The gastric H+,K+-ATPase is a major autoantigen in chronic Helicobacter pylori gastritis with body mucosa atrophy.
OBJECTIVE
A subgroup of Helicobacter pylori-infected patients develops autoantibodies to gastric parietal cell canaliculi. The aim of this study was to define the unknown autoantigen.


METHODS
We screened 72 H. pylori-infected patients, 5 patients with autoimmune gastritis, and 36 healthy controls for immunoglobulin G autoantibodies to canaliculi by immunohistochemistry. The antigen specificity was determined by immunoprecipitation of the murine gastric H+,K+-adenosine triphosphatase (H+,K+-ATPase) expressed in oocytes and by immunoblotting on human gastric membranes from the body mucosa.


RESULTS
Autoantibodies specific for the conformational peptides of the H+,K+-ATPase were detected in 3% (1/36) of controls, in all patients with autoimmune gastritis (5/5), in 25% (18/72) of H. pylori-infected patients, and in 47% (15/32) of the infected patients with anticanalicular autoantibodies. No other major autoantigen was identified. Atrophy in the gastric body mucosa was found in 60% (9/15) of infected patients with both anticanalicular and anti-H+,K+-ATPase antibodies, but only in 13% (5/37) of infected patients lacking both autoantibodies (P < 0.01).


CONCLUSIONS
The gastric H+,K+-ATPase is a major autoantigen in H. pylori-associated antigastric autoimmunity. Thus, anti-H+,K+-ATPase autoantibodies, which are closely linked to classical autoimmune gastritis, are also significant indicators for body mucosa atrophy in chronic H. pylori gastritis.
Claeys
D
D
Institute of Biochemistry and Swiss Institute for Experimental Cancer Research, Lausanne, Switzerland.
Faller
G
G
Appelmelk
B J
BJ
Negrini
R
R
Kirchner
T
T
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001284:Atrophy; D001323:Autoantibodies / Q000032:analysis; D001324:Autoantigens / Q000276:immunology*; D002908:Chronic Disease; D005260:Female; D005753:Gastric Mucosa / Q000473:pathology; D005756:Gastritis / Q000276:immunology* / Q000382:microbiology* / Q000473:pathology; D017506:H(+)-K(+)-Exchanging ATPase / Q000276:immunology*; D016481:Helicobacter Infections / Q000276:immunology*; D016480:Helicobacter pylori; D006801:Humans; D007519:Isoantigens / Q000032:analysis; D007983:Lewis Blood Group Antigens / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010295:Parietal Cells, Gastric / Q000276:immunology; D013270:Stomach / Q000201:enzymology*
D001323:Autoantibodies; D001324:Autoantigens; D007519:Isoantigens; D007983:Lewis Blood Group Antigens; D017506:H(+)-K(+)-Exchanging ATPase