Low incidence of Epstein-Barr virus presence in primary cutaneous T-cell lymphoproliferations

Multiple biopsies taken from 76 European human immunodeficiency virus (HIV)-negative patients with primary cutaneous T-cell lymphoproliferations, including mycosis fungoides (MF), pleomorphic T-cell lymphoma (PMTCL), anaplastic large cell lymphoma (ALCL) and lymphomatoid papulosis (LyP) were investigated for the presence of Epstein-Barr virus (EBV) through a combined approach. Polymerase chain reaction (PCR) was employed for EBV-DNA detection, in situ hybridization (ISH) for cellular localization of EBV-encoded nuclear RNAs (EBER1 and EBER2) and immediate early Bam H-fragment; lower frame (BHLF) RNA, and immunohistology (IH) for the identification of EBV-encoded latent membrane protein 1 (LMP1) and of nuclear antigen (EBNA) 2 expression. EBV-DNA was detectable by PCR in 15 of 76 cases (19.7%). EBER-ISH combined with IH identified a variable, usually very low, number of infected neoplastic cells in only seven of the 15 EBV-DNA-harbouring cases. This discrepancy between the results obtained with PCR and ISH is apparently caused by the low number of the infected cells per tissue section. The PMTCL entity produced the greatest number of positive cases, whilst ALCL and LyP cases were almost constantly devoid of the virus. BHLF transcripts were not detectable in any case, nor did any of the EBER-positive cells show an LMP1 or EBNA2 expression. These data show that primary cutaneous T-cell lymphoproliferations display an infrequent association with a latent EBV infection and that the pathogenic role of the virus in the positive cases remains obscure as the virus frequently infects only a minority of the atypical cells.