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Context Biomarkers that can accurately predict risk of type 1 diabetes (T1D) in genetically predisposed children can facilitate interventions to delay or prevent the disease. Objective This work aimed to determine if a combination of genetic, immunologic, and metabolic features, measured at infancy, can be used to predict the likelihood that a child will develop T1D by age 6 years. Methods Newborns with human leukocyte antigen (HLA) typing were enrolled in the prospective birth cohort of The Environmental Determinants of Diabetes in the Young (TEDDY). TEDDY ascertained children in Finland, Germany, Sweden, and the United States. TEDDY children were either from the general population or from families with T1D with an HLA genotype associated with T1D specific to TEDDY eligibility criteria. From the TEDDY cohort there were 702 children will all data sources measured at ages 3, 6, and 9 months, 11.4% of whom progressed to T1D by age 6 years. The main outcome measure was a diagnosis of T1D as diagnosed by American Diabetes Association criteria. Results Machine learning–based feature selection yielded classifiers based on disparate demographic, immunologic, genetic, and metabolite features. The accuracy of the model using all available data evaluated by the area under a receiver operating characteristic curve is 0.84. Reducing to only 3- and 9-month measurements did not reduce the area under the curve significantly. Metabolomics had the largest value when evaluating the accuracy at a low false-positive rate. Conclusion The metabolite features identified as important for progression to T1D by age 6 years point to altered sugar metabolism in infancy. Integrating this information with classic risk factors improves prediction of the progression to T1D in early childhood.

Zinc transporter 8 (ZnT8) is a newly discovered islet autoantigen in human type 1A diabetes (T1D).The objective was to document changes in ZnT8 autoantibody (ZnT8A) titer and prevalence after onset of disease in relationship to 65 kDa glutamate decarboxylase antibody (GADA) and islet cell antigen antibody (IA2A).Autoantibody radioimmunoprecipitation assays were performed on sera from three groups: 21 individuals monitored every 3 months from diagnosis for 2.5 yr; 61 individuals monitored at six monthly intervals for 5-12 yr; and a cross-sectional study of 424 patients with T1D of 20-57 yr duration. Circulating C-peptide was determined as an index of residual β-cell function.ZnT8A titers declined exponentially from clinical onset of T1D with a t(1/2) ranging from 26 to 530 wk, similar to C-peptide (23-300 wk). Life-table analysis of antibody prevalence to 12 yr indicated that ZnT8A measured with either Arg325 or Trp325 probes persisted for a shorter interval than IA2A. Although prevalence of ZnT8A, IA2A, and GADA were comparable at disease onset (70.4 vs. 73.4 vs. 64%), only 6.7% of individuals remained ZnT8A positive after 25 yr compared with 19.5% for IA2A and 25.9% for GADA. Titers of ZnT8A and IA2A in seropositive individuals decreased progressively, whereas GADA remained elevated consistent with periodic reactivation of GADA humoral autoimmunity.ZnT8 humoral autoreactivity declines rapidly in the first years after disease onset and is less persistent than IA2A or GADA in the longer term. ZnT8A determination may be a useful measure of therapeutic efficacy in the context of immune-based clinical interventions.

Autoantibodies to islet antigen-2 (IA-2A) and glutamic acid decarboxylase (GADA) are markers for diagnosis, screening, and measuring outcomes in National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) consortia studies. A harmonization program was established to increase comparability of results within and among these studies.Large volumes of six working calibrators were prepared from pooled sera with GADA 4.8-493 World Health Organization (WHO) units/ml and IA-2A 2-235 WHO units/ml. Harmonized assay protocols for IA-2A and GADA using (35)S-methionine-labelled in vitro transcribed and translated antigens were developed based on methods in use in three NIDDK laboratories. Antibody thresholds were defined using sera from patients with recent onset type 1 diabetes and healthy controls. To evaluate the impact of the harmonized assay protocol on concordance of IA-2A and GADA results, two laboratories retested stored TEDDY study sera using the harmonized assays.The harmonized assays gave comparable but not identical results in the three laboratories. For IA-2A, using a common threshold of 5 DK units/ml, 549 of 550 control and patient samples were concordantly scored as positive or negative, specificity was greater than 99% with sensitivity 64% in all laboratories. For GADA, using thresholds equivalent to the 97th percentile of 974 control samples in each laboratory, 1051 (97.9%) of 1074 samples were concordant. On the retested TEDDY samples, discordance decreased from 4 to 1.8% for IA-2A (n = 604 samples; P = 0.02) and from 15.4 to 2.7% for GADA (n = 515 samples; P0.0001).Harmonization of GADA and IA-2A is feasible using large volume working calibrators and common protocols and is an effective approach to ensure consistency in autoantibody measurements.

