[Helicobacter pylori CagA antigen antibodies]

Abstract

Background: CagA antigen of Helicobacter pylori is highly immunogenic in humans. There is an increasing evidence that infection with CagA-positive strains is related to the development of peptic ulcer disease, atrophic gastritis, or gastric cancer. The aim of our study was to assess seropositivity to CagA in a group of 95 clinically symptomatic adults who underwent gastroduodenoscopy and to correlate results to their disease characteristics.

Methods and results: Serum immunoglobulin G antibodies to CagA detected by ELISA kit (Helicobacter p120, Viva Diagnostika, Germany) were compared to standard IgG specific antibodies against a pool of H. pylori antigens Synelisa Pin plate, ELIAS, Germany). Immunoglobulin G antibodies to CagA were present in 5/31 (16%) serum samples from H. pylori negative persons and 10/28 (36%) serum samples from H. pylori positive patients without peptic ulcer disease compared with 8/11 (73%) H. pylori positive patients with peptic ulcer disease in the past, 11/13 (85%) H. pylori positive patients with duodenal ulcers or duodenitis and 4/5 (80%) H. pylori positive (1/7, 14% H. pylori negative) serum samples from patients with gastric resection for peptic ulcers in the past. Serum levels of antibodies to CagA in the groups of patients with peptic ulcer disease in the past, with present duodenal ulcers of duodenitis and in H. pylori infected patients with gastric resection were significantly higher then those of H. pylori infected patients without peptic ulcer disease (P < 0.05). On the other hand, there was no significant difference in the presence of the specific antibodies against at pool of H. pylori antigens between these four groups.

Conclusions: These data suggest that serologic response to the CagA antigen is more prevalent in H. pylori positive persons with present or past peptic ulceration than among infected persons without peptic ulcer disease. The presence of antibodies to CagA in H. pylori positive persons may be useful for the identification of patients with higher risk or more severe disease.