2006 Volume 20 Issue 4 Pages 309-319
Helicobacter pylori is a Gram-negative helical bacterium which colonizes gastric mucosa persistently. H. pylori induces acute and chronic gastritis, and acts as recurrence factor or healing-delaying factor for peptic ulcer diseases. In addition, it is implicated that H. pylori infection has been associated with malignant diseases such as gastric cancer and gastric MALT lymphoma. Virulence factors of H. pylori are grouped into bacterial and host virulence factors. Urease, adhesin, VacA cytotoxin, CagA, cagPAI, OipA, NapA, heat-shock protein etc have been reported as bacterial virulence factors. Translocation of CagA into a host cell through the Type IV secretion system induces considerable changes in cellular function, and plays an important role in pathogenesis following H. pylori infection. Cytokines (TNFα, IL-6, IL-8 etc) produced by gastric epithelial cells and immune cells, oxyradicals and nitiric oxide (NO) have been reported as host virulence factors. In addition, the association of H. pylori with extra-gastroduodenal diseases such as idiopathic thrombocytopenic purpura, chronic urticaria, coronary artery diseases etc.) has been reported, and improvement of the above diseases was reported after H. pylori eradication therapy.
