Anti-TSHR antibodies are autoantibodies directed against the thyrotropin receptor (TSHR). Anti-TSHR antibodies are a specific marker for the diagnosis of Graves' disease, the most common cause of hyperthyroidism. After the diagnosis of the disease, they can be used to predict its course and evaluate the effectiveness of pharmacotherapy. Check what the research is, what is its price and how to interpret the research results.

Anti-TSHR antibodies , or anti-TSHR antibodies or TRAb for short, are IgG autoantibodies that can stimulate or inhibit the synthesis of thyroid hormones. Anti-TSHR antibodies are the result of the autoimmunity process that results from an inappropriate immune response directed against the body's own tissues.

However, the exact mechanism of this phenomenon is not known. It is likely due to an interaction between inborn genetic predisposition and environmental factors. The appearance of anti-TSHR antibodies in the body causes autoimmune hyperthyroidism known as Graves' disease.

Anti-TSHR antibodies - types

Anti-TSHR antibodies may differ in their biological activity and on this basis the following are distinguished:

  • thyroid stimulating immunoglobulin (TSI) antibodies, which bind to the thyrotropin receptor, mimic it, and cause the thyroid gland to become overactive; this type of antibody is the most common
  • anti-TSHR antibodies that inhibit and block the binding of thyrotropin (TBII - TSH binding inhibiting immunoglobulins), which by binding to the thyrotropin receptor block its activity and cause hypothyroidism
  • Neutral anti-TSHR antibodies that neither stimulate nor block the thyrotropin receptor; their physiological and clinical significance has not yet been established

The change in the concentration of particular types of anti-TSHR antibodies in one person is rare and may cause changes in the clinical picture of Graves' disease, i.e. the transition from hyperthyroidism to hypothyroidism and vice versa.

Anti-TSHR antibodies - indications for the test

  • suspected hyperthyroidism with symptomsis, among others tachycardia (increased heart rate), muscle weakness, weight loss, goiter, trembling, exophthalmos
  • determining the cause of hypothyroidism / hyperthyroidism:

- confirmation or exclusion of Graves' disease (in this case, the presence of anti-TSHR stimulating antibodies is tested) - suspicion of autoimmune hypothyroidism in people without the presence of anti-Tg or anti-TPO antibodies (in this case, the presence of anti-Tg or anti-TPO antibodies is tested) anti-TSHR blocking antibodies)

  • risk assessment of recurrence of Graves' disease
  • diagnosis of thyroid orbitopathy (or thyroid ophthalmopathy) without coexisting hyperthyroidism
  • in pregnant women, risk assessment of congenital hyperthyroidism in the newborn
Worth knowing

Anti-TSHR antibodies - price

The price of an immunochemical test is PLN 50-100.

Anti-TSHR antibodies - what is the test?

The presence of thyroid-stimulating anti-TSHR antibodies is assessed by measuring the activity of adenylate cyclase in a culture of thyrocytes (thyroid cells) under the influence of the patient's blood serum.

The presence of anti-TSHR blocking antibodies is indicated by:

  • assessment of the ability of the patient's serum to block the binding of thyrotropin to the receptor (this test uses thyrotropin labeled with radioactive iodine)
  • assessment of the ability of the patient's serum to inhibit cAMP synthesis in thyrocytes in the presence of thyrotropin (the amount of cAMP increases in thyrocytes after receptor stimulation by thyrotropin and increases the synthesis of thyroid hormones)

The above methods are called biological tests and although they are able to differentiate the types of anti-TSHR antibodies, they are not used routinely due to the complicated process of their implementation and high cost.

Laboratory methods are routinely used that do not allow the assessment of the biological activity of anti-TSHR antibodies, but nevertheless have a recognized diagnostic value.

In this case, immunochemical methods such as ECLIA or ELISA are used. Second-generation tests using the recombinant human thyrotropin receptor are characterized by high sensitivity (95%) and specificity (98%) in the diagnosis of Graves' disease.

