The dynamic changes of zinc transporter 8 autoantibodies in Czech children from the onset of Type 1 diabetes mellitus
Abstract
AimsThe prevalence of autoantibodies to zinc transporter8 (ZnT8) in Czech children at the onset of Type1 diabetes mellitus and dynamic changes in ZnT8 autoantibody levels during disease progression were studied. The value of ZnT8 autoantibody measurements in diagnosis of Type1 diabetes was assessed.
MethodsSerum samples from 227 children with newly diagnosed Type1 diabetes and from 101 control children without diabetes were analysed in a retrospective cross-sectional study. One hundred and seventy-one samples from 116 of the patients with diabetes were analysed in a follow-up study at (median) intervals of 1, 3, 5 and 10years after onset of Type1 diabetes.
ZnT8 autoantibodies were measured using a bridging enzyme-linked immunosorbent assay, while antibodies to glutamic acid decarboxylase, insulinoma antigen2 and insulin were measured by radioimmunoassays. ResultsZnT8 autoantibodies were detected in 163/227 (72%) of children at Type1 diabetes onset and in 1/101 (1%) of the control subjects.
Sixteen out of 227 (7%) patients with Type1 diabetes were antibody negative based on three antibodies (glutamic acid decarboxylase, insulinoma antigen2 and insulin). This false-negative rate was reduced to 10/227 (4.4%) (P<0.05) after inclusion of ZnT8 autoantibody measurements.
Of the children, 142/227 (63%) were positive for at least three antibodies and the most common combination was insulinoma antigen2, glutamic acid decarboxylase and ZnT8. ZnT8 autoantibody levels decreased over time after Type1 diabetes onset and the presence and level of ZnT8 autoantibodies correlated with IA-2 autoantibodies.
ConclusionsA ZnT8 autoantibody enzyme-linked immunosorbent assay showed 72% disease sensitivity and 99% specificity at Type1 diabetes onset. Measurements of ZnT8 autoantibodies are important for Type1 diabetes diagnosis and should be included in the panel of autoantibodies tested at the onset of Type1 diabetes.