Did you know Hashimoto’s is the most common cause of hypothyroidism (1)? This Disease has been estimated to affect 5 in 100 Americans and is 40% more common in women (1). Not only is there an autoimmune form of hypothyroidism, but there is also an autoimmune version of hyperthyroidism known as Graves’ Disease. Graves’ Disease is the most common form of hyperthyroidism (2).
Hypothyroidism occurs when you have low levels of thyroid hormones T4 and T3 circulating. On blood work, this could look like elevated levels of thyroid stimulating hormone (TSH) and low or low-normal levels of T4 and T3 (1). Conversely, hyperthyroidism occurs when TSH levels are low and you have elevated levels of T4 and T3.
Every cell in your body depends on thyroid hormones to function. With high levels of TSH, as seen in hypothyroidism, cellular processes will slow down. In hyperthyroidism, there are high levels of thyroid hormones, increasing the speed at which your cells function. An increase or decrease in thyroid hormones will cause disruptions in various body areas.
The diagnosis of Hashimoto’s or Graves’ Disease will show elevated levels of thyroid antibodies. Thyroid peroxidase antibodies are just one type of antibody that can occur in these autoimmune thyroid conditions. But three other antibodies can arise in either situation.
- 𝐓𝐡𝐲𝐫𝐨𝐢𝐝 𝐏𝐞𝐫𝐨𝐱𝐢𝐝𝐚𝐬𝐞 𝐀𝐧𝐭𝐢𝐛𝐨𝐝𝐲: thyroid peroxidase is an enzyme that is responsible for converting iodide to iodine (3). Iodine is then incorporated with a protein called thyroglobulin to produce thyroid hormones (4). Blocking this enzyme can make it challenging for your body to produce sufficient levels of thyroid hormones.
- 𝐓𝐒𝐇 𝐑𝐞𝐜𝐞𝐩𝐭𝐨𝐫 𝐁𝐥𝐨𝐜𝐤𝐢𝐧𝐠 𝐀𝐧𝐭𝐢𝐛𝐨𝐝𝐲: just like the name says, it blocks your TSH receptors. If TSH is unable to bind to its receptor, then we see low levels of thyroid hormones (5).
- 𝐓𝐡𝐲𝐫𝐨𝐠𝐥𝐨𝐛𝐮𝐥𝐢𝐧 𝐀𝐧𝐭𝐢𝐛𝐨𝐝𝐲: thyroglobulin is a protein that iodine molecules will attach to. When these antibodies are present, they interfere with the actual production of thyroid hormones. Although it can lead to hypothyroidism symptoms, it is actually more commonly seen in differentiated thyroid cancer (6)
- 𝐓𝐒𝐇 𝐑𝐞𝐜𝐞𝐩𝐭𝐨𝐫 𝐒𝐭𝐢𝐦𝐮𝐥𝐚𝐭𝐢𝐧𝐠 𝐀𝐧𝐭𝐢𝐛𝐨𝐝𝐲: these antibodies can stimulate your thyroid cells even without TSH being around. These antibodies are commonly elevated in patients with Graves’ Disease (5).
The most exciting part about these antibodies is that there can be overlap. For example, many might think that anti-TPO antibody is only present in patients with Hashimoto’s Disease, but it can also be present in patients with Graves’ Disease. Although anti-TPO is not needed to diagnose Graves, it is essential to understand how antibodies can impact thyroid health and, ultimately, thyroid hormone production. Measuring thyroid antibodies should be done at least once a year to help measure treatment and its efficacy. If you have an autoimmune condition, you will always have thyroid antibodies. Still, supporting your immune system and thyroid aims to help reduce those numbers and protect your thyroid for as long as possible.
- U.S. Department of Health and Human Services. (2021, June 1). Hashimoto’s disease. National Institute of Diabetes and Digestive and Kidney Diseases. Retrieved June 12, 2022, from https://www.niddk.nih.gov/health-information/endocrine-diseases/hashimotos-disease
- Girgis, C. M., Champion, B. L., & Wall, J. R. (2011). Current concepts in graves’ disease. Therapeutic advances in endocrinology and metabolism, 2(3), 135–144. https://doi.org/10.1177/2042018811408488
- U.S. National Library of Medicine. (2015, September 1). TPO gene: Medlineplus genetics. MedlinePlus. Retrieved June 12, 2022, from https://medlineplus.gov/genetics/gene/tpo/
- Heppel, M. (2021, June 15). Hypothyroidism: Causes, diagnosis, and treatment. The Pharmaceutical Journal. Retrieved June 12, 2022, from https://pharmaceutical-journal.com/article/ld/hypothyroidism-causes-diagnosis-and-treatment
- McLachlan, S. M., & Rapoport, B. (2013). Thyrotropin-blocking autoantibodies and thyroid-stimulating autoantibodies: potential mechanisms involved in the pendulum swinging from hypothyroidism to hyperthyroidism or vice versa. Thyroid: official journal of the American Thyroid Association, 23(1), 14–24. https://doi.org/10.1089/thy.2012.0374
- Jo, K., & Lim, D. J. (2018). Clinical implications of anti-thyroglobulin antibody measurement before surgery in thyroid cancer. The Korean journal of internal medicine, 33(6), 1050–1057. https://doi.org/10.3904/kjim.2018.289