Human herpesvirus-6-associated malignant lymphoma in a bone marrow transplant recipient

Human herpesvirus-6 (HHV-6), the sixth member of the herpesvirus family, can infect and replicate in human hematopoetic cell lines and can cause various illnesses in humans. HHV-6 has been suggested to be linked to various lymhoproliferative disorders. In vitro studies have demonstrated the oncogenic potential of HHV-6. The role of HHV-6 in human lymphomas needs to be examined.

To determine the involvement of HHV-6 in an immunoblastic lymphoma which developed in a bone marrow transplant patient, who had HHV-6 viremia.

Paraffin-embedded lymphoma tissues were examined for the presence of HHV-6 by immunohistochemistry, PCR and in-situ hybridization. This is a case report investigation.

An acute myelogenous leukemia patient received an allogeneic bone marrow transplant. He developed human herpesvirus-6 (HHV-6) viremia approximately 6 weeks after transplantation and HHV-6 was concurrently isolated from his bone marrow. Soon afterward, a large cell immunoblastic lymphoma was diagnosed. Complications of this tumor subsequently resulted in the patient's death. Periaortic lymph nodes and tumor cells infiltrating the liver and kidneys showed the presence of HHV-6 by immunohistochemistry and polymerase chain reaction (PCR). Southern blot analysis of the PCR amplified DNAs confirmed the presence of transforming pZVH14 DNA sequences of HHV-6 in the tumor tissues. Lymph nodes of 6 immunologically intact individuals were negative for HHV-6 by immunohistochemistry and PCR analysis. Tumor tissues were negative for EBV DNA by in situ hybridization with DNA probes specific for the EBV EBER RNAs.

Our data suggest that HHV-6 may be involved in the pathogenesis of some immunoblastic lymphomas.