[Anti-thyroid peroxidase in non-neoplastic thyroid pathology]

Anti-thyroid peroxidase antibodies were prospectively assayed and compared with anti-microsome and anti-thyroglobulin antibodies in 203 patients (188 women, 15 men; mean age 42 +/- 14 years). These patients consulted for hyperthyroidism (n = 42, including 18 with Graves' disease), fumary hypothyroidism (n = 50, including 20 at the diagnosis stage), euthyroid diffuse or nodular goitre (n = 81) or benign euthyroid nodule (n = 14). Sixteen patients examined for fatigue, gynecomastia, menstrual disorders or overweight had normal thyroid function. Anti-thyroid peroxidase, anti-microsome and anti-thyroglobulin antibodies were assayed by radioimmunology or indirect immunofluorescence. Anti-thyroid peroxidase antibodies were most frequently present in patients with autoimmune thyroid diseases, such as Graves' disease (72%) or primary hypothyroidism (70%), and correlated with anti-microsome antibody levels (r = 0.87; p less than 0.001). Anti-thyroid peroxidase antibodies were absent in patients with benign euthyroid nodule; they were present in 22% of patients with euthyroid goitre and in 12% of control patients; their level decreased during replacement therapy for hypothyroidism. It is concluded that radioimmunological assays of anti-thyroid peroxidase antibodies should replace anti-microsome and anti-thyroglobulin antibodies in thyroid evaluation.