Clinicopathological, immunological and genetic studies of CD30+ anaplastic large cell lymphoma of B-cell type; association with Epstein-Barr virus in a Japanese population.

The clinicopathological features, the immunophenotype, and the presence of Epstein-Barr virus (EBV)-associated genomes and gene products were examined in 17 cases of CD30+ anaplastic large cell lymphoma (ALCL) of B-cell type. Microscopically, the 17 cases were divided into ten cases of the monomorphic type and seven cases of the pleomorphic type. EBV was detected in 6 of 17 cases (38 per cent) by RNA in situ hybridization (ISH) with EBV-encoded RNA (EBER1). EBER1+ cases consisted of two cases (20 per cent) of the monomorphic type and four cases (57 per cent) of the pleomorphic type. The five EBER1+ cases showed clonality of the EBV genome by Southern blotting, consistent with the presence of EBV in a monoclonal proliferation. The EBV-encoded latent membrane protein 1 (LMP1) was found in all six EBER1+ cases and EBV-encoded nuclear antigen 2 (EBNA2) was present in two cases by immunohistochemistry. No expression of LMP1 or EBNA2 was observed in the EBER1-cases. The EBER1+ cases had a tendency for a more favourable prognosis than the EBER1-cases. It is concluded that EBV has an association with CD30+ ALCL of B-cell type in the Japanese population studied, and especially with the large pleomorphic type. EBV infection may play a pathoaetiological role and may influence clinical behaviour.