Serum thyroglobulin is associated with orbitopathy in Graves\u2019 disease

S Khamisi,F A Karlsson,M Lundqvist,Ö Ljunggren,P Emadi,K Almby

doi:10.1007/s40618-021-01505-8

S Khamisi, F A Karlsson + Show 4 more

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https://doi.org/10.1007/s40618-021-01505-8

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Abstract

PurposeSerum thyroglobulin levels are often elevated in Graves’ disease (GD) and in most cases decrease during treatment. Its relation to Graves’ orbitopathy (GO) has not been clarified. Previously, a risk of GO has been linked to smoking, TSH receptor stimulation, high TSH-receptor antibodies (TRAb), low thyroid peroxidase and thyroglobulin antibodies (TPOAb, TgAb).MethodsWe examined Tg levels in 30 consecutive patients with GD were given drug therapy (methimazole + thyroxine) for up to 24 months. GO was identified by clinical signs and symptoms. 17 patients had GO, 11 of whom had it at diagnosis while 6 developed GO during treatment. During the study, 5 subjects were referred to radioiodine treatment, 3 to surgery. The remaining 22 subjects (GO n = 12, non-GO n = 10) completed the drug regimen.ResultsAt diagnosis, Tg levels in GO patients (n = 11) were higher (84, 30–555 µg/L, median, range) than in non-GO patients (n = 19) (38, 3.5–287 µg/L), p = 0.042. Adding the 6 subjects who developed eye symptoms during treatment to the GO group (n = 17), yielded p = 0.001 vs. non-GO (n = 13). TRAb tended to be higher, while TPOAb and TgAb tended to be lower in the GO group. For the 22 patients who completed the drug regimen, Tg levels were higher in GO (n = 12) vs. non-GO (n = 10), p = 0.004, whereas TRAb levels did not differ.ConclusionThe data may suggest that evaluation of thyroglobulin levels in GD could contribute to identify patients at increased risk of developing GO. Possibly, thyroidal release of Tg in GD reflects a disturbance that also impacts retroorbital tissues.

Highlights

Thyroglobulin (Tg) is produced by the follicular cells of the thyroid gland and secreted into the apical lumen of the follicles where it is concentrated and used as a substrate for the synthesis of thyroid hormone [1]
Thyroglobulin Tg levels differed significantly between subjects who presented with Graves’ orbitopathy (GO) at the baseline visit (n = 11) and those who did not (n = 19) (Fig. 1a), while there were no differences in other thyroidal biomarkers (Table 1)
We found no significant correlations between Tg levels and TSH-receptor antibodies (TRAb), fT3, or fT4

Summary

Introduction

Thyroglobulin (Tg) is produced by the follicular cells of the thyroid gland and secreted into the apical lumen of the follicles where it is concentrated and used as a substrate for the synthesis of thyroid hormone [1]. Madeddu et al [4] studied 12 patients with subacute thyroiditis over 3–4 months, ten of whom demonstrated similar patterns with initially elevated Tg values 300 ± 204 ug/L Druetta et al [5] in a skillful study showed that Tg molecules released in subacute thyroiditis are iodinated, i.e. contain thyroid hormones and likely reflect a destruction of thyroid follicles.

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