On the role of human herpesvirus 6 in viral latency in nervous tissue and in cerebral lymphoma.

Latent infections by human herpesvirus 6 (HHV6) in nervous tissue and its role in human disease are poorly understood. For the present study, an improved PCR method has been applied to brain tissue samples from 5 different brain regions from 20 forensic post-mortem cases without neurologic involvement. Spleen tissue from these cases as well as 5 cerebral lymphoma tissue samples were also examined. HHV6 DNA was detected in 3 of 20 brains. The viral sequences could be amplified from cortical brain tissue from these 3 cases. In one of these cases, HHV6 DNA was detectable in two separate tissue samples. PCR was negative in brain lymphoma and spleen tissue. These findings point toward HHV6 latency in brain tissue and might thus support the reported glial tropism of this virus. No role could be found for HHV6 in the pathogenesis of cerebral lymphoma.