Relationship between autoantibodies against glutamic acid decarboxylase, thyroglobulin/thyroid microsome and DNA topoisomerase II in the clinical manifestation of patients with type 1 diabetes mellitus in Taiwan

Objective: In a preliminary cross-sectional study, we discovered that DNA t opoisomerase II autoantibodies (anti-TopII) were detected in 49.2% of 195 C hinese type 1 diabetes mellitus (type 1 DM) patients with a mean age of 14. 5 years and a mean duration of disease of 4.6 years. In order to demonstrat e the relationship between anti-TopII and other immunological characteristi cs in Chinese type 1 DM patients, and to evaluate its putative prediction e fficacy in Chinese patients, we simultaneously examined the frequency of an ti-glutamic acid decarboxylase autoantibodies (anti-GAD), anti-TopII, antit hyroglobulin/antimicrosomal autoantibodies (ATA/AMiA) and C-peptide concent rations in our patients in the present study. Design and Methods: The frequency of anti-GAD and C-peptide levels, anti-To pII, and ATA/AMiA were examined in our patients by radioimmunoassay, enzyme -linked immunosorbant assay and hemagglutination respectively. Univariate c omparisons were performed using Student's t-test for normal distributed dat a and Chi-square test for diclomatous data. Multivariate analysis was used for interpreting the independent risk factors which increased the incidence of anti-TopII, Results and Conclusions: The positivities for anti-GAD, anti-TopII, ATA/AMi A and C-peptide were 45.8%, 50.2%, 13.4% and 11.4% respectively. Anti-GAD a nd anti-TopII frequencies in our patients were similar when we stratified t he patients by age, age at onset and duration. These observations imply tha t anti-GAD and anti-TopII remain persistent in Chinese patients with long-t erm type 1 DM duration. The most interesting finding is that anti-TopII fre quency is more persistent than anti-GAD in our patients, especially when th e diabetic duration is longer than 11 years. This indicates that anti-TopII , rather than anti-GAD, might act as a better indicator for monitoring the pathogenesis of Chinese type 1 DM patients especially in patients with a lo ng-standing duration of disease. The late age of onset (>18 years) is a ris k factor which increased the incidence of anti-TopII according to multivari ate analysis. We further analyzed different manifestations between the yout h- and adult-onset type 1 DM and found that adult-onset type 1 DM is charac terized by better preservation of residual beta-cell function and higher fr equencies of antoantibodies.