Autoimmune thyroiditis and Helicobacter pylori--is there a connection?

Objectives: In this study we examined the anti-Helicobacter pylori (anti-H. pylori) antibodies in patients with autoimmune thyroiditis, with and without different polyglandular involvement, and in healthy controls.

Material & Methods: Patients with autoimmune thyroiditis (AT) were divided into three groups: Group A: 23 patients with isolated AT, Group B: 30 patients with AT as a part of polyglandular activation of autoimmunity, and Group C: 7 patients with AT as a part of autoimmune polyglandular syndrome type II. Thirty healthy individuals served as controls (Group D). Anti-H. pylori antibodies were determined first by ELISA for classes IgG, IgA, and IgM, and subsequently by immunoblot for classes IgG and IgA.

Results: ELISA: The number of patients with IgA antibodies in Group A (39%) and Group B (30%) differed significantly from controls (7%, p<0.05). Immunoblot: Anti-CagA antibodies were found in 13% of patients in Group A, 7% of Group B, 0% of Group C, and 20% of Group D. A higher seroprevalence, as compared to controls, was found for IgG to the VacA (p=0.01), 30 kDa (p=0.001), and 17 kDa (p=0.008) antigens in Group A and for IgG to the 30 kDa antigen in Group C (p=0.037). A significantly higher seroprevalence, as compared to controls, was likewise found for IgA to the 17 kDa antigen in Group A (p=0.015).

Conclusions: A different distribution of antibodies to H. pylori antigens was found in patients with isolated AT compared to patients with AT coupled with a polyglandular syndrome.