Combination of Helicobacter pylori strain and tumor necrosis factor-alpha polymorphism of the host increases the risk of peptic ulcer disease in children.

Background: Helicobacter pylori infection is probably acquired in childhood and causes a vigorous immune response. It is unclear why only a subgroup of infected children develops peptic ulcer disease. We have previously reported that iceA1 strains tend to be associated with duodenal disease in children.