Seroprevalence of eight Helicobacter pylori antigens among 182 patients with peptic ulcer, MALT gastric lymphoma or non-ulcer dyspepsia. Higher rate of seroreactivity against CagA and 35-kDa antigens in patients with peptic ulcer originating from Europe and Africa.

Abstract

It has been suggested that Helicobacter pylori may induce more or less severe gastroduodenal disease according to the strain virulence. We used Western blot to determine antigenic profiles associated with duodenal or gastric ulcer disease, MALT lymphoma and non-ulcer dyspepsia, and to identify geographical differences. One hundred and eighty-two consecutive patients with H. pylori infection were studied. H. pylori infection was diagnosed by a rapid urease test or histological examination of gastric biopsy samples. Bacterial density and gastritis were assessed histologically by using the Sydney scoring system. Western blot was used to identify antibodies against eight antigens (CagA, VacA, urease A, heat shock protein B, and 19.5, 26.5, 30 and 35 kDa). Patients were questioned on their smoking habits and place of birth and childhood. There were 73 patients with duodenal ulcer, 30 with gastric ulcer, eight with erosive duodenitis, 17 with gastric MALT lymphoma and 54 with non-ulcer dyspepsia. Most (>85%) were seropositive for the heat shock protein B and 26.5-kDa antigens. The prevalence of the other antigens ranged from 45% (VacA) to 68% (urease B). The seroprevalence of CagA antigen was significantly higher (P < 0.01) in cases of gastroduodenal ulcer (84%) than non-ulcer dyspepsia (37%). Similarly, 35-kDa antigen reactivity was more frequent (P < 0.05) in duodenal ulcer patients (75%) than in those with non-ulcer dyspepsia (50%). The antigenic profiles associated with MALT gastric lymphoma and non-ulcer dyspepsia were similar. Multivariate analysis showed that only gastroduodenal ulcer was significantly associated with CagA. Gastroduodenal ulcer and a childhood spent in Africa were both associated with 35-kDa and combined CagA-35-kDa reactivity. This study confirms the strong seroprevalence of H. pylori CagA antigen and shows a high prevalence of the 35-kDa antigen in patients with gastroduodenal ulcer, especially those raised in Africa. There was no difference in the serological pattern between patients with non-ulcer dyspepsia and those with MALT lymphoma. Tests for antibodies to the CagA-35-kDa antigen combination might be used to select H. pylori-infected dyspeptic patients warranting treatment.