Endocrine Abstracts

Background & objectives: There are multiple forms of functional TSHR autoantibodies which stimulate or inhibit the thyroid. The TSH-Receptor blocking antibody (TSBAb) exists in the serum of Graves’ disease, which is functionally different from TSH receptor stimulating antibody (TSAb). TSBAb that blocks the action of TSH is also associated with idiopathic myxedema and some Hashimoto’s disease. We measured TSBAb levels and evaluated the pathogenetic significance of TSBAb in gestational women.

Subjects & methods: Thirty two Japanese pregnant women were enrolled to measure TSBAb, TSAb, thyroglobulin antibody (TgAb) and anti-thyroid peroxidase antibody (TPOAb), TSH, free T4 and Free T3. Thyroid function was evaluated with TSH levels (standard values; 0.55 to 4.18 μU/l). The biological activity of TSBAb were assayed with porcine thyroid cell suspensions using cAMP measurement by RIA.

Results: Demographic data were 30.2±6.2 years olds for age, 12.6±5.3 weeks for the gestational stage, thirteen women on hyperthyroidism, four women on hypothyroidism and fifteen women on euthyroidism. TSBAb levels in pregnant women were not correlated with the gestational periods. In thirteen hyperthyroid and fifteen euthyroid state TSBAb were within normal range, whereas three of four hypothyroid women demonstrated high levels of TRBAb (more than 45.6%). Two hypothyroism subjects with high titer of TRBAb, TgAb and TPOAb.

Speculation & conclusions: In the gestational stages thyroid function varies from hypo- to hyper-function of thyroid, our results suggested that TSBAb might play an important role in hypothyroidism of the pregnant women with or without Hashimoto’s disease.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector