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.
Institute of Biochemistry and Swiss Institute for Experimental Cancer Research, Lausanne, Switzerland.
D
D
Claeys
G
G
Faller
B J
BJ
Appelmelk
R
R
Negrini
T
T
Kirchner
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