Presence of Epstein-Barr virus in cutaneous lesions of mycosis fungoides and Sézary syndrome.

It has been suggested that prolonged antigenic stimulation contributes to the development of epidermotropic cutaneous T cell lymphoma (CTCL), mycosis fungoides and Sézary syndrome, characterized by a cutaneous infiltration of proliferating helper T cells. Since Epstein-Barr virus (EBV) antibodies were increased in CTCL sera, we investigated a possible etiologic role for EBV in epidermotropic CTCL by looking for the EBV genome in 25 cutaneous biopsies of mycosis fungoides or Sézary syndrome and 12 reactional inflammatory skin lesions. The use of a non-isotopic in situ hybridization procedure based on the detection of Epstein-Barr encoded RNAs with biotinylated oligonucleotide probes (EBER) revealed 32% of the lesions with CTCL to be positive for EBV (3 in dermis, 3 in epidermis, 2 both in dermis and epidermis), as compared to no detection of the EBV genome in the reactional inflammatory skin lesions. Moreover, a combined hybridization (EBER probe) and immunochemistry technique (anti-CD3 or anti-Kil monoclonal antibody) permitted the identification of EBV in T cells of dermis and in keratinocytes, respectively. The identification of EBV in epidermotropic CTCL suggests that this virus could play a role in the development of these CTCLs, either as an etiological agent or more probably as a chronic activating agent. Indeed, the infection of keratinocytes by EBV could activate them and so induce the production of in situ cytokines (IL1a, IL6, TNFa) playing a role in the development of tumoral infiltrate.