Possible heterogeneity of initial pancreatic islet beta-cell autoimmunity heralding type 1 diabetes

Paediatric screening in Italy as a gateway to secondary prevention in type 1 diabetes

This article explores Italy's pioneering national paediatric screening initiative for type 1 diabetes (T1D), the first of its kind to be mandated by the Italian law for the general population aged 1-17 years. This initiative is designed to facilitate early detection and secondary prevention of T1D and coeliac disease (CD), aiming to identify children in presymptomatic stages of T1D, regardless of family history. Emphasis is placed on autoantibody screening for T1D and CD to refine risk prediction and enhance secondary prevention efforts. Furthermore, the anti-CD3 + T cell monoclonal antibody teplizumab, which may be considered at present for compassionate use only, represents a step forward in delaying T1D onset in stage 2 patients. Italy's comprehensive screening law, passed in 2023, allows for early detection of T1D minimising the risk of consequences such as DKA at diagnosis. The screening will also advance our understanding of T1D disease pathogenesis and progression. These insights advocate for tailored prevention strategies, thus improving the design of clinical trials.

Looking back at the TEDDY study: lessons and future directions

The goal of the TEDDY (The Environmental Determinants of Diabetes in the Young) study is to elucidate factors leading to the initiation of islet autoimmunity (first primary outcome) and those related to progression to type 1 diabetes mellitus (T1DM; second primary outcome). This Review outlines the key findings so far, particularly related to the first primary outcome. The background, history and organization of the study are discussed. Recruitment and follow-up (from age 4 months to 15 years) of 8,667 children showed high retention and compliance. End points of the presence of autoantibodies against insulin, GAD65, IA-2 and ZnT8 revealed the HLA-associated early appearance of insulin autoantibodies (1-3 years of age) and the later appearance of GAD65 autoantibodies. Competing autoantibodies against tissue transglutaminase (marking coeliac disease autoimmunity) also appeared early (2-4 years). Genetic and environmental factors, including enterovirus infection and gastroenteritis, support mechanistic differences underlying one phenotype of autoimmunity against insulin and another against GAD65. Infant growth and both probiotics and high protein intake affect the two phenotypes differently, as do serious life events during pregnancy. As the end of the TEDDY sampling phase is approaching, major omics approaches are in progress to further dissect the mechanisms that might explain the two possible endotypes of T1DM.

Infections and antibiotic use in early childhood have limited importance in developing manifest type 1 diabetes - The ABIS cohort study

Aims

To investigate the effect of early childhood infections and antibiotic use on the risk of type 1 diabetes in a general population cohort.

Research Design and Methods

The All Babies In Southeast Sweden (ABIS) cohort followed 16 428 children from birth. Questionnaires collected at 1 year (n=11 093), 3 years (n=8 890) and 5 years of age (n=7 445) included data on infections and antibiotic use and were validated against national registers. After a mean follow-up of 25 years, 168 individuals have been diagnosed with type 1 diabetes (1.0% of the original cohort, aged 1-24.5 years).

Results

There were few significant differences in type or frequency of early childhood infections or antibiotic use between cases with type 1 diabetes and the reference group (remaining individuals who did not develop type 1 diabetes) after adjusting for sex, heredity and socioeconomic status. A small number of type 1 diabetes children (4.8% compared to 0.8% of the reference group) reported six or more episodes of gastroenteritis in the 1-3-year age group, resulting in an adjusted odds ratio (aOR) of 8.21; 95% CI 2.70-25.01, p<0.001. Cases of type 1 diabetes with an increased genetic risk (n=91) reported fewer episodes of the common cold between 1 and 3 years of age compared to the reference group (aOR 0.27; 0.13-0.58, p<0.001). Individuals with type 1 diabetes without risk-associated HLA alleles (n=14) reported a higher frequency of pneumonia in the 1-3- and 3-5-year age group (aOR 26.08; 6.29-108.17, p<0.001 and aOR 35.63; 4.10-309.96, p=0.001 respectively), and had more viral and total infections registered in the National Patient Register from 0-5 years (aOR 5.72; 1.59-20.57, p=0.008 and aOR 18.71; 1.95-179.55, p=0.01).

