[Significance of catalase antibody in Helicobacter pylori infection].

Helicobacter pylori (H. pylori) has been identified as a causative agent of various gastroduodenal diseases. The pathophysiology and various clinical outcomes of this infection can be explained by bacterial factors, host factors and their interactions. To investigate the interaction between H. pylori and host, the author studied H. pylori catalase, which scavenges hydrogen peroxide from neutrophils in the H. pylori-infected stomach, and production of antibody to catalase in the sera of patients as a host response to the organism. Sera from 120 H. pylori-positive patients and H. pylori strains were studied. ELISA to detect anti-H. pylori catalase antibody in serum was established with the use of recombinant catalase protein as a coated antigen. Sixty-nine patients (58%) were positive for anti-catalase antibody in the sera, and histology of the stomach demonstrated infiltration of numerous mononuclear cells and infiltration of less neutrophils in the antrum. In contrast, 51 patients (42%) were negative for anti-catalase antibody in the sera, and the histology exhibited infiltration of numerous neutrophils and infiltration of less mononuclear cells in the antrum. Forty-five patients (37%) were negative for the antibody in the sera even though they were infected with H. pylori-catalase-producing strains. Only 6 patients (5%) were proved to be infected with non-catalase-producing strains and negative for the antibody. However, the structure of catalase genes did not differ between non-catalase-producing strains and catalase-producing strains, which was determined by southern blot and PCR. The presence of anti-H. pylori catalase antibody in the sera might indicate the histological characteristics of the stomach infected with H. pylori.