals. However, most studies have focused on circulating microRNA rather than long non-coding RNA or circular RNA. In addition, a few studies have evaluated sex differences in ncRNA biomarkers. Therefore, this article summarises current knowledge about circulating ncRNAs as potential biomarkers for type 1 diabetes and explores the effects of sex on such biomarkers.

Dietary Components in the Pathogenesis and Prevention of Type 1 Diabetes in Children

BACKGROUND

Type 1 diabetes (T1D) is a disease closely linked to nutrition and modifications in various dietary components have been part of the effort to prevent or slow the progression of the disease even before the discovery of insulin.

SUMMARY

The scientific focus in the prevention or progression modification of T1D is mostly centered on four dietary compounds and their modifications - gluten and its omission, vitamin D supplementation, omega-3 fatty acids supplementation, and decreasing of the amount of ingested carbohydrates. The aim of this narrative review was to provide an overview of nutritional interventions studied in children either as preventive methods or as modifiers in the early stages of T1D from autoantibody positive individuals to persons with newly diagnosed T1D.

KEY MESSAGES

Our review shows that dietary modifications in various dietary components might be useful but none of them seems to provide universal effects in T1D prevention or progression modification. More research is therefore needed with focus on promising modes of action of individual dietary components.

The INNODIA Type 1 Diabetes Natural History Study: a European cohort of newly diagnosed children, adolescents and adults

AIMS/HYPOTHESIS

Type 1 diabetes is an heterogenous condition. Characterising factors explaining differences in an individual's clinical course and treatment response will have important clinical and research implications. Our aim was to explore type 1 diabetes heterogeneity, as assessed by clinical characteristics, autoantibodies, beta cell function and glycaemic outcomes, during the first 12 months from diagnosis, and how it relates to age at diagnosis.

METHODS

Data were collected from the large INNODIA cohort of individuals (aged 1.0-45.0 years) newly diagnosed with type 1 diabetes, followed 3 monthly, to assess clinical characteristics, C-peptide, HbA1c and diabetes-associated antibodies, and their changes, during the first 12 months from diagnosis, across three age groups: <10 years; 10-17 years; and ≥18 years.

RESULTS

The study population included 649 individuals (57.3% male; age 12.1±8.3 years), 96.9% of whom were positive for one or more diabetes-related antibodies. Baseline (IQR) fasting C-peptide was 242.0 (139.0-382.0) pmol/l (AUC 749.3 [466.2-1106.1] pmol/l × min), with levels increasing with age (p<0.001). Over time, C-peptide remained lower in participants aged <10 years but it declined in all age groups. In parallel, glucose levels progressively increased. Lower baseline fasting C-peptide, BMI SD score and presence of diabetic ketoacidosis at diagnosis were associated with lower stimulated C-peptide over time. HbA1c decreased during the first 3 months (p<0.001), whereas insulin requirement increased from 3 months post diagnosis (p<0.001).

CONCLUSIONS/INTERPRETATION

In this large cohort with newly diagnosed type 1 diabetes, we identified age-related differences in clinical and biochemical variables. Of note, C-peptide was lower in younger children but there were no main age differences in its rate of decline.

Increased Severity of Presentation Signs in Children with Newly Diagnosed Type 1 Diabetes during the COVID-19 Pandemic: A Tertiary Center Experience

INTRODUCTION

Diabetic ketoacidosis (DKA) is an important complication of type 1 diabetes mellitus (T1DM) which is worsened when the diagnosis of T1DM is delayed. The aim of this study was to evaluate the presentation patterns, severity, autoantibody status, and seasonal variability of newly diagnosed T1DM patients during the pandemic period of 2 years compared to those in the pre-pandemic period.

METHODS

In this single tertiary center retrospective cohort study, newly diagnosed T1DM patients were grouped as pre-pandemic and pandemic period. Age, gender, the month of diagnosis, hemoglobin A1c, venous blood gas parameters, duration of symptoms, glutamic-acid-decarboxylase-antibody (anti-GAD), islet-cell antibody (ICA), and insulin autoantibody levels were recorded. The data obtained were compared between the groups.

RESULTS

Number of patients presenting with DKA was significantly higher during the pandemic period (92 [65.7%] vs. 62 [40.8%] patients, p < 0.001). In terms of clinical severity of DKA, pH, and HCO3 levels were lower during the pandemic period (p < 0.001), while the number of patients presenting with severe DKA was significantly higher during the pandemic period (41 [44.6%] vs. 17 [27.4%] patients, p = 0.031). ICA positivity was significantly higher in patients admitted during the pandemic period (47 [36.4%] vs. 21 patients [16.9%], p < 0.001), especially in the second year of the pandemic (p < 0.001). Anti-GAD-ICA co-positivity was significantly higher in patients admitted during the pandemic period and also in second year of the pandemic (p < 0.001).

CONCLUSION

DKA rates increased in newly diagnosed T1DM cases during the pandemic. Despite the relaxation of bans, the second year of the pandemic also saw increased rates of DKA and severe DKA compared to the pre-pandemic period. The significantly increased ICA positivity in the pandemic may support the effects of COVID-19 on autoimmune T1DM.

Advances in risk predictive performance of pre-symptomatic type 1 diabetes via the multiplex Antibody-Detection-by-Agglutination-PCR assay

Introduction

Achieving early diagnosis of pre-symptomatic type 1 diabetes is critical to reduce potentially life-threatening diabetic ketoacidosis (DKA) at symptom onset, link patients to FDA approved therapeutics that can delay disease progression and support novel interventional drugs development. The presence of two or more islet autoantibodies in pre-symptomatic type 1 diabetes patients indicates high-risk of progression to clinical manifestation.

Method

Herein, we characterized the capability of multiplex ADAP assay to predict type 1 diabetes progression. We obtained retrospective coded sera from a cohort of 48 progressors and 44 non-progressors from the NIDDK DPT-1 study.

Result

The multiplex ADAP assay and radiobinding assays had positive predictive value (PPV)/negative predictive value (NPV) of 68%/92% and 67%/66% respectively. The improved NPV stemmed from 12 progressors tested positive for multiple islet autoantibodies by multiplex ADAP assay but not by RBA. Furthermore, 6 out of these 12 patients tested positive for multiple islet autoantibodies by RBA in subsequent sampling events with a median delay of 2.8 years compared to multiplex ADAP assay.

Discussion

In summary, multiplex ADAP assay could be an ideal tool for type 1 diabetes risk testing due to its sample-sparing nature (4µL), non-radioactiveness, compatibility with widely available real-time qPCR instruments and favorable risk prediction capability.

Secondary Prevention of Diabetes Type 1 with Oral Calcitriol and Analogs, the PRECAL Study

Screening for Type 1 Diabetes (T1D, incidence 1:300) with T1D autoantibodies (T1Ab) at ages 2 and 6, while sensitive, lacks a preventive strategy. Cholecalciferol 2000 IU daily since birth reduced T1D by 80% at 1 year. T1D-associated T1Ab negativized within 0.6 years with oral calcitriol in 12 children. To further investigate secondary prevention of T1D with calcitriol and its less calcemic analog, paricalcitol, we initiated a prospective interventional non-randomized clinical trial, the PRECAL study (ISRCTN17354692). In total, 50 high-risk children were included: 44 were positive for T1Ab, and 6 had predisposing for T1D HLA genotypes. Nine T1Ab+ patients had variable impaired glucose tolerance (IGT), four had pre-T1D (3 T1Ab+, 1 HLA+), nine had T1Ab+ new-onset T1D not requiring insulin at diagnosis. T1Ab, thyroid/anti-transglutaminase Abs, glucose/calcium metabolism were determined prior and q3-6 months on calcitriol, 0.05 mcg/Kg/day, or paricalcitol 1-4 mcg × 1-3 times/day p.o. while on cholecalciferol repletion. Available data on 42 (7 dropouts, 1 follow-up < 3 months) patients included: all 26 without pre-T1D/T1D followed for 3.06 (0.5-10) years negativized T1Ab (15 +IAA, 3 IA2, 4 ICA, 2 +GAD, 1 +IAA/+GAD, 1 +ICA/+GAD) within 0.57 (0.32-1.3) years or did not develop to T1D (5 +HLA, follow-up 3 (1-4) years). From four pre-T1D cases, one negativized T1Ab (follow-up 1 year), one +HLA did not progress to T1D (follow-up 3.3 years) and two +T1Ab patients developed T1D in 6 months/3 years. Three out of nine T1D cases progressed immediately to overt disease, six underwent complete remission for 1 year (1 month-2 years). Five +T1Ab patients relapsed and negativized again after resuming therapy. Four (aged <3 years) negativized anti-TPO/TG, and two anti-transglutaminase-IgA. Eight presented mild hypercalciuria/hypercalcemia, resolving with dose titration/discontinuation. Secondary prevention of T1D with calcitriol and paricalcitol seems possible and reasonably safe, if started soon enough after seroconversion.

Islet autoantibody screening in at-risk adolescents to predict type 1 diabetes until young adulthood: a prospective cohort study

BACKGROUND

Screening for islet autoantibodies in children and adolescents identifies individuals who will later develop type 1 diabetes, allowing patient and family education to prevent diabetic ketoacidosis at onset and to enable consideration of preventive therapies. We aimed to assess whether islet autoantibody screening is effective for predicting type 1 diabetes in adolescents aged 10-18 years with an increased risk of developing type 1 diabetes.

