SEROLOGIC DETECTION OF CAGA POSITIVE HELICOBACTER-PYLORI INFECTION INA 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 high ly 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 ul cer more frequently than in those with gastritis alone. It is unclear whether this finding is consistent in different geographical populatio ns. We investigated the relationship between anti-CagA seropositivity and peptic ulcer disease in a Northern Italian population. Materials a nd Methods. We studied 135 H. pylori infected patients: 65 with duoden al ulcer (DU), 28 with gastric ulcer (GU) and 42 with non ulcer dyspep sia (NUD). Sera from these patients were assayed by EIA (enzyme immuno assay) for anti-CagA Igc. Results. A high prevalence of anti-CagA was found associated with DU (86.1%) and GU (96.4%), while NUD patients sh owed anti-CagA seropositivity of 52.4% (Odd ratio, 5.66; 95% confidenc e interval, 2.23 to 14.32; p<.001, DU vs. NUD; Odd ratio, 24.5; 95% co nfidence interval, 3.05 to 197.6; p=.003, GU vs. NUD). DU patients sho wed anti-CagA seropositivity titer (1.15 (0.61 OD, mean (SD) higher th an that of NUD patients (0.78 (0.60 OD, mean (SD) (p<.05). Conclusions . These data demonstrate in a Northern Italian population that anti-Ca gA seropositivity is strongly associated with peptic ulcer disease and suggest that CagA might play an important role in ulcer pathogenesis.