Published online Sep 14, 2014. doi: 10.3748/wjg.v20.i34.11939
Revised: March 31, 2014
Accepted: May 19, 2014
Published online: September 14, 2014
Helicobacter pylori (H. pylori) is a pathogenic, extracellular bacterium that colonizes the stomach in approximately 50% of the world population. It strongly interacts with the gastric epithelium and mostly causes asymptomatic gastritis. The colonization of H. pylori leads to ulcer development in around 20% of infected patients and may progress to gastric cancer or mucosa-associated lymphoid tissue lymphoma in 1%. Thus, H. pylori is the major cause of gastric cancer worldwide. It has been classified as a class I carcinogen by the World Health Organization. Since its discovery in the early eighties by Warren and Marshall, research has been focused on the investigation of H. pylori biology, host-pathogen interaction, prevention and treatment. Although H. pylori induces a strong humoral and local cellular immune response, the pathogen is not cleared and establishes a chronic infection after encounters in childhood. The ability to colonize the stomach is mediated by several virulence factors that change the host environment, promote adhesion to the epithelium, influence the gastric inflammation and induce immune evasion. H. pylori can be eradicated by antibiotic treatment in combination with a proton-pump inhibitor, but efficacy is decreasing. Current therapies are expensive, have side effects and contribute to increasing antibiotic resistance, underlining the need for novel therapeutics.
Core tip:Helicobacter pylori (H. pylori) is a carcinogenic pathogen colonizing the human stomach. In the advent of rising antibiotic resistance, it is of major interest to introduce novel therapies. Immunization is a potent candidate although all efforts to generate an effective vaccine have failed as yet. The host-pathogen interaction and especially the immune-modulating capacity of H. pylori contribute to this development of resistance to treatment. In this review potential solutions with a focus on the immune response to the pathogen are discussed.