[Helicobacter pylori and gastroduodenal disease].

Gastroduodenal infection by Helicobacter pylori is a known cause of many gastric and duodenal disorders. Infection by H. pylori is very frequent ant its prevalence increases with age by about 1% per year. Human-to-human transmission appears probable. H. pylori lives under the mucous layer of gastric-type epithelium. It is the main causal agent of chronic diffuse superficial gastritis (type B). After several decades lesions of superficial gastritis can evolve to atrophic gastritis. Spontaneous short- or long-term disappearance of H. pylori from the antral mucosa is rare. H. pylori infection appears to be necessary for the recurrence of duodenal as well as gastric ulcer. Eradication decreases the frequency of relapses, but its long-term effect remains to be evaluated. The presence of H. pylori, however, is not itself sufficient for ulcer development. Why only some patients infected with H. pylori develop ulcer has not been elucidated. The role of H. pylori infection in the gastrotoxicity of non-steroid anti-inflammatory agents is still debated. It has not yet been determined whether eradication leads to reduction of the high digestive morbidity linked to intake of such agents, but it is known that eradication of H. pylori does not obviate the risk of ulcer and of complication. There is a significant association between H. pylori infection, atrophic gastritis and intestinal type gastric cancer. H. pylori infection appears to be one of the factors in gastric cancerogenesis. Cellular proliferation of gastric lymphomas to low-grade B cells would in most cases be secondary to chronic H. pylori infection.(ABSTRACT TRUNCATED AT 250 WORDS)