CLINICAL-SIGNIFICANCE OF MEASUREMENTS OF ANTITHYROID ANTIBODIES IN THE DIAGNOSIS OF HASHIMOTOS-THYROIDITIS - COMPARISON WITH HISTOLOGICAL-FINDINGS

Measurements of antithyroglobulin and antimicrosomal (antiperoxidase) antibodies have been performed widely for the clinical diagnosis of au toimmune thyroid diseases. The present study was designed to compare t hese antibody titers with histological findings of the thyroid in pati ents with diffuse goiter who were suspected of having Hashimoto's thyr oiditis. One hundred and ten euthyroid or hypothyroid patients (10 mal es and 100 females; age 48+/-15 (SD) years old) with diffuse goiter we re studied for the measurement of antithyroglobulin and antimicrosomal or antiperoxidase antibodies by a hemagglutination technique (TGHA an d MCHA, respectively) and by a newly developed radioassay (TgAb and TP OAb, respectively). The antibody titers were compared with the histolo gical findings obtained by needle biopsy. TgAb, TPOAb, TGHA, and MCHA were detected in 80 (96.4%), 61 (73.5%), 37 (44.6%), and 54 (65.1%) of 83 patients with histologically proven Hashimoto's thyroiditis, respe ctively, but in only one (3.7%) of 27 patients without any inflammator y changes in the biopsy specimen. In 55 patients with negative TGHA an d MCHA, the TgAb positivity was more closely associated with the histo logical diagnosis of Hashimoto's thyroiditis than the TPOAb positivity was, the incidence of each antibody in Hashimoto's thyroiditis being 89.7% (26/29) and 27.6% (8/29), respectively. In conclusion, the histo logical diagnosis of Hashimoto's thyroiditis can most precisely be pre dicted by the newly developed radioassay for TgAb.