Thyrotrophin binding inhibition by anti-thyrotrophin receptor antibodies in Graves' disease which is not reflected by 1.6 M ammonium sulphate precipitates.
In ten patients with Graves' disease before, during and after treatment and three patients in remission, we have compared the TSH-binding inhibition caused by serum, 1.6 M ammonium sulphate precipitates from serum and by the fractions (19S, 7S and 4S) obtained after G-200 gel chromatography of serum and ammonium sulphate precipitates. Five out of ten patients had a positive thyrotrophin-binding inhibitor immunoglobulin (TBII) index before treatment, three of whom relapsed. The binding inhibition caused by 7S fractions from ammonium sulphate precipitates of ten untreated patients could be correlated with their TBII index (r=0.9, P less than 0.001). By contrast, the 7S fractions prepared directly from the sera of the same ten patients all showed marked TSH-binding inhibition (P less than 0.001) when compared with normal plasma 7S, and no correlation with the TBII index could be demonstrated (r=0.21, P less than 0.05). It is concluded that ammonium sulphate precipitates, which are used to calculate the TBII index, do not reflex the presence of anti-TSH receptor antibodies in serum accurately in all patients.
D000328:Adult; D000368:Aged; D000645:Ammonium Sulfate / Q000378:metabolism; D005260:Female; D006111:Graves Disease / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism*; D018828:Immunoglobulins, Thyroid-Stimulating; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay; D011956:Receptors, Cell Surface / Q000378:metabolism*; D013972:Thyrotropin / Q000276:immunology / Q000378:metabolism*
D007074:Immunoglobulin G; D018828:Immunoglobulins, Thyroid-Stimulating; D011956:Receptors, Cell Surface; D013972:Thyrotropin; D000645:Ammonium Sulfate