Autoantibodies Against GAD65, IA-2 and Insulin in Czech Childrenat Type 1 Diabetes Mellitus Onset

Overview

Background.
Autoimmune insulitis leading to insulin dependent diabetes mellitus (IDDM, Type 1 Diabetes) isaccompanied by autoantibodies as its invaluable markers. The aim of the study was to determine the frequency ofautoantibodies against GAD65, IA2 and insulin in Czech diabetic children at the disease onset.Methods and Results. Sera of 105 newly diagnosed children with IDDM drawn within 24 hours after the firstinsulin dose were investigated for anti-GAD65, anti-IA2 and insulin autoantibodies (IAA) using RIA methods. Thecut-off normal levels were determined as the 99th percentile of 105 non-diabetic children. At given 99 % specificity,the sensitivity was 71 % for anti-GAD65, 73 % for anti-IA2, and 46 % for IAA. 29 % diabetic children were positivefor all three autoantibodies, 25 % had anti-GAD65 and anti-IA2 (IAA negative), 5,7 % anti-GAD65 and IAA(anti-IA2 negative), 7,6 % anti-IA2 and IAA (anti-GAD65 negative). As the only positive autoantibody, anti-GAD65was found in 12 %, anti-IA2 in 11 %, and IAA in 3,8 % children. In 5,7 % children, none of the investigatedautoantibodies was positive. Diabetic children diagnosed before the age of 5 years had significantly higher prevalenceof IAA than the older ones.Conclusions. We have determined normal levels in healthy children, and prevalence at childhood IDDM onset ofautoantibodies against three main molecular-defined autoantigens.

Key words:
IDDM, childhood, autoantibodies, prevalence, IAA, GAD65, IA2.