Epstein-Barr virus (EBV) in infectious mononucleosis: detection of the virus in tonsillar B lymphocytes but not in desquamated oropharyngeal epithelial cells.

AIMS Despite its well established tropism for B cells, the nature of the cellular compartment(s) mediating primary and persistent Epstein-Barr virus (EBV) infection is still a matter of controversy. In view of the association of EBV with several lymphoid and epithelial malignancies, resolution of this issue is important. METHODS Desquamated oropharyngeal epithelial cells from 10 patients with acute infectious mononucleosis and from seven chronic virus carriers were studied for evidence of EBV infection using in situ hybridisation for the detection of the small EBV encoded RNAs (EBERs) and of the viral genome. In addition, immunocytochemistry was used to detect the BZLF1 transactivator protein of EBV. RESULTS There was no evidence of latent or replicative EBV infection in oropharyngeal epithelial cells in any of the samples. In contrast, EBV infected B cells were readily identified in a tonsil from a patient with infectious mononucleosis. CONCLUSIONS The results suggest that oropharyngeal epithelial cells are not a major site of EBV infection and provide further support for the notion that B cells mediate primary and persistent EBV infection.