The role of thyrotropin receptor antibodies in Grave’s Ophthalmopathy treatment

Abstract

Background. Graves' ophthalmopathy (GO) is an autoimmune inflammatory disorder affecting the retroorbital tissues. Although the role of TRAb in GO is now accepted by many researchers and clinicians, their use in the disease management of GO is less well studied than the role of TRAb for the diagnosis and therapy monitoring of Graves’ disease.Aim: to evaluate the relation between TRAb level and the activity of GO, the course of GO and the effectiveness of the treatment.Materials and methods. We have studied 26 patients with GO and Grave’s Disease. Activity of GO was measured with the clinical activity score (CAS), we defined active GO as a CAS≥3. TSH, FT4 and TRAb were evaluated. All patients had received intravenous methylprednisolone (ivMP) pulse therapy in cumulative dose 6000 mg. We observed patients for 1 year after pulse therapy. TRAb level was evaluated before, 3, 6 and 12 months after pulse therapy.Results: At the time of initial treatment all patients had active GO, 60% with CAS 3-4 and 40% with CAS 5-7. On year after the pulse therapy of GO, all patients were classified into responders (69,2%) and non-responders (30,8%) according to their clinical manifestations. Pulse therapy considered as effective if GO activity decreased with CAS ≤ 2. Serum TRAb level was significantly higher in patients who non-responded to therapy – 34,8 U/L vs 17,5 U/L (p≤0,01). This level was significantly decreased in patients responded to treatment – 1,6 U/L vs 12,4 U/L (p≤0,01). TRAb level above 28,8 U/L before treatment (p≤0,01), 10,1 U/L after 3 months of treatment (p≤0,01), 5,1 U/L after 6 months of treatment (p≤0,01) and 8,2 U/L after 3 months of treatment (p≤0.01) was associated with higher risk of non-responding.Conclusion: We conclude, that TRAb level may serve not only as predictor of GO activity and severity, but changes in the level of antibodies could be of additional help for the disease management with ivMP.