Conclusions

Childhood infections could increase the risk of developing type 1 diabetes in a small group of individuals without risk-associated HLA alleles, but this was not seen in the majority with HLA-risk. More research is required for this overlooked population, including screening and prevention trials. The association to frequent gastrointestinal infections in the first years of life needs to be reproduced in other studies to be confirmed.

Autoimmune Type 1 Diabetes: An Early Approach Appraisal for Spain by the AGORA Diabetes Collaborative Group

Type 1 diabetes (T1D) is an autoimmune disorder characterized by the destruction of insulin-producing pancreatic beta-cells, leading to lifelong insulin dependence. This review explores the current understanding of T1D pathogenesis, clinical progression, and emerging therapeutic approaches. We examined the complex interplay between genetic predisposition and environmental factors that could trigger the autoimmune response as well as the immunological mechanisms involved in beta-cell destruction. The clinical phases of T1D are discussed from the preclinical stage through diagnosis and long-term management, highlighting the importance of early detection and intervention. Recent advancements in treatment strategies are presented, including immunomodulatory therapies and potential cell-based treatments aimed at preserving or restoring beta-cell function. Additionally, this review critically evaluates the feasibility and potential benefits of implementing a population-wide screening program for T1D in Spain. The epidemiological, economic, and ethical implications of such an initiative were considered by the national expert panel, focusing on the potential of early diagnosis to improve clinical outcomes in the face of the challenges of large-scale implementation. This comprehensive analysis aims to provide healthcare professionals, researchers, and policymakers with valuable insights into the current landscape of T1D management and prospects for enhanced prevention and treatment strategies in the Spanish context.

Family History of Diabetes and Clinical Characteristics in Children at Diagnosis of Type 1 Diabetes-A Swedish Population-Based Study

OBJECTIVE

To compare the prevalence of parental diabetes between children with and without type 1 diabetes (T1D), and to compare clinical characteristics at diagnosis of T1D in children with, versus without, a family history of diabetes.

RESEARCH DESIGN AND METHODS

Parental diabetes among children with T1D was compared with a general population cohort. Clinical characteristics were compared by family history of diabetes in parents and grandparents of 3,603 children with T1D using relative risk (RR) and ANOVA.

RESULTS

Children with T1D more often had parents with type 2 diabetes (T2D) (RR 1.88; P < 0.001) than did children without diabetes. Children with T1D and a family history of T2D were more likely to be overweight or obese (P = 0.002).

CONCLUSIONS

A family history of T2D and being overweight may contribute to increased risk of T1D.

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.

Untangling the genetics of beta cell dysfunction and death in type 1 diabetes

BACKGROUND

Type 1 diabetes (T1D) is a complex multi-system disease which arises from both environmental and genetic factors, resulting in the destruction of insulin-producing pancreatic beta cells. Over the past two decades, human genetic studies have provided new insight into the etiology of T1D, including an appreciation for the role of beta cells in their own demise.

SCOPE OF REVIEW

Here, we outline models supported by human genetic data for the role of beta cell dysfunction and death in T1D. We highlight the importance of strong evidence linking T1D genetic associations to bona fide candidate genes for mechanistic and therapeutic consideration. To guide rigorous interpretation of genetic associations, we describe molecular profiling approaches, genomic resources, and disease models that may be used to construct variant-to-gene links and to investigate candidate genes and their role in T1D.

MAJOR CONCLUSIONS

We profile advances in understanding the genetic causes of beta cell dysfunction and death at individual T1D risk loci. We discuss how genetic risk prediction models can be used to address disease heterogeneity. Further, we present areas where investment will be critical for the future use of genetics to address open questions in the development of new treatment and prevention strategies for T1D.

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 programs are being increasingly emphasized. Once broadly implemented, screening initiatives will identify significant numbers of islet autoantibody-positive (IAb+) children and adults who are at risk for (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 nonspecialized 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 emphasizes significant unmet needs for further research on early-stage type 1 diabetes to increase the rigor of future recommendations and inform clinical care.

