Early epitope- and isotype-specific humoral immune responses to GAD65 in young children with genetic susceptibility to type 1 diabetes

Objective: The pattern of the humoral immunity to disease-associated autoantigens may reflect the severity of the autoimmune disease process. The purpose of this study was to delineate the maturation of the humoral immunity to one of the main autoantigens in type 1 diabetes (T1D), glutamic acid decarboxylase (GAD65). Design and methods: Serum samples were obtained for the detection of epitope- and isotype-specific antibodies sequentially with short intervals from 36 young children with HLA-conferred genetic susceptibility to T1D starting from the first appearance of GAD65Ab. During prospective observation, ten children developed T1D. Antibodies were analyzed using biotinylated anti-human immunoglobulin (Ig) antibodies and chimeric GAD molecules in radio-binding assays. Results: The immune response to GAD65 started as reactivity to the middle region and spread rapidly to the C-terminal region. IgG1 antibodies dominated among the isotypes from the first appearance of GAD65Ab, while other IgG subclasses were observed to a lesser extent. IgG4 antibodies emerged clearly as the last IgG subclass. A broad initial response comprising three to four IgG subclasses and the lack of an emerging IgG4 response during follow-up was associated with increased risk for progression to clinical diabetes (P<0.05). Conclusions: The humoral response to GAD65 epitope clusters is relatively uniform in young children, whereas there is conspicuous individual variation in IgG subclass responses except for IgG1. A narrow initial IgG subclass response to GAD65 and the emergence of IgG4 antibodies were characteristic of those who remained non-diabetic over the first few years of GAD65 autoimmunity.

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Monogenic Diabetes and Integrated Stress Response Genes Display Altered Gene Expression in Type 1 Diabetes

10.2337/figshare.14612202.v1 ◽

2021 ◽

Author(s):

Helmut Hiller ◽

Dawn E. Beachy ◽

Joseph J. Lebowitz ◽

Stefanie Engler ◽

Justin R. Mason ◽

...

Keyword(s):

Type 1 Diabetes ◽

Stress Response ◽

Stress Responses ◽

Disease Process ◽

Monogenic Diabetes ◽

Integrated Stress Response ◽

Altered Expression ◽

Increased Risk ◽

Gene And Protein Expression

Type 1 diabetes has a multifactorial autoimmune etiology, involving environmental prompts and polygenic predisposition. We hypothesized that pancreata from individuals with and at risk for type 1 diabetes would exhibit dysregulated expression of genes associated with monogenic forms of diabetes caused by non-redundant single-gene mutations. Employing a “monogenetic transcriptomic strategy,” we measured the expression of these genes in human type 1 diabetes, autoantibody positive (autoantibody+), and control pancreas tissues using RTqPCR in accordance with the Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guidelines. Gene and protein expression were visualized <i>in situ</i> using immunofluorescence, RNAScope, and confocal microscopy. Two-dozen monogenic diabetes genes showed altered expression in human pancreata from individuals with type 1 diabetes versus unaffected controls. Six of these genes also saw dysregulation in pancreata from autoantibody+ persons at increased-risk for type 1 diabetes. As a subset of these genes are related to cellular stress responses, we measured integrated stress response (ISR) genes and identified 20 with altered expression in type 1 diabetes pancreata, including three of the four eIF2a-dependent kinases. Equally intriguing, we observed significant repression of the three arms of the ISR in autoantibody+ pancreata. Collectively, these efforts suggest monogenic diabetes and ISR genes are dysregulated early in the type 1 diabetes disease process and likely contribute to the disorder’s pathogenesis.

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Natural History of β-Cell Autoimmunity in Young Children with Increased Genetic Susceptibility to Type 1 Diabetes Recruited from the General Population

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jc.2002-020018 ◽

2002 ◽

Vol 87 (10) ◽

pp. 4572-4579 ◽

Cited By ~ 99

Author(s):

T. Kimpimäki ◽

P. Kulmala ◽

K. Savola ◽

A. Kupila ◽

S. Korhonen ◽

...

Keyword(s):

Type 1 Diabetes ◽

General Population ◽

Natural History ◽

Young Children ◽

Genetic Susceptibility ◽

Β Cell ◽

History Of

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Autoantibodies to N-Terminally Truncated GAD65(96–585): HLA Associations and Predictive Value for Type 1 Diabetes

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/clinem/dgab816 ◽

2021 ◽

Author(s):

Petra M Pöllänen ◽

Taina Härkönen ◽

Jorma Ilonen ◽

Jorma Toppari ◽

Riitta Veijola ◽

...

