Chronic Helicobacter pylori (HP) infection is associated with local and systemic antibodies response. The aim of this study was to evaluate IgG and IgA anti-HP antibodies. Thirty patients with duodenal ulcers (HP-positive) were examined before treatment, 4 weeks and 3 months after anti-HP eradication therapy. IgG and IgA antibodies were estimated by means of ELISA. There was no correlation between serum IgG and IgA anti-HP antibodies. If a cut-off of 400 is chosen, 26 subjects were positive (87%) for IgG and 24 patients for IgA (80%) respectively. In cut-offs 200, 29 persons were positive (97%) for IgG and 30 patients for IgA (100%) before treatment. Mean IgG anti-HP antibodies decreased by 34% (4 weeks after eradication therapy) and by 72% (after 3 months), respecti- vely. Elevated values persisted in 22/30 (73%) (after 4 weeks) and in (50%) patients (after 3 months). Mean IgA anti-HP antibodies fell by 40% (in 4 weeks) and by 72% (3 months). Elevated values persisted in 14/30 (47%) (after 4 weeks) and in 10/30 (33%) patients (after 3 months), respectively. Anti-HP antibodies investigation is a global non-invasive test. Antibodies testing is readily available and cheap. IgG anti-HP estimation should be preferred. Interpretation of results can be done only with a good knowledge of the patient’s clinical situation.

        Key words: Helicobacter pylori, serum IgG and IgA antibodies, peptic duodenal ulcer disease, eradication therapy.