[Simultaneous detection by non-isotopic in situ hybridization of human papilloma viruses and Epstein-Barr virus during the lytic cycle in oral hairy leukoplakia lesions].

Oral hairy leukoplakia is almost only described in patients infected by the human immunodeficiency virus. Epstein-Barr virus, sometimes associated with human papillomavirus, is always involved in the occurrence of these lesions. We have investigated two cases of oral hairy leukoplakia with the goal of detecting EBV and HPV by using both in situ hybridization and immunohistochemistry. EBV genome was detected with biotinylated BamHI W cDNA probe in the two cases. Furthermore, EBV was found to be in lytic phase as demonstrated by the strong signal observed with FITC-labelled anti-sense BHLF1 oligonucleotide probes. This finding was further supported by the absence of labelling with EBV-latent-cycle markers such as EBER1/2 oligoprobes and anti-latent membrane protein 1 antibody. In addition, these two cases were positive for HPV genomes: 31-33-51 (n = 1) and 31-33-51 plus 6-11 (n = 1) as detected by in situ hybridization using different sets of biotinylated probes. The signal obtained with in situ hybridization (both HPV and EBV) was localized to the upper layers of epithelial cells. The mechanism of oral hairy leukoplakia remains still unknown, but this work emphasizes the value of in situ hybridization with nonisotopic probes in the detection of viral nucleic acids on routinely processed tissue sections. The fact that these lesions seem to precede the AIDS phase emphasizes the clinical implications of this diagnosis in HIV infected patients.