Clinical Thyroidology® for the Public

Summaries for the Public from recent articles in Clinical Thyroidology
Table of Contents | PDF File for Saving and Printing

GRAVES’ DISEASE
Functional TSI tests: a new step in personal care for Graves’ Disease?

12

Instagram Youtube LinkedIn Facebook X

 

BACKGROUND
Graves’ disease is the most common cause of hyperthyroidism in the United States. It is caused by the body producing an antibody that attacks and turns on the thyroid and makes it overactive. When the antibody is active, Graves’ disease is active and requires treatment with antithyroid medications. When the antibody level drops or becomes inactive, Graves’ disease can go into remission. While in remission, if the antibody returns or becomes active, Graves’ disease relapses. This antibody is called thyroid stimulating immunoglobulin (TSI). TSI can be active (stimulating the thyroid), inactive (no effect on the thyroid) or blocking (actually block thyroid function). A new functional TSI test can determine if the TSI is actually stimulating the thyroid to make thyroid cells work harder.

This study compared a functional TSI assay with a traditional thyroid receptor antibody assay (TRAb) to determine if the new assay could better determine remission or relapse of Graves’ disease.

THE FULL ARTICLE TITLE
 Peng R et al. Significance of thyroid-stimulating immunoglobulin and thyrotropin receptor antibody in Graves disease. J Clin Endocrinol Metab 2025;110(9):e3002- e3010. doi: 10.1210/clinem/dgae892. PMID: 39715350.

SUMMARY OF THE STUDY
This study in China looked at 957 people with newly diagnosed Graves’ disease. They measured TRAb and functional TSI levels when patients started antithyroid medication (ATD), during treatment and after the antithyroid medication was stopped. The main outcome was remission (sustained normal thyroid levels ≥12 months after ATD withdrawal) or relapse (recurrent hyperthyroidism after stopping ATDs).

Both baseline TRAb and functional TSI levels were positive in patients with newly diagnosed Graves’ disease. Patients with relapsed or persistent hyperthyroidism showed less decline in antibody levels during treatment compared to patients in remission. In a subset of 206 patients with at least 12 months of follow-up after ATD withdrawal, the overall relapse rate was 41.26%. Relapses were more common in patients with positive functional TSI levels at the time of ATD withdrawal compared to those who were TSI-negative (54.84% vs. 35.42%). TRAb levels at the time of ATD withdrawal did not significantly differ between the relapse group and the remission group. Positive functional TSI at withdrawal, younger age, prior episode of hyperthyroidism due to Graves’ disease, and mild thyroid eye disease were independently associated with relapse.

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
This study shows that a functional TSI test may help doctors personalize treatment for Graves’ disease and better predict who might relapse. More studies are needed before this test becomes part of everyday thyroid care.

— Joanna Miragaya, MD

ABBREVIATIONS & DEFINITIONS

Hyperthyroidism: a condition where the thyroid gland is overactive and produces too much thyroid hormone. Hyperthyroidism may be treated with antithyroid meds (Methimazole, Propylthiouracil), radioactive iodine or surgery.

Graves’ disease: the most common cause of hyperthyroidism in the United States. It is caused by antibodies that attack the thyroid and turn it on.

TRAb: antibodies often present in the serum of patients with Graves disease that are directed against the TSH receptor, often causing stimulation of this receptor with resulting hyperthyroidism.

Thyroid stimulating immunoglobulin (TSI): antibodies often present in the serum of patients with Graves’ disease that are directed against the TSH receptor, that cause stimulation of this receptor resulting in increased levels of thyroid hormones in the blood and hyperthyroidism

Table of Contents | PDF File for Saving and Printing