METHODS

Data were harmonised from prospective studies from Finland (the Diabetes Prediction and Prevention study), Germany (the BABYDIAB study), and the USA (Diabetes Autoimmunity Study in the Young and the Diabetes Evaluation in Washington study). Autoantibodies against insulin, glutamic acid decarboxylase, and insulinoma-associated protein 2 were measured at each follow-up visit. Children who were lost to follow-up or diagnosed with type 1 diabetes before 10 years of age were excluded. Inverse probability censoring weighting was used to include data from remaining participants. Sensitivity and the positive predictive value of these autoantibodies, tested at one or two ages, to predict type 1 diabetes by the age of 18 years were the main outcomes.

FINDINGS

Of 20 303 children with an increased type 1 diabetes risk, 8682 were included for the analysis with inverse probability censoring weighting. 1890 were followed up to 18 years of age or developed type 1 diabetes between the ages of 10 years and 18 years, and their median follow-up was 18·3 years (IQR 14·5-20·3). 442 (23·4%) of 1890 adolescents were positive for at least one islet autoantibody, and 262 (13·9%) developed type 1 diabetes. Time from seroconversion to diabetes diagnosis increased by 0·64 years (95% CI 0·34-0·95) for each 1-year increment of diagnosis age (Pearson's correlation coefficient 0·88, 95% CI 0·50-0·97, p=0·0020). The median interval between the last prediagnostic sample and diagnosis was 0·3 years (IQR 0·1-1·3) in the 227 participants who were autoantibody positive and 6·8 years (1·6-9·9) for the 35 who were autoantibody negative. Single screening at the age of 10 years was 90% (95% CI 86-95) sensitive, with a positive predictive value of 66% (60-72) for clinical diabetes. Screening at two ages (10 years and 14 years) increased sensitivity to 93% (95% CI 89-97) but lowered the positive predictive value to 55% (49-60).

INTERPRETATION

Screening of adolescents at risk for type 1 diabetes only once at 10 years of age for islet autoantibodies was highly effective to detect type 1 diabetes by the age of 18 years, which in turn could enable prevention of diabetic ketoacidosis and participation in secondary prevention trials.

FUNDING

JDRF International.

SARS-CoV-2 and type 1 diabetes in children in Finland: an observational study

BACKGROUND

Some epidemiological studies have suggested an increase in incidence of type 1 diabetes during the COVID-19 pandemic, however the mechanism(s) behind such an increase have yet to be identified. In this study we aimed to evaluate the possible role of the SARS-CoV-2 virus in the reported increase in the rate of type 1 diabetes.

METHODS

In this observational cohort study using data from the Finnish Pediatric Diabetes Register (FPDR), we assessed the incidence of type 1 diabetes (number of children with newly diagnosed type 1 diabetes per 100 000 person-years during the pandemic and the reference period) during the first 18 months of the COVID-19 pandemic in children in Finland younger than 15 years old compared with a reference period which included three corresponding pre-pandemic periods also obtained from the FPDR. Children with confirmed monogenic diabetes were excluded. We also compared the phenotype and HLA genotype of the disease between these two cohorts, and analysed the proportion of newly diagnosed people with type 1 diabetes testing positive for SARS-CoV-2 antibodies.

FINDINGS

785 children and adolescents in Finland were diagnosed with type 1 diabetes from March 1, 2020, to Aug 31, 2021. In the reference period, which comprised three similar 18-month terms (from March 1, 2014, to Aug 31, 2015; March 1, 2016, to Aug 31, 2017; and March 1, 2018, to Aug 31, 2019) 2096 children and adolescents were diagnosed. The incidence of type 1 diabetes was 61·0 per 100 000 person-years (95% CI 56·8-65·4) among children younger than 15 years old during the pandemic, which was significantly higher than during the reference period (52·3 per 100 000 person-years; 50·1-54·6). The incidence rate ratio adjusted for age and sex for the COVID-19 pandemic was 1·16 (1·06-1·25; p=0·0006) when compared with the reference period. The children diagnosed during the COVID-19 pandemic had more often diabetic ketoacidosis (p<0·001), had a higher HbA_1c (p<0·001), and tested more frequently positive for glutamic acid debarboxylase antibodies at diagnosis (p<0·001) than those diagnosed before the pandemic. There were no significant differences in the distribution of HLA genotypes between the two periods. Only five of those diagnosed during the pandemic (0·9%) of 583 tested positive for infection-induced SARS-CoV-2 antibodies.

INTERPRETATION

Children and adolescents diagnosed with type 1 diabetes during the pandemic had a more severe disease at diagnosis. The observed increase in type 1 diabetes incidence during the first 18 months could be a consequence of lockdown and physical distancing rather than a direct effect of SARS-CoV-2 infection.

FUNDING

Helsinki University Hospital Research Funds, EU Horizon 2020 (Versatile emerging infectious disease observatory project), Academy of Finland, Sigrid Jusélius Foundation, Jane & Aatos Erkko Foundation, and Medicinska understödsföreningen Liv och Hälsa.

TRANSLATIONS

For the Finnish and Swedish translations of the abstract see Supplementary Materials section.

The prevalence of diabetes and thyroid related autoantibodies in Sri Lankan children with type 1 diabetes and their unaffected siblings - The utility of a new screening assay

BACKGROUND

There is limited information about diabetes and thyroid related autoantibodies in children with type 1 diabetes (T1D) or their siblings in Sri Lanka.

OBJECTIVES

To assess in T1D children and their unaffected siblings the prevalence of autoantibodies to (1) glutamic acid decarboxylase (GADA), insulinoma associated antigen-2 (IA-2A) and zinc transporter 8 (ZnT8A) using 3 Screen ICA™ (3-Screen) and individual ELISA assays; (2) insulin (IAA); and (3) thyroid peroxidase (TPOA), thyroglobulin (TgA) and the TSH receptor (TSHRA).

METHODS

We selected - (a) consecutive T1D children, and (b) their unaffected siblings of both sexes, from the T1D Registry at Lady Ridgeway Hospital, Colombo.

RESULTS

The median age (IQR) of 235 T1D children and 252 unaffected siblings was 11 (8.4, 13.2) and 9 (5.4, 14.9) years respectively, and the duration of T1D was 23 (7, 54) months. (1) T1D children (a) 79.1% were 3-Screen positive; (b) all 3-Screen positives were individual antibody positive (GADA in 74%; IA-2A 31.1%; ZnT8A 38.7%); (c) and were younger (p=0.01 vs 3-Screen negatives); (d) multiple autoantibodies were present in 45.1%; (e) IA-2A (p=0.002) and ZnT8A (p=0.006) prevalence decreased with T1D duration. (f) TPOA and TgA prevalence was higher in T1D children compared to unaffected siblings (28%, p=0.001 and 31%, p=0.004, respectively). (2) Unaffected siblings (a) 6.3% were 3-Screen positive (p=0.001 vs T1D), and 2.4% were positive for IAA; (b) four subjects had two diabetes related autoantibodies, one of whom developed dysglycaemia during follow-up.

CONCLUSIONS

The 3-Screen assay, used for the first time in Sri Lankan T1D children and their siblings as a screening tool, shows a high prevalence of T1D related Abs with a high correlation with individual assays, and is also a helpful tool in screening unaffected siblings for future T1D risk. The higher prevalence of thyroid autoantibodies in T1D children is consistent with polyglandular autoimmunity.

Clinical Significance of Diabetes-Mellitus-Associated Antibodies in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a canonical autoimmune disease that shares numerous risk factors with diabetes mellitus (DM). The production of autoantibodies is a characteristic feature in both diseases. To determine the frequency and specificity of DM-related antibodies (DMab) in RA patients and to study whether DMab associates with new DM cases in RA patients, we measured DMab defined as IgG against glutamic acid decarboxylase (GADA), tyrosine phosphatase (IA2-ab), and zinc transporter (ZnT8-ab) in a cohort of 290 RA patients (215 women and 75 men, median disease duration 11 years). Of those, 21 had a DM diagnosis at baseline. The development of new DM cases and mortality were traced in a 10-year prospective follow-up. Predictive analyses for DM and mortality were carried out by the Mantel-Cox regression. We found that 27 of the patients (9.3%) had DMab, equally often men and women. The presence of DMab was more frequent in patients with DM (p = 0.027. OR 4.01, 95%CI [1.20; 11.97]), suggesting their specificity for the disease. Men had more prevalent incidental DM at the baseline (12% vs. 5%, p = 0.030) and among the new DM cases (p = 0.012. HR 6.08, 95%CI [1.57; 25]). New DM developed equally frequently in DMab-positive and DMab-negative patients. DM, but not DMab, significantly increased the estimated mortality rate in RA patients (p = 0.021, OR 4.38 [1.2; 13.52]). Taken together, we conclude that DMab are associated with DM in RA patients, but they are not solely enough to predict disease development or mortality in those patients.

