Autoantibodies are antibodies that the body forms in order to recognize and bind endogenous cells in tissues, hormones or other antibodies. By binding the autoantibodies to these structures, the immune system is activated and fights these structures. Autoantibodies are produced in the context of autoimmune diseases.
Autoantibodies therefore do not help our immune system to remove foreign bacteria or viruses from our body as normal antibodies do, but attack our own body. Whenever the immune system forms autoantibodies against its own body, it is highly pathological and leads to the destruction of actually healthy tissue. This destruction, in turn, leads to the loss of tasks that the tissue should actually take over.
So the immune system makes the body sick instead of keeping it healthy and functional. Many different autoantibodies are known to cause different diseases depending on the structure they attack. Examples of such diseases include diabetes mellitus type I, which can be caused by four different autoantibodies. But also lupus erythematosus or rheumatoid arthritis are caused by autoantibodies.
Since Hashimoto’s thyroiditis is one of the autoimmune diseases, the blood serum of the affected patient usually contains antibodies specific for this disease, which can be determined by means of a blood sample and a laboratory test and measured in their present quantity. On the one hand, this serves to diagnose Hashimoto’s disease, if at first only a suspicion exists. On the other hand, it also serves to monitor and observe the progress of an already diagnosed, existing Hashimoto’s thyroiditis.
The characteristic antibodies in this disease are the so-called thyroglobulin antibodies (Tg-Ak) and the thyroperoxidase antibodies (TPO-Ak). The Tg antibodies are directed against thyroglobulin, a protein produced by thyroid cells, which is used to store thyroid hormones before they are released into the blood. The TPO antibodies, on the other hand, are directed against the thyroid enzyme thyroid peroxidase, which is involved in thyroid hormone production.
In about 10-20% of Hashimoto patients, these antibodies are not found in the blood, although Hashimoto disease is present. In contrast to Graves’ thyroid disease, it is not assumed that these autoantibodies against the thyroid tissue are responsible for the damage or destruction of the thyroid gland in Hashimoto’s disease, as they are often only increased in phases and the level of the antibody values does not correlate with the intensity of the disease.