Thyroid hormone autoantibodies in patients with untreated Graves' disease: with special reference to age.

We examined thyroid hormone autoantibodies (THAA) in 170 patients with untreated Graves' disease (145 women and 25 men, aged 8-74yr). THAA were found in 28 patients (16.5%, group I), but not detected in the remaining 142 patients (83.5%, group II). Neither the male/female ratio nor prevalence of antithyroid antibodies (Ab) (thyroglobulin Ab and/or microsomal Ab) differed between the 2 groups. The mean age of group I was significantly lower than that of group II. Furthermore, prevalence in group I decreased progressively with age. In addition, there was a negative correlation between T4 Ab titers (but not T3 Ab titers) and age in group I. These results indicate that the production of THAA, especially T4 Ab, is influenced by age in untreated Graves' patients. The present study also indicates that the age of the patients is one of the important factors causing different results concerning the prevalence of THAA in Graves' disease.