Serologic Testing for Celiac Disease in Graves' Hyperthyroidism: Should We Act Early?

Background: The general practice is to screen patients with autoimmune thyroid disease for celiac disease (CD); however, optimal timing for CD screening for patients with Graves'Disease (GD) has not been identified yet. The aim of the study was to show whether positive celiac antibodies persist after euthyroidism is achieved.

Materials and methods: Serum samples were collected from 35 patients with GD (23 female and 12 male) who applied to the endocrine outpatient clinic. Patients and healthy controls were screened for CD with IgG and IgA antigliadin antibodies (IgG - AGA and IgA - AGA), IgA endomysial antibody (IgA-EMA) and IgA tissue transglutaminase antibody (IgA anti-tTG). These antibodies were reevaluated when patients were euthyroid under antithyroid therapy. Small intestine biopsy was offered to the patients who remained antibody positive after being euthyroid.

Results: Screening 35 patients with GD revealed positive results for IgA-AGA (n = 6/35, 17%), IgG-AGA (n = 9/35, 26%), IgA-EmA (n = 2/35, 6%) and IgA-tTG (n = 2/35, 6%). No patient had multiple antibodies positive. Selective IgA deficiency was not detected in patients and controls. When patients were euthyroid, baseline positive IgA-AGA, IgG-AGA, and IgA-EmA became negative, while positive anti-tTG persisted in two patients. Endoscopic duodenal biopsy showed a normal villi/crypts ratio in these patients. None of the controls had positive antibodies.

Conclusion: Due to possibility of false seropositivity of celiac antibodies in patients with Graves' thyrotoxicosis, one should defer testing for CD until euthyroidism has been achieved.