Clinical applications of assays for thyrotropin-receptor antibodies in Graves' disease

Graves' disease is characterized by hyperthyroidism, diffuse goitre, infiltrative ophthalmopathy and, rarely, pretibial myxedema. In 1956 a substance capable of prolonged thyroid stimulation was discovered in the serum of some patients with Graves' disease and termed long-acting thyroid stimulator (LATS). It was shown to be an antibody that could interact with the receptor for thyroid-stimulating hormone (TSH). The term LATS is usually reserved for the activity measured in a laborious in-vivo bioassay in mice. Today the activity of TSH-receptor antibodies (TSH-R Ab) can be measured by in-vitro bioassays or by radioreceptor assays. These assays are now becoming commercially available. TSH-R Ab assays may be useful in predicting the response to therapy for Graves' disease, investigating euthyroid ophthalmopathy and predicting the likelihood of neonatal hyperthyroidism.