  • TSH results: thyroid test to measure the level of thyrotropin (TSH)
  • Anti-TPO antibodies - normal. How to interpret the test results?
  • TRAb Anti-Thyroid Antibodies - Standards and Test Results

Anti-TSHR antibodies - results

Reference values ​​for anti-TSHRs are dependent on the laboratory method used. The normal concentration of anti-TSHR antibodies should usually be below 1 IU / L.

In people with suspected hyperthyroidism, the increased level of anti-TSHR antibodies confirms the diagnosis of Graves-Basedow's disease, as anti-TSHR antibodies are practically absent in he althy people.

Additionally, high titer of anti-TSHR antibodies at diagnosis of Graves' disease increases the risk of pharmacotherapy failure and the occurrence of thyroid orbitopathy.

In people with treated Graves' disease, an increase in anti-TSHR antibodies may indicate relapse.

A high titer of anti-TSHR antibodies (especially stimulants) in the third trimester of pregnancy is an indicator of a high risk of hyperthyroidism in a child after delivery. This is because anti-TSHR antibodies may pass through the placenta to the fetus.

High levels of anti-TSHR antibodies are also observed in 5% of people with Hashimoto's hypothyroidism (especially blocking antibodies).

Worth knowing

Anti-TSHR antibodies and thyroid orbitopathy

Thyroid orbitopathy is caused by the cellular response of T lymphocytes against thyrotropin receptors in orbit fibroblasts. The release of pro-inflammatory cytokines causes the accumulation of hydrophilic substances and swelling of the orbital tissues.

The consequence is the protrusion of the eyeballs beyond the eye socket and their bulging. Orbitopathy is one of the hallmark symptoms of Graves' disease. High levels of anti-TSHR antibodies are associated with a greater risk of developing thyroid orbitopathy.

Thyroid tests

Thyroid examinations can be divided into two parts - examining the level of hormones produced by the thyroid gland and imaging examinations, the most popular of which is ultrasound. Our expert - endocrinologist Marta Kunkel from Medicover Hospital tells what these thyroid tests look like and what they show.

References

  1. Internal diseases, edited by Szczeklik A., Medycyna Praktyczna Kraków 2005
  2. Laboratory diagnostics with elements of clinical biochemistry. A textbook for medical students edited by Dembińska-Kieć A. and Naskalski J.W., Elsevier Urban & Partner Wydawnictwo Wrocław 2009, 3rd edition
  3. Barbesino G. and Tomer Y. Clinical Utility of TSH Receptor Antibodies. J Clin Endocrinol Metab, 2013, 98, 6, 2247-2255.
  4. Michalek K. et al. TSH receptor autoantibodies. Autoimmun Rev 2009, 9, 2, 113-116.
About the authorKarolina Karabin, MD, PhD,molecular biologist, laboratory diagnostician, Cambridge Diagnostics Polska A biologist by profession, specializing in microbiology, and a laboratory diagnostician with over 10 years of experience in laboratory work. A graduate of the College of Molecular Medicine and a member of the Polish Society of Human Genetics. Head of research grants at the Laboratory of Molecular Diagnostics at the Department of Hematology, Oncology and Internal Diseases of the Medical University of Warsaw. She defended the title of doctor of medical sciences in the field of medical biology at the 1st Faculty of Medicine of the Medical University of Warsaw. Author of many scientific and popular science works in the field of laboratory diagnostics, molecular biology and nutrition. On a daily basis, as a specialist in the field of laboratory diagnostics, he runs the content department at Cambridge Diagnostics Polska and cooperates with a team of nutritionists at the CD Dietary Clinic. He shares his practical knowledge on diagnostics and diet therapy of diseases with specialists at conferences, training sessions, and in magazines and websites. She is particularly interested in the influence of modern lifestyle on molecular processes in the body.

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