Molecular detection of host cytokine expression in Helicobacter pylori infected patients via semi-quantitative RT-PCR

Background: Helicobacter pylori (Hp) is a bacterium recognised as a main causative agent for the development of chronic active gastritis, peptic ulcer disease, gastric adenocarcinoma and primary gastric lymphoma. Objective: Determination of the levels of IFN-γ (pro-inflammatory) and IL-4 (anti inflammatory) cytokine expression as indicators of Th1 and Th2 immune responses in gastric cancer (GC) and non gastric cancer (Non GC) dyspeptic patients by gene specific RT-PCR. Materials and Methods: Biopsy specimens were collected from three groups of gastric cancer (GC=18), non ulcer dyspepsia (NUD = 38) and peptic ulcer patients (PUD=20). Total RNA was extracted and complementary DNA was synthesised. PCR amplification was performed for HPRT, IFN-γ and IL-4 cytokines and the intensity of each band was measured by densitometry and normalized against HPRT expression as a house keeping gene. Results: Comparison of the results from different groups of patients indicated that IFN-γ gene expression was similar in nonGC dyspeptic patients (NUD and PUD groups; 3.38 ± 0.57,3.43 ± 0.41, respectively) whereas, in GC patients, it was significantly higher than others (5.52 ± 0.59; P < 0.0001). On the other hand, IL-4 gene expression showed no significant difference between NUD and GC patients (2.81 ± 0.43,2.3 ± 0.12 respectively), whereas the expression rate of this cytokine was significantly higher in PUD patients (3.7 ± 0.1; P 0.05). Our data indicate an association between Th1 and Th2 immune responses and the development of gastric cancer and peptic ulcer disease respectively.