[Estimation of anti-thyroid peroxidase autoantibody (TPOAb) and anti-thyroglobulin autoantibody (TgAb) in patients with various thyroid disease--comparison between histopathological findings and serological results in patients with Hashimoto's thyroiditis]

Abstract

We compared and evaluated titers of AMC (anti-microsome antibody), and ATG (anti-thyroglobulin antibody) by passive gelatin-agglutination and by radioimmunoassay in 170 sera from 129 patients with various thyroid diseases and 41 normal subjects. The results of conventional ATG and TgAb by RIA correlated (r = 0.731) and those of conventional AMC and TPOAb correlated well (r = 0.907), with discrepancies mostly limited to sera with low antibody titers. Five patients with Hashimoto's thyroiditis showed positive results in AMC, whilst negative in TPOAb. These sera had positive ATG autoantibody and preincubation with thyroglobulin inhibited the agglutination reaction of AMC tests, suggesting ATG producing false positive results in AMC assay. The prevalences of positive TgAb rates were higher than (p < 0.001) ATG in patients with Hashimoto's disease (96.6% vs 50.0%) and Graves' disease (76.9% vs 46.1%). However, the prevalences of positive TPOAb were not different from AMC (Hashimoto's disease 75.9% vs 81.0%: Graves' disease 80.8% vs 76.9%). In patients with Hashimoto's thyroiditis, our study demonstrates the results of TgAb by RIA reflects the pathological findings and the diagnostic sensitivity increases by using in combination with TPOAb.