Introduction:
The co-existence of tissue-specific autoantibodies in autoimmune thyroid disease (ATD) is well established. The published prevalence of anti-parietal cell antibodies (PC-Ab) is 20–25%, and that of celiac antibodies is 2–5%. The goal of this study was to determine the prevalence of PC-Ab and anti-tissue transglutaminase antibodies (tTG-Ab) in patients with ATD and to evaluate the correlation between anti-thyroid antibodies and the other antibodies.

Material and methods:
The files of 120 Israeli Jews and Arabs with ATD were evaluated for anti-thyroglobulin antibodies (Tg-Ab), anti-thyroid peroxidase antibodies (TPO-Ab), PC-Ab and tTG-Ab. For patients with positive PC-Ab and/or tTG-Ab, upper gastrointestinal (GI) endoscopy results were recorded. Gastrin levels were collected in patients with positive PC-Ab.

Results:
Twelve (10%) males and 108 (90%) females were evaluated, of whom 93.33% had Hashimoto’s thyroiditis. Thirty-four (28.3%) subjects had positive PC-Ab. This rate was not affected by gender, ethnicity or thyroid disease. Abnormal gastroscopy findings were documented in 95.2% of the upper GI endoscopies. The mean gastrin level in this subgroup was 660.4 pg/ml. Five of 114 tTG-Ab tests were positive (4.4%). All were females with Hashimoto’s thyroiditis. Rates were equal among Jews and Arabs. Higher TPO-Ab levels were associated with higher risk for PC-Ab positivity (p = 0.027), but not tTG-positivity. Higher Tg-Ab levels were not associated with higher levels of other antibodies.

Conclusions:
Considering the frequency of PC-Ab and tTG-Ab positivity in ATD, checking for the presence of these two entities should be an integral part of the workup of this disease.