Seroprevalence of anti-Helicobacter pylori and anti-CagA antibodies in peptic ulcer and healthy subjects in the city of Rafsanjan

BACKGROUND: Helicobacter pylori (H. pylori) infection is thought to play an etiologic role in several gastroduodenal diseases including gastric ulcer, duodenal ulcer, gastric MALT lymphoma, and distal gastric cancer. Several studies have suggested that H. pylori which express cytotoxin-associated gene A (CagA) may be more virulent than those that do not, but limited populations have been studied to date. The aims of the present study were to evaluate the seroprevalence of anti-H. pylori IgG, IgA and anti-CagA antibodies in peptic ulcer (PU) patients and healthy individuals in the city of Rafsanjan.
 METHODS: A total of 60 PU patients (30 males and 30 females, aged 17 to 60 years) and 138 age-matched healthy individuals (65 males, 73 females) were enrolled in this study. Diagnosis of PU disease was established on the basis of findings by gastrointestinal endoscopy. The control group was recruited from among healthy blood donors referred to Blood Transfusion Center of Rafsanjan. A blood sample was collected from each participant and the sera were tested for the presence of anti- H. pylori IgG and IgA antibodies and antibody to bacterial virulence factor (CagA) by use of enzyme-linked immunosorbent assay. The serum concentrations of anti-H. pylori IgA and anti-CagA antibody were expressed as mean ± SD in each group.
 RESULTS: In PU patients the overall seroprevalence of anti-H. pylori IgG (95.8%), IgA (96.6%) and anti-CagA (91.6%) were higher than those observed in the control group (73.2%, P<0.003; 79%, P<0.002; 47.82%, P<0.0000001; respectively). In the control group the prevalence of serum anti-CagA IgG antibodies was significantly higher in males compared to females (58.46% vs. 38.35%; P<0.01). Moreover, the mean titer of anti-H. pylori IgA antibodies was significantly higher in anti-CagA+ subjects compared to anti-CagA- subjects (47.5 Uarb/ml ± 35 vs. 27 Uarb/ml ± 18; P<0.01). Furthermore, an inverse association was found between levels and the prevalence of anti-CagA with advanced
 age.
 CONCLUSIONS: These results show that the H. pylori-specific antibodies, especially anti-CagA were more prevalent among PU patients compared to the control group. Moreover, it seems that the males are more susceptible to infection with CagA+ strains compared to females. It was also found that the magnitude of the IgG response to CagA decreased with advanced age. Furthermore, the results of the present study demonstrated that the seroprevalence of H. pylori infection is widespread among the healthy subjects in the city of Rafsanjan.
 KEY WORDS: Seroprevalence, Helicobacter pylori, IgG, IgA, Anti-CagA, peptic ulcer, Rafsanjan