Understanding disease outcome following acquisition of Helicobacter pylori infection during childhood.

Helicobacter pylori causes chronic active (type B) gastritis in the overwhelming majority of infected individuals. The relative contribution of virulence factors in the bacterium and host responses to the microbial infection in determining which subjects will go on to develop complications - such as peptic ulceration, gastric cancers and gastric lymphomas - is the subject of current investigative activities.