[Causal relationship between Helicobacter pylori infection and upper gastroduodenal diseases].

Helicobacter pylori infection causes chronic gastritis (nonatrophic gastritis), which progresses to atrophic gastritis and intestinal metaplasia over a period of decades. Atrophy may result from inflammation and apoptosis caused by H. pylori infection. H. pylori is an important risk factor for peptic ulcer disease. Duodenitis in the gastric metaplasia of the duodenum, hypergastrinemia, and impaired proximal duodenal mucosal bicarbonate secretion are considered causal factors for duodenal ulcer disease. Low-grade B-cell gastric lymphoma of mucosa-associated lymphoid tissue (MALT) develops in response to H. pylori infection. Studies of Mongolian gerbil model demonstrated that H. pylori had an initiator or promoter effect on gastric carcinogenesis.