AUGMENTED LEVELS OF GASTRIC-MUCOSAL LEUKOCYTE ACTIVATION BY INFECTIONWITH CAGA GENE-POSITIVE HELICOBACTER-PYLORI

The possession of the cytotoxin-associated gene (cagA) of Helicobacter pylori is thought to be highly associated with peptic ulcer disease. However, the pathogenic role of cagA is still unknown. We have emphasi zed the importance of the interrelationship between H. pylori-derived ammonia and oxygen radicals from infiltrated leucocytes. The aim of th e present study was to explore the relationship between oxygen radical production and H. pylori strain diversity based on cagA possession. A n endoscopic examination and gastric mucosal biopsy were performed in 30 H pylori-infected patients with gastric ulcer. Myeloperoxidase (MPO ) content and the luminol-dependent chemiluminescence value in the bio psied gastric specimens were measured as an index for leucocyte infilt ration and oxygen radical production. From the precipitates of culture d bacterial isolates of biopsied specimens, bacterial DNA was purified and analysed by polymerase chain reaction to characterize the possess ion of cagA. While all patients had ureC-positive strains, 22 had cagA -positive and eight had cagA-negative strains. In patients with cagA-p ositive strains, MPO contents as well as chemiluminescence values in t he gastric corpus were significantly higher than those in patients wit h cagA-negative strains. Gastric mucosal leucocyte recruitment and act ivation are suggested to be enhanced by cagA gene-positive H. pylori i nfection.