Assessment of the relationship of chronic opisthorchiasis to Epstein-Barr virus infection as well as some cytogenetical and immunological parameters in two comparable Siberian regions.

Abstract

Previous studies have shown an increase in the frequency of chromosomal abnormalities in the peripheral blood lymphocytes from opisthorchiasis patients. Some evidence suggests that there is an association between chronic opisthorchiasis and certain herpes viruses. To study the relationship of opisthorchiasis to the reactivation of Epstein-Barr virus (EBV) infection as well as the influence of opisthorchis infection on some cytogenetical and immunological parameters, we used the indirect immunofluorescence for measuring some virus specific antibodies, the cytokinesis-block lymphocyte micronucleus assay, and the quantitative immunodiffusion method for measuring immunoglobulin concentrations in serum. A total of 1,580 people were monitored in two comparable Siberian regions: in the Ob River region which is endemically related to opisthorchiasis caused by Opisthorchisfelineus and in the nonendemic control Yenisey River region. There was no significant difference in each of the tested parameters between two uninfected controls from the endemic Ob and nonendemic Yenisey regions. We have found significant difference (p < 0.01) in the frequency of micronucleated cytokinesis-block lymphocytes and the antibody levels against certain EBV antigens between the examined inhabitants of the opisthorchis-infected Ob and uninfected Yenisey regions. Furthermore, there were a good correlation (r = + 0.72) between the increase in titres of antibody to the EBV capsid antigen and the high frequency of micronucleated lymphocytes in the opisthorchis-infected Ob population. Also, levels of both IgG and IgM were increased in opisthorchiasis patients. This study confirms an association between chronic opisthrochiasis and reactivation of EBV which may be implicated in the development of cancer in opisthorchiasis patients.