Antigen-specific immunotherapies in type 1 diabetes

Type 1 diabetes mellitus (T1DM) is an autoimmune disease caused by the destruction of pancreatic beta cells, in which immune system disorder plays an important role. Finding a cure for T1DM and restoring beta cell function has been a long-standing goal. Research has shown that immune regulation with pancreatic islet auto-antigens may be the most specific and safe treatment for T1DM. Immunological intervention using diabetogenic auto-antigens as a target can help identify T1DM in high-risk individuals by early screening of autoantibodies (AAbs) before the loss of pancreatic islet function and thus achieve primary prevention of T1DM. However, induction of self-tolerance in patients with pre-diabetes can also slow down the attack of autoimmunity, and achieve secondary prevention. Antigen-based immune therapy opens up new avenues for the prevention and treatment of T1DM. The zinc transporter 8 (ZnT8) protein, presents in the serum of pre-diabetic and diabetic patients, is immunogenic and can cause T1D autoimmune responses. ZnT8 has become a potential target of humoral autoimmunity; it is of great significance for the early diagnosis of T1D. ZnT8-specific CD8⁺ T cells can be detected in most T1DM patients, and play a key role in the progression of T1D. As an immunotherapy target, it can improve the dysfunction of beta cells in T1DM and provide new ideas for the treatment of T1D. In this review, we summarize research surrounding antigen-specific immunotherapies (ASI) over the past 10 years and the ZnT8 antigen as an autoimmune target to induce self-tolerance for T1DM.

The relationship between GAD65 autoantibody and the risk of T1DM onset

Objectives

Type 1 diabetes mellitus (T1DM) is a well-known autoimmune disease, characterized by β-cell destruction in pancreas islet cells, which results insulin deficiency and subsequent hyperglycemic sequelae. While there is screening for type 2 DM that leads to better glycemic control and outcome, the majority of T1DM patients are diagnosed when much of the pancreatic cells and their function are disturbed. The aim of this article is to present an overview of the effective factors in the positivity of Glutamic acid decarboxylase antibody )GADA( and identifying the high-risk individuals for T1DM.

Methods

We searched English literature available at National Library of Medicine via PubMed, and Google Scholar through December 2020. Finally, 79 papers have been included in the study. Studies were summarized based on the number of positive autoantibodies and onset of T1DM over time and GADA correlation with different variables.

Conclusions

GADA is an easy marker to measure that can be detected many months prior to the clinical presentation and remains positive even after early childhood.

GAD65 autoantibodies and glucose tolerance in offspring born to women with and without type 1 diabetes (The EPICOM study)

The aims of this study were to examine presence of GAD65 autoantibodies (GAD65aab) in offspring born to women with type 1 diabetes (T1D) and controls and if more were GAD65aab‐positive if diagnosed with diabetes or pre‐diabetes. This EPICOM study is a prospective follow‐up study focussing on pregnancies complicated by maternal T1D. The EPICOM study includes offspring (n = 278) born to mothers with pre‐gestational T1D between 1993 and 1999 and matched un‐exposed controls (n = 303). Age at the time of follow‐up was 16.7 years (13.0–20.4 years). GAD65aab was measured using the Glutamic Acid Decarboxylase Autoantibody RIA kit from RSR^©. An Oral Glucose Tolerance Test (OGTT) was performed, and abnormal glucose tolerance was defined as having either diabetes, impaired fasting glucose (IFG) or impaired glucose tolerance (IGT). GAD65aab could be measured in 561 participants. Of these, 17 (3%) were positive for GAD65aab (≥25 U/ml) with 11 (4%) offspring being born to women with T1D and 6 (2%) controls. The difference in GAD65aab status was not statistically significant (p = .2). One was diagnosed with GAD65aab‐negative diabetes during the study, 18 were diagnosed with IFG, and 44 with IGT. Overall, more were GAD65aab‐positive if diagnosed with abnormal glucose tolerance (p = .03). We found no association between GAD65aab status and HOMA‐IR, HOMA‐IS, birthweight, mode of delivery or maternal BMI prior to pregnancy. Our study found no overall difference in GAD65 status between offspring born to women with T1D and their matched controls. However, among the participants diagnosed with pre‐diabetes more were GAD65‐positive.

Advances in Type 1 Diabetes Prediction Using Islet Autoantibodies: Beyond a Simple Count

Islet autoantibodies are key markers for the diagnosis of type 1 diabetes. Since their discovery, they have also been recognized for their potential to identify at-risk individuals prior to symptoms. To date, risk prediction using autoantibodies has been based on autoantibody number; it has been robustly shown that nearly all multiple-autoantibody-positive individuals will progress to clinical disease. However, longitudinal studies have demonstrated that the rate of progression among multiple-autoantibody-positive individuals is highly heterogenous. Accurate prediction of the most rapidly progressing individuals is crucial for efficient and informative clinical trials and for identification of candidates most likely to benefit from disease modification. This is increasingly relevant with the recent success in delaying clinical disease in presymptomatic subjects using immunotherapy, and as the field moves toward population-based screening. There have been many studies investigating islet autoantibody characteristics for their predictive potential, beyond a simple categorical count. Predictive features that have emerged include molecular specifics, such as epitope targets and affinity; longitudinal patterns, such as changes in titer and autoantibody reversion; and sequence-dependent risk profiles specific to the autoantibody and the subject's age. These insights are the outworking of decades of prospective cohort studies and international assay standardization efforts and will contribute to the granularity needed for more sensitive and specific preclinical staging. The aim of this review is to identify the dynamic and nuanced manifestations of autoantibodies in type 1 diabetes, and to highlight how these autoantibody features have the potential to improve study design of trials aiming to predict and prevent disease.

Predictive Value of GAD Antibody for Diabetes in Normal Chinese Adults: A Retrospective Cohort Study in China

PURPOSE

To investigate the prevalence of GAD antibody (GADA) in the general adult population and to evaluate its predictive value for diabetes in China.

PATIENTS AND METHODS

We searched the PUMCH-HM database and identified 36,731 adult subjects with GADA test results from 2012 to 2015. We then established a retrospective cohort of 4835 nondiabetic subjects at baseline with complete annual health evaluation records through 2019. The median follow-up time was 4.8 (3.0-7.3) years.

RESULTS

The overall prevalence of GADA was 0.53% and was higher in diabetic subjects (1.25%) than in nondiabetic subjects (0.47%). We found a decrease in baseline body mass index (BMI) from the GADA- to GADA_high subgroups among baseline diabetic and prediabetic patients and also those who developed diabetes later in the cohort study. A total of 136 subjects (2.8%) developed diabetes after a median follow-up of 3.5 years. For GADA⁺ participants, BMI was not associated with the risk for diabetes. In the Cox regression model, the GADA_low and GADA_high exhibited 2.63-fold and 4.16-fold increased risk for diabetes, respectively. This increased risk for diabetes by GADA-positivity is only found in male adults (HR 4.55, 95% CI 2.25-9.23).

CONCLUSION

GADA has a low prevalence in China but is associated with a 2.63-4.16-fold increased risk for diabetes.

Autoantibodies associated with primary biliary cholangitis are common among patients with systemic lupus erythematosus even in the absence of elevated liver enzymes

Knowledge of concomitant autoimmune liver diseases (AILD) is more detailed in primary Sjögren's syndrome (pSS) compared to systemic lupus erythematosus (SLE). Herein, the prevalence of autoantibodies associated with autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) was investigated in stored sera from patients with SLE (n = 280) and pSS (n = 114). Antibodies against mitochondria (AMA), liver-kidney microsomal (LKM) antigen, smooth muscle (SMA) and anti-nuclear antibodies (ANA) were analysed with immunofluorescence microscopy. In addition, AILD-associated autoantibodies were tested with immunoblot. Prior to sampling, eight SLE (2·9%) and three pSS (2·6%) cases were diagnosed with AILD. Among SLE-cases without known AILD (n = 272), 26 (9·6%) had PBC-associated autoantibodies, 15 (5·5%) AIH-associated autoantibodies (excluding ANA) and one serological overlap. Most subjects with PBC-associated autoantibodies had liver enzymes within reference limits (22 of 27, 81%) or mild laboratory cholestasis (two of 27, 7·4%), while one fulfilled the diagnostic PBC-criteria. AMA-M2 detected by immunoblot was the most common PBC-associated autoantibody in SLE (20 of 272, 7·4%). The prevalence of SMA (4·4%) was comparable with a healthy reference population, but associated with elevated liver enzymes in four of 12 (25%), none meeting AIH-criteria. The patient with combined AIH/PBC-serology had liver enzymes within reference limits. Among pSS cases without known AILD (n = 111), nine (8·1%) had PBC-associated, 12 (10·8%) AIH-associated autoantibodies and two overlapped. PBC-associated autoantibodies were found as frequently in SLE as in pSS but were, with few exceptions, not associated with laboratory signs of liver disease. Overall, AILD-associated autoantibodies were predominantly detected by immunoblot and no significant difference in liver enzymes was found between AILD autoantibody-negative and -positive patients.

