Persistent infection by HCV and EBV in peripheral blood mononuclear cells and risk of non-Hodgkin's lymphoma.

Hepatitis C virus (HCV) and Epstein-Barr virus (EBV) have been repeatedly associated with risk of non-Hodgkin's lymphoma (NHL) in studies focusing on serological evidence of infection. We investigated NHL risk in association with detection of HCV-RNA or EBV-DNA in the peripheral blood mononuclear cells (PBMC). The study involved 91 NHL cases and 182 controls nested in the Italian branch of the EPIC (European Prospective Investigation of Cancer and nutrition) cohort, which obtained blood samples from 47,749 healthy volunteers between 1993 and 1998 in 5 Italian cities. NHL cases were identified until June 2005 through linkage with records of the Cancer, Mortality, and Hospital Discharge Registries. For all study subjects, we performed viral genome analyses on DNA and RNA extracted from buffy-coats and analysed EBV and HCV antibodies. The odds ratios (ORs) of NHL were 1.2 (95% confidence intervals: 0.4-3.8; 5 exposed cases) for PBMC HCV infection and 1.2 (0.7-2.3; 24 exposed cases) for PBMC EBV infection. Similar OR estimates were found for detection of EBV and HCV antibodies. These null results, although based on a relatively small sample size, suggest that persistent EBV and HCV infection in the PBMC is not a stronger predictor of NHL risk than serological evidence of infection.