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Chapter 74 : Human Herpesviruses 6, 7, and 8
This chapter focuses on the immunologic and molecular diagnosis and monitoring of infections with human herpesvirus 6 (HHV-6), HHV-7, and HHV-8 and provides information on the unique features of the epidemiology and biological and clinical characteristics of these viruses. Monoclonal antibodies suitable for the direct detection of HHV-6 antigens by immunofluorescence have been developed and employed with tissue samples. HHV-6 can be isolated from peripheral blood mononuclear cells (PBMC) grown in primary culture or by cocultivation of these cells with stimulated cord blood cells (CBC) or donor PBMC. A number of tests have been developed for the serodiagnosis of HHV-6 infection, of which indirect immunofluorescence assay (IFA), anti-complement immunofluorescence (ACIF), enzyme immunoassay (EIA), and the neutralization (NT) test have been most commonly employed. The IFA is the most widely used method for detecting. Western immunoblots and radioimmunoprecipitation are other serologic assays that are used to measure antibody to HHV-6. These assays have been used mainly to identify and analyze the role of specific proteins in the immune response to HHV-6. The diagnosis of HHV-6 infection is increasingly being made by the amplification of viral DNA by PCR. The methods for laboratory diagnosis of HHV-7 are essentially identical to those for diagnosis of HHV-6 and currently include the direct examination of clinical specimens for viral antigens by immunohistochemistry or viral nucleic acids by in situ hybridization and PCR antibodies to HHV-6.