Thyroid Hormone and Immunological Studies in Endemic Goiter*

Abstract

Iodized oil (1 ml im) was given to 58 goitrous patients from a mildly iodine-deficient area in Greece. Goiter size, urinary iodine, and serum T4, T3RU, T3, rT3, TSH, thyroxine-binding globulin (TBG), and thyroid autoantibodies were measured before and 1, 3, and 6 months after the injection. Goiter size decreased. Serum T4 remained relatively constant, but TBG decreased and therefore T3RU and FTI increased. Serum T3 and rT3 initially decreased (P less than 0.001) and then increased at the sixth month (P less than 0.001), both showing roughly parallel changes. Serum TSH, initially normal (1.42 +/- 0.11 (SEM) mU/liter), decreased to 0.65 +/- 0.01 and 0.76 +/- 0.05 mU/liter at the third and sixth month (difference from baseline P less than 0.001). Thyroid autoantibodies, both against thyroglobulin and the microsomal antigen, were undetectable before treatment, but became positive in 42.8% of the patients 3 and 6 months later. Three patients developed transient hyperthyroidism. This occurred 3 or 6 months after treatment, and was associated with high titers of thyroid autoantibodies. These results indicate that: 1) transient hyperthyroidism may occur after the administration of iodized oil, possibly because of thyroid tissue necrosis and leakage of hormones, and 2) serum TBG decreases after iodized oil, a finding not previously reported and one whose cause is not known.

Enhanced Iodination of Thyroglobulin Facilitates Processing and Presentation of a Cryptic Pathogenic Peptide

“…In conjunction with the available TCR repertoire, the host MHC haplotype would dictate, via determinant selection, the relative contribution of each peptide in the disease process. This hypothesis would explain why only certain individuals develop autoimmune thyroiditis after high I intake (16) or why they occasionally present with enhanced B cell autoreactivity to Tg without overt symptoms of thyroiditis (53). The validity of this hypothesis will be further tested following the discovery of additional pathogenic T cell epitopes in Tg.…”

Fine-needle aspiration biopsy of the thyroid in an area of endemic goitre: influence of restored sufficient iodine supplementation on the clinical significance of cytological results

“…However, similar observations were reported in a study from Greece by Doufas et al (35) and from Argentina by Harach & Williams (28) (although during much longer intervals before and after introduction of iodine prophylaxis). Autoimmune thyroid diseases are more common in iodine-sufficient areas than in areas with low iodine intake (31,36), but the true incidence of Hashimoto thyroiditis has not yet been clearly demonstrated with the aid of epidemiological methods (29). It is believed that iodine intake might modulate the activity (and/or clinical expression) of thyroid autoimmune diseases in genetically susceptible individuals, but there is no evident proof that the amount of iodine intake (at least when in the range between iodine deficiency and full physiological doses) is involved in the de novo triggering of thyroid autoimmunity (37,38).…”

Study of Antithyroid Peroxidase Antibodies in People with Normal Range Thyroid Stimulating Hormone

“…5 Also, the prevalence of thyroid autoantibody positivity in such areas rises to over 40% within 5 years of initiating supplementation. 6 Besides, in…”