Autoimmune Thyroiditis - Anti-thyroid Antibodies

The anti-thyroid antibodies involved with autoimmune thyroiditis are:

•  Anti-thyroid peroxidase (TPO Ab) -  attack the thyroperoxidase enzyme (TPO), responsible for thyroid hormone production.

•  Anti-thyroglobulin (Tg Ab) -  block a protein made by the thyroid, necessary for making thyroid hormones.

•  TSH Receptor Antibody (TRAb) - stimulate thyroid hormone production by binding to Thyroid Stimulating Hormone (TSH) receptors.

 And possibly:

•  Na+/I- Symporter (NIS) Antibody - the NIS transports iodide into the thyroid follicular cell and this antibody is present in 20% of Grave's disease and 26% of Hashimoto's thyroiditis.

Saravanan P, Dayan CM (June 2001). "Thyroid autoantibodies".Endocrinol. Metab. Clin. North Am: 315-37, viii..

Thyroid damage ==> immune system anti-thyroid antibodies ==> increased or decreased TH production

Thyroid problems can develop when damage to thyroid gland components /thyroid inflammation causes the immune system to produce anti-thyroid antibodies - which can result in a malfunctioning thyroid which either  (1) DECREASES or (2) INCREASES  thyroid hormone production:

Thyroid damage / inflammation =>

(1)  Anti-thyroid antibodies TPOAb or TgAb => Reduced thyroid hormone production ▼▼▼ 

Antibody against TPO (TPOAb) - These antibodies damage the TPO enzyme responsible for adding iodine to thyroglobulin protein in TH production; usually a consequence of iodine and/or selenium deficiencies; high TPO Ab found in ~90% of patients with Hashimoto's thyroiditis.

Antibodies against thyroglobulin (TgAb) - These antibodies block thyroglobulin (Tg),a protein synthesized by the thyroid, required for making thyroid hormones (T4 and T3).High TgAb levels seen in patients with Hashimoto's thyroiditis.

-    Also, women's high level TgAb linked to Infertility/miscarriage - for currently unclear reasons, TgAb can interfere with implantation of the embryo in the uterus.

(2) TSH Receptor Antibodies (TRAb) =>Increased thyroid hormone production ▲▲▲ 

TSH Receptor Antibodies (TRAb)  - found in ~95% of those with Grave's hyperthyroidism. These antibodies stimulate thyroid hormone production by binding to thyroid stimulating hormone (TSH) receptors.