Celiac disease in North Italian patients with autoimmune thyroid diseases.

Background: Patients with autoimmune thyroid diseases (AITDs) are prone to develop other autoimmune manifestations and to display autoimmune polyendocrine syndromes. An increased prevalence of celiac disease (CD) was demonstrated in adult European and Italian patients with AITDs; conversely, an increased prevalence of AITDs was demonstrated in patients with CD. An IgA deficiency is the most frequent immunodeficiency in humans and, in general, high frequency of this disorder was demonstrated in those with autoimmune diseases.

Aim: To define the prevalence of both CD and IgA deficiency in North Italian patients with AITDs.

Methods: 276 Italian patients with AITD were enrolled (mean age 42.6 years range 12-89, 186 of whom had chronic thyroiditis and 90 had Graves' disease). The tissue transglutaminase autoantibodies of the IgA class (IgA-tTGAbs) were evaluated using an ELISA method in these patients. Furthermore, the serological levels of the IgA were determined.

Results: Five of the patients (1.8%) were affected by previously diagnosed CD and were on a gluten-free diet. Ten out of the remaining 271 patients (3.6%) were found to be positive for celiac-related autoantibodies. All of these patients agreed to undergo endoscopy and duodenal biopsies and silent CD was found in 5 of them but 5 had not histopathological signs of CD. CD (clinical, silent or latent) was present in 15/276 (5.4%) of the North Italian patients with AITD; this prevalence is significantly higher with respect to the general population (p < 0.00001). The genetic pattern of the 10 patients with both AITDs and CD was characterized by the presence of DQ2 in 8 patients and DQ8 in 2. An IgA deficiency was present in 2/276 of the patients (0.72%).

Conclusions: CD is significantly increased in patients with thyroid autoimmune disorders for this reason it is important to screen for CD in patients with AITDs.