Association of Helicobacter pylori-associated Duodenal Ulcer and Precancerous Findings with Toll-like Receptor-4 Asp299Gly and Toll-like Receptor-9 123T/C Polymorphism and Cag-A, Vac-A in Children

Abstract

Objective: We aim to show whether endoscopic, histopathological and precancerous findings in childhood Helicobacter pylori (H. pylori) infection are associated with some changes in the host immune system and some virulence factors of the bacteria. For this purpose, we interpreted the changes in endoscopic and histopathological findings of TLR-4 and TLR-9 gene polymorphisms in the innate immune system of the host and cytotoxin associated gene A (Cag-A) and vacuolating cytotoxin A (Vac-A) positivity, the main virulence factors of the bacteria. Method: Between April 2009 and October 2010, 100 H. pylori-positive and 100 H. pylori-negative cases were cross-sectionally selected by retrospectively reviewing the files of patients admitted to a tertiary hospital with dyspepsia. After obtaining informed consent, blood samples from these patients were analysed for TLR-4 [Asp 299 Gly (rs4986790)] and TLR-9 [1237 TC (rs5743836)] gene polymorphisms and for the presence of Cag-A and Vac-A in isolates obtained from pathological specimens. Results: Poor socio-economic conditions were an important risk factor for H. pylori. The presence of Cag-A increased the likelihood of duodenal ulcer. There was no significant difference between TLR-4 [Asp 299 Gly (rs4986790)] gene polymorphism and endoscopic and histopathological findings. However, TLR-9 [-1237TC (rs5743836)] polymorphism increased precancerous intestinal metaplasia and atrophy. Conclusion: The presence of Cag-A increases the risk of duodenal ulceration due to H. pylori infection. The TLR-9 [-1237TC (rs5743836)] polymorphism is associated with gastric atrophy and intestinal metaplasia in the pathogenesis of H. pylori infection. Studies in large groups of patients are needed.

Keywords

• h. pylori
• toll-like receptors
• vac-a
• cag-a