Prognostic Significance of Viral Load and Humoral Immune Response to Epstein Barr Virus in Gastric Cancer Patients Infected With Helicobacter Pylori

Abstract

Both Epstein-Barr virus (EBV) and H. pylori (НР) have been implicated in the carcinogenesis of the stomach. The results of studying НР-infection, antiviral humoral immune response to EBV and viral load in tumor tissues as well as their prognostic significance were analyzed in 54 patients with stage I-IV gastric cancer. It was shown that high titers of IgG to viral capsid antigen (VCA) (>1: 320), IgА to VCA (>1: 10) and IgG to EBV early antigens (EA) were typical for gastric cancer patients, thus indicating high antiviral immune responses. High titers of antiviral antibodies (IgG to VCA, IgG to EBV EA) and high intensity of viral load in the tumor (more than 3 copies of EBV DNA per 105 cells) were found to correlate with absence of HP infection. On the contrary, low concentrations of serum IgG to VCA were observed in most HP-positive patients (81%). The analysis of prognostic significance of parameters associated with infectious agents showed that the only concentration of IgA to EBV VCA in blood serum had a prognostic potential in the assessment of overall survival. The 2-and 3-year overall survival rates were higher in gastric cancer patients in whom serum EBV VCA-IgA antibody titers were not detected than in patients with serum EBV VCA-IgA antibody titers of >1: 10 (43.2±1.7% and 37.7±1.9% versus 12.1±1.5% and 8.7±0.9%, respectively; р<0.05).