Challenges in the diagnosis of diabetes type in pediatrics

The incidence of diabetes, both type 1 and type 2, is increasing. Health outcomes in pediatric diabetes are currently poor, with trends indicating that they are worsening. Minority racial/ethnic groups are disproportionately affected by suboptimal glucose control and have a higher risk of acute and chronic complications of diabetes. Correct clinical management starts with timely and accurate classification of diabetes, but in children this is becoming increasingly challenging due to high prevalence of obesity and shifting demographic composition. The growing obesity epidemic complicates classification by obesity's effects on diabetes. Since the prevalence and clinical characteristics of diabetes vary among racial/ethnic groups, migration between countries leads to changes in the distribution of diabetes types in a certain geographical area, challenging the clinician's ability to classify diabetes. These challenges must be addressed to correctly classify diabetes and establish an appropriate treatment strategy early in the course of disease for all. This may be the first step in improving diabetes outcomes across racial/ethnic groups. This review will discuss the pitfalls in the current diabetes classification scheme that is leading to increasing overlap between diabetes types and heterogeneity within each type. It will also present proposed alternative classification schemes and approaches to understanding diabetes type that may improve the timely and accurate classification of pediatric diabetes type.

Risk factors for type 1 diabetes, including environmental, behavioural and gut microbial factors: a case-control study

Type 1 diabetes (T1D) is a common autoimmune disease that is characterized by insufficient insulin production. The onset of T1D is the result of gene-environment interactions. Sociodemographic and behavioural factors may contribute to T1D, and the gut microbiota is proposed to be a driving factor of T1D. An integrated preventive strategy for T1D is not available at present. This case-control study attempted to estimate the exposure linked to T1D to identify significant risk factors for healthy children. Forty children with T1D and 56 healthy controls were included in this study. Anthropometric, socio-economic, nutritional, behavioural, and clinical data were collected. Faecal bacteria were investigated by molecular methods. The findings showed, in multivariable model, that the risk factors for T1D include higher Firmicutes levels (OR 7.30; IC 2.26-23.54) and higher carbohydrate intake (OR 1.03; IC 1.01-1.05), whereas having a greater amount of Bifidobacterium in the gut (OR 0.13; IC 0.05 - 0.34) was a protective factor for T1D. These findings may facilitate the development of preventive strategies for T1D, such as performing genetic screening, characterizing the gut microbiota, and managing nutritional and social factors.

Characterization of plasma lipidomics in adolescent subjects with increased risk for type 1 diabetes in the DiPiS cohort

INTRODUCTION

Type 1 diabetes (T1D) is caused by the destruction of pancreatic islet beta cells resulting in total loss of insulin production. Recent studies have suggested that the destruction may be interrelated to plasma lipids.

OBJECTIVES

Specific lipids have previously been shown to be decreased in children who develop T1D before four years of age. Disturbances of plasma lipids prior to clinical diagnosis of diabetes, if true, may provide a novel way to improve prediction, and monitor disease progression.

METHODS

A lipidomic approach was utilized to analyze plasma from 67 healthy adolescent subjects (10-15 years of age) with or without islet autoantibodies but all with increased genetic risk for T1D. The study subjects were enrolled at birth in the Diabetes Prediction in Skåne (DiPiS) study and after 10-15 years of follow-up we performed the present cross-sectional analysis. HLA-DRB345, -DRB1, -DQA1, -DQB1, -DPA1 and -DPB1 genotypes were determined using next generation sequencing. Lipidomic profiles were determined using ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry. Lipidomics data were analyzed according to genotype.

RESULTS

Variation in levels of several specific phospholipid species were related to level of autoimmunity but not development of T1D. Five glycosylated ceramides were increased in insulin autoantibody (IAA) positive adolescent subjects compared to adolescent subjects without this autoantibody. Additionally, HLA genotypes seemed to influence levels of long chain triacylglycerol (TG).

CONCLUSION

Lipidomic profiling of adolescent subjects in high risk of T1D may improve sub-phenotyping in this high risk population.

Temporal trends in diabetic ketoacidosis at diagnosis of paediatric type 1 diabetes between 2006 and 2016: results from 13 countries in three continents

AIMS/HYPOTHESIS

The aim of this work was to evaluate geographical variability and trends in the prevalence of diabetic ketoacidosis (DKA), between 2006 and 2016, at the diagnosis of childhood-onset type 1 diabetes in 13 countries over three continents.

METHODS

An international retrospective study on DKA at diagnosis of diabetes was conducted. Data on age, sex, date of diabetes diagnosis, ethnic minority status and presence of DKA at diabetes onset were obtained from Australia, Austria, Czechia, Denmark, Germany, Italy, Luxembourg, New Zealand, Norway, Slovenia, Sweden, USA and the UK (Wales). Mean prevalence was estimated for the entire period, both overall and by country, adjusted for sex and age group. Temporal trends in annual prevalence of DKA were estimated using logistic regression analysis for each country, before and after adjustment for sex, age group and ethnic minority status.

RESULTS

During the study period, new-onset type 1 diabetes was diagnosed in 59,000 children (median age [interquartile range], 9.0 years [5.5-11.7]; male sex, 52.9%). The overall adjusted DKA prevalence was 29.9%, with the lowest prevalence in Sweden and Denmark and the highest in Luxembourg and Italy. The adjusted DKA prevalence significantly increased over time in Australia, Germany and the USA while it decreased in Italy. Preschool children, adolescents and children from ethnic minority groups were at highest risk of DKA at diabetes diagnosis in most countries. A significantly higher risk was also found for females in Denmark, Germany and Slovenia.

CONCLUSIONS/INTERPRETATION

DKA prevalence at type 1 diabetes diagnosis varied considerably across countries, albeit it was generally high and showed a slight increase between 2006 and 2016. Increased awareness of symptoms to prevent delay in diagnosis is warranted, especially in preschool children, adolescents and children from ethnic minority groups.

Decreased HLA-DQ expression on peripheral blood cells in children with varying number of beta cell autoantibodies

The risk for type 1 diabetes is strongly associated with HLA-DQ and the appearance of beta cell autoantibodies against either insulin, glutamate decarboxylase (GAD65), insulinoma-associated protein-2 (IA-2), or zinc transporter 8 (ZnT8). Prolonged exposure to autoantibodies may be related to T cell exhaustion known to occur in chronic infections or autoimmune disorders. It was hypothesized that autoantibody exposure may affect HLA-DQ expression on peripheral blood cells and thereby contribute to T cell exhaustion thought to be associated with the pathogenesis of type 1 diabetes. The aim of this study was to determine whether autoantibody exposure as an expression of autoimmunity burden was related to peripheral blood cell HLA-DQ cell surface expression in either 1) a cross-sectional analysis or 2) cumulative as area under the trajectory of autoantibodies during long term follow-up in the Diabetes Prediction in Skåne (DiPiS) study. Children (n = 67), aged 10–15 years were analyzed for complete blood count, HLA-DQ cell surface median fluorescence intensity (MFI), autoantibody frequency, and HLA genotypes by Next Generation Sequencing. Decreased HLA-DQ cell surface MFI with an increasing number of autoantibodies was observed in CD16⁺, CD14⁺CD16⁻, CD4⁺ and CD8⁺ cells but not in CD19⁺ cells and neutrophils. HLA-DQ cell surface MFI was associated with HLA-DQ2/8 in CD4⁺ T cells, marginally in CD14⁺CD16⁻ monocytes and CD8⁺ T cells. These associations appeared to be related to autoimmunity burden. The results suggest that HLA-DQ cell surface expression was related to HLA and autoimmunity burden.

•

PBMC HLA-DQ surface expression in beta cell autoimmunity is poorly understood.

•

Children, 10–15 years of age without or with beta cell autoantibodies were analyzed.

•

HLA-DQ cell surface expression decreased with increasing number of autoantibodies.

•

HLA-DQ cell surface expression was related to HLA and autoimmunity burden.

Serum 25-hydroxyvitamin D concentration in childhood and risk of islet autoimmunity and type 1 diabetes: the TRIGR nested case-control ancillary study

AIMS/HYPOTHESIS

Our aim was to study the association between serum 25-hydroxyvitamin D (25OHD) concentration and islet autoimmunity and type 1 diabetes in children with an increased genetic risk of type 1 diabetes.

METHODS

Serum samples for 25OHD measurements were obtained in the Trial to Reduce IDDM in the Genetically at Risk (TRIGR) ancillary study (Divia) from children in 15 countries. Case children (n = 244) were defined as having positivity for at least two out of four diabetes-associated autoantibodies measured at any one sample. For each case child, two control children were selected matched for country and date of birth (±1 year) (n = 488). Of the case children, 144 developed type 1 diabetes. Serum 25OHD was measured repeatedly in infancy and childhood and was compared according to age at the first seroconversion (at 6, 12 and 18 months prior to and at seroconversion) and calendar age (0, 6, 12 and 18 months).

RESULTS

In children with islet autoimmunity, mean serum 25OHD concentration was lower 18 months prior to the age of first seroconversion of the case children compared with the control children (57.7 vs 64.8 nmol/l, p = 0.007). In children with type 1 diabetes (n = 144), mean serum 25OHD concentration was lower 18 months prior to the age of the first seroconversion (58.0 vs 65.0 nmol/l, p = 0.018) and at the calendar age of 12 months (70.1 vs 75.9 nmol/l, p = 0.031) than in their control counterparts. Analyses were adjusted for month of sample collection, human leucocyte antigen genotype, maternal type 1 diabetes and sex.

