Thyrotropin receptor antibodies in black South African patients with Graves’ disease and their response to medical therapy

Abstract

Graves' disease is increasing in incidence amongst urban black South Africans. The pathogenic role of thyrotropin receptor antibodies (TRAb), crucial in other populations, has not been formally evaluated in African communities. We therefore prospectively investigated the prevalence of TRAb in 30 consecutive urban black South African patients with classical Graves' disease at the onset of their illness. This was compared with the frequency of thyroid microsomal and thyroglobulin antibodies in the same patients. Ten patients with euthyroid goitres unrelated to Graves' disease and 10 healthy controls were also studied. Twenty of the hyperthyroid patients were retested 4-6 months after starting carbimazole therapy and ten of them again after 1 year. Initially 83% of patients were positive for TRAb as against 54% for thyroid microsomal and 1 7% for thyroglobulin antibodies. After 4-6 months of treatment, 65% of patients still had elevated (>15% inhibition of binding) TRAb titres, while at 1 year this had dropped to 40% (4 out of 10 patients). All positive patients had relapsed biochemically, while TRAb negative patients were all in remission. We conclude that TRAb are a sensitive and specific marker of Graves' disease in black South Africans and closely parallels the response to medical therapy at 1 year. However, their predictive value for delayed relapse requires the study of a larger cohort of patients over a longer time-frame.

Impact of iodination on thyroid pathology in Africa

“…40 The clinical presentation of Graves' disease appears no different from elsewhere; females are more commonly affected, 40 ophthalmopathy is common, 42 and thyroidstimulating hormone-receptor antibodies are present in over 80% of patients. 43 However, as a result of late presentations, a disproportionate amount of cardiac complications are seen. 44 The approach to management is dictated by existing local facilities.…”

Schilddrüsenautoantikörper

“…Schwerpunkt der Entwicklung sensitiverer TRAK-Assays war es deshalb, einen Spezifi t ä tsverlust zu vermeiden [88,91,92] . In den heute verwendeten Assays der zweiten Generation weisen bis zu 100 % der Patienten zum Zeitpunkt der Erstdiagnose (also unbehandelt) positive TRAK in Ihrem Serum auf [13,82,94] . Dass dies unabh ä ngig von der Herkunft des verwendeten TSH-Rezeptors (human oder porcin) ist, wurde bereits oben im Abschnitt " TRAK-Assays der 2.…”