Post-mortem diagnosis of encephalitis in a 75-year-old man associated with human herpesvirus-6 variant A

Abstract

An HHV-6 variant A infection is described in a 75 year-old man in association with meningoencephalitis identified at autopsy. The patient presented with fever and anorexia, then he developed altered consciousness, motor weakness, progressive lethargy, and coma, and died 21 days after hospital admission. Histopathological examination showed perivascular lymphocytic infiltrates in the central nervous system (CNS). Serum and cerebral spinal fluid (CSF) samples drawn from the patient were tested for viruses by a nested polymerase chain reaction (nPCR). HHV-6 primers A and C [Aubin et al., 1991: J Clin Microb 29: 367-372] and HS6AE and HS6AF from [Dewhurst et al. (1993): J Clin Microb 31: 416-418] disclosed a 750 bp genomic product of HHV-6 in both types of biological samples. Restricted site analysis showed that the HHV-6 DNA amplified belonged to the variant A of the virus. Short sequences of HHV-6 DNA could also be detected in the DNA extracted from formalin-fixed, paraffin-embedded sections of CNS tissues by use of one (GM5 and GM6) of three pairs of HHV-6 primers that were selected. Immunohistochemical examination of brain sections, employing a specific monoclonal antibody directed against the HHV-6 gp 102 protein, detected the viral antigen in neurons and glial cells.