one thyroid stimulating immunoglobulin, or TSI, a type of molecule created by the immune system, known as an autoantibody. when disease threatens the body, makes the immune system what is called antibodies that bind to specific targets on abnormal cells or infectious agents and trigger reactions to destroy them. in what is called an autoimmune disease, the immune system antibodies that bind to healthy cells of the body, usually causing side effects. a thyroid stimulating immunoglobulin is an example of such autoantibody, and it is able to act on the thyroid gland in the same way that a hormone called thyroid stimulating hormone, or TSH, which stimulates the thyroid gland to produce and release more thyroid hormone. an excessive release of thyroid hormone leads to a condition called hyperthyroidism, or grave illness.
When the pituitary gland senses that blood levels of thyroid hormone has increased, it stops doing so much TSH. when a thyroid immunoglobulin attached to the TSH receptor in a thyroid gland cell, TSH causes the gland to grow and production of thyroid hormone to increase. pituitary have no control over how much thyroid stimulating immunoglobulins in the blood, so TSI keeps stimulate the thyroid gland to make more and more thyroid hormone, leading to a condition known as Grave’s disease.
in grave disease, abnormally high levels of thyroid hormone which causes symptoms including fatigue, sweating, palpitations and anxiety. as a thyroid stimulating immunoglobulins can bind to receptors in other tissues, such as around the eyes or the skin, can cause physical signs like protrusion of the eyeballs and skin swelling, especially in the legs. Grave’s disease can be treated with drugs that block production of thyroid hormone, by destroying the thyroid gland with radioactive iodine, or by removing the surgically. when the gland is effectively removed, stop thyroid hormone production and a person must take a hormone replacement for life.