Autoimmune thyroid disease and associated autoimmunity

Autoimmune diseases are manifested in a broad spectrum. Classic examples of organ-specific autoimmune disease include Addison?s disease, insulin-dependent type-1 Diabetes mellitus, Grave?s disease (MGB), and Hashimoto thyroiditis (HT). The initial report of this autoimmune thyroid disease (AITD) dates back to Hakira Hashimoto (1912). In HT, as an organ-specific autoimmune disease, massive infiltration of lymphoid cells and parenchyma destruction are a consistent feature. The infiltration appears to be immune-mediated, primarily lymphocytic (T helper, T suppressor cells), NK cells and B cells. The pathological characteristics of AITD include development of the goitre (atrophic form is not so frequent), impaired thyroid gland function (from hyperthyroidism to subclinical and manifested hypothyroidism) and the formation of antithyroidal antibodies against thyroglobulin (AbTg) and the microsomal antigen (Ab TPO). There is a very good correlation between the antibodies against TPO and the histological findings. Morbus Graves Basedow is characterized by autoimmune hyperthyroidism with goitre, and infiltrative orbitopathy. Autoantibodies against the TSH-receptor molecule on the plasma membrane of the thyroid gland follicles cause a nonphysiological activation and an increase of the cellular function. Besides this hyperthyroidal condition, an autoimmune attack against the retrobulbar tissue leading to endocrine orbitopathy, can be noted in about 40% of patients suffering from MGB.