Viral infection in induction of Hashimoto's thyroiditis: a key player or just a bystander?
OBJECTIVE
Viral infection activates both the innate and adaptive immunity and is implicated as a trigger of autoimmune diseases including Hashimoto's thyroiditis. This review summarizes our knowledge respecting the role of viral infection in the cause of Hashimoto's thyroiditis.


RESULTS
Components of several viruses such as hepatitis C virus, human parvovirus B19, coxsackie virus and herpes virus are detected in the thyroid of Hashimoto's thyroiditis patients. Bystander activation of autoreactive T cells may be involved in triggering intrathyroidal inflammation. Signaling molecules associated with antiviral responses including Toll-like receptors may participate in Hashimoto's thyroiditis induction. However, studies have provided insufficient direct evidence for the viral hypothesis in Hashimoto's thyroiditis.


CONCLUSIONS
Despite interesting circumstantial evidence, whether viral infection is responsible for Hashimoto's thyroiditis remains unclear. Studies addressing this issue are required to substantiate a contribution from viral infection to Hashimoto's thyroiditis and, consequently, the prospect for developing preventive modalities for Hashimoto's thyroiditis.
Mori
Kouki
K
Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Japan. mail: kokimori@mail.tains.tohoku.ac.jp
Yoshida
Katsumi
K
D000818:Animals; D005260:Female; D050031:Hashimoto Disease / Q000821:virology*; D006801:Humans; D006920:Hygiene; D007422:Intestines / Q000276:immunology / Q000382:microbiology; D051379:Mice; D051381:Rats; D017452:Receptors, IgG / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology / Q000821:virology; D013961:Thyroid Gland / Q000276:immunology / Q000821:virology*; D051193:Toll-Like Receptors / Q000276:immunology; D014777:Virus Diseases / Q000150:complications*; D014780:Viruses / Q000276:immunology / Q000302:isolation & purification*
D017452:Receptors, IgG; D051193:Toll-Like Receptors