Helicobacter pylori infection is probably acquired in childhood and persists as an asymptomatic infection for decades in most individuals. It is unclear why only a minority of those infected develop a clinical manifestation, even in childhood, such as peptic ulcer disease. H. pylori infection activates local immune responses and causes lymphocyte infiltration in the gastric mucosa. We have previously reported that both T and B cells in the lamina propria play important roles in the local immune response of H. pylori-infected children. The aim of this study was to investigate the association between H. pylori genotypes and gastric mucosal lymphocytes.

Twenty-five H. pylori-infected children (10 with peptic ulcer disease and 15 with gastritis) were enrolled in this study. We investigated the genotypes (cagA, cagE, vacA, and babA2) and evaluated the association with clinical manifestations, histopathology, and gastric mucosal lymphocytes.

The prevalence of cagA, cagE, vacA s1m1, and babA2 was 80%, 60%, 84%, and 88%, respectively. The most prevalent (68%) combination of cagA, vacA, and babA2 genotypes was cagA+/ vacA s1m1+/babA2+. H. pylori genotypes were not associated with clinical manifestations, histopathology, or gastric mucosal lymphocytes.

There was no association between the cagA, cagE, vacA, or babA2 status and gastric mucosal lymphocytes. The role of the host immune response in relation to H. pylori genotypes and disease potential in children needs further studies.