Association of human herpesvirus 6 (HHV-6) in hematological malignancies and vertical transmission of HHV-6 genome

点击翻译按钮获取中文摘要

1. Over the past 15 years three new human hepesviruses (HHV-6, HHV-7 and HHV-8) have been recognized and implicated as eliological agents of several human diseases. HHV-6 has been cited as a possible cause or as a modulating element of certain human lymphoproliferative disorders. We found two cases of lymphoma and ALL carrying chromosomally integrated HHV-6 genomes. To assess the possibility of chromosomal transmission of HHV-6 DNA, we looked for the viral genome in their families. In both cases, the HHV-6 genomes were detected in their offspring at the identical sites of viral integration of the patients. We propose a novel latent form for HHV-6, in which integrated HHV-6 genome can be chromosomally inherited.2.(1) Despite the genomic homology, and serological cross-reactivity between HHV-6 and HHV-7, evidence for the association of HHV-7 with lymphoproliferative disorders has been scarce. We searched for the HHV-7 genome in patients with lymphocytic leukemia. Sixty-one patients were enrolled : 33 adult ALL ; 15 childhood ALL ; and 13 CLL. HHV-7 genome was not found in any of our samples, suggesting that HHV-7 is unlikely to play a pathogenetic role in lymphocytic leukemia.(2) We evaluated the presence of four human herpesviruses (EBV, HHV-6, HHV-7 and HHV-8) in the specimens from 14 patients with primary ocular MALT lymphoma. EBV DNA were detected in 4 samples by PCR, and 4 cases were positive for HHV-6DNA. Neither HHV-7 nor HHV-8DNA could by detected. These findings suggested the possible involvement of EBV and HHV-6 in the pathogenesis of a subset of low-grade primary ocular lymphomas.(3) HHV-6 genome was detected in the brain lesions of progressive multifocal leukoencephalopathy (PML) developing in a lymphoma patient. HHV-6 is known to be reactivated during immunosuppression and can cause several fatal complications. We propose an association of HHV-6 with the pathogenesis of PML in immunocompromised hosts.