Thyroglobulin Autoantibodies Are Associated with Refractoriness to Antithyroid Drug Treatment for Graves' Disease

Abstract

Objective The recurrence rate associated with antithyroid drug (ATD) treatment for Graves' disease (GD) is high compared with that for radioiodine therapy or surgery. It is important to identify patients in whom remission is unlikely, so that they are not given treatment that is destined to fail. The objective of this study was thus to evaluate factors influencing the prognosis of GD patients treated with ATDs. Patients One hundred and sixty-one patients were divided into two groups: 100 patients who could not discontinue ATDs for eight years or more (refractory group) and 61 patients who achieved remission within eight years after starting ATD treatment (nonrefractory group). The groups were compared in terms of age, thyroid function and thyroid-related autoantibodies at diagnosis, and the durations to the recovery of thyroid function and thyroid-related autoantibodies. Results The baseline levels of free triiodothyronine (T3), free thyroxine (T4), thyroid-stimulating antibodies (TSAbs) and thyroid-stimulating hormone (TSH) receptor antibodies (TRAbs) were high, and the age at diagnosis and the baseline level of thyroglobulin autoantibodies (TgAbs) were low in the refractory group compared with those in the nonrefractory group. The durations to the recovery of TSH, free T4, TRAb and TSAb levels were longer in the refractory group than in the nonrefractory group. No significant difference was observed with regard to thyroid peroxidase autoantibodies. Conclusion We compared the clinical features of these two groups in order to identify factors influencing the prognosis of GD patients treated with ATDs. A low baseline level of TgAbs is associated with the refractoriness of GD to ATD treatment.

The Effect of Radioiodine Treatment on TRAb, Anti-TPO, and Anti-TG in Graves’ Disease

“…This is in line with the knowledge that younger GD patients are more prone to produce higher TRAb levels and to have an increased relapse rate [15]. The role of anti-TG in the pathogenesis of GD is unclear, but in a previous study examining discontinuation of ATD, it was shown that patients with low levels of anti-TG at the diagnosis of GD had a lower chance to stop the treatment with ATD, indicating a higher activity of GD in these patients [16]. A low level of anti-TPO at the diagnosis of GD has been coupled with an increased risk to develop GO both at diagnosis and during follow-up [8].…”

Changes in Thyroid Peroxidase and Thyroglobulin Antibodies Might Be Associated with Graves' Disease Relapse after Antithyroid Drug Therapy

“…This may indicate that TSAb increases TPOAb titers by mediating an increase in microsomal antigen [1721]. However, some other studies showed opposite results [142223]. Those reports showed decreased recurrence or even progression to hypothyroidism after ATD therapy in patients with high TPOAb or TbAb titers.…”

Resistance to Anti-Thyroid Drugs in Graves’ Disease: Clinical-Biological Characteristics and Alternative Therapy in Tropical Area

“…The mechanisms behind resistance to ATS are poorly understood [8] [9]. The MDR-1 multidrug resistance gene, which is responsible for resistance to a wide variety of drugs in human cells, is potentially involved [10].…”

“…Recent studies demonstrated that low baseline thyroglobulin autoantibodies are associated with refractoriness of Graves' disease to ATD treatment [8] [9]. Therefore, they could serve as biomarkers to predict the failure of ATD treatment in such patients.…”