title: Diagnostic assays for active infection with human herpesvirus 6 (HHV-6).
abstract: BACKGROUND
  Human herpesvirus 6 (HHV-6) causes ubiquitous infection in early childhood with lifelong latency or persistence. Reactivation of HHV-6 has been associated with multiple diseases including encephalitis. Chromosomal integration of HHV-6 also occurs. Previous studies have suggested that the detection of HHV-6 DNA in plasma is an accurate marker of active viral replication.
  
  
  OBJECTIVE
  We sought to determine whether PCR assays on plasma could correctly differentiate between primary HHV-6 infection, chromosomal integration of HHV-6 and latent HHV-6 infection.
  
  
  METHODS
  We performed qualitative PCR, real-time quantitative PCR (RQ-PCR), and reverse-transcriptase PCR (RT-PCR) assays on samples of peripheral and cord blood mononuclear cells, as well as plasma, from groups of subjects with well defined HHV-6 infection, including subjects with chromosomally integrated HHV-6.
  
  
  CONCLUSIONS
  The detection of HHV-6 DNA in plasma was 92% sensitive compared to viral isolation for the identification of primary infection with HHV-6. All plasma samples from infants with chromosomally integrated HHV-6 had HHV-6 DNA detectable in plasma while only 5.6% were positive by RT-PCR. The specificity of plasma PCR for active replication of HHV-6 was 84% compared to viral culture while the specificity of RT-PCR was 98%. Our results demonstrate that qualitative or quantitative PCR of plasma is insufficient to distinguish between active viral replication and chromosomal integration with HHV-6. We found a higher specificity of RT-PCR performed on PBMC samples compared to PCR or RQ-PCR performed on plasma when evaluating samples for active HHV-6 replication.
authors.affiliation: Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, United States. mary_caserta@urmc.rochester.edu
authors.forename: Mary T
authors.initials: MT
authors.lastname: Caserta
authors.forename: Caroline Breese
authors.initials: CB
authors.lastname: Hall
authors.forename: Kenneth
authors.initials: K
authors.lastname: Schnabel
authors.forename: Geraldine
authors.initials: G
authors.lastname: Lofthus
authors.forename: Andrea
authors.initials: A
authors.lastname: Marino
authors.forename: Lynne
authors.initials: L
authors.lastname: Shelley
authors.forename: Christina
authors.initials: C
authors.lastname: Yoo
authors.forename: Jennifer
authors.initials: J
authors.lastname: Carnahan
authors.forename: Linda
authors.initials: L
authors.lastname: Anderson
authors.forename: Hongyue
authors.initials: H
authors.lastname: Wang
mesh_terms: D002648:Child; D004279:DNA, Viral / Q000097:blood; D015654:Herpesvirus 6, Human / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods; D019349:Roseolovirus Infections / Q000097:blood / Q000175:diagnosis / Q000821:virology*; D012680:Sensitivity and Specificity; D014773:Virology / Q000379:methods; D016662:Virus Integration; D014779:Virus Replication
chemical_list: D004279:DNA, Viral