TNF-α, IL-8 and CD14 gene polymorphisms in Helicobacter pylori-positive duodenal ulcer patients

Background: The activation of inflammatory cytokines plays an important role in the pathogenesis of the development of Helicobacter pylori (HP)-positive duodenal ulcer (DU). Cytokine production is determined in part by the nucleotide polymorphisms of cytokine genes. The aim was to evaluate the frequency of TNF-α, IL-8 and CD14 gene polymorphisms in HP-positive DU patients. Patients. 69 patients with HP-positive DU (mean age 46.8 years) and 47 HP- positive healthy blood donors (mean age 42.6 years) were included in the study. Methods: The TNFα-308A (G to A) gene polymorphism was determined by NcoI RFLP (restriction fragment length polymorphism), the IL-8–251A (T to A) gene polymorphisms by ARMS (amplification refractory mutation system) methods and the CD14–159T (C to T) polymorphism by melting point analysis.

Results: The genotype frequency of TNF-α308A was found to be 35% in the controls, and 20% in the HP-positive DU patients. The genotype frequency of CD14–159T was 49% in the controls and 45% in the DU patients. A significant difference could not be observed in these cases. In contrast, the frequency of the IL-8–251A allele proved to be significantly (P<0,05) higher in the HP-positive DU patients (65%) than in the controls (36%), resulting in an overproduction of IL-8.

Conclusion: The host factors play a key role in HP-positive DU. Though TNF-α and IL-8 production is increased after HP infection, our analysis of the genetic predisposition to enhanced cytokine production revealed a significant association only for the IL-8 polymorphism.