Autoimmune thyroid disorders—An update

Abstract

Autoimmune thyroid disease (AITD), a common organ specific autoimmune disorder is seen mostly in women between 30-50 yrs of age. Thyroid autoimmunity can cause several forms of thyroiditis ranging from hypothyroidism (Hashimoto's thyroiditis) to hyperthyroidism (Graves'Disease). Prevalence rate of autoimmune mediated hypothyroidism is about 0.8 per 100 and 95% among them are women. Graves' disease is about one tenth as common as hypothyroidism and tends to occur more in younger individuals. Both these disorders share many immunologic features and the disease may progress from one state to other as the autoimmune process changes. Genetic, environmental and endogenous factors are responsible for initiation of thyroid autoimmunity. At present the only confirmed genetic factor lies in HLA complex (HLA DR-3) and the T cell regulatory gene (CTLA 4). A number of environmental factors like viral infection, smoking, stress & iodine intake are associated with the disease progression. The development of antibodies to thyroid peroxidase (TPO) thyroglobulin (TG) and Thyroid stimulating hormone receptor (TSH R) is the main hallmark of AITD. Circulating T Lymphocytes are increased in AITD and thyroid gland is infiltrated with CD4+ and CD8+ T Cells. Wide varieties of cytokines are produced by infiltrated immune cells, which mediate cytotoxicity leading to thyroid cell destruction. Circulating antibodies to TPO and TG are measured by immunofluorescense, hemagglutination, ELISA & RIA. TSHR antibodies of Graves' disease can be measured in bioassays or indirectly in assays that detect antibody binding to the receptor.

Correlation of Anti-Thyroid Peroxidase Antibodies (Anti-Tpo) With Thyroid Hormones in Local Population of Western Nepal.

“…In addition, Mohanty et al [16] showed that 45 of the 61 subclinical hypothyroid patients had elevated anti-TPO (73.78%), this finding also be in accord with our study. In agreement with our study Swain et al has also reported that most (95%) of the patients with autoimmune thyroid disease were women, mainly belonging to the age group of 30-50 years [2].…”

“…An autoimmune thyroid disease (AITD) is by far the most frequent cause of Hypothyroidism and is characterized by the presence of antithyroid antibodies. Autoimmune thyroid diseases are common organ-specific autoimmune disorders mostly seen in women 30-50 years old [2]. It occurs due to loss of tolerance to autoantigens thyroid peroxidase (TPO), thyroglobulin (Tg), thyroid stimulating hormone receptor (TSH-R) which leads to the infiltration of the gland.…”

Are human herpes viruses associated with autoimmune thyroid disease?

“…Susceptibility to the diseases is determined by a combination of genetic, environmental, and endogenous factors [2].…”

Relationship of thyroid peroxidase antibody test with abnormal thyroid function tests

“…Anti-TPOAb reflects lymphocytic infiltration even in subclinical state of thyroid dysfuction. 2,4,5 The present study has evaluated anti-TPOAb level in patients with abnormal thyroid function test.…”