Initiation Of Islet Autoimmunity Research Articles

Enteroviruses and risk of islet autoimmunity or type 1 diabetes: systematic review and meta-analysis of controlled observational studies detecting viral nucleic acids and proteins

Enteroviruses are routinely detected with molecular methods within large cohorts that are at risk of type 1 diabetes. We aimed to examine the association between enteroviruses and either islet autoimmunity or type 1 diabetes. For this systematic review and meta-analysis, we searched PubMed and Embase for controlled observational studies from inception until Jan 1, 2023. Cohort or case-control studies were eligible if enterovirus RNA or protein were detected in individuals with outcomes of islet autoimmunity or type 1 diabetes. Studies in pregnancy or other types of diabetes were excluded. Data extraction and appraisal involved author contact and deduplication, which was done independently by three reviewers. Study quality was assessed with the Newcastle-Ottawa Scale and National Health and Medical Research Council levels of evidence. Pooled and subgroup meta-analyses were done in RevMan version 5.4, with random effects models and Mantel-Haenszel odds ratios (ORs; 95% CIs). The study is registered with PROSPERO, CRD42021278863. The search returned 3266 publications, with 897 full texts screened. Following deduplication, 113 eligible records corresponded to 60 studies (40 type 1 diabetes; nine islet autoimmunity; 11 both), comprising 12077 participants (5981 cases; 6096 controls). Study design and quality varied, generating substantial statistical heterogeneity. Meta-analysis of 56 studies showed associations between enteroviruses and islet autoimmunity (OR 2·1, 95% CI 1·3-3·3; p=0·002; n=18; heterogeneity χ2/df 2·69; p=0·0004; I2=63%), type 1 diabetes (OR 8·0, 95% CI 4·9-13·0; p<0·0001; n=48; χ2/df 6·75; p<0·0001; I2=85%), or within 1 month of type 1 diabetes (OR 16·2, 95% CI 8·6-30·5; p<0·0001; n=28; χ2/df 3·25; p<0·0001; I2=69%). Detection of either multiple or consecutive enteroviruses was associated with islet autoimmunity (OR 2·0, 95% CI 1·0-4·0; p=0·050; n=8). Detection of Enterovirus B was associated with type 1 diabetes (OR 12·7, 95% CI 4·1-39·1; p<0·0001; n=15). These findings highlight the association between enteroviruses and islet autoimmunity or type 1 diabetes. Our data strengthen the rationale for vaccine development targeting diabetogenic enterovirus types, particularly those within Enterovirus B. Prospective studies of early life are needed to elucidate the role of enterovirus timing, type, and infection duration on the initiation of islet autoimmunity and the progression to type 1 diabetes. Environmental Determinants of Islet Autoimmunity, European Association for the Study of Diabetes, JDRF, Australian National Health and Medical Research Council, and University of New South Wales.

107-OR: Novel Genetic Risk Factors Influence Islet Autoimmunity Progression

Background: Type 1 diabetes (T1D) is determined by unknown environmental factors in genetically susceptible individuals. The design of most genome wide association studies of T1D involves comparison of cases (with varying duration of disease) with controls; hence, the genetic variants associated with T1D reflect current disease, ignoring variants that play a key role in the initiation of islet autoimmunity and the progression of subclinical disease. In this study, we focus on the genetic contribution to progression of islet autoimmunity using whole-genome sequencing in a collection of participants of the Diabetes AutoImmunity Study in the Young (DAISY). Methods: A total of 160 persistent islet autoantibody positive DAISY subjects were sequenced, including 87 subjects who progressed to T1D and 73 “non-progressors” over a mean of 11 years since seroconversion. Following whole genome sequence alignment, single nucleotide polymorphisms (SNPs) and small insertion/deletions (indels) were identified (∼6.8 million variants), and statistical analyses performed. Results: Genes with multiple SNPs associated with progression to T1D in subjects with islet autoimmunity (P &amp;lt; 8.5x10-8) did not overlap with known T1D risk loci; instead, four novel regions were identified - 1q21.3 (MRPS21-PRPF3), 2p25.2 (NRIR), 3q22.1 (COL6A6), and 20p12.1 (TASP1). Functional mapping of the associated SNPs within these risk loci indicates pathways critical for response to viral infections and response to interferon signaling contribute to progression to T1D once islet autoimmunity is initiated. Discussion: This study presents evidence that different genetic pathways may contribute to progression of islet autoimmunity from those identified once disease is established and support the need for follow-up studies to understand genetic risk factors that modulate progression of subclinical disease. Disclosure S. Onengut-Gumuscu: None. U. Paila: None. W. Chen: None. A. Ratan: None. Z. Zhu: None. A. Steck: None. B.I. Frohnert: None. K. Waugh: None. B. Webb-Robertson: None. J.M. Norris: None. L. Lange: None. M. Rewers: None. S.S. Rich: None.

