title: Diagnosis of human herpesvirus 6B primary infection by polymerase chain reaction in young children with exanthematic disease.
abstract: BACKGROUND
  Exanthem subitum is a classical rash disease of early childhood caused by human herpesvirus 6B (HHV-6B). However, the rash is frequently misdiagnosed as that of either measles or rubella.
  
  
  METHODS
  In this study, a nested multiplex polymerase chain reaction (PCR) was used to diagnose HHV-6B primary infection, differentiate it from infections caused by HHV-6A and compare it to antibody avidity tests. The samples were separated into case group and control group according to the results of the indirect immunofluorescence assay (IFA) technique.
  
  
  RESULTS
  From the saliva samples analyzed, HHV-6A DNA was detected in 3.2% of the case group and in 2.6% of the control group. Regarding HHV-6B, PCR detected viral DNA in 4.8% of the case group and in 1.3% of the control group. Among the serum samples studied, a frequency of 1.7% was determined for HHV-6A in the case group and 1.2% in the control group. PCR did not detect HHV-6B DNA in serum samples. The sensitivity and specificity of the PCR technique ranged from 0% to 4.8% and 97.5% to 100%, respectively, compared to IFA.
  
  
  CONCLUSIONS
  The PCR technique was not suitable for diagnosing primary infection by HHV-6B in children with exanthematic disease and should not substitute the IFA.
authors.affiliation: Laboratório de Diagnóstico Virológico, Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, RJ, Brasil.
authors.forename: Ivna de Melo
authors.initials: Ide M
authors.lastname: Magalhães
authors.forename: Rebeca Vasquez Novo
authors.initials: RV
authors.lastname: Martins
authors.forename: Renata Oliveira
authors.initials: RO
authors.lastname: Vianna
authors.forename: Solange Artimos
authors.initials: SA
authors.lastname: Oliveira
authors.forename: Silvia Maria Baeta
authors.initials: SM
authors.lastname: Cavalcanti
mesh_terms: D000914:Antibodies, Viral / Q000097:blood*; D000915:Antibody Affinity; D002648:Child; D004279:DNA, Viral / Q000032:analysis*; D003937:Diagnosis, Differential; D005077:Exanthema Subitum / Q000175:diagnosis* / Q000821:virology; D019084:Fluorescent Antibody Technique, Indirect; D015654:Herpesvirus 6, Human / Q000235:genetics* / Q000276:immunology; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods; D012463:Saliva / Q000821:virology; D012680:Sensitivity and Specificity
chemical_list: D000914:Antibodies, Viral; D004279:DNA, Viral