Thyroid autoimmunity in endemic goitre caused by excessive iodine intake

Area of Science:

• Endocrinology
• Immunology
• Pediatrics

Background:

• Excessive iodine intake is implicated in endemic goitre pathophysiology.
• Iodine excess may trigger autoimmune thyroid diseases like lymphocytic thyroiditis (LT).
• The role of autoantibodies in iodine-induced goitre requires further investigation.

Purpose of the Study:

• To compare autoantibody prevalence in children with endemic goitre from iodine-excess areas versus healthy children from iodine-sufficient areas.
• To investigate the potential role of thyroid autoantibodies in the pathophysiology of endemic goitre.

Main Methods:

• Serum autoantibodies (MAb, TgAb, CA2-Ab, TBII) were measured in goitrous and healthy children.
• Thyroid growth-stimulating activity (TGI) was assessed using cytochemical bioassay (CBA) and mitotic arrest assay (MAA).
• Correlation between TGI activity and goitre size was analyzed.

Main Results:

• No increased prevalence of lymphocytic thyroiditis or common thyroid autoantibodies (MAb, TgAb, CA2-Ab) was found in goitrous children.
• Thyroid growth-stimulating immunoglobulins (TGI) were significantly more prevalent in goitrous children (60%) compared to healthy children (0%).
• TGI activity correlated positively with goitre size, suggesting a pathophysiological role.

Conclusions:

• Endemic iodine goitre in children is not associated with Hashimoto's lymphocytic thyroiditis.
• Autoimmune factors, specifically thyroid growth-stimulating immunoglobulins (TGI), may play a primary role in the pathogenesis of thyroid growth in endemic goitre due to iodine excess.