Expression of Epstein-Barr virus in cutaneous T-Cell lymphoma including mycosis fungoides

Cutaneous T-Cell lymphoma (CTCL) is a non-Hodgkin's lymphoma of unknown pat hogenesis. Mycosis fungoides (MF) is a clinically determined subset of CTCL with intensive infiltration of lymphoma cells into the epidermis. To deter mine whether Epstein-Barr virus (EBV) is associated with these lymphoma cel ls, we performed mRNA in situ hybridization in 5 cases of CTCL and 7 cases of MF using an RNA probe transcribed from BamHI W fragment of EBV genome. T hese transcripts were detected in the majority of lymphoma cells in all cas es examined. We also detected intensive hybridization signals on epidermal squamous cells contiguous to strong infiltration with lymphoma cells into t he subcutaneous connective tissue. Similarly, positive signals were detecte d using the probes transcribed from the sequences of EBV-encoded small nonp olyadenylated RNAs-1 (EBER1) and EBV-determined nuclear antigen-2 (EBNA2). The EBNA2 latent membrane protein-1 (LMP1) and BZLF1 product (ZEBRA) were a lso detected by immunofluorescence staining using monoclonal antibodies. Fu rther in the same experiment, we detected immunofluorescence of epi dermal cells. EBV DNA was detected in all cases tested by DNA in site hybridizatio n. Moreover, we also identified the signals on epidermal cells via this tec hnique. Polymerase chain reaction revealed amplified EBV DNA for most cases tested. Double staining with immunohistochemistry and RNA in situ hybridiz ation showed that T-cell marker-positive cells, but not EBV-carrying B-cell s, exhibited signals for the EB viral RNA. These findings suggest that EBV is involved in the neoplastic transformation of CTCL and MF. (C) 2001 Wiley -Liss, Inc.