Proinsulin/Insulin autoantibodies measured with electrochemiluminescent assay are the earliest indicator of prediabetic islet autoimmunity

Diabetes Care. 2013 Aug;36(8):2266-70. doi: 10.2337/dc12-2245. Epub 2013 Feb 19.


Objective: We evaluated a novel electrochemiluminescent assay for insulin/proinsulin autoantibodies (ECL-IAA) as a new marker of the onset of islet autoimmunity and as a predictor of type 1 diabetes.

Research design and methods: The Diabetes Autoimmunity Study in the Young (DAISY) prospectively follows children at increased genetic risk for development of islet autoimmunity (defined as presence of autoantibodies to insulin, GAD65, IA-2, or zinc transporter 8 [ZnT8]) and type 1 diabetes (general population of children and first-degree relatives). Serial serum samples from subjects who progressed to type 1 diabetes and who had their first islet autoantibodies measured by age 18 months (N = 47) were tested using ECL-IAA.

Results: Almost all prediabetic children tested positive for ECL-IAA (46 of 47, 98%) during follow-up. ECL-IAA was almost always the first autoantibody to appear (94% total; 21% very first [by itself]; 23% with only mIAA; 19% with another islet autoantibody [GAD or ZnT8]; and 30% with ≥ 2 other antibodies [mIAA, GAD, IA-2, or ZnT8]). Among the 46 subjects who were ECL-IAA positive, ECL-IAA antedated the onset of other islet autoantibodies by a mean of 2.3 years (range, 0.3-7.2 years). Both the age of appearance of autoantibody and IAA levels (but not GAD65, IA2, or ZnT8 levels) are major determinants of the age of diabetes onset.

Conclusions: This new ECL-IAA assay defines more precisely the onset of prediabetic autoimmunity and may help identify events triggering islet autoimmunity, as well as allow earlier intervention for type 1 diabetes. Nearly all young children progressing to diabetes are insulin autoantibody positive.

Publication types

  • Evaluation Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Autoantibodies / blood*
  • Cation Transport Proteins / immunology
  • Child, Preschool
  • Diabetes Mellitus, Type 1 / immunology*
  • Glutamate Decarboxylase / immunology
  • Humans
  • Infant
  • Insulin Antibodies / blood*
  • Islets of Langerhans / immunology*
  • Luminescent Measurements
  • Prediabetic State / diagnosis
  • Prediabetic State / immunology*
  • Proinsulin / immunology*
  • Prospective Studies
  • Sensitivity and Specificity
  • Zinc Transporter 8


  • Autoantibodies
  • Cation Transport Proteins
  • Insulin Antibodies
  • SLC30A8 protein, human
  • Zinc Transporter 8
  • Proinsulin
  • Glutamate Decarboxylase
  • glutamate decarboxylase 2