CONCLUSIONS/INTERPRETATION

The results suggest that early postnatal vitamin D may confer protection against the development of type 1 diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00179777.

Insulin-Like Growth Factor Dysregulation Both Preceding and Following Type 1 Diabetes Diagnosis

Insulin-like growth factors (IGFs), specifically IGF1 and IGF2, promote glucose metabolism, with their availability regulated by IGF-binding proteins (IGFBPs). We hypothesized that IGF1 and IGF2 levels, or their bioavailability, are reduced during type 1 diabetes development. Total serum IGF1, IGF2, and IGFBP1-7 levels were measured in an age-matched, cross-sectional cohort at varying stages of progression to type 1 diabetes. IGF1 and IGF2 levels were significantly lower in autoantibody (AAb)⁺ compared with AAb^- relatives of subjects with type 1 diabetes. Most high-affinity IGFBPs were unchanged in individuals with pre-type 1 diabetes, suggesting that total IGF levels may reflect bioactivity. We also measured serum IGFs from a cohort of fasted subjects with type 1 diabetes. IGF1 levels significantly decreased with disease duration, in parallel with declining β-cell function. Additionally, plasma IGF levels were assessed in an AAb⁺ cohort monthly for a year. IGF1 and IGF2 showed longitudinal stability in single AAb⁺ subjects, but IGF1 levels decreased over time in subjects with multiple AAb and those who progressed to type 1 diabetes, particularly postdiagnosis. In sum, IGFs are dysregulated both before and after the clinical diagnosis of type 1 diabetes and may serve as novel biomarkers to improve disease prediction.

Prediction and Prevention of Type 1 Diabetes

Type 1 Diabetes (T1D) is one of the most common chronic autoimmune diseases in children. The disease is characterized by the destruction of beta cells, leading to hyperglycemia, and to a lifelong insulin-dependent state. Although several studies in the last decades have added relevant insights, the complex pathogenesis of the disease is not yet completely understood. Recent studies have been focused on several factors, including family history and genetic predisposition (HLA and non-HLA genes) as well as environmental and metabolic biomarkers, with the aim of predicting the development and progression of T1D. Once a child becomes symptomatic, beta cell mass has already reached a critical threshold (usually a residual of 20-30% of normal amounts), thus representing only the very late phase of the disease. In particular, this final stage follows two preceding asymptomatic stages, which have been precisely identified. In view of the long natural history and complex pathogenesis of the disease, many strategies may be proposed for primary, secondary, and tertiary prevention. Strategies of primary prevention aim to prevent the onset of autoimmunity against beta cells in asymptomatic individuals at high risk for T1D. In addition, the availability of novel humoral and metabolic biomarkers that are able to characterize subjects at high risk of progression, have stimulated several studies on secondary and tertiary prevention, aimed to preserve residual beta cell destruction and/or to prolong the remission phase after the onset of T1D. This review focuses on the major current knowledge on prediction and prevention of T1D in children.

Gastrointestinal Microbiota and Type 1 Diabetes Mellitus: The State of Art

The incidence of autoimmune type 1 diabetes (T1DM) is increasing worldwide and disease onset tends to occur at a younger age. Unfortunately, clinical trials aiming to detect predictive factors of disease, in individuals with a high risk of T1DM, reported negative results. Hence, actually there are no tools or strategies to prevent T1DM onset. The importance of the gut microbiome in autoimmune diseases is increasingly recognized and recent data suggest that intestinal dysbiosis has a pathogenic role in T1DM by affecting both intestinal immunostasis and the permeability of the gut barrier. An improved understanding of the mechanisms whereby dysbiosis in the gut favors T1DM development may help develop new intervention strategies to reduce both the incidence and burden of T1DM. This review summarizes available data on the associations between gut microbiota and T1DM in both experimental animals and humans and discusses future perspectives in this novel and exciting area of research.

Characteristics of Slow Progression to Type 1 Diabetes in Children With Increased HLA-Conferred Disease Risk

CONTEXT

Characterization of slow progression to type 1 diabetes (T1D) may reveal novel means for prevention of T1D. Slow progressors might carry natural immunomodulators that delay β-cell destruction and mediate preservation of β-cell function.

OBJECTIVE

To identify demographic, genetic, and immunological characteristics of slow progression from seroconversion to clinical T1D.

DESIGN

HLA-susceptible children (n = 7410) were observed from birth for islet cell antibody (ICA), insulin autoantibody (IAA), glutamic acid decarboxylase (GADA), and islet antigen-2 autoantibodies (IA-2A), and for clinical T1D. Disease progression that lasted ≥7.26 years (slowest) quartile from initial seroconversion to diagnosis was considered slow. Autoantibody and genetic characteristics including 45 non-HLA single nucleotide polymorphisms (SNPs) predisposing to T1D were analyzed.

RESULTS

By the end of 2015, 1528 children (21%) had tested autoantibody positive and 247 (16%) had progressed to T1D. The median delay from seroconversion to diagnosis was 8.7 years in slow (n = 62, 25%) and 3.0 years in other progressors. Compared with other progressors, slow progressors were less often multipositive, had lower ICA and IAA titers, and lower frequency of IA-2A at seroconversion. Slow progressors were born more frequently in the fall, whereas other progressors were born more often in the spring. Compared with multipositive nonprogressors, slow progressors were younger, had higher ICA titers, and higher frequency of IAA and multiple autoantibodies at seroconversion. We found no differences in the distributions of non-HLA SNPs between progressors.

CONCLUSIONS

We observed differences in autoantibody characteristics and the season of birth among progressors, but no characteristics present at seroconversion that were specifically predictive for slow progression.

Extracellular Vesicles in Type 1 Diabetes: Messengers and Regulators

PURPOSE OF REVIEW

Theories about the pathogenesis of type 1 diabetes (T1D) refer to the potential of primary islet inflammatory signaling as a trigger for the loss of self-tolerance leading to disease onset. Emerging evidence suggests that extracellular vesicles (EV) may represent the missing link between inflammation and autoimmunity. Here, we review the evidence for a role of EV in the pathogenesis of T1D, as well as discuss their potential value in the clinical sphere, as biomarkers and therapeutic agents.

RECENT FINDINGS

EV derived from β cells are enriched in diabetogenic autoantigens and miRNAs that are selectively sorted and packaged. These EV play a pivotal role in antigen presentation and cell to cell communication leading to activation of autoimmune responses. Furthermore, recent evidence suggests the potential of EV as novel tools in clinical diagnostics and therapeutic interventions. In-depth analysis of EV cargo using modern multi-parametric technologies may be useful in enhancing our understanding of EV-mediated immune mechanisms and in identifying robust biomarkers and therapeutic strategies for T1D.

Antibodies to oxidized insulin improve prediction of type 1 diabetes in children with positive standard islet autoantibodies

BACKGROUND

Antibodies to posttranslationally modified insulin (oxPTM-INS-Ab) are a novel biomarker of type 1 diabetes (T1D). Here, we evaluated whether oxPTM-INS-Ab can improve T1D prediction in children with positive standard islet autoantibodies (AAB).

METHODS

We evaluated sensitivity, specificity, accuracy, and risk for progression to T1D associated with oxPTM-INS-Ab and the standard islet AAB that include insulin (IAA), GAD (GADA), and tyrosine phosphatase 2 (IA-2A) in a cohort of islet AAB-positive (AAB⁺ ) children from the general population (median follow-up 8.8 years).

RESULTS

oxPTM-INS-Ab was the most sensitive and specific autoantibody biomarker (74% sensitivity, 91% specificity), followed by IA-2A (71% sensitivity, 91% specificity). GADA and IAA showed lower sensitivity (65% and 50%, respectively) and specificity (66% and 68%, respectively). Accuracy (AUC of ROC) of oxPTM-INS-Ab was higher than GADA and IAA (P = 0.003 and P = 0.017, respectively), and similar to IA-2A (P = 0.896). oxPTM-INS-Ab and IA-2A were more effective than IAA for detecting progr-T1D when used as second-line biomarker in GADA⁺ children. Risk for diabetes was higher (P = 0.03) among multiple AAB⁺ who were also oxPTM-INS-Ab⁺ compared with those who were oxPTM-INS-Ab^- . Importantly, when replacing IAA with oxPTM-INS-Ab, diabetes risk increased to 100% in children with oxPTM-INS-Ab⁺ in combination with GADA⁺ and IA-2A⁺ , compared with 84.37% in those with IAA⁺ , GADA⁺ , and IA-2A⁺ (P = 0.04).

CONCLUSIONS

Antibodies to oxidized insulin (oxPTM-INS-Ab), compared with IAA which measure autoantibodies to native insulin, improve T1D risk assessment and prediction accuracy in AAB⁺ children.

Circulating anti-glutamic acid decarboxylase-65 antibody titers are positively associated with the capacity of insulin secretion in acute-onset type 1 diabetes with short duration in a Japanese population

Aims/Introduction

To elucidate the relationship between titers of islet autoantibodies, the C‐X‐C motif chemokine 10 – a circulating chemokine that activates T‐helper 1 cells leading to β‐cell destruction – and β‐cell function in type 1 diabetes.