Childhood screening for type 1 diabetes comparing automated multiplex Antibody Detection by Agglutination-PCR (ADAP) with single plex islet autoantibody radiobinding assays

BACKGROUND

Two or more autoantibodies against either insulin (IAA), glutamic acid decarboxylase (GADA), islet antigen-2 (IA-2A) or zinc transporter 8 (ZnT8A) denote stage 1 (normoglycemia) or stage 2 (dysglycemia) type 1 diabetes prior to stage 3 type 1 diabetes. Automated multiplex Antibody Detection by Agglutination-PCR (ADAP) assays in two laboratories were compared to single plex radiobinding assays (RBA) to define threshold levels for diagnostic specificity and sensitivity.

METHODS

IAA, GADA, IA-2A and ZnT8A were analysed in 1504 (54% females) population based controls (PBC), 456 (55% females) doctor's office controls (DOC) and 535 (41% females) blood donor controls (BDC) as well as in 2300 (48% females) patients newly diagnosed (1-10 years of age) with stage 3 type 1 diabetes. The thresholds for autoantibody positivity were computed in 100 10-fold cross-validations to separate patients from controls either by maximizing the χ2-statistics (chisq) or using the 98th percentile of specificity (Spec98). Mean and 95% CI for threshold, sensitivity and specificity are presented.

FINDINGS

The ADAP ROC curves of the four autoantibodies showed comparable AUC in the two ADAP laboratories and were higher than RBA. Detection of two or more autoantibodies using chisq showed 0.97 (0.95, 0.99) sensitivity and 0.94 (0.91, 0.97) specificity in ADAP compared to 0.90 (0.88, 0.95) sensitivity and 0.97 (0.94, 0.98) specificity in RBA. Using Spec98, ADAP showed 0.92 (0.89, 0.95) sensitivity and 0.99 (0.98, 1.00) specificity compared to 0.89 (0.77, 0.86) sensitivity and 1.00 (0.99, 1.00) specificity in the RBA. The diagnostic sensitivity and specificity were higher in PBC compared to DOC and BDC.

INTERPRETATION

ADAP was comparable in two laboratories, both comparable to or better than RBA, to define threshold levels for two or more autoantibodies to stage type 1 diabetes.

FUNDING

Supported by The Leona M. and Harry B. Helmsley Charitable Trust (grant number 2009-04078), the Swedish Foundation for Strategic Research (Dnr IRC15-0067) and the Swedish Research Council, Strategic Research Area (Dnr 2009-1039). AL was supported by the DiaUnion collaborative study, co-financed by EU Interreg ÖKS, Capital Region of Denmark, Region Skåne and the Novo Nordisk Foundation.

A multi-ancestry genome-wide association study in type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease caused by destruction of the pancreatic β-cells. Genome-wide association (GWAS) and fine mapping studies have been conducted mainly in European ancestry (EUR) populations. We performed a multi-ancestry GWAS to identify SNPs and HLA alleles associated with T1D risk and age at onset. EUR families (N = 3223), and unrelated individuals of African (AFR, N = 891) and admixed (Hispanic/Latino) ancestry (AMR, N = 308) were genotyped using the Illumina HumanCoreExome BeadArray, with imputation to the TOPMed reference panel. The Multi-Ethnic HLA reference panel was utilized to impute HLA alleles and amino acid residues. Logistic mixed models (T1D risk) and frailty models (age at onset) were used for analysis. In GWAS meta-analysis, seven loci were associated with T1D risk at genome-wide significance: PTPN22, HLA-DQA1, IL2RA, RNLS, INS, IKZF4-RPS26-ERBB3, and SH2B3, with four associated with T1D age at onset (PTPN22, HLA-DQB1, INS, and ERBB3). AFR and AMR meta-analysis revealed NRP1 as associated with T1D risk and age at onset, although NRP1 variants were not associated in EUR ancestry. In contrast, the PTPN22 variant was significantly associated with risk only in EUR ancestry. HLA alleles and haplotypes most significantly associated with T1D risk in AFR and AMR ancestry differed from that seen in EUR ancestry; in addition, the HLA-DRB1*08:02-DQA1*04:01-DQB1*04:02 haplotype was 'protective' in AMR while HLA-DRB1*08:01-DQA1*04:01-DQB1*04:02 haplotype was 'risk' in EUR ancestry, differing only at HLA-DRB1*08. These results suggest that much larger sample sizes in non-EUR populations are required to capture novel loci associated with T1D risk.

