Helicobacter pylori : Prevalence, heterogeneity, and ulcerogenic properties

University dissertation from Linköping : Linköpings universitet

Abstract: In 117. unselected patients H. pylori infection was found in 49.6% by combining culture and acndme orange stammg of hssue sections. Infection was equally common in the gastric body and antrum. The activity of gastritis was generally higher in the antrum. The overallagreement between acridine orange stain and culture was 0.93.Formalin treated H. pylori whole cells were used to immunize rabbits. With the aid of coagglutination and indirect immunofluorescence all H. pylori strains tested were shown to contain cross reactive antigens, but no serum cross-reacted with all strains tested. Multiple, antigenically different, isolates were found in some patients and a provisional serogrouping based on heat-stable antigens was proposed.Acid glycine extracts from four H. pylori strains were prepared. Rabbit antisera against these, and ten further, strains showed extensive cross-reactions with all four extracts. An EIA based on H. pylori strain NCTC 11637 had a sensitivity of 90 % and a specificity of 87 %.In 197 unselected patient culture, histopathology using acridine orange or Giemsa staining, and serology was evaluated. 33.5 % of patients were infected by H. pylori. The sensitivities for culture/acridine orange stain/Giemsa stain were 0.94/0.86/0.91 respectively. The specificities were 1.0/1.0/0.84. For two commercial serologic tests the negative predictive values were 0.93/0.95 respectively. A strategy of serologic screening to avoidunnecessary endoscopies was suggested, but that positive serology be confirmed by histopathology.Sixty-one human gastric isolates of H. pylori were tested for their ability to induce oxidative burst in human neutrophils. A cell bound, heat-labile, property able to induce a strong and rapid oxidative burst in neutrophils in the abscence of opsonins, was found in about one third of strains tested. This property was significantly associated with peptic ulcer disease(p=0.0261, Fisher's exact test).Fifty-four clinical isolates of H. pylori were tested for cytotoxin production and their ability to induce oxidative burst in human neutrophils. Nonopsonised, 20 strains showed a rapid and strong oxidative burst, 30 a slow and weak response, and four remaining gave inconclusive results. Cytotoxin production was seen in 10 of 20 rapid and strong inducers, but only in 3 of 30 with a slow and weak response (p=0.0027, Fisher's exact test). 11/15 of the cytotoxin producing strains (p=0.0135) and 13/20 of the rapid and strong inducers (p=0.0209) were from 22 patients with peptic ulcer disease. The ability of some nonopsonised H. pylori to activate neutrophils showed eo-variation with cytotoxin production, but the two properties seem to be independent markers of peptic ulcer disease.With theuse of electron microscopy the interactions of human neutrophils with four nonopsonised H. pylori strains, two rapid and strong, two slow and weak inducers of neutrophil oxidative burst were studied in morphologic detail. The rapid inducers were phagocytosed within minutes, whereas the slow inducers showed little reaction even after one hour.Conclusions: Histopathology using acridine orange or Giernsa stains correlates well with culture. Serologic screening might be of value to reduce unnecessary endoscopies. A cellbound heat-labile property of some H. pylori strains able to nonopsonised induce a rapid oxidative burst in neutrophils is significantly associated with peptic ulcer disease. This property is also associated with, but independent of, cytotoxin production.

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