Inverse relationship between GAD65 antibody levels and severe retinopathy in younger type 1 diabetic patients

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Abstract

Several risk factors for severe non-proliferative and proliferative retinopathy in type 1 diabetes mellitus have been proposed without explaining the rapid progression of retinopathy in some patients. Since GAD65 autoantibodies (GAD65Abs) are detected against glutamic acid decarboxylase (GAD), which is mainly expressed in islets and nervous tissue in type 1 diabetic patients, the aim of the present investigation was to test the hypothesis whether GAD65Abs are associated with rapidly progressing severe retinopathy. Patients with severe non-proliferative or proliferative retinopathy (n = 27) were compared with another group, which in spite of long diabetes duration had no or only mild signs of retinopathy (n = 28). GAD65Abs were analysed in a radioimmunoassay using in vitro translated human GAD65, and the levels were expressed as an index in relation to positive and negative reference samples. Using a cut-off level representing the 99th percentile of normals, 6/27 (22%) with and 9/28 (32%) without severe retinopathy were considered GAD65Ab positive. Although there was no difference in the number of GAD65Ab positive patients, the GAD65Ab levels were lower in patients with (0.30; 0.11-0.64) than without (0.68; 0.34-1.12) severe retinopathy (P = 0.03). The patients were also subjected to HLA-DR and DQ typing by PCR and hybridization with oligospecific probes. DQ2/8 was more common in patients with (56%) than without (29%) severe retinopathy (P = 0.05), but DQ2/8 could not account for the lower GAD65Ab levels in patients with severe retinopathy. It is concluded that GAD65Ab levels are inversely correlated with severe retinopathy in young type 1 diabetic patients.

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Authors
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Endocrinology and Diabetes

Keywords

  • GAD65Ab, Genotype, HLA-DR, HLA-DQ, Type 1 diabetes, Proliferative retinopathy
Original languageEnglish
Pages (from-to)9-14
JournalDiabetes Research and Clinical Practice
Volume40
Issue number1
Publication statusPublished - 1998
Publication categoryResearch
Peer-reviewedYes

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Paediatric Endocrinology Research Group (013243010), Diabetes and Celiac Unit (013241540), Medicine (Lund) (013230025), Unit on Vascular Diabetic Complications (013241510)