Relationship between gastric ulcer and Helicobacter pylori VacA detected in gastric juice using bead-ELISA method

VacA is an important pathogenetic factor produced by Helicobacter pylori. VacA has often been detected in supernatants of liquid cultures or lysates of whole bacterial cells. However, no studies have ever tried to assay VacA produced in the human stomach. We applied a very sensitive and simple method, bead-ELISA, to detect VacA in gastric juice.

Forty-eight H. pylori-positive patients (16 nonulcer dyspepsia, 16 gastric ulcer, and 16 duodenal ulcer) and four H. pylori-negative nonulcer dyspepsia patients had endoscopy performed and gastric juice were aspirated. Polystyrene beads coated with the antibody to VacA, were used in this bead-ELISA method. The nucleotide sequences of vacA in the signal and middle regions were investigated.

Of the 48 samples that were positive for H. pylori, 21 [43.8%] were found to be VacA positive in gastric juice. The average and maximum concentrations of detected VacA in gastric juice were 143.2 +/- 216.5 and 840 pg/ml, respectively. The average density of VacA from gastric ulcer patients (227.5 +/- 276.7 pg/ml) was higher than that found in nonulcer dyspepsia (51.8 +/- 39.8 pg/ml) and duodenal ulcer (49.2 +/- 21.5 pg/ml) patients. There was no relationship between VacA in gastric juice and vacA genotype.

VacA in gastric juice could be directly detected by bead-ELISA. In this study, the diversity of disease outcome was associated with not the quality but the quantity of VacA. Therefore, not only the quality but also the quantity of VacA is important etiological factors in the pathogenesis of mucosal damage.