Gastric mucosa-associated lymphoid tissue in autoimmune thyroid diseases

Background: There is increasing evidence for a link between Helicobacter pylori infection and the development of lymphoid follicles in the gastric mucosa. It is not known whether other factors may also play a role. The aim of this study was to investigate the role played by the host with peculiar immunogenic disorders, in the presence or absence of a known antigenic stimulus such as H. pylori. For this, we studied patients with autoimmune thyroid diseases. Methods: Thirty patients with autoimmune thyroid diseases and 30 dyspeptic patients without a history of thyroid disorders (as control group) underwent upper endoscopy. Lymphoid follicles and H. pylori status were assessed by histopathologic and enzymatic analysis. Results: Organized mucosa-associated lymphoid tissue was found in 73.3% of the patients and in 33.3% of control group. Lymphoid follicles were found in 87.5% of the H. pylori-positive patients and in 57.1% of the H. pylori-negative patients (P = NS). In the control group these follicles were present in 50% of H. pylori- positive subjects and in 14.3% of those who were H. pylori-negative. Conclusions: Lymphoid follicles in the gastric mucosa are common in autoimmune thyroid diseases. Besides H. pylori infection, other factors (environmental, unknown infectious agents) or mechanisms related to the underlying disease may play a causal role.