CELLULAR-LOCALIZATION OF HUMAN HERPESVIRUS-6 IN THE BRAINS OF CHILDREN WITH AIDS ENCEPHALOPATHY

Human herpesvirus-6, the etiologic agent of exanthem subitum, is a ubi quitous virus that infects almost all children by the age of 2 years a nd that has previously been shown to be neuroinvasive. These character istics suggest that human herpesvirus-6 may be important in the neurop athogenesis of acquired immune deficiency syndrome (AIDS) in children. To address this hypothesis, we evaluated postmortem pediatric brain t issues for the presence of human herpesvirus-6 infection. Using in sit u hybridization with a digoxigenin-labeled DNA probe for the large teg ument protein gene of human herpesvirus-6, we detected nuclear signals in postmortem brain tissue from 4/5 children with human immunodeficie ncy virus-1 encephalitis. Human herpesvirus-6 DNA was found in numereo us oligodendrocytes of the white matter and less frequently in astrocy tes, macrophages, microglia and neurons. The human herpesvirus-6 posit ive cells detected by in situ hybridization were not immunoreactive ei ther for human herpesvirus-6 early nuclear phosphoproteins or for surf ace glycoproteins associated with productive infection. Only rare huma n herpesvirus-6 infected cells were found in age-matched control brain tissues. No human herpesvirus-6 infected cells were found in human fe tal brain tissue. These data suggest that human herpesvirus-g is more extensively disseminated in neural cells in the presence of human immu nodeficiency infection and immunodeficiency in pediatric AIDS patients , and it may contribute to the pathogenesis of AIDS encephalopathy.