Thyroid growth-stimulating immunoglobulins in goitrous disease: relationship to thyroid-stimulating immunoglobulins

Abstract

Thyroid growth stimulating immunoglobulins (TGI) were assayed in IgG concentrates prepared from human plasma using a cytochemical bioassay (CBA) based on the measurement of changes in glucose-6-phosphate dehydrogenase (G6PD) activity in guinea pig thyroid follicular cells. TGI was present in all 8 patients studied who had goitrous Graves' disease, in 9 who had toxic diffuse goitres with asymmetric uptake on scintigram and/or symptomatic ophthalmopathy and in 4:8 who had toxic uninodular goitre with autonomously functioning nodules. TGI were also present in 34:54 (64%) of patients who had non-toxic goitres. In contrast, TGI were undetectable in 4 patients who had Graves' disease without palpable goitre and in all 18 euthyroid non-goitrous volunteers. Maximum increases in G6PD activity occurred at an IgG concentration of 50 \g=m\g/ml in all patients who had goitrous Graves' disease and in 5:7 who had diffuse non-toxic goitres. In contrast, IgG concentrates from 20:27 patients with nodular goitres caused maximum increases in G6PD activity at an IgG concentration of 500 \g=m\g/ml . A comparison of the prevalence of TGI with that of thyroid stimulating immunoglobulins (TSI), also measured by CBA, in 63 patients showed that although both stimulators were present in 8 patients who had goitrous Graves' disease they were only simultaneously present in 18:43 (42%) who had non-toxic goitres of various aetiologies. Thyrotrophin receptor antibodies (TRAb) were present in 11/44 (25%) of non-toxic goitrous patients but there was no significant correlation with IgG stimulators in such patients. It is concluded that the finding of IgG stimulators in a variety of thyroid disorders suggests common immunological features in their pathogenesis. The presence or absence of such stimulators and their relative potencies may play a part in determining functional or structural variations between common forms of goitre.

Simultaneous Assay of Thyroid Adenylate Cyclase‐ and Growth‐stimulating Antibodies Using Frtl‐5 Cells. Evidence Suggesting Their Identity in Patients With Graves' Disease

“…Previous authors reported the presence of TGSAb in Graves' patients, and in several instances these antibodies could be detected in IgG preparations devoid of thyroid adenylate cyclase stimulatory activity (Drexhage et al, 1980;Chiovato et al, 1983;Valente er al., 1983a;Smyth et al, 1986). The discrepancy with our data could be attributed to the use of independent assays for the measurement of the two activities, although other explanations such as selection of patients can not be excluded.…”

“…Autoantibodies able to stimulate thyroid growth (TGSAb) have been described in the serum of goitrous patients with Graves' disease or Hashimoto's thyroiditis as well as in patients with goitre not associated with the usual features of thyroid autoimmunity, such as sporadic and endemic goitre (Drexhage et al, 1980;Chiovato et al, 1983;Valente et al, 1983a;Ealey et al, 1985;Medeiros-Net0 er al., 1986;Smyth et al, 1986). The relationship between these antibodies and the thyroid adenylate cyclase-stimulating antibodies (TSAb) of Graves' disease is a matter of controversy.…”

Evaluation of a radioreceptor assay for TSH receptor autoantibodies

“…In hyperthyroid Graves' disease the presence of TKAb has been reported in varying frequencies from about 50% [l 11 to 100Y0 161 with most frequencies around 90% [5,7,[13][14][15][16]. but also with somewhat lower values (10,12,(17)(18)(19).…”