Background: Helicobacter pylori infection is likely to be acquired at an early age. The factors leading to active inflammation in childhood, however, are largely unknown.
Subjects and methods: We determined the CagA status, the best characterized virulence factor of H. pylori, and serum antibodies of IgG and IgA classes to H. pylori in 39 infected children.
Results: Mononuclear cell infiltration in the antrum but not in the gastric body was more intense in CagA-positive children than in CagA-negative children. The degree of polymorphonuclear cell infiltration on the other hand was independent of the CagA status. The antibody titers of IgG and IgA classes to H. pylori were higher in CagA-positive than in CagA-negative infections (P<0.001 and P<0.01, respectively). IgG antibody titers to H. pylori correlated directly with the density of mononuclear and polymorphonuclear cell infiltration in the gastric antrum but not in the gastric body.
Conclusion: H. pylori-infected children with CagA antibodies seem to have a more severe inflammation in the gastric antrum than CagA-negative children as shown by an increase in the density of antral mononuclear cells. A finding of higher serum antibody titers to H. pylori in CagA-positive children may be related to this enhancement of inflammation.