Hashimoto's thyoiditis is a common thyroid disorder that can occur at any age. the incidence of this disease is 1 in 10,000 people and is most commonly observed in the middle aged women. The onset of the disease is slow and is associated with a slow increase in the size of the thyroid gland and its chronic destruction. The etiology of this disorder is poorly understood, however, it is thought that this disease has an autoimmune origin. Hashimoto's thyroiditis may be associated with other autoimmune endocrine disorders such as diabetes mellitus, Addison's disease, hypoparathyroidism, hypopituitarism, Graves' disease, and vitiligo. The thyroid gland involved by the Hashimoto's disease is infiltrated by lymphoid cells, some of which form germinal centers

In the Feb 14, 97 issue of science, Giordano et al report that Fas-Fas ligand interaction may play a role in the autoimmune reactions that takes place in the thyroid glands involved by Hashimoto's thyroiditis. Normal thyrocytes do not express Fas but express FasL. However, when stimulated with IL-1 beta, they do express Fas and cross linking of the Fas molecules leads to the rapid destruction of the thyrocytes by apoptosis. In Hashimoto's thyroiditis, the thyrocytes express both Fas and FasL and stimulation of these cells by IL-1 beta leads to their apoptosis which can be prevented by the antibodies that block Fas. Based on these findings, Giordano et al concluded that Fas-FasL interactions are implicated in the pathogenesis of the Hashimoto's thyroiditis

Figure legend: From the top: Side view of a thyroid enlarged by Hashimoto's thyroiditis. Thyroid scan revealing the enlarged thyroid. Gross appearance of the thyroid involved by the Hashimoto's thyroiditis. Low power microscropic view of a section of a thyroid involved by the Hashimoto's thyroiditis. The thyroid follicles are surronded by the lymphoid cells which have formed a germinal center. Mid-power microscropic view showing the lymphoid infiltrate. High power microscropic view of the thyroid showing intimate contacts between the thyrocytes and the lymphoid cells.

REFERENCE:

C. Giordano, G. Stassi, R. De Maria, M. Todaro, P. Richiusa, G. Papoff, G. Ruberti, M. Bagnasco, R. Testi, A.Galluzzo:Potential Involvement of Fas and Its Ligand in the pathogenesis of Hashimoto's Thyroiditis. Science 275 (5302):960-963, 1997

RESOURCES:

Hashimoto's thyroiditis
Hashimoto's thyroiditis
Hypothyroidism
Hypothyroidism
Unmasking Thyroid Disease
Clinical Practice Guidelines for the Diagnosis and Management of Thyroid Nodules
Autoimmunity and Immune Complex Diseases

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Hashimoto's thyroiditis