A total of 156 Helicobacter pylori strains isolated from adult patients (81 men, 75 women) with diagnosis of gastritis (43 strains GAS) and gastric ulcer (113 strains GU) were analyzed for the production of CagA protein by quantitative and qualitative immunoblot methods. 80% of gastric ulcer group strains (84% in men, 73% in women) produced CagA protein, while in the gastritis patients group only 63% of strains were CagA protein positive (59% in men, 65% in women). Quantitative production was estimated by CagA index (mean production of CagA protein in CagA positive strains) in both groups of strains GAS andGU in men and women. Strains ofGU group were shown to be higher producers (index CagA 2,42) as compared to GAS group (2,09). Index CagA was higher in strains isolated frommen (index CagA 2,54) than is strains fromwomen (index CagA 2,13). Conclusion: CagA production has been proved in 75% of analysed Helicobacter pylori strains. CagA positive strains were more frequent in gastric ulcer disease patients, slightly higher in the male than in the female patients. Strains isolated from men, irrespective of diagnosis (GAS and GU), are higher producers of CagA protein.

        Key words: CagA protein – Helicobacter pylori – gastric ulcer disease – gastritis – immunoblot.