5Gastrointestinal and Hepatology Research center, Shiraz Medical School, Shiraz University of Medical Sciences, Shiraz-Iran
Background: Polymorphisms in the immune related genes are important in the clinical outcome of Helicobacter pylori infection. Myeloperoxidase -463 G/A polymorphism has been shown to reduce enzyme expression and activity. Objective: the aim of the present study is to investigate the association of myeloperoxidase G-463A polymor-phism with clinical outcome of Helicobacter pylori infection. Methods: two hundred and eighty five patients with positive culture of Helicobacter pylori from their gastric biopsies are included in this study. Human leukocyte DNA was extracted using salting out method and myeloperoxidase G-463A polymorphism was investigated by PCR-RFLP. All clinicopathological data were collected from individual records. Results: When the patients were categorized according to the high (GG) and low + intermediate (AG+AA) genotypes of myeloperoxidase producers, there was a significant association between myeloperoxidase G-463A genotypes and clinical outcome of Helicobacter py-lori infection (p=0.006). In search for combined effect of cagA status and myeloperoxi-dase genotypes on clinical presentations, only in cagA- Helicobacter pylori infected pa-tients a significant association between myeloperoxidase genotypes and clinical out-come was found (p=0.0001). Also this association was found only in patients infected with vacA s1m1 genotype (p=0.008). Conclusions: Our findings suggest that the mye-loperoxidase G-463A polymorphism is a host genetic factor which determines the clini-cal outcome of Helicobacter pylori infection. Moreover, the combination of host and bacterial genetics could provide a better understanding of clinical outcome after infec-tion with Helicobacter pylori.