title: Human herpesvirus-6 and -7 in pediatric stem cell transplantation.
abstract: BACKGROUND
  Human herpesvirus-6 (HHV-6) and -7 (HHV-7) may reactivate with immunosuppression and cause symptoms varying from subclinical to severe organ manifestations. The presence of HHV-6 and -7 and their possible association with clinical problems among pediatric recipients of stem cell grafts was studied in a single institution setting between November 1999 and December 2001.
  
  
  METHODS
  A total of 60 patients, mean age 8.5 years, were transplanted: 2/3 received allogeneic grafts and 1/3 autologous stem cell rescue. The presence of HHV-6 and -7 was studied in blood by polymerase chain reaction (PCR) (HHV-6) and antigenemia (HHV-6 and -7).
  
  
  RESULTS
  Both HHV-6 and -7 were frequently present in the blood of stem cell graft recipients. No significant difference in the incidence of HHV-6 or -7 reactivations between the allogeneic and autologous patients nor recipients of sibling or unrelated donor (URD) grafts was observed. HHV-6 antigenemia was associated with fever, rash, and delayed engraftment. Among symptomatic patients two cases of encephalitis were encountered with both having HHV-6 detectable in their cerebrospinal fluid (CSF) by PCR.
  
  
  CONCLUSIONS
  HHV-6 and -7 seem to be common in blood both pre- and post-transplant among pediatric recipients of stem cell grafts. Prolonged reactivations appear to correlate with clinical symptoms such as fever, rash, and bone marrow suppression in the post-stem cell transplant setting (SCT), but severe complications are rare. Transient reactivations appear to be of very limited clinical significance.
authors.affiliation: Division of Hematology-Oncology and Stem Cell Transplantation, Hospital for Children and Adolescents, University of Helsinki, Finland. helena.savolainen@hus.fi
authors.forename: Helena
authors.initials: H
authors.lastname: Savolainen
authors.forename: Irmeli
authors.initials: I
authors.lastname: Lautenschlager
authors.forename: Heli
authors.initials: H
authors.lastname: Piiparinen
authors.forename: Ulla
authors.initials: U
authors.lastname: Saarinen-Pihkala
authors.forename: Liisa
authors.initials: L
authors.lastname: Hovi
authors.forename: Kim
authors.initials: K
authors.lastname: Vettenranta
mesh_terms: D000293:Adolescent; D000328:Adult; D001853:Bone Marrow / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D005076:Exanthema / Q000209:etiology; D005260:Female; D005334:Fever / Q000209:etiology; D005500:Follow-Up Studies; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D015654:Herpesvirus 6, Human; D016199:Herpesvirus 7, Human; D006801:Humans; D007165:Immunosuppression Therapy / Q000009:adverse effects; D008297:Male; D015995:Prevalence; D019349:Roseolovirus Infections / Q000150:complications / Q000175:diagnosis / Q000209:etiology*; D014182:Transplantation, Autologous; D014184:Transplantation, Homologous; D014775:Virus Activation