HLA Class II (DR, DQ, DP) Genes Were Separately Associated With the Progression From Seroconversion to Onset of Type 1 Diabetes Among Participants in Two Diabetes Prevention Trials (DPT-1 and TN07)

OBJECTIVE

To explore associations of HLA class II genes (HLAII) with the progression of islet autoimmunity from asymptomatic to symptomatic type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

Next-generation targeted sequencing was used to genotype eight HLAII genes (DQA1, DQB1, DRB1, DRB3, DRB4, DRB5, DPA1, DPB1) in 1,216 participants from the Diabetes Prevention Trial-1 and Randomized Diabetes Prevention Trial with Oral Insulin sponsored by TrialNet. By the linkage disequilibrium, DQA1 and DQB1 are haplotyped to form DQ haplotypes; DP and DR haplotypes are similarly constructed. Together with available clinical covariables, we applied the Cox regression model to assess HLAII immunogenic associations with the disease progression.

RESULTS

First, the current investigation updated the previously reported genetic associations of DQA1*03:01-DQB1*03:02 (hazard ratio [HR] = 1.25, P = 3.50*10-3) and DQA1*03:03-DQB1*03:01 (HR = 0.56, P = 1.16*10-3), and also uncovered a risk association with DQA1*05:01-DQB1*02:01 (HR = 1.19, P = 0.041). Second, after adjusting for DQ, DPA1*02:01-DPB1*11:01 and DPA1*01:03-DPB1*03:01 were found to have opposite associations with progression (HR = 1.98 and 0.70, P = 0.021 and 6.16*10-3, respectively). Third, DRB1*03:01-DRB3*01:01 and DRB1*03:01-DRB3*02:02, sharing the DRB1*03:01, had opposite associations (HR = 0.73 and 1.44, P = 0.04 and 0.019, respectively), indicating a role of DRB3. Meanwhile, DRB1*12:01-DRB3*02:02 and DRB1*01:03 alone were found to associate with progression (HR = 2.6 and 2.32, P = 0.018 and 0.039, respectively). Fourth, through enumerating all heterodimers, it was found that both DQ and DP could exhibit associations with disease progression.

CONCLUSIONS

These results suggest that HLAII polymorphisms influence progression from islet autoimmunity to T1D among at-risk subjects with islet autoantibodies.

A Bioartificial Pancreas with "Immune Stealth" and Continuous Oxygen Supply for Islet Transplantation

Transplantation of microencapsulated islet cells remains a promising strategy for the normalization of glucose metabolism control in type 1 diabetes mellitus. However, vigorous host immunologic rejection, fibrotic overgrowth around the microcapsules, and poor oxygen supply often lead to graft failure. Herein, a bioartificial pancreas is constructed, which incorporates the "stealth effect" based on polyethylene glycol copolymers and the high oxygen-carrying performance of fluorinated nanoparticles. Polycationic poly(l-lysine)-grafted-poly(ethylene glycol) is successfully coated on the surface of alginate microcapsules through electrostatic interaction, which can not only resist fibrinogen adhesion and avoid excessive fibrosis around the microcapsules but also isolate the host immune system from attacking, achieving a "stealth effect" of microencapsulated islet cells. Furthermore, the coloading of fluoride-based O2 nanocarriers gives them enhanced oxygen-carrying and continuous oxygen supply capabilities, thereby effectively prolonging the survival of islet cells. The intracapsular islet cells still display similar cell viability and almost normal insulin secretion function even in long-term culture under hypoxic conditions. Collectively, here a new approach is opened for microencapsulated islets to efficiently evade host immune attack and improve oxygen supply and a promising strategy is provided for islet transplantation in type 1 diabetes mellitus.