Serological Response to Helicobacter Pylori Infection Evaluated By Immunoblot Assay in Health Adults, Patients with Non-Ulcer Dyspepsia, Peptic Ulcer Disease, and Gastric Cancer

Abstract

It is well known that helicobacter pylori (H. pylori, Hp) Plays a role in the pathogenesis of chronic gastritis and peptic ulcer diseases. Increasing evidences emphasize the close relationship between the bacterium and gastric cancer. The aim of this study is to elucidate the pathogenic role of H. pylori can predict particular disease entities. A total of 138 patients were recruited in this prospective study and they were divided in five groups after receiving upper gastrointestinal endoscopic examination: normal control; non-ulcer dyspepsia; gastric ulcer; duodenal ulcer; and gastric cancer. The normal control, non-ulcer dyspepsia and gastric cancer groups were further divided into Hp (+) and Hp (-) subgroups, while the gastric and duodenal ulcer groups were all Hp (+). Hp (-) implies positive results in at least two of the following studies: CLO test, Giemsa stain and culture, and they were all negative in the Hp (-) subgroup. The sera of the TOTALITY OF patients were analyzed with the immunoblotting technique. Five reaction bands could be recognized: 116 kDa (CagA), 89kDa (VacA), 35kDa, 26.5 kDa and 19.5 kDa. Analyzing the seroprevalence of the antibodies to Cag-A and VacA-positive H. pylori strain is high among the patients enrolled in this study and they are not a useful marker for screening high risk patients for a determined disease. According to this study, the immunoblot assay has no predictive value in Taiwanese patients. Interestingly, 8 ort of 9 Hp(-) gastric cancer patients(89%) the immunoblot assay for the H. pylori infection was found to be positive. This finding suggests that the bacterium may not survive in a hostile gastric environment such as mucosa atrophy, but its remote infection is still detected in the serum by the immunoblot assay which emphasizes on the possible role of the H. pylori in the pathogenesis of gastric cancer. In addition, the sera of these 8 CA-Hp (-) patients with a positive immuneoblotting were further analyzed with enzyme-immune-assay (EIA) and an interesting comparison between the two tests was done.