Materials and Methods

In total, 58 type 1 diabetes patients positive for glutamic decarboxylase‐65 autoantibodies (GADA)‐radioimmunoassay (mean age 54.1 years; 27 acute‐onset cases and 31 slowly progressive cases) were enrolled; serum C‐X‐C motif chemokine 10 (n = 50), zinc transporter 8 autoantibodies (n = 50) and GADA (n = 58) by an enzyme‐linked immunosorbent assay, and insulinoma‐associated antigen‐2 autoantibodies by radioimmunoassay (n = 50) were measured. The ratio of 100 × random C‐peptide (ng/mL)‐to‐plasma glucose levels (mg/dL; C‐peptide index [CPI]) was measured.

Results

The CPI significantly decreased in both groups with the progression of disease duration. GADA titers by radioimmunoassay and enzyme‐linked immunosorbent assay were strongly correlated with the CPI in acute‐onset type 1 diabetes patients with a shorter disease duration (≤10 years), but not in those with a longer duration or slowly progressive type 1 diabetes. Neither insulinoma‐associated antigen‐2 nor zinc transporter 8 autoantibodies titers were correlated with the CPI. Serum C‐X‐C motif chemokine 10 levels in both groups were significantly higher than in non‐diabetic controls, and persisted at high levels even in those with chronic duration.

Conclusions

Among islet autoantibodies, the intensity of the humoral immune response, as defined by GADA titers, reflected the degree of residual β‐cell function in acute‐onset type 1 diabetes patients with short duration. Prolonged disease activity might accelerate β‐cell impairment in both subtypes of type 1 diabetes.

Pancreas Volume Declines During the First Year After Diagnosis of Type 1 Diabetes and Exhibits Altered Diffusion at Disease Onset

OBJECTIVE

This study investigated the temporal dynamics of pancreas volume and microstructure in children and adolescents with recent-onset type 1 diabetes (T1D) and individuals without diabetes, including a subset expressing autoantibodies associated with the early stages of T1D.

RESEARCH DESIGN AND METHODS

MRI was performed in individuals with recent-onset stage 3 T1D (n = 51; median age 13 years) within 100 days after diagnosis (mean 67 days), 6 months, and 1 year postdiagnosis. Longitudinal MRI measurements were also made in similarly aged control participants (n = 57) and in autoantibody-positive individuals without diabetes (n = 20). The MRI protocol consisted of anatomical imaging to determine pancreas volume and quantitative MRI protocols interrogating tissue microstructure and composition.

RESULTS

Within 100 days of diabetes onset, individuals with T1D had a smaller pancreas (median volume 28.6 mL) than control participants (median volume 48.4 mL; P < 0.001), including when normalized by individual weight (P < 0.001). Longitudinal measurements of pancreas volume increased in control participants over the year, consistent with adolescent growth, but pancreas volume declined over the first year after T1D diagnosis (P < 0.001). In multiple autoantibody-positive individuals, the pancreas volume was significantly larger than that of the T1D cohort (P = 0.017) but smaller than that of the control cohort (P = 0.04). Diffusion-weighted MRI showed that individuals with recent-onset T1D had a higher apparent diffusion coefficient (P = 0.012), suggesting a loss of cellular structural integrity, with heterogeneous pancreatic distribution.

CONCLUSIONS

These results indicate that pancreas volume is decreased in stages 1, 2, and 3 of T1D and decreases during the first year after diabetes onset and that this loss of pancreatic volume is accompanied by microstructural changes.

Expression of recombinant glutamic acid decarboxylase in insect larvae and its application in an immunoassay for the diagnosis of autoimmune diabetes mellitus

Autoimmune Diabetes Mellitus (DM) is a chronic disease caused by the selective destruction of insulin producing beta cells in human pancreas. DM is characterized by the presence of autoantibodies that bind a variety of islet-cell antigens. The 65 kDa isoform of glutamate decarboxylase (GAD65) is a major autoantigen recognized by these autoantibodies. Autoantibodies to GAD65 (GADA) are considered predictive markers of the disease when tested in combination with other specific autoantibodies. In order to produce reliable immunochemical tests for large scale screening of autoimmune DM, large amounts of properly folded GAD65 are needed. Herein, we report the production of human GAD65 using the baculovirus expression system in two species of larvae, Rachiplusia nu and Spodoptera frugiperda. GAD65 was identified at the expected molecular weight, properly expressed with high yield and purity in both larvae species and presenting appropriate enzymatic activity. The immunochemical ability of recombinant GAD65 obtained from both larvae to compete with [³⁵S]GAD65 was assessed qualitatively by incubating GADA-positive patients’ sera in the presence of 1 μM of the recombinant enzyme. All sera tested became virtually negative after incubation with antigen excess. Besides, radiometric quantitative competition assays with GADA-positive patients’ sera were performed by adding recombinant GAD65 (0.62 nM–1.4 µM). All dose response curves showed immunochemical identity between proteins. In addition, a bridge-ELISA for the detection of GADA was developed using S. frugiperda-GAD65. This assay proved to have 77.3% sensitivity and 98.2% of specificity. GAD65 could be expressed in insect larvae, being S. frugiperda the best choice due to its high yield and purity. The development of a cost effective immunoassay for the detection of GADA was also afforded.

Type 1 Diabetes-related Autoantibodies in Different Forms of Diabetes

Autoantibodies against Glutamic Acid Decarboxylase (GADA), insulinoma antigen-2 (IA- 2A), insulin (IAA) and the most recently Zinc Transporter 8 (ZnT8A) are one of the most reliable biomarkers for autoimmune diabetes in both children and adults. They are today the only biomarkers that can distinguish Latent Autoimmune Diabetes in Adults (LADA) from phenotypically type 2 diabetes. As the frequency of autoantibodies at diagnosis in childhood type 1 diabetes depends on age, GADA is by far the most common in adult onset autoimmune diabetes, especially LADA. Being multiple autoantibody positive have also shown to be more common in childhood diabetes compared to adult onset diabetes, and multiple autoantibody positivity have a high predictive value of childhood type 1 diabetes. Autoantibodies have shown inconsistent results to predict diabetes in adults. Levels of autoantibodies are reported to cause heterogeneity in LADA. Reports indicate that individuals with high levels of autoantibodies have a more type 1 diabetes like phenotype and individuals with low levels of autoantibody positivity have a more type 2 diabetes like phenotype. It is also well known that autoantibody levels can fluctuate and transient autoantibody positivity in adult onset autoimmune diabetes have been reported to affect the phenotype.

Serum biomarkers for diagnosis and prediction of type 1 diabetes

Type 1 diabetes (T1D) culminates in the autoimmune destruction of the pancreatic βcells, leading to insufficient production of insulin and development of hyperglycemia. Serum biomarkers including a combination of glucose, glycated molecules, C-peptide, and autoantibodies have been well established for the diagnosis of T1D. However, these molecules often mark a late stage of the disease when ∼90% of the pancreatic insulin-producing β-cells have already been lost. With the prevalence of T1D increasing worldwide and because of the physical and psychological burden induced by this disease, there is a great need for prognostic biomarkers to predict T1D development or progression. This would allow us to identify individuals at high risk for early prevention and intervention. Therefore, considerable efforts have been dedicated to the understanding of disease etiology and the discovery of novel biomarkers in the last few decades. The advent of high-throughput and sensitive "-omics" technologies for the study of proteins, nucleic acids, and metabolites have allowed large scale profiling of protein expression and gene changes in T1D patients relative to disease-free controls. In this review, we briefly discuss the classical diagnostic biomarkers of T1D but mainly focus on the novel biomarkers that are identified as markers of β-cell destruction and screened with the use of state-of-the-art "-omics" technologies.

Precision medicine in diabetes prevention, classification and management

Diabetes has become a major burden of healthcare expenditure. Diabetes management following a uniform treatment algorithm is often associated with progressive treatment failure and development of diabetic complications. Recent advances in our understanding of the genomic architecture of diabetes and its complications have provided the framework for development of precision medicine to personalize diabetes prevention and management. In the present review, we summarized recent advances in the understanding of the genetic basis of diabetes and its complications. From a clinician's perspective, we attempted to provide a balanced perspective on the utility of genomic medicine in the field of diabetes. Using genetic information to guide management of monogenic forms of diabetes represents the best-known examples of genomic medicine for diabetes. Although major strides have been made in genetic research for diabetes, its complications and pharmacogenetics, ongoing efforts are required to translate these findings into practice by incorporating genetic information into a risk prediction model for prioritization of treatment strategies, as well as using multi-omic analyses to discover novel drug targets with companion diagnostics. Further research is also required to ensure the appropriate use of this information to empower individuals and healthcare professionals to make personalized decisions for achieving the optimal outcome.

Relationship between islet autoantibody status and the clinical characteristics of children and adults with incident type 1 diabetes in a UK cohort

OBJECTIVES

To describe the characteristics of children and adults with incident type 1 diabetes in contemporary, multiethnic UK, focusing on differences between the islet autoantibody negative and positive.

DESIGN

Observational cohort study.

SETTING

146 mainly secondary care centres across England and Wales.

