Improved Specificity of ICA Assays in the Fourth International Immunology of Diabetes Serum Exchange Workshop

Abstract

The goal of the Fourth International Workshop for Standardization of ICA Measurements was to determine the specificity of ICA assays and their ability to distinguish between control sera (n = 57) and sera from IDDM-related individuals--representing relatives of IDDM patients (n = 21), healthy individuals who later developed IDDM (n = 8), or newly diagnosed IDDM patients (n = 23). Results from 28 laboratories were analyzed. The mean specificity (percentage of control sera reported as negative) among 27 laboratories was 91%, including 6 laboratories with 100% specificity. Nevertheless, 78% of laboratories found at least one control sample > 0 JDF U. Among samples from first-degree relatives, the mean concordance was 86%, including three sera found negative (0 JDF U) by all laboratories. Among individuals who later developed diabetes, the mean concordance was 93%, with two sera found positive by 100% of laboratories. In sera from newly diagnosed IDDM patients, the mean concordance was 82%. Three sera were found positive and one serum negative by all laboratories. The JDF U of the sera considered to be positive were significantly greater than each laboratory's average for the controls. In conclusion, the results from laboratories participating in the Fourth International ICA Workshop demonstrated excellent specificity, good concordance, and an ability to separate control sera from defined, IDDM-related subjects.

Distinct clinical and laboratory characteristics of latent autoimmune diabetes in adults in relation to type 1 and type 2 diabetes mellitus

“…On the other hand, one should bear in mind that the limitations of ICA assay are the demanding standardization and challenging interpretation of the results. Despite those restrictions, in the 4 th International ICA Workshop it was reported that ICA diagnostic test has exceptional specificity and acceptable concordance among the different laboratories [21] . There is a bunch of studies addressing the ICAs relevance to T1D.…”

Relationship Between Ljungan Virus Antibodies, HLA-DQ8, and Insulin Autoantibodies in Newly Diagnosed Type 1 Diabetes Children

“…Our laboratory participated in the 13 th Immunology of Diabetes Workshop Standardization and showed 100% sensitivity and specificity. Levels of ICA are expressed in Juvenile Diabetes Foundation Units ( JDF-U), using the world reference standard curve based on the international JDF reference sera (14).…”

International Workshop on Lessons From Animal Models for Human Type 1 Diabetes

“…These diagnostic and predictive abilities did not naturally present themselves, as much of the early literature regarding autoantibodies in type 1 diabetes was subject to controversies and conflicting information-factors due in large part to variances in the methods and substrates used for autoantibody detection. Considerable advances toward overcoming these difficulties came through the voluntary performance of many investigators in more than a dozen international autoantibody workshops, often organized under the auspices of the Immunology of Diabetes Workshops, an organization that later became known as the Immunology of Diabetes Society (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). Among their many findings, these workshops validated insulin, GAD, and IA-2 as autoantigens associated with type 1 diabetes in humans; identified sensitive and specific methods for autoantibody measurement; and introduced reference standards for diabetesassociated autoantibodies.…”