CagA protein seropositivity in a random sample of adult population and gastric cancer patients in Estonia.

Objective The prevalence of antibodies to CagA protein, associated with the risk of developing gastric cancer (GC), was studied in an Estonian adult population with a high prevalence of Helicobacter pylori (HP) infection and in a group of GC patients. Design In a representative sample of a random adult population from the South Estonian town of Karksi-Nuia, containing 199 subjects (86 M, 113 F, mean age 42.4) and in 45 (22 M, 23 F, mean age 64.5) consecutive patients with gastric adenocarcinoma, recruited during the periods 1986-87 and 1995-96 in the Hospital of Oncology, University of Tartu, anti-CagA IgG antibodies were determined by enzyme-linked immunosorbent assay (ELISA) using a recombinant fragment of CagA protein. The occurrence of anti-CagA IgG in ELISA was compared with immunoblot results for 141 subjects. Results Seropositivity to acid glycine extracted cell surface proteins of HP was 85% in the population and 91% in GC patients (p = 0.39). Anti-CagA IgG antibodies were present in 63% of the population and in 87% of GC patients (p = 0.004). The highest prevalence of anti-CagA IgG in the population sample occurred in the age group 20-29 (76%). A comparison of anti-CagA positivity evaluated by using ELISA and immunoblot showed an agreement of results in 80% of cases. Conclusion HP seropositivity was similarly high in the Estonian random adult population sample and in GC patients, however, the prevalence of anti-CagA IgG was significantly higher in GC patients. Moreover, persons aged 20-29 years in the population possess the highest prevalence of anti-CagA IgG and should be given further attention with respect to the development of GC later in life.