The immune response to Helicobacter pylori (Hp) importantly determines the pathogenesis of infection as well as the success of antibiotic eradication of the bacteria. The investigators want to demonstrate the importance of cathepsin X (CTSX), a cysteine protease, for the Hp eradication success. The diversity of the innate immune response to H. pylori antigens leading to either successful eradication of the infection or maintenance of chronic inflammation is connected to CTSX. The aim of this study is to determine whether H. pylori suppresses the CTSX expression and cytokine secretion in macrophage cell line THP-1 in the individuals that are not capable of eradicating the infection, opposite to H pylori in patients with successful H pylori eradication . The investigators also investigate the possibility whether strain-dependent differences in H. pylori lipopolysaccharide (LPS) influence the CTSX expression and cytokine secretion.

Inclusion Criteria:People with helicobacter gastritis and Helicobacter sensitive to antibiotic therapy but failure of therapy -

Exclusion Criteria:People with helicobacter gastritis who did not eradicate Helicobacter pylori because of primary resistance to antibiotics.

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The investigators invited people who had problems with H. pylori(Hp) infection. They were tested for Hp and if positive they were enrolled in the study.All patients were treated with appropriate therapy.3 months after antibiotic therapy, the patients were re-examined. The patients that had a positive test were invited to another re-evaluation.If H. pylori sensitive to all antibiotics tested was isolated, we enrolled the patient in the study-7 patients. The investigators took the patient's first isolate and used it to prepare antigens for the study. All patients in the control group, 7 patients, were successfully cured with first attempt of antimicrobial therapy.Seven months after last patient enrolled, all the participants will be re-evaluated to see if they are still infected with Hp.