Keyword(s):

Type 1 Diabetes ◽

Predictive Value ◽

Dietary Intervention ◽

Venous Blood ◽

Islet Cell Antibodies ◽

Acid Decarboxylase ◽

Prediction And Prevention ◽

Increased Risk ◽

Combining Data

Abstract Objective To evaluate the role of autoantibodies to N-terminally truncated glutamic acid decarboxylase GAD65(96–585) (t-GADA) as a marker for type 1 diabetes (T1D) and to assess the potential HLA-associations with such autoantibodies. Design In this cross-sectional study combining data from the Finnish Pediatric Diabetes Register, the Type 1 Diabetes Prediction and Prevention (DIPP) Study, the DIABIMMUNE Study, and the Early Dietary Intervention and Later Signs of Beta-Cell Autoimmunity (EDIA) Study, venous blood samples from 760 individuals (53.7% males) were analyzed for t-GADA, autoantibodies to full-length GAD65 (f-GADA), and islet cell antibodies. Epitope-specific GAD autoantibodies were analyzed from 189 study participants. Results T1D had been diagnosed in 174 (23%) participants. Altogether 631 (83%) individuals tested positive for f-GADA and 451 (59%) for t-GADA at a median age of 9.0 years (range 0.2–61.5). t-GADA demonstrated higher specificity (46%) and positive predictive value (30%) for T1D than positivity for f-GADA alone (15% and 21%, respectively). Among participants positive for f-GADA, those who tested positive for t-GADA carried more frequently HLA genotypes conferring increased risk for T1D than those who tested negative for t-GADA (77 vs. 53%; P<0.001). Conclusions Autoantibodies to N-terminally truncated GAD improve the screening for T1D compared to f-GADA and may facilitate the selection of participants for clinical trials. HLA class II-mediated antigen presentation of GAD(96–585)-derived or structurally similar peptides might comprise an important pathomechanism in T1D.

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Danish children born with glutamic acid decarboxylase-65 and islet antigen-2 autoantibodies at birth had an increased risk to develop type 1 diabetes

Acta Endocrinologica ◽

10.1530/eje-10-0792 ◽

2011 ◽

Vol 164 (2) ◽

pp. 247-252 ◽

Cited By ~ 7

Author(s):

Stefanie Eising ◽

Anita Nilsson ◽

Bendix Carstensen ◽

David M Hougaard ◽

Bent Nørgaard-Pedersen ◽

...

Keyword(s):

Type 1 Diabetes ◽

Glutamic Acid ◽

Glutamic Acid Decarboxylase ◽

Case Control ◽

Acid Decarboxylase ◽

Increased Risk ◽

Parental Diabetes ◽

Glutamic Acid Decarboxylase 65 ◽

Islet Antigen

ObjectiveA large, population-based case–control cohort was used to test the hypothesis that glutamic acid decarboxylase-65 (GAD65) and islet antigen-2 autoantibodies (IA-2A) at birth predict type 1 diabetes.Design and methodsThe design was an individually matched case–control study of all Danish type 1 diabetes patients born between 1981 and 2002 and diagnosed before May 1 2004 (median age at diagnosis was 8.8 years). Dried blood spot samples collected 5 days after birth in the 1981–2002 birth cohorts and stored at −25 °C were identified from 2023 patients and from two matched controls (n=4042). Birth data and information on parental age and diabetes were obtained from Danish registers. GAD65A and IA-2A were determined in a radiobinding assay. HLA-DQB1 alleles were analyzed by PCR using time-resolved fluorescence.ResultsGAD65A and IA-2A were found in 70/2023 (3.5%) patients compared to 21/4042 (0.5%) controls resulting in a hazard ratio (HR) of 7.49 (P<0.0001). The HR decreased to 4.55 but remained significant (P<0.0003) after controlling for parental diabetes and HLA-DQB1 alleles. Conditional logistic regression analysis showed a HR of 2.55 (P<0.0001) for every tenfold increase in the levels of GAD65A and IA-2A. This HR decreased to 1.93 but remained significant (P<0.001) after controlling for parental diabetes and HLA-DQB1 alleles.ConclusionThese data suggest that GAD65A and IA-2A positivity at birth are associated with an increased risk of developing type 1 diabetes in Danish children diagnosed between 1981 and 2004.

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