Evaluation of Serum Interleukin-18 levels in Helicobacter Pylori-infected Peptic Ulcer Patients and its Association with Bacterial CagA Virulence Factor

Background: Helicobacter pylori infection is one of the most common gastrointestinal infections worldwide. Predominant T-helper 1 (Th1) responses with increased gamma interferon (IFN- γ) levels have been proposed to play an important role in H. pylori-induced peptic ulcer. However, bacterial factors contributing to the initiation of Th1 polarization of H. pylori-specific immune responses have not been characterized. Objective: Comparing serum concentrations of IL-18 in H. pylori-infected peptic ulcer (PU) patients, H. pylori-infected asymptomatic (AS) carriers and healthy control group and its association with bacterial virulence factor CagA. Methods: Thirty H. pylori-infected PU patients (20 patients were positive for anti-CagA antibody and 10 patients were negative for anti-CagA antibody), 30 H. pylori-infected (AS) carriers (15 subjects with positive test for anti-CagA antibody and 15 subjects with negative test for anti-CagA antibody) and 20 healthy uninfected subjects were included in this study. Serum concentration of IL-18 was measured by ELISA method. Results: The mean serum levels of IL-18 in PU patients (333.2 pg/ml ± 158), was significantly higher than those found in AS (146.5 pg/ml ± 90.1; P