Common patterns of gene regulation associated with Cesarean section and the development of islet autoimmunity \u2013 indications of immune cell activation

Birth by Cesarean section increases the risk of developing type 1 diabetes later in life. We aimed to elucidate common regulatory processes observed after Cesarean section and the development of islet autoimmunity, which precedes type 1 diabetes, by investigating the transcriptome of blood cells in the developing immune system. To investigate Cesarean section effects, we analyzed longitudinal gene expression profiles from peripheral blood mononuclear cells taken at several time points from children with increased familial and genetic risk for type 1 diabetes. For islet autoimmunity, we compared gene expression differences between children after initiation of islet autoimmunity and age-matched children who did not develop islet autoantibodies. Finally, we compared both results to identify common regulatory patterns. We identified the pentose phosphate pathway and pyrimidine metabolism - both involved in nucleotide synthesis and cell proliferation - to be differentially expressed in children born by Cesarean section and after islet autoimmunity. Comparison of global gene expression signatures showed that transcriptomic changes were systematically and significantly correlated between Cesarean section and islet autoimmunity. Moreover, signatures of both Cesarean section and islet autoimmunity correlated with transcriptional changes observed during activation of isolated CD4+ T lymphocytes. In conclusion, we identified shared molecular changes relating to immune cell activation in children born by Cesarean section and children who developed autoimmunity. Our results serve as a starting point for further investigations on how a type 1 diabetes risk factor impacts the young immune system at a molecular level.

Early childhood CMV infection may decelerate the progression to clinical type 1 diabetes.

Evidence of the role of cytomegalovirus (CMV) infection in the pathogenesis of type 1 diabetes (T1D) has remained inconclusive. Our aim was to elucidate the possible role of CMV infection in the initiation of islet autoimmunity and in the progression to clinical T1D among children with human leukocyte antigen (HLA)-conferred T1D risk. A total of 1402 children from the prospective Type 1 Diabetes Prediction and Prevention (DIPP) study were analyzed for CMV-specific IgG antibodies during early childhood. All the children carried HLA-DQ genotypes associated with increased risk for T1D. The effect of CMV infection on the appearance of T1D-associated autoantibodies (insulin autoantibodies [IAA], glutamic acid decarboxylase [GADA], and insulinoma antigen-2 [IA-2A], n = 356) and on the progression rate to clinical T1D (n = 233) were analyzed with Kaplan-Meier survival analysis and Log-rank test. Early childhood CMV infection was inversely associated with the development of T1D during childhood. Cumulative progression to T1D was decreased in subjects with an early CMV infection (P = 0.035). In further analyses, the effect of early CMV infection on the initiation of islet autoimmunity and progression to clinical T1D were examined separately. Interestingly, early CMV infection did not affect the appearance of T1D-associated autoantibodies but a decelerating effect was observed on the progression rate from islet autoimmunity to clinical T1D (P = 0.015). Our results suggest that an early childhood CMV infection may decelerate the progression from islet autoimmunity to clinical T1D among at-risk children and may thus protect these children from progressing to T1D during childhood.

Deficiency in Type I Interferon Signaling Prevents the Early Interferon–Induced Gene Signature in Pancreatic Islets but Not Type 1 Diabetes in NOD Mice

Type I interferons (IFNs) have been implicated in the initiation of islet autoimmunity and development of type 1 diabetes. To directly test their involvement, we generated NOD mice deficient in type I IFN receptors (NOD.IFNAR1(-/-)). Expression of the type I IFN-induced genes Mx1, Isg15, Ifit1, Oas1a, and Cxcr4 was detectable in NOD islets as early as 1 week of age. Of these five genes, expression of Isg15, Ifit1, Oas1a, and Mx1 peaked at 3-4 weeks of age, corresponding with an increase in Ifnα mRNA, declined at 5-6 weeks of age, and increased again at 10-14 weeks of age. Increased IFN-induced gene expression was ablated in NOD.IFNAR1(-/-) islets. Loss of Toll-like receptor 2 (TLR2) resulted in reduced islet expression of Mx1 at 2 weeks of age, but TLR2 or TLR9 deficiency did not change the expression of other IFN-induced genes in islets compared with wild-type NOD islets. We observed increased β-cell major histocompatibility complex class I expression with age in NOD and NOD.IFNAR1(-/-) mice. NOD.IFNAR1(-/-) mice developed insulitis and diabetes at a similar rate to NOD controls. These results indicate type I IFN is produced within islets in young mice but is not essential for the initiation and progression of diabetes in NOD mice.

Next-generation sequencing for viruses in children with rapid-onset type 1 diabetes.