During pregnancy, maternal type 1 diabetes-associated autoantibodies may cross the placenta. It is proposed that insulin antibodies (IA) allow transfer of insulin across the placenta, contributing to fetal hyperinsulinemia and macrosomia. We assessed the prevalence of IA, the tyrosine phosphatase IA-2, and glutamic acid decarboxylase (GADA) in cord blood from offspring of mothers with type 1 diabetes (ODM, n = 138) and control mothers (control, n = 47) and further assessed cross-sectional relationships of antibody titers to birth weight and fetal insulin. In ODM, antibodies were frequently present in cord blood; 124 ODM (95%) were positive for IA, 82 (59%) were positive for GADA antibodies, and 61 (44%) were positive for IA-2 antibodies. In controls, GADA and IA-2 antibodies were absent, whereas seven controls (15%) were positive for IA at low titers (P0.0001 ODM vs. controls for all).ODM with IA (IA positive) or without IA (IA negative) had similar birth weights (mean +/- sd: IA positive, 3.8 +/- 0.7 kg; IA negative, 4.0 +/- 0.6 kg; P = 0.31) and cord insulin concentrations (IA positive: median, 112 pmol/liter; interquartile range, 62-219 pmol/liter; IA negative: median, 114 pmol/liter; interquartile range, 59-194 pmol/liter; P = 0.96). Similarly, the presence of GADA and/or IA-2 autoantibodies (n = 103) was not associated with differences in birth weight or insulin concentrations. Antibody titers were not associated with birth weight or insulin as continuous variables in either controls or ODM. Islet autoantibodies and IA are a common finding in cord blood of ODM, but we found no evidence that they influence offspring insulin concentrations or weight at birth.

Gestational diabetes mellitus (GDM) is a risk factor for the development of insulin-dependent diabetes mellitus (IDDM) and noninsulin-dependent diabetes mellitus postpartum. To evaluate whether there is any association of human leukocyte antigen (HLA) class II alleles (DR and DQ) with GDM and the postpartum development of IDDM, we analyzed 184 women with GDM from Germany for HLA class II alleles, islet autoantibodies [islet cell autoantibodies (ICA), glutamic acid decarboxylase autoantibodies (GADA), and protein tyrosine phosphatase IA-2 autoantibodies (IA-2A), and the postpartum development of diabetes. No elevation in the frequency of any HLA class II alleles was observed in GDM patients compared to 254 nondiabetic unrelated subjects. DR3 allele frequency was significantly increased in 43 women with islet autoantibodies [corrected P value (Pc) = 0.02], in particular in those with GADA (Pc = 0.002), or in the 24 women who developed IDDM postpartum (Pc= 0.005). In women with GADA, DR4 and DQB1∗0302 were s...

Insulin autoantibodies (IAA) are early sensitive markers of pre-diabetes in the young. The aim of this study was to assess whether, using IgG-specific measurement with a protein A/G assay, IAA are already present at birth, and whether this assay is suitable for early autoantibody screening. Cord blood and follow-up samples from offspring of parents with type 1 diabetes included in the BABYDIAB study were analyzed. Although insulin antibodies in cord blood from children of mothers with type 1 diabetes were readily detected and correlated well with levels in the maternal circulation, no insulin binding was detected in 247 cord blood samples from children of father probands. IgG IAA were detected at 2 yr in all 21 children who had multiple islet autoantibodies or who later developed type 1 diabetes, but were confirmed in only 6 of 58 with IAA by the conventional IAA assay in the absence of other islet autoantibodies. False positive IAAs in the conventional assay were often attributable to hemolysis. Hemolysis did not affect protein A/G IAA measurement, and results in whole capillary blood samples were comparable to those in corresponding serum samples (r2 = 0.99). These data show that IgG IAA appear early and after birth, and that the protein A/G IAA assay is sufficiently sensitive for early screening. The specificity of this assay requires further evaluation.