Anti-CagA antibodies, a new diagnostic tool in peptic ulcer and non-ulcer dyspepsia: a case control study

Background: Helicobacter pylori is a gram negative microaerophilic spiral bacilli, which causes duodenal and gastric ulceration. Also this organism cause distal gastric adenocarcinoma and primary gastric lymphoma. The most important Helicobacter pylorus virulence factor is cytotoxin associated gene A (cagA) Pathogenicity Island that cause secretion of antibody by stimulation of immune system. Measurement of the serum antibody can be used to diagnosis strain of Helicobacter pylorus that causes peptic ulcer disease (PUD). Serological discrimination between strain types would reduce the need to emergent endoscopic studies. The aim of this study was comparison of serum anti-CagA antibodies of patients with peptic ulcer disease and patients with Non-ulcer dyspepsia. Methods: This case-control study was carried out from october 2011 to october 2012, in 130 patients who complained of dyspepsia more than six months and referred to gastroenterology and endoscopic ward of Firoozgar Hospital, Iran University of Medical Sciences, Tehran. Serum sample obtained from all patients. Anti-CagA antibodies levels were measured in serum samples using ELISA technique. Patients with peptic ulcers as cases and patients without peptic ulcer in endoscopy study were considered as controls. Results: One hundred thirty patients were enrolled in the study and equally two groups (65 patients in case group and 65 patients in control group). Fifty nine subjects of case group (90.76%) and 37 subjects of control group (56.92%) had positive serum anti-CagA antibody (P= 0.003). Sixty one percent of anti-CagA antibodies positive patients and 17.6% of anti-CagA antibodies negative patients had peptic ulcer (P= 0.003). (Odds ratio= 7.4; 95%CI: 2.8-19.7; P= 0.003). Conclusion: The detection of CagA antibodies as an additional and noninvasive test in association with determination of serum anti-CagA antibodies, could help better detection of risk factors of peptic ulcer disease. Also it can reduce the emergency endoscopy process. We can use this technique in patients with dyspepsia who had no warning signs or malignant disease and not taking a nonsteroidal anti-inflammatory drugs in primary care of clinical practices