Gastric B-Cell Clonal Expansion and Helicobacter pylori Infection in Patients with Autoimmune Diseases and with Dyspepsia: A Follow-up Study

Abstract

Background: It is not clear whether gastric B-cell clonal expansion, a possible precursor of mucosa-associated lymphatic tissue (MALT) lymphoma, is exclusively linked to Helicobacter pylori infection and virulence. Methods: In this study we followed up, for up to 33 months, 16 VDJ polymerase chain reaction-positive patients (4 with dyspepsia, 9 with Sjögren's syndrome, and 3 with other autoimmune diseases). Of these, 12 were H. pylori-positive. In addition, in H. pylori-positive patients we tested whether the serum anti-cag-A (a potential marker of virulence) was preferentially associated with B-cell clonality. Results: In all hut one patient clonality appeared temporally unrelated to H. pylori infection. The prevalence of anti-cagA was not higher in H. pylori/VDJ-positive patients than in controls. Conclusions: These data indicate that, in addition to H. pylori, gastric B-cell clonality may be sustained by other agents/mechanisms. Anti-cag-A does not appear to be involved in the pathogenesis of clonality.

Key Words:

• Autoimmunity
• B-cell clonal expansion
• cag-A
• gastric mucosa-associated lymphatic tissue
• Helicobacter pylori
• lymphoproliteration