Relation of Serum Gastrin and Pepsinogen Levels to Serologic Recognition of CagA and VacA in Helicobacter pylori Infection

Background/Aims: Helicobacter pylori(H. pylori) infection is associated with increases in serum gastrin and pepsinogen(PG) in patients with gastritis and peptic ulcer disease. H. pylori strains show phenotypic heterogeneity in their ability to express CagA(cytotoxin-associated protein) and VacA(vacuolating cytotoxin), which are tbought to be virulence factors. The aim of the study was to investigate whether the biochemical(serum gastrin and PG) changes in H. pylori infection are related to the bacterial expression of CagA and VacA. Methods: The subjects were 80 patients who had underwent diagnostic esophagogastroduodenoscopy; 49 with functional dyspepsia(FD), 10 with gastric ulcer(GU), 10 with duodenal ulcer(DU) and 11 with gastric cancer(GC). H. pylori infection was assessed by rapid urease(CLO) test and histology. Bacterial expression of CagA and VacA was determined indirectly by assaying serum IgG antibodies to these proteins by Western blotting using a Helico Blot 2.0 kit. Basal serum levels of gastrin, PG I and PG II were determined by radioimmunoassay. Results: The serologic positive rate for CagA in H. pylori-positive patients with FD, GU, DU and GC, was 80%, 88%, 100% and 88% respectively. For VacA, positive rate was 41%, 38%, 88%, and 63%, respectively(FD vs DU, p