In the first available samples with detectable multiple antibodies, the most frequent autoantibodies were GADA (92%), followed by ZnT8A (62%), IAA (59%) and IA-2A (41%).
Relatives positive for IAA and GADA (<i>n</i> = 54) progressed more slowly than double-autoAb<sup>+</sup> individuals carrying IA-2A and/or ZnT8A (<i>n</i> = 38; <i>P</i> = 0.001).
We used serum samples collected longitudinally from the 'All Babies in Southeast Sweden (ABIS)' cohort tested for the gold standard islet autoantibodies to insulin (IAA), GAD (GADA), tyrosine phosphatase 2 (IA-2A) and zinc transporter 8 (ZnT8A).
In the 132 samples collected more than 10 years after diagnosis, 86 participants (65.2%) had at least one islet autoantibody: 42 (31.8%) were positive for GADA, 69 (52.3%) for IA-2A and 14 of 104 tested were positive for ZnT8A (13.5%).
These were tested for association with three islet autoantibodies-against autoantibodies to GAD (GADA), IA-2 (IA-2A), and zinc transporter 8 (ZnT8A)-and autoantibodies against thyroid peroxidase (TPOA) in autoimmune thyroid disease, gastric parietal cells (PCA) in autoimmune gastritis, transglutaminase (TGA) in celiac disease, and 21-hydroxylase (21-OHA) in autoimmune hypoadrenalism.
Rapid and slow progressors were similar with respect to HLA-DR/HLA-DQ genotypes, development of IAA, GADA and ZnT8A, and progression to multiple autoantibodies.
ZnT8As were measured by a radioimmunoprecipitation assay using recombinant ZnT8 COOH-terminal or NH(2)-terminal proteins in 193 patients with adult-onset autoimmune diabetes having antibodies to either GAD (GADAs) or IA-2 (IA-2As) and in 1,056 antibody-negative patients with type 2 diabetes from the Non Insulin Requiring Autoimmune Diabetes (NIRAD) study.