PARTICIPANTS

3312 people aged ≥5 years were recruited within 6 months of a clinical diagnosis of type 1 diabetes via the National Institute for Health Research Clinical Research Network. 3021 were of white European ethnicity and 291 (9%) were non-white. There was a small male predominance (57%). Young people <17 years comprised 59%.

MAIN OUTCOME MEASURES

Autoantibody status and characteristics at presentation.

RESULTS

The majority presented with classical osmotic symptoms, weight loss and fatigue. Ketoacidosis was common (42%), especially in adults, and irrespective of ethnicity. 35% were overweight or obese. Of the 1778 participants who donated a blood sample, 85% were positive for one or more autoantibodies against glutamate decarboxylase, islet antigen-2 and zinc transporter 8. Presenting symptoms were similar in the autoantibody-positive and autoantibody-negative participants, as was the frequency of ketoacidosis (43%vs40%, P=0.3). Autoantibody positivity was less common with increasing age (P=0.0001), in males compared with females (82%vs90%, P<0.0001) and in people of non-white compared with white ethnicity (73%vs86%, P<0.0001). Body mass index was higher in autoantibody-negative adults than autoantibody-positive adults (median, IQR 25.5, 23.1-29.2vs23.9, 21.4-26.7 kg/m²; P=0.0001). Autoantibody-negative participants were more likely to have a parent with diabetes (28%vs16%, P<0.0001) and less likely to have another autoimmune disease (4%vs8%, P=0.01).

CONCLUSIONS

Most people assigned a diagnosis of type 1 diabetes presented with classical clinical features and islet autoantibodies. Although indistinguishable at an individual level, autoantibody-negative participants as a group demonstrated features more typically associated with other diabetes subtypes.

TRIAL REGISTRATION NUMBER

ISRCTN66496918; Pre-results.

Autoantibodies against islet cell antigens in children with type 1 diabetes mellitus

We investigated the prevalence of glutamic acid decarboxylase 65 autoantibody (GADA), insulinoma-associated protein 2 autoantibody (IA2A), and insulin autoantibody (IAA) in 750 children with type 1 diabetes (T1D) living in Taiwan. GADA, IA2A, and IAA were measured by radioimmunoassay. The data were assessed by χ² test, binary logistic regression, and Spearman rank correlation. Of the 750 T1D patients, 66.3% had GADA, 65.3% IA2A, 35.7% IAA, and 17.2% no autoantibodies. The prevalence of GADA and IA2A significantly decreased along T1D duration. The positivity of either GADA or IA2A was 89.4% within the first year of disease and decreased to 36.7% after 9 years (P = 1.22 × 10^–20). Female patients had significantly higher prevalence of GADA compared with male patients (72.3% vs. 59.7%, P = 0.00027). The patients diagnosed before 12 years of age had a positive rate of 92.2% for either GADA or IA2A. Patients diagnosed at age 12 or above had a significantly lower positive rate of 81.6% (P = 0.011). GADA and IA2A significantly correlated with each other (rs = 0.245, P = 1.09 × 10^–11). We concluded that autoantibodies were detectable in 89.4% of T1D patients within one year after diagnosis. Their prevalence declined with disease duration. GADA was more prevalent in female patients. GADA and IA2A weakly correlated with each other.

Early life origin of type 1 diabetes

Type 1 diabetes (T1D) is perceived as a chronic immune-mediated disease with a subclinical prodromal period characterized by selective loss of insulin-producing beta cells in the pancreatic islets in genetically susceptible subjects. The incidence of T1D has increased manifold in most developed countries after World War II in parallel with a series of other immune-mediated diseases. T1D results from gene-environmental interactions. The appearance of disease-associated autoantibodies into the peripheral circulation is the first detectable sign of the initiation of the disease process leading to clinical T1D. The first autoantibodies may appear already before the age of 6 months and the seroconversion rate peaks during the second year of life. This implies that exogenous factors involved in the pathogenesis of T1D must be operative in early life, some of them most likely already during pregnancy. Here, we discuss putative endogenous factors that may contribute to the development of T1D during fetal and early postnatal life. Many environmental factors operative in early life have been implicated in the pathogenesis of T1D, but relatively few have been firmly confirmed.

Modulation of Type 1 Diabetes Risk by the Intestinal Microbiome

PURPOSE OF REVIEW

The purpose of this review is to summarize potential modulations of the intestinal microbiome aimed at preventing or delaying progression to overt type 1 diabetes in the light of recently identified perturbations of the gut microbiota associated with the development of type 1 diabetes.

RECENT FINDINGS

Accumulated data suggest that the gut microbiota is involved at two different steps in the evolution of type 1 diabetes. At the first step, the intestinal tract is colonized by a microbial community unable to provide an adequate education of the immune system. As a consequence, the infant acquires susceptibility to immune-mediated diseases, type 1 diabetes included. At the other step, the young child seroconverts to positivity for diabetes-associated autoantibodies. This is preceded or accompanied by a decrease in the diversity of the intestinal microbiota and an increased abundance of Bacteroides species. These changes will affect the disease process promoting progression toward overt type 1 diabetes. By providing specific probiotics, one can affect the colonization of the intestinal tract in the newborn infant or strengthen the immune education in early life. Human milk oligosaccharides function as nutrients for "healthy" bacteria. Dietary interventions applying modified starches can influence the numbers and activities of both autoreactive and regulatory T cells and provide protection against autoimmune diabetes in non-obese diabetic mice. Modulation of the intestinal microbiome holds the promise of effective protection against human type 1 diabetes.

Early prediction of autoimmune (type 1) diabetes

Underlying type 1 diabetes is a genetic aetiology dominated by the influence of specific HLA haplotypes involving primarily the class II DR-DQ region. In genetically predisposed children with the DR4-DQ8 haplotype, exogenous factors, yet to be identified, are thought to trigger an autoimmune reaction against insulin, signalled by insulin autoantibodies as the first autoantibody to appear. In children with the DR3-DQ2 haplotype, the triggering reaction is primarily against GAD signalled by GAD autoantibodies (GADA) as the first-appearing autoantibody. The incidence rate of insulin autoantibodies as the first-appearing autoantibody peaks during the first years of life and declines thereafter. The incidence rate of GADA as the first-appearing autoantibody peaks later but does not decline. The first autoantibody may variably be followed, in an apparently non-HLA-associated pathogenesis, by a second, third or fourth autoantibody. Although not all persons with a single type of autoantibody progress to diabetes, the presence of multiple autoantibodies seems invariably to be followed by loss of functional beta cell mass and eventually by dysglycaemia and symptoms. Infiltration of mononuclear cells in and around the islets appears to be a late phenomenon appearing in the multiple-autoantibody-positive with dysglycaemia. As our understanding of the aetiology and pathogenesis of type 1 diabetes advances, the improved capability for early prediction should guide new strategies for the prevention of type 1 diabetes.

Antibodies to post-translationally modified insulin as a novel biomarker for prediction of type 1 diabetes in children

AIMS/HYPOTHESIS

We have shown that autoimmunity to insulin in type 1 diabetes may result from neoepitopes induced by oxidative post-translational modifications (oxPTM). Antibodies specific to oxPTM-insulin (oxPTM-INS-Ab) are present in most newly diagnosed individuals with type 1 diabetes and are more common than autoantibodies to native insulin. In this study, we investigated whether oxPTM-INS-Ab are present before clinical onset of type 1 diabetes, and evaluated the ability of oxPTM-INS-Ab to identify children progressing to type 1 diabetes.

METHODS

We used serum samples collected longitudinally from the 'All Babies in Southeast Sweden (ABIS)' cohort tested for the gold standard islet autoantibodies to insulin (IAA), GAD (GADA), tyrosine phosphatase 2 (IA-2A) and zinc transporter 8 (ZnT8A). We studied 23 children who progressed to type 1 diabetes (progr-T1D) and 63 children who did not progress to type 1 diabetes (NP) after a median follow-up of 10.8 years (interquartile range 7.7-12.8). Of the latter group, 32 were positive for one or more islet autoantibodies (NP-AAB⁺). oxPTM-INS-Ab to insulin modified by ^•OH or HOCl were measured by our developed ELISA platform.

RESULTS

Antibodies to at least one oxPTM-INS were present in 91.3% of progr-T1D children. oxPTM-INS-Ab co-existed with GADA, IA-2A, IAA or ZnT8A in 65.2%, 56.5%, 38.9% and 33.3% progr-T1D children, respectively. In addition, oxPTM-INS-Ab were present in 17.4%, 26.1%, 38.9% and 41.6% of progr-T1D children who were negative for GADA, IA-2A, IAA and ZnT8A, respectively. ^•OH-INS-Ab were more common in progr-T1D children than in NP-AAB⁺ children (82.6% vs 19%; p < 0.001) and allowed discrimination between progr-T1D and NP-AAB⁺ children with 74% sensitivity and 91% specificity. None of the NP-AAB^- children were positive for oxPTM-INS-Ab.

CONCLUSIONS/INTERPRETATION

oxPTM-INS-Ab are present before the clinical onset of type 1 diabetes and can identify children progressing to type 1 diabetes.

Characterisation of rapid progressors to type 1 diabetes among children with HLA-conferred disease susceptibility

AIMS/HYPOTHESIS

In this study, we aimed to characterise rapid progressors to type 1 diabetes among children recruited from the general population, on the basis of HLA-conferred disease susceptibility.

