EVALUATING THE RELATIONSHIP BETWEEN SERUM IMMUNOGLOBULIN G (IGG) AND A (IGA) ANTI-CAGA ANTIBODY AND THE CAGA GENE IN PATIENTS WITH DYSPEPSIA

Background and Aim:The cytotoxin-associated gene (cag) pathogenicity island is reported to be a major virulence factor of Helicobacter pylori infection. It is previously reported that the cagA-positive strains are more virulent, so it can be postulated that the cagA-positive gastritis will be more severe and the serum immunoglobulin G (IgG) and A (IgA) anti- CagA antibody titer will be higher. The aim of this study was to compare the relationship between IgG and IgA anti-CagA antibody and the cagA gene expression in patients with dyspepsiaMethods:Serum samples obtained from 130 dyspeptic patients with positive H. pylori in histological and Geimsa staining were tested for serum IgG and IgA anti-CagA antibody using the enzyme-linked immunosorbent Assay. The expression of the cagA gene was determined using PCR on the biopsy samples, taken via endoscopy.Results:The sensitivity of IgG anti-CagA antibody in identifying patients with a proven infection with the cagA-positive strains was 97.67%, and the negative likelihood ratios was 0.06. There was not significant correlation between serum IgA anti-CagA and the expression of the cagA gene among the dyspeptic patientsConclusion:The IgG antibody titer was significantly higher in patients with the cagA-positive H. pylori strain. However, in daily practice, the level of the IgG antibody titer cannot predict whether or not an individual carries a cagA-positive H. pylori strain, because there is a major overlap in the IgG antibody titer between the cagA-positive and cagA-negative patients

Keywords:

cagA , IgG anti-CagA , Dyspepsia