Published online Sep 21, 2006. doi: 10.3748/wjg.v12.i35.5711
Revised: May 15, 2006
Accepted: May 25, 2006
Published online: September 21, 2006
AIM: To investigate reactivated Epstein-Barr virus (EBV) infection as a cause for chronic hepatitis.
METHODS: Patients with occasionally established elevated serum aminotransferases were studied. HIV, HBV and HCV-infections were excluded as well as any other immunosuppressive factors, metabolic or toxic disorders. EBV viral capsid antigen (VCA) IgG and IgM, EA-R and EA-D IgG and Epstein-Barr nuclear antigen (EBNA) were measured using IFA kits. Immunophenotyping of whole blood was performed by multicolor flow cytometry. CD8+ T cell responses to EBV and PHA were determined according to the intracellular expression of IFN-γ.
RESULTS: The mean alanine aminotransferase (ALT) and gamma glutamyl transpeptidase (GGTP) values exceeded twice the upper normal limit, AST/ALT ratio < 1. Serology tests showed reactivated EBV infection in all patients. Absolute number and percentages of T, B and NK cells were within the reference ranges. Fine subset analysis, in comparison to EBV+ healthy carriers, revealed a significant decrease of naive T cells (P < 0.001), accompanied by increased percentage of CD45RA- (P < 0.0001), and terminally differentiated CD28-CD27-CD8+ T cells (P < 0.01). Moderately elevated numbers of CD38 molecules on CD8+ T cells (P < 0.05) proposed a low viral burden. A significantly increased percentage of CD8+ T cells expressing IFN-γ in response to EBV and PHA stimulation was registered in patients, as compared to controls (P < 0.05). Liver biopsy specimens from 5 patients revealed nonspecific features of low-grade hepatitis.
CONCLUSION: Chronic hepatitis might be a manifestation of chronic EBV infection in the lack of detectable immune deficiency; the expansion of CD28-CD27- and increase of functional EBV-specific CD8+ T cells being the only surrogate markers of viral activity.