Detection of EBER nuclear RNA in T-cell lymphomas involving the skin--an in situ hybridization study

To examine the relationship of Epstein-Barr virus (EBV) to cutaneous T-cell lymphoma (CTCL), a retrospective study was performed using formalin-fixed paraffin-embedded skin biopsies from 12 patients with cutaneous T-cell lymphoma. All cases were immunophenotyped with a panel of monoclonal antibodies including CD45RO, CD43, MB-2, CD20, and CD68. In situ hybridization studies to detect the EBV genome were performed, using the EBV-RNA probes for the early RNAs of EBV, namely EBER and BHLF. Among the 12 patients, six had primary CTCL, and six had secondary CTCL. The nasal cavity was the most frequent extracutaneous primary site. Immunophenotypically, all of the cases were of the T-cell lineage. In situ hybridization demonstrated a diffuse strong positive reaction for EBV transcripts (EBER) nuclear RNA in five out of 12 cases (41.7%) and a negative reaction for BHLF nuclear RNA probe in all the cases studied. Angiocentric lymphomas were positive in three out of the five cases (60%) studied. Secondary CTCL had a higher correlation with EBV than did primary CTCL, especially primary nasal T-cell lymphoma with subsequent cutaneous involvement. The EBV genome in lymphoma cells existed in a latently infected form but not in an actively replicating form. Three out of the five EBV-positive patients died, 8 months to 4 years after diagnosis. EBV infection alone in the lymphoma does not seem to affect the prognosis of CTCL patients significantly.