[Evaluation of Western Blot method for the detection of antibodies to Helicobacter pylori antigens in patients with gastric carcinoma and cases with epigastric complaints].

Helicobacter pylori proteins CagA (cytotoxin-associated gene A) and VacA (vacuolating cytotoxin A) are among the virulence factors of this species. CagA gene carrying H. pylori strains are particularly associated with gastric adenocarsinoma. This study was conducted to evaluate Western Blot (WB) method to determine specific H. pylori antibodies in a group of patients with gastric cancer and in a control group with no malignancy. A total of 99 patients with gastric cancer (94 adenocarcinoma, 2 adenosquamous cell carcinoma, 3 non-Hodgkin lymphoma) and 150 control cases with epigastric complaints such as nausea, vomiting, diarrhea, gastroesophageal reflux and abdominal pain, were included to the study. H. pylori IgG-ELISA was positive in all study (mean age: 56.7 +/- 1.2 years, 62 male) and control (mean age: 24.2 +/- 1.3 years, 64 male) patients. Specific antibodies against CagA, VacA, OMP (outer membrane protein)-67, urease-A, urease-B, HSP (heat shock protein) and flagellin antigens determined by a commercial WB-based kit (RIDA Blot Helicobacter, R-Biopharm GmbH, Germany). Interestingly, no anti-VacA positivity was detected in none of the patient and control groups. The positivity rates for H. pylori CagA, OMP-67, urease A, urease-B, flagellin and HSP specific antibodies were as 78%, 54%, 37%, 60%, 53% and 82% in the gastric cancer group and 85%, 71%, 55%, 43%, 61% and 75% in the control group, respectively. There was no statistically significant difference (p > 0.05) between gastric carcinoma and control groups in terms of CagA, HSP and flagellin antibodies (p > 0.05). On the other hand, a statistically significant difference was found between the 2 groups in terms of urease-A, urease-B and OMP-67 (p < 0.01). These results suggested that this test should be assessed again by the manufacturer for its detection power directed towards specific H. pylori antibodies, especially for Vac-A. Further molecular and clinical studies are necessary to determine the factors that affect H. pylori virulence and disease prognosis.