[Anti/TSH antibodies in thyroidal diseases]

The negative values in the assay for TSH receptor antibody (TRAb) led to the discovery of TSH binding antibody. The existence of anti-TSH antibodies have been reported mainly in Graves' disease and other thyroidal diseases (Hashimoto's thyroiditis, silent thyroiditis and subacute thyroiditis). Some reports suggest that the TRAb in Graves' disease may be an anti-idiotype antibody against an anti-TSH antibody, or that anti-TSH antibodies may be anti-idiotype antibodies against TRAb. However, TSH binding of TSH binding antibody was not inhibited by TRAb. These TSH binding antibodies showed a reaction in several mammalian species except humans. We demonstrated that almost all TSH binding antibodies reacted with not only bovine and porcine TSH, FSH, and LH but also the alpha-subunit of these 3 hormones. However, no reaction with the beta-subunit of these 3 hormones was observed. These results indicate that these TSH antibodies are found mainly in epitope in the alpha-subunit of bovine pituitary glycoprotein hormones (TSH, FSH, LH).