Serologic Detection ofCagA PositiveHelicobacter pyloriInfection in a Northern Italian Population: Its Association with Peptic Ulcer Disease

Background. About 60–70% of Helicobacter pylori strains possess cagA (cytotoxin associated gene A) gene and express its product CagA, a highly immunogenic 128–140kD protein. Patients infected with CagA positive strains develop serum IgG anti-CagA. A serologic response to CagA has been detected in Helicobacter pylori infected patients with peptic ulcer more frequently than in those with gastritis alone. It is unclear whether this finding is consistent in different geographical populations. We investigated the relationship between anti-CagA seropositivity and peptic ulcer disease in a Northern Italian population. Materials and Methods. We studied 135 H. pylori infected patients: 65 with duodenal ulcer (DU), 28 with gastric ulcer (GU) and 42 with non ulcer dyspepsia (NUD). Sera from these patients were assayed by EIA (enzyme immunoassay) for anti-CagA IgG. Results. A high prevalence of anti-CagA was found associated with DU (86.1%) and GU (96.4%), while NUD patients showed anti-CagA seropositivity of 52.4% (Odd ratio, 5.66; 95% confidence interval, 2.23 to 14.32;p~