METHODS

We monitored 7410 HLA-predisposed children participating in the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) study for the development of beta cell autoimmunity and type 1 diabetes from birth over a median follow-up time of 16.2 years (range 0.9-21.1 years). Islet cell antibodies (ICA) and autoantibodies to insulin (IAA), GAD (GADA) and islet antigen 2 (IA-2A) were assessed as markers of beta cell autoimmunity. Rapid progression was defined as progression to clinical type 1 diabetes within 1.5 years of autoantibody seroconversion. We analysed the association between rapid progression and demographic and autoantibody characteristics as well as genetic markers, including 25 non-HLA SNPs predisposing to type 1 diabetes.

RESULTS

Altogether, 1550 children (21%) tested positive for at least one diabetes-associated autoantibody in at least two samples, and 248 (16%) of seroconverters progressed to type 1 diabetes by the end of 2015. The median time from seroconversion to diagnosis was 0.51 years in rapid progressors (n = 42, 17%) and 5.4 years in slower progressors. Rapid progression was observed both among young (<5 years) and early pubertal children (>7 years), resulting in a double-peak distribution of seroconversion age. Compared with slower progressors, rapid progressors had a higher frequency of positivity for multiple (≥2) autoantibodies and had higher titres of ICA, IAA and IA-2A at seroconversion, and there was a higher prevalence of the secretor genotype in the FUT2 gene among those carrying the high-risk HLA genotype. Compared with autoantibody-positive non-progressors, rapid progressors were younger, were more likely to carry the high-risk HLA genotype and a predisposing SNP in the PTPN22 gene, had higher frequency of ICA, IAA, GADA and IA-2A positivity and multipositivity, and had higher titres of all four autoantibodies at seroconversion.

CONCLUSIONS/INTERPRETATION

At seroconversion, individuals with rapid progression to type 1 diabetes were characterised by a younger age, higher autoantibody titres, positivity for multiple autoantibodies and higher prevalence of a FUT2 SNP. The double-peak profile for seroconversion age among the rapid progressors demonstrates for the first time that rapid progression may take place not only in young children but also in children in early puberty. Rapid progressors might benefit from careful clinical follow-up and early preventive measures.

A drop in the circulating concentrations of soluble receptor for advanced glycation end products is associated with seroconversion to autoantibody positivity but not with subsequent progression to clinical disease in children en route to type 1 diabetes

BACKGROUND

Advanced glycation end products (AGEs) and their interaction with the receptor for AGEs (RAGE) have been studied for their role in the pathogenesis and complications of type 1 diabetes. Decreased concentrations of soluble RAGE (sRAGE) have been reported in acute autoimmune inflammation. We set out to analyze the changes in sRAGE concentration during preclinical diabetes in children seroconverting to islet autoantibody positivity.

METHODS

We measured serum concentrations of sRAGE in 168 children who progressed to clinical disease and 43 children who turned positive for at least 2 diabetes-associated autoantibodies but remained nondiabetic. We analyzed the sRAGE before seroconversion in the first autoantibody-positive sample and annually thereafter until the diagnosis of type 1 diabetes or end of follow-up.

RESULTS

Both groups had similar sRAGE before seroconversion, but subsequently, sRAGE concentrations were lower (P < .001) in the progressors. The progressors had significantly higher sRAGE concentrations before than after seroconversion (P < .001). The nonprogressors did not experience a similar decrease. The sRAGE concentrations remained stable after seroconversion in both groups.

CONCLUSIONS

These data indicate that sRAGE may be involved in the initiation of beta-cell autoimmunity but not in the progression from beta-cell autoimmunity to clinical disease.

Immunometabolism in early and late stages of rheumatoid arthritis

One of the fundamental traits of immune cells in rheumatoid arthritis (RA) is their ability to proliferate, a property shared with the joint-resident cells that form the synovial pannus. The building of biomass imposes high demands for energy and biosynthetic precursors, implicating metabolic control as a basic disease mechanism. During preclinical RA, when autoreactive T cells expand and immunological tolerance is broken, the main sites of disease are the secondary lymphoid tissues. Naive CD4⁺ T cells from patients with RA have a distinct metabolic signature, characterized by dampened glycolysis, low ATP levels and enhanced shunting of glucose into the pentose phosphate pathway. Equipped with high levels of NADPH and depleted of intracellular reactive oxygen species, such T cells hyperproliferate and acquire proinflammatory effector functions. During clinical RA, immune cells coexist with stromal cells in the acidic milieu of the inflamed joint. This microenvironment is rich in metabolic intermediates that are released into the extracellular space to shape cell-cell communication and the functional activity of tissue-resident cells. Increasing awareness of how metabolites regulate signalling pathways, guide post-translational modifications and condition the tissue microenvironment will help to connect environmental factors with the pathogenic behaviour of T cells in RA.

Clinical worthlessness of genetic prediction of common forms of diabetes mellitus and related chronic complications: A position statement of the Italian Society of Diabetology

AIM

We are currently facing several attempts aimed at marketing genetic data for predicting multifactorial diseases, among which diabetes mellitus is one of the more prevalent. The present document primarily aims at providing to practicing physicians a summary of available data regarding the role of genetic information in predicting diabetes and its chronic complications.

DATA SYNTHESIS

Firstly, general information about characteristics and performance of risk prediction tools will be presented in order to help clinicians to get acquainted with basic methodological information related to the subject at issue. Then, as far as type 1 diabetes is concerned, available data indicate that genetic information and counseling may be useful only in families with many affected individuals. However, since no disease prevention is possible, the utility of predicting this form of diabetes is at question. In the case of type 2 diabetes, available data really question the utility of adding genetic information on top of well performing, easy available and inexpensive non-genetic markers. Finally, the possibility of using the few available genetic data on diabetic complications for improving our ability to predict them will also be presented and discussed. For cardiovascular complication, the addition of genetic information to models based on clinical features does not translate in a substantial improvement in risk discrimination. For all other diabetic complications genetic information are currently very poor and cannot, therefore, be used for improving risk stratification.

CONCLUSIONS

In all, nowadays the use of genetic testing for predicting diabetes and its chronic complications is definitively of little value in clinical practice.

Reclassification of asymptomatic beta cell autoimmunity: a critical perspective

Type 1 diabetes is an immune-mediated disease leading to almost total beta cell destruction and permanent exogenous insulin dependency. The appearance of clinical symptoms is preceded by an asymptomatic preclinical period, the duration of which is highly individual. The emergence of diabetes-associated autoantibodies into the peripheral circulation is the first detectable sign of beta cell autoimmunity. If type 1 diabetes is diagnosed in childhood the preclinical period lasts for an average of 2.5-3 years, but clinical symptoms may in some cases appear within a few months or be delayed for more than 20 years. In this issue of Diabetologia, Bonifacio and colleagues (doi: 10.1007/s00125-016-4144-8 ) suggest that asymptomatic beta cell autoimmunity should be considered as a pathological and diagnostic entity. Although such a strategy may have some positive consequences, it might also have serious drawbacks. To label an asymptomatic child that may have 10-20 years of a healthy life ahead of him/her as a patient will most likely affect both the life of the family and the child. Therefore, we think that one should not adapt the new diagnosis before the psychological consequences of such a strategy have been assessed. Instead, since metabolic abnormalities precede the appearance of clinical symptoms of type 1 diabetes, analysis of a combination of immunological and metabolic markers will provide better insight into the likelihood of progression to clinical disease, with a shorter 'sickness' period.

Tissue distribution and clonal diversity of the T and B cell repertoire in type 1 diabetes

The adaptive immune repertoire plays a critical role in type 1 diabetes (T1D) pathogenesis. However, efforts to characterize B cell and T cell receptor (TCR) profiles in T1D subjects have been largely limited to peripheral blood sampling and restricted to known antigens. To address this, we collected pancreatic draining lymph nodes (pLN), "irrelevant" nonpancreatic draining lymph nodes, peripheral blood mononuclear cells (PBMC), and splenocytes from T1D subjects (n = 18) and control donors (n = 9) as well as pancreatic islets from 1 T1D patient; from these tissues, we collected purified CD4⁺ conventional T cells (Tconv), CD4⁺ Treg, CD8⁺ T cells, and B cells. By conducting high-throughput immunosequencing of the TCR β chain (TRB) and B cell receptor (BCR) immunoglobulin heavy chain (IGH) on these samples, we sought to analyze the molecular signature of the lymphocyte populations within these tissues and of T1D. Ultimately, we observed a highly tissue-restricted CD4⁺ repertoire, while up to 24% of CD8⁺ clones were shared among tissues. We surveyed our data set for previously described proinsulin- and glutamic acid decarboxylase 65-reactive (GAD65-reactive) receptors, and interestingly, we observed a TRB with homology to a known GAD65-reactive TCR (clone GAD4.13) present in 7 T1D donors (38.9%), representing >25% of all productive TRB within Tconv isolated from the pLN of 1 T1D subject. These data demonstrate diverse receptor signatures at the nucleotide level and enriched autoreactive clones at the amino acid level, supporting the utility of coupling immunosequencing data with knowledge of characterized autoreactive receptors.