Dataset Information

A novel triple mix radiobinding assay for the three ZnT8 (ZnT8-RWQ) autoantibody variants in children with newly diagnosed diabetes.

ABSTRACT:

Background and aims

Autoantibodies against the zinc transporter 8 (ZnT8A) are common in type 1 diabetes (T1D). ZnT8A analyses are complicated by the fact that there are three variants of the autoantigen at amino acid position 325 representing ZnT8-R (Arginine), ZnT8-W (Tryptophan) and ZnT8-Q (Glutamin). The aims of the study were: 1) to develop an autoantigen triple mix Radio-Binding Assay (RBA) for ZnT8A; 2) to identify the individual ZnT8-R,-W,-QA reactivity and 3) to validate the triple mix ZnT8A RBA in children with newly diagnosed T1D.

Methods

Serum samples were obtained from 2664 (56% males, n=1436) patients in the Swedish nationwide Better Diabetes Diagnosis (BDD) study representing patients with T1D (97%, n=2582), T2D (1.7%, n=46), MODY (1.0%, n=28) and secondary diabetes (0.3%, n=8). cDNA coding for the C-terminal end of each variant was prepared by site-directed mutagenesis and subcloned into a high efficiency in vitro transcription translation vector. The ZnT8 variants were labeled with 35S-methionine and used in a standard RBA separating free from autoantibody-bound autoantigen with Protein A-Sepharose.

Results

ZnT8-TripleA was detected in 1678 (65%) patients with T1D, 4 (9%) T2D, 3 (11%) MODY and in none (0%) of the patients with secondary diabetes. Among the T1D patients ZnT8-RA was detected in 1351 (52%) patients, ZnT8-WA in 1209 (47%) and ZnT8-QA in 790 (31%) demonstrating that 1661 (64%) had one or several ZnT8A. The ZnT8-TripleA assay showed a false positive rate of 1.9% (n=49). Only 1.2% (n=32) of the T1D patients were false negative for ZnT8-TripleA compared to 0/46 (0%) of the T2D patients. The precision (intra assay CV) and reproducibility (inter assay CV) of the ZnT8-TripleA assay did not differ from the RBA of the individual ZnT8 variants.

Conclusion

We conclude that the ZnT8-TripleA assay had low false positive and false negative rates. The ZnT8-TripleA assay would therefore be highly suitable not only to analyze patient with newly diagnosed diabetes but also for screening the general population since this assay demonstrated high sensitivity and very high specificity.

SUBMITTER: Vaziri-Sani F

PROVIDER: S-EPMC3170126 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature

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Publications

A novel triple mix radiobinding assay for the three ZnT8 (ZnT8-RWQ) autoantibody variants in children with newly diagnosed diabetes.

Vaziri-Sani Fariba F Delli Ahmed J AJ Elding-Larsson Helena H Lindblad Bengt B Carlsson Annelie A Forsander Gun G Ivarsson Sten A SA Ludvigsson Johnny J Marcus Claude C Lernmark Åke Å

Journal of immunological methods 20110625 1-2

<h4>Background and aims</h4>Autoantibodies against the zinc transporter 8 (ZnT8A) are common in type 1 diabetes (T1D). ZnT8A analyses are complicated by the fact that there are three variants of the autoantigen at amino acid position 325 representing ZnT8-R (Arginine), ZnT8-W (Tryptophan) and ZnT8-Q (Glutamin). The aims of the study were: 1) to develop an autoantigen triple mix Radio-Binding Assay (RBA) for ZnT8A; 2) to identify the individual ZnT8-R,-W,-QA reactivity and 3) to validate the trip ...[more]

PMID: 21708156

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Project description:ObjectivesTo assess the long term clinical and cost effectiveness of the diabetes education and self management for ongoing and newly diagnosed (DESMOND) intervention compared with usual care in people with newly diagnosed type 2 diabetes.DesignWe undertook a cost-utility analysis that used data from a 12 month, multicentre, cluster randomised controlled trial and, using the Sheffield type 2 diabetes model, modelled long term outcomes in terms of use of therapies, incidence of complications, mortality, and associated effect on costs and health related quality of life. A further cost-utility analysis was also conducted using current "real world" costs of delivering the intervention estimated for a hypothetical primary care trust.SettingPrimary care trusts in the United Kingdom.ParticipantsPatients with newly diagnosed type 2 diabetes.InterventionA six hour structured group education programme delivered in the community by two professional healthcare educators.Main outcome measuresIncremental costs and quality adjusted life years (QALYs) gained.ResultsOn the basis of the data in the trial, the estimated mean incremental lifetime cost per person receiving the DESMOND intervention is pound209 (95% confidence interval - pound704 to pound1137; euro251, -euro844 to euro1363; $326, -$1098 to $1773), the incremental gain in QALYs per person is 0.0392 (-0.0813 to 0.1786), and the mean incremental cost per QALY is pound5387. Using "real world" intervention costs, the lifetime incremental cost of the DESMOND intervention is pound82 (- pound831 to pound1010) and the mean incremental cost per QALY gained is pound2092. A probabilistic sensitivity analysis indicated that the likelihood that the DESMOND programme is cost effective at a threshold of pound20 000 per QALY is 66% using trial based intervention costs and 70% using "real world" costs. Results from a one way sensitivity analysis suggest that the DESMOND intervention is cost effective even under more modest assumptions that include the effects of the intervention being lost after one year.ConclusionOur results suggest that the DESMOND intervention is likely to be cost effective compared with usual care, especially with respect to the real world cost of the intervention to primary care trusts, with reductions in weight and smoking being the main benefits delivered.

Dataset Information

A novel triple mix radiobinding assay for the three ZnT8 (ZnT8-RWQ) autoantibody variants in children with newly diagnosed diabetes.

Background and aims

Methods

Results

Conclusion

Publications

A novel triple mix radiobinding assay for the three ZnT8 (ZnT8-RWQ) autoantibody variants in children with newly diagnosed diabetes.

Similar Datasets

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