Viruses are candidate causative agents in the pathogenesis of autoimmune (type 1) diabetes. We hypothesised that children with a rapid onset of type 1 diabetes may have been exposed to such agents shortly before the initiation of islet autoimmunity, possibly at high dose, and thus study of these children could help identify viruses involved in the development of autoimmune diabetes. We used next-generation sequencing to search for viruses in plasma samples and examined the history of infection and fever in children enrolled in The Environmental Determinants of Diabetes in the Young (TEDDY) study who progressed to type 1 diabetes within 6 months from the appearance of islet autoimmunity, and in matched islet-autoantibody-negative controls. Viruses were not detected more frequently in plasma from rapid-onset patients than in controls during the period surrounding seroconversion. In addition, infection histories were found to be similar between children with rapid-onset diabetes and control children, although episodes of fever were reported less frequently in children with rapid-onset diabetes. These findings do not support the presence of viraemia around the time of seroconversion in young children with rapid-onset type 1 diabetes.

Viruses and Cytotoxic T Lymphocytes in Type 1 Diabetes

Histopathological studies on pancreas tissues from individuals with recent-onset type 1 diabetes (T1D) consistently find that CD8 T cells substantially contribute to the formation of islet lesions. CD8 T cells reactive against islet-associated antigens can also be found in blood samples from T1D patients. Mechanistic studies on the pathogenic role of this T cell subset have mostly focused on two animal models, i.e., the non-obese diabetic mouse and the virally induced rat insulin promoter-lymphocytic choriomeningitis virus model. Data were obtained in support of a role for viral infection in expanding a population of diabetogenic cytotoxic T lymphocytes. In view of the theorized association of viral infection with initiation of islet autoimmunity and progression to clinically overt disease, CD8 T cells thus represent an attractive target for immunotherapy. We will review here arguments in favor of a pivotal role for CD8 T cells in driving T1D development and speculate on etiologic agents that may provoke their aberrant activation.

Immunotherapy for the Prevention and Treatment of Type 1 Diabetes

In the past 15 years, multiple clinical trials have attempted to find prevention for type 1 diabetes. The accompanying article by Bresson and von Herrath (1) reviews basic mechanisms underlying immunoprevention and immunotherapy of type 1 diabetes as well as selected human trials in the context of data from animal models. The second part of this mini-symposium provides an overview of the recent or ongoing human trials. Immunotherapy for prevention of type 1 diabetes or to ameliorate the course of the disease after clinical diagnosis is currently restricted to research studies. References are provided to the clinical.trials.gov database or other sources where the reader can find additional information. Type 1 diabetes is an autoimmune disease caused by interplay of genetic and environmental factors. Figure 1 summarizes the main stages in the development of type 1 diabetes and examples of prevention trials at these stages. The initial step—development of islet autoimmunity marked by the presence of autoantibodies to insulin, GAD (GAD65), insulinoma-associated protein 2 (IA-2), and tyrosine phosphatase or zinc transporter (ZnT8)—is believed to be driven by environmental trigger(s) (2). Over the past 40 years, the incidence of childhood type 1 diabetes worldwide has increased by 3–5% annually (3–6). Elimination of the environmental trigger(s) responsible for this epidemic would be the most efficient approach to primary prevention. However, there is lack of consensus regarding which environmental factor(s) initiates islet autoimmunity. The National Institutes of Health have established The Environmental Determinants of type 1 Diabetes in the Young (TEDDY) consortium to evaluate the leading candidates (7,8). Figure 1 Natural history of type 1 diabetes and prevention opportunities. After initiation of islet autoimmunity, most patients have a long preclinical period (9–12) that offers opportunity for secondary prevention—halting progression to clinical diabetes (Fig. 1). Large randomized trials initiated …

No major association of breast-feeding, vaccinations, and childhood viral diseases with early islet autoimmunity in the German BABYDIAB Study.

Environmental factors have been suggested to play an important role in the pathogenesis of type 1 diabetes. The aim of this study was to assess the influence of breast-feeding, vaccinations, and childhood viral diseases on the initiation of islet autoimmunity in early childhood. Data were prospectively collected from questionnaires obtained at birth, at 9 months of age, and at 2 years of age in 823 offspring from parents with type 1 diabetes. By 2 years of age, 31 offspring had islet antibodies, and 10 developed overt diabetes by the time of follow-up. In offspring from mothers with type 1 diabetes, duration of exclusive and total breast-feeding did not differ between islet antibody-positive and -negative children, regardless of HLA genotype, and breast-feeding of 3 months or longer was not associated with protection from antibody development or diabetes onset. In offspring from diabetic fathers, non-statistically significant reductions in exclusive and total breast-feeding times were observed in the antibody-positive cohort. Neither type nor quantity of vaccinations (including Bacille Calmette-Guerin vaccine; haemophilus influenzae vaccine; diphtheria, tetanus, and pertussis vaccine; tick-born encephalitis vaccine; or measles, mumps, and rubella vaccine) were associated with the development of islet antibodies and diabetes. Measles, mumps, and rubella were not reported in children with islet antibodies or diabetes. This study showed no evidence that proposed environmental factors affect islet antibody development in the first 2 years of life in offspring from parents with type 1 diabetes.