Endocrine Abstracts

Early stages of thyroid autoimmunity can be identified by thyroid hypoechogenecity and/or thyroid antibodies in serum. To get better insight in these early stages, we assembled a large group of women at risk for AITD (all had one or more 1st or 2nd degree relatives with AITD), who were in self-proclaimed good health and followed for 5 yr (the Amsterdam AITD cohort).

At study entrance, euthyroid women had reduced CD25 expression on CD4+T-cells and lower serum sIL-2R, irrespective of the presence of TPO-Ab. The findings suggest an early defect in CD4+CD25+ Treg, which contributes to breaking immunological tolerance. Stress exposure was similar in TPO-Ab positive and negative women. Yersinia enterocolitica antibodies were more prevalent in AITD relatives than in controls, irrespective of thyroid function or antibodies. Current smoking and the ever use of estrogens protected against TPO-Ab at baseline. In the 5-yr follow-up discontinuation of smoking likewise increased the risk of de novo occurrence of TPO-Ab.

The cumulative event rate of overt hypo- or hyperthyroidism was 7.5% over 5 yr. Independent risk factors for events were baseline findings for TSH (risk starting already at values >2.0 mU/l), TPO-Ab (>100 kU/l) and family background (having two relatives with Hashimoto’s disease was associated with higher risk). Weighing these three risk factors proportionately to their relative risks provided the predictive THEA (Thyroid Events Amsterdam) score, which gives a rather accurate estimate of the 5-yr risk on developing overt hypo- or hyperthyroidism in female relatives of AITD patients.