Relationship between gastric localization of hepatitis C virus and mucosa-associated lymphoid tissue in Helicobacter pylori infection

Background: Hepatitis C virus (HCV) has been localized in several extra-hepatic sites. Recent evidence suggests that the stomach can harbour HCV. We therefore evaluated the prevalence of gastric localization of HCV and its possible relationship with the chronic inflammatory response to Helicobacter pylori infection. Methods: Sixty patients with HCV infection (group A) and 60 subjects without HCV infection (control group), who underwent upper endoscopy for dyspeptic symptoms, were consecutively enrolled. Biopsy specimens of gastric mucosa obtained from each patient were assessed for H. pylori and chronic inflammatory infiltrates (classified as mild, moderate or marked). Furthermore, polymerase chain reaction (PCR) analyses were performed on the gastric biopsies to detect HCV and immunoglobulin heavy-chain (IgH) gene rearrangements of mucosal B cells. Results: In group A, 24 of 36 patients with H. pylori infection and 6 of 24 without H. pylori hosted HCV in their stomach (P = 0.0017). In these subjects, the presence of both HCV in the gastric mucosa and H. pylori was significantly associated with marked or moderate inflammatory infiltrates. Oligoclonal IgH gene rearrangements were detected in three group A patients who harboured both H. pylori and HCV in their stomach. In the control group, PCR analyses failed to find HCV in the gastric mucosa, and polyclonal patterns were detected in all individuals. Conclusions: HCV is frequently localized in the stomach and is associated with the chronic lymphocytic inflammatory response to H. pylori. H. pylori and HCV, when both present, may favour the selection of clonal B cells.