Iron deficiency and IL1β polymorphisms in Helicobacter pylori-infected children

Background: Helicobacter pylori-infection has been associated with an imbalance of iron homeostasis. IL-1 has been related with iron absorption disturbances through a variety of mechanisms. The aim of this study was to evaluate the presence of polymorphic variants for IL-1 cluster and gastric IL1β mRNA expression in H. pylori-infected children and their relationship with hypoclorhydria and iron deficiency (ID). Patients and Methods: Prospective study of 123 symptomatic children. At endoscopy, antral biopsies were taken for urease test, pathology and culture and blood for analysis of ferritin, transferrin, serum iron and total iron-binding capacity. Polymorphisms in the IL-1 cluster (positions -511, -31, +3954, ILRN) were determined by PCR-RFLP. Gastric mucosal expression of IL-1 mRNA was determined by RT-PCR. Results: After exclusions, out of 105 patients, 33 (31.4%) were H. pylori positive. Nine (8.6%) children were classified as iron deficient (ID). H. pylori positivity was associated with ID (OR: 5.1; 95% CI: 1.2-21.9) (p = 0.04). No significant differences were found in allele frequency for IL1β gene cluster polymorphisms between infected and uninfected children. H. pylori-infected children with ID had significantly increased gastric IL1β mRNA in comparison to infected children without ID. In addition a significant positive correlation was observed between mucosal IL-1β mRNA and fasting gastric juice pH. Gastric pH values were significantly increased in H. pylori infected patients with ID compared to uninfected children. Conclusions: The established association between H. pylori infection and ID in children may be mediated by increased gastric mucosal IL-1.