Positive correlation between H,K-adenosine triphosphatase autoantibodies and Helicobacter pylori antibodies in patients with pernicious anemia.

Background: Helicobacter pylori is a major cause of gastritis, and the parietal cell H,K-adenosine triphosphatase (ATPase) is a major autoantigen in autoimmune atrophic corpus gastritis, which may eventually lead to pernicious anemia and/or neuropathy. Whether the bacterium induces the autoimmune response is unknown.
Methods: By means of enzyme-linked immunosorbent assay the occurrence of antibodies against porcine H,K-ATPase and H. pylori was determined in sera from 30 patients with pernicious anemia.
Results: All sera scored positive against H,K-ATPase, and 25 (83%) scored positive against H. pylori. The titers of antibodies against both antigen preparations inversely correlated with the duration of disease. A possible common epitope in the antigen preparations was tested with a competition assay. There was no indication of a common epitope in either human or porcine H,K-ATPase and H. pylori.
Conclusions: There was a positive correlation and a high incidence of antibodies against H,K-ATPase and H. pylori in sera from patients with pernicious anemia. These antibodies recognized different epitopes.