Infection by Cag A Positive Strains of Helicobacter pylori is Associated with Autoimmune Thyroid Disease in Iranian Patients

Background: Infectious agents have been suspected as a triggering factor for development of autoimmune thyroid disease (ATD). Some reports from Western countries have suggested association between Helicobacter pylori (HP) infection and ATD. Objective: To investigate the association of ATD with Cag A seropositivity in a population with high rate and early age of onset of HP infection. Methods: IgG anti HP and anti Cag A antibodies were measured in 88 patients with ATD and compared with results of 112 healthy individuals. Results: The rate of infection with HP was not significantly different in patient and control groups, but there was significant association between ATD and infection with Cag A strains (p