CONTEXT: The mechanisms linking thyroid autoimmunity and iodine use in humans are unknown. OBJECTIVE: Our aim was to correlate iodine intake, thyroid autoimmunity, and recognition of thyroglobulin (Tg) epitopes after implementation of iodine prophylaxis. SETTING: The general community living in an Italian village was evaluated. MAIN OUTCOME MEASURES: Thyroglobulin autoantibodies (TgAb), thyroperoxidase autoantibodies (TPOAb), and urinary iodine excretion were assessed in 906 iodized salt users (IS-users) and 389 nonusers (IS-nonusers). Ultrasound (US) was performed to identify thyroid hypoechogenicity, suggestive of Hashimoto thyroiditis (HT). TgAb epitope pattern in 16 IS-users and 17 IS-nonusers was evaluated by an inhibition binding assay to Tg, using human monoclonal TgAb-Fab directed to A, B, C, and D epitopes on Tg. RESULTS: Median urinary iodine excretion was slightly higher in IS-users than in IS-nonusers (112.0 μg/L vs 86.5 μg/L; P < .01). TgAb, and not TPOAb, was more frequent in IS-users (18.9% vs 13.6%, P = .02). HT-US was found in 87 subjects, among whom both positive TgAb (58.4% vs 31.8%, P = .03) and TPOAb (61.5% vs 45.4%. P = .04) were more frequent in IS-users. In this group significantly higher serum levels of TgAb (median 108 U/mL vs 30 U/mL; P = .02), but not of TPOAb, were present. Iodized salt use had no effect on the 1208 non HT-US subjects. TgAb directed to the epitope B of Tg were more frequent in IS-users than in IS-nonusers (27.5% vs 3.0%, P = .047). CONCLUSIONS: Iodine-induced thyroid autoimmunity is related to TgAb and the unmasking of a cryptic epitope on Tg contributes to this relationship in humans.
CONTEXT: The mechanisms linking thyroid autoimmunity and iodine use in humans are unknown. OBJECTIVE: Our aim was to correlate iodine intake, thyroid autoimmunity, and recognition of thyroglobulin (Tg) epitopes after implementation of iodine prophylaxis. SETTING: The general community living in an Italian village was evaluated. MAIN OUTCOME MEASURES: Thyroglobulin autoantibodies (TgAb), thyroperoxidase autoantibodies (TPOAb), and urinary iodine excretion were assessed in 906 iodized salt users (IS-users) and 389 nonusers (IS-nonusers). Ultrasound (US) was performed to identify thyroid hypoechogenicity, suggestive of Hashimoto thyroiditis (HT). TgAb epitope pattern in 16 IS-users and 17 IS-nonusers was evaluated by an inhibition binding assay to Tg, using human monoclonal TgAb-Fab directed to A, B, C, and D epitopes on Tg. RESULTS: Median urinary iodine excretion was slightly higher in IS-users than in IS-nonusers (112.0 μg/L vs 86.5 μg/L; P < .01). TgAb, and not TPOAb, was more frequent in IS-users (18.9% vs 13.6%, P = .02). HT-US was found in 87 subjects, among whom both positive TgAb (58.4% vs 31.8%, P = .03) and TPOAb (61.5% vs 45.4%. P = .04) were more frequent in IS-users. In this group significantly higher serum levels of TgAb (median 108 U/mL vs 30 U/mL; P = .02), but not of TPOAb, were present. Iodized salt use had no effect on the 1208 non HT-US subjects. TgAb directed to the epitope B of Tg were more frequent in IS-users than in IS-nonusers (27.5% vs 3.0%, P = .047). CONCLUSIONS:Iodine-induced thyroid autoimmunity is related to TgAb and the unmasking of a cryptic epitope on Tg contributes to this relationship in humans.
Authors: L Tomisti; C Urbani; G Rossi; F Latrofa; C Sardella; L Manetti; I Lupi; C Marcocci; L Bartalena; O Curzio; E Martino; F Bogazzi Journal: J Endocrinol Invest Date: 2016-01-13 Impact factor: 4.256
Authors: F Latrofa; D Ricci; L Montanelli; P Piaggi; B Mazzi; F Bianchi; F Brozzi; P Santini; E Fiore; M Marinò; M Tonacchera; P Vitti Journal: Clin Exp Immunol Date: 2014-12 Impact factor: 4.330