Proinflammatory cytokine expression in gastric tissue from children with Helicobacter pylori-associated gastritis

Background: Helicobacter pylori infection of the gastric mucosa in humans i s usually acquired early in life. The chronic inflammation that ensues invo lves the increased production of inflammatory cytokines. Published data on production of these mediators by gastric mucosa of H. pylori-infected child ren are few. Methods: Seventy-nine children, aged 5 to 18 years, referred for upper gast rointestinal endoscopy to four separate hospitals in Chile, were studied. T he concentrations of interleukin (IL)-1 beta, IL-6, IL-8, and tumor necrosi s factor a were measured in homogenates of gastric mucosal biopsy specimens . Cytokine expression was confirmed by reverse transcription polymerase cha in reaction. These data were correlated with the patients' clinical, histol ogic and sociodemographic status. Results: Patient rate of colonization by H. pylori was inversely correlated with socioeconomic status (P < 0.005) and positively correlated with age ( P < 0.0025). In gastric mucosa, concentrations of IL-1 beta, IL-8, and tumo r necrosis factor a were all significantly higher in H. pylori-positive pat ients than in H. pylori-negative patients and in patients who had histologi c gastritis than in those with normal gastric mucosa. In patients with pept ic ulcer disease, only IL-1 beta and IL-8 concentrations were significantly elevated when compared with those of patients without ulcers. Interleukin- 6 concentrations were comparable among the different groups analyzed. Conclusions: This study suggests that increased gastric mucosal production of the proinflammatory cytokines IL-1 beta and IL-8 is probably involved in H. pylori-associated gastric damage in children and may be crucial in dete rmining the different clinical outcomes.