The prevalence of thyroid-stimulating antibodies in goitrous disease assessed by cytochemical section bioassay.

Thyroid-stimulating antibodies (TSAb) were detectable using a highly sensitive cytochemical section bioassay in plasma from all 56 hyperthyroid patients studied, including those who had either diffuse hyperplasia or nodular goiters. The maximum dilution at which TSAb was detectable ranged from 10(-2) - 10(-6). Six of these patients had scintigraphic evidence of single functioning nodules, and, surprisingly, TSAb was present in all. Of 27 patients who had nontoxic goiter, 14 (52%) had positive titers for TSAb ranging from 10(-2) - 10(-4). The mean serum T3 value in nontoxic goitrous patients who had TSAb was significantly higher than that in subjects in whom TSAb was absent; in contrast, mean serum T4 values were not significantly different in those two groups. It is concluded that idiopathic nontoxic goiter, toxic nodular goiter with functioning nodules (Plummer's disease), and toxic diffuse goiter (Graves' disease) share, in part, a common pathogenesis.