Screening of ZnT8 autoantibodies in the diagnosis of autoimmune diabetes in a large French cohort

Abstract

Aim of the study: Evaluate the added value of screening anti-ZnT8 antibodies (ZnT8A) in addition to the classical anti-GAD (GADA) and anti-IA-2 (IA-2A) antibodies for the diagnosis of type-1 diabetes (T1D) within a large cohort of both children and adults.

Materials and methods: Retrospective 2-year study including 516 patients (215 children, 301 adults) who had blood tests at diabetes onset and/or for diabetes classification. ZnT8A, GADA, and IA-2A were analyzed in all samples.

Results: Among those individuals included, 142 (28%) were ZnT8A-positive. A total of 228/516 suffered from T1D, of whom 110 (48%) were ZnT8A-positive and 166 (73%) GADA and/or IA-2A positive. When adding ZnT8A to GADA/IA-2A, 184 (81%) patients were positive for ≥1 Ab. Regarding the 122 patients at T1D onset, 75 (61%) were positive for ZnT8A and the proportion of patients with T1D with ≥1 Ab reached 89%. The highest prevalence of ZnT8A was observed in children aged 6-10years. Fourteen of the 124 patients positive for ZnT8A with a known clinical diagnosis suffered from a disease other than T1D.

Conclusions: ZnT8A should be included in routine evaluation at diabetes onset and is a valuable biological marker to classify newly-diagnosed diabetics. The predictive value in our high-risk subjects has to be confirmed.

Keywords: Anti-GAD autoantibodies; Anti-IA-2 autoantibodies autoimmune diabetes; Anti-ZnT8 autoantibodies; Type 1 diabetes.