Iodine Contributes to Thyroid Autoimmunity in Humans by Unmasking a Cryptic Epitope on Thyroglobulin

Abstract

Iodine-induced thyroid autoimmunity is related to TgAb and the unmasking of a cryptic epitope on Tg contributes to this relationship in humans.

Iodine, Thyroid Autoimmunity and Cancer

“…An increased frequency of hypothyroidism has also been reported after the careful introduction of IS in Denmark [14]. Similar findings were reported in the Pescopagano survey, where an increased frequency of TAb and of Hashimoto's thyroiditis (HT) was observed after the beginning of iodine prophylaxis [20]. This study showed that iodine intake modulates the pattern of thyroid diseases, even in case of slight differences in intake and doses below 150 μg daily recommended for preventing IDD.…”

“…We have approached this matter in the population of Pescopagano. In a second survey conducted in this village in 2010 [20], 70% of subjects declared to routinely use IS (IS users) and 30% never to use IS (IS non-users). Accordingly, median urinary iodine excretion was slightly higher in IS users than in IS non-users (112.0 vs. 86.5 µg/l; p < 0.01; fig.…”

“…Positive anti-Tg antibodies (TgAb) were more frequently detected in IS users (18.9 vs. 13.6%; p = 0.02), while this difference was not statistically different for anti-thyroperoxidase antibodies (TPOAb; table 1). We, therefore, investigated whether iodine supply was associated with changes in the antigenic characteristics of Tg [20]. To this purpose, we evaluated the epitope pattern of TgAb from IS users and IS non-users.…”

Comparison of thyroglobulin and thyroid peroxidase antibodies measured by five different kits in autoimmune thyroid diseases

“…Therefore, we searched for recent reports on screening studies of TgAb and TPOAb. To avoid the influence of diseases themselves, we only considered studies done on healthy control subjects in various regions in different countries [24][25][26][27][28][29][30][31][32][33][34][35][36][37]. In healthy subjects, the incidence of positive TgAb or TPOAb is …”

Thyroid Autoimmunity and Cancer

“…HT appears to be worsened by iodine intake [46]; in fact, increased levels of thyroid antibodies result after iodine replacement [47]. The proposed mechanism is an increase in thyroglobulin immunogenicity, as a consequence of the presentation of a cryptic pathogenic peptide induced by iodination [48].…”