TABLE 1

Autoimmune vs environmental metaplastic atrophic gastritis

	Autoimmune-mediated metaplastic atrophic gastritis	Helicobacter pylori-mediated metaplastic atrophic gastritis
Location	Primary involvement of the gastric body and fundus	All gastric epithelium including antrum
Acid production	Lost entirely	Decreased
Fasting gastrin level	Markedly elevated	Variable
Antibodies	Antibodies to intrinsic factor and parietal cells	Antibodies to H pylori
Vitamin B₁₂ deficiency	Present, often severe	May be present, usually mild
Association	Other autoimmune disorders	Peptic ulcer disease, adenocarcinoma, “MALToma”