Association between Helicobacter suis infection and the pathogenesis of gastric mucosa-associated lymphoid tissue lymphoma

Objective: In patients with Helicobacter pylori-negative gastric mucosa-associated lymphoid tissue (MALT) lymphoma, eradication therapy is only effective in some cases, suggesting that infections with non-H. pylori Helicobacter (NHPH) species may also be involved. Therefore, we examined the prevalence of infection with Helicobacter suis, an NHPH, in gastric MALT lymphoma patients.
Methods: We examined the H. suis infection status of 15 patients with H. pylori-negative gastric MALT lymphoma. To examine the infection prevalence through species-specific PCR analysis, DNA was extracted from the lymphoma lesion and the background gastric mucosa. We compared the PCR products amplified from DNA extracted from different lesions.
Results: H. suis was detected in 3 of the 15 cases (20.0%), but only in the background gastric mucosa and not in the lymphoma lesion. H. suis was completely eradicated in all three cases and two of the three cases exhibited complete remission of the lymphoma.
Conclusion: These results indicated that H. suis infection may be involved in the pathogenesis of gastric MALT lymphoma. We conclude that it is desirable to use multiple biopsies, including the background mucosa, to evaluate NHPH infection in gastric MALT lymphoma patients.