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Autoantibody Committee Report

Polly Bingley

The results of the first Diabetes Autoantibody Standardization Program (DASP) proficiency evaluation have now been analyzed, and preparation of the resulting manuscript is almost complete. It is hoped to circulate the manuscript to participating labs very soon. For the DASP 2000 evaluation, samples from 50 patients with newly diagnosed Type 1 diabetes, and 50 healthy controls were circulated to 46 laboratories in 13 countries. These included 46 assays for GAD antibodies, 44 for IA-2 antibodies, and 23 for insulin autoantibodies. Radiobinding assays for GADA and IA-2A generally achieved high sensitivity and specificity, and inter-laboratory concordance was good when samples were ranked, or if results were expressed in common units based on the WHO reference reagent.

On the basis of these results, the Immunology of Diabetes Society now recommends that all GAD and IA-2 antibody results be expressed in WHO units/ml. The ELISA-based assays that participated did not perform so well. The evaluation did, however, indicate that problems persist in the measurement of autoantibodies to insulin. Some IAA microassays had high levels of sensitivity and specificity with good concordance among laboratories, but the sensitivity of assays in most laboratories was low.

Following the proficiency evaluation, each laboratory received a full analysis of its own assay characteristics compared to other laboratories, and a report is being prepared for publication. In addition, laboratories that met a set of criteria based on performance in DASP 2000 will be designated to provide details of assay methods, and to offer training.

The next DASP proficiency testing evaluation will take place in the next few months. Deadline for registration is April 1, 2002. This will include 150 samples from patients and controls, as well as WHO reference reagent and diluent. This will allow participating laboratories to calibrate their in-house standards and start to express their GAD and IA-2 antibody results in WHO units/ml. Participation is open to all laboratories for a small fee. This fee is waived for Centres that are able to donate serum samples suitable for inclusion in the programme. The organisers are anxious that as many as possible of the laboratories measuring islet autoantibodies take part in this programme. Participants from industry are particularly welcome. To register for this, please contact Polly Bingley, or see the Immunology of Diabetes Society Website for the registration form.

There is a desperate need to acquire more samples from newly diagnosed patients. The ability to conduct these workshops is jeopardised without your contribution of further samples.

Heres What Is Needed:

50 ml serum from newly diagnosed patients below 30 years of age. Samples must be collected within 7 days of starting insulin treatment. If the volume required is a limiting factor in getting samples from small children, 25 ml would be acceptable as a minimum and would allow limited circulation.
A separate 1.2 ml side vial with each patient sample for HIV and hepatitis screening.

If you can contribute please contact (Fax: +44-117-959-5336, Tel: +44-117-959-5337).

Previous Autoantibody Committee Reports: