title: Human herpesvirus types 6 and 7 infection in pediatric hematopoietic stem cell transplant recipients.
abstract: BACKGROUND
  The immunosuppressed state in patients undergoing hematopoietic stem cell transplantation (HSCT) predisposes them to activation of latent viral infections such as herpesvirus types 6 and 7 (HHV6 and HHV7). We aimed to evaluate the incidence, manifestations, outcomes, and risk factors of HHV 6 and HHV 7 infections after pediatric hematopoietic stem cell transplantation.
  
  
  METHODS
  We performed 106 HSCTs (86 allogeneic and 20 autologous) on 94 children (56 boys, median age 7.1 years) during 2006-2012. Patients suspected to have HHV6 or HHV7 infections were tested using polymerase chain reaction on serum and/or cerebrospinal fluid.
  
  
  RESULTS
  Among the 63 patients tested for HHV, 10 patients (15.9%) were infected (HHV-6 (n=6), HHV-7 (n=4)) at a median of 18 days post-HSCT (cumulative incidence 11.5% at 1 year). Manifestations included fever (90%), rash (70%), hepatitis (80%), pneumonitis (50%), central nervous system (CNS) manifestations (40%), and graft failure (10%). One patient had persistent CNS infection despite treatment with foscarnet, ganciclovir, and cidofovir. Seven patients cleared herpesvirus after a median of 22 days. Four patients died (relapse of malignancy [n=3], acute graft-versus-host disease [aGVHD] [n=1]). Herpesvirus infections were associated with adenovirus infection (p=0.001) and severe (grade III-IV) aGVHD (p=0.037).
  
  
  CONCLUSIONS
  We concluded that HHV6 and HHV7 infections are common after pediatric HSCT. Most infections were self-limited and could be associated with adenovirus infection and severe aGVHD. Further studies are needed to evaluate predictors of severe morbidity or mortality, and define optimal prophylaxis and treatment.
authors.affiliation: Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital and The University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Joseph Delano
authors.initials: JD
authors.lastname: Fule Robles
authors.affiliation: Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital and The University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Daniel Ka Leung
authors.initials: DK
authors.lastname: Cheuk
authors.affiliation: Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital and The University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Shau Yin
authors.initials: SY
authors.lastname: Ha
authors.affiliation: Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital and The University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Alan Kwok Shing
authors.initials: AK
authors.lastname: Chiang
authors.affiliation: Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital and The University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: Godfrey Chi Fung
authors.initials: GC
authors.lastname: Chan
mesh_terms: D000257:Adenoviridae Infections / Q000188:drug therapy / Q000453:epidemiology / Q000276:immunology; D000293:Adolescent; D000998:Antiviral Agents / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D004279:DNA, Viral / Q000235:genetics; D005260:Female; D006086:Graft vs Host Disease / Q000453:epidemiology / Q000276:immunology; D019337:Hematologic Neoplasms / Q000628:therapy; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D052163:Human papillomavirus 6 / Q000235:genetics / Q000276:immunology*; D006801:Humans; D016867:Immunocompromised Host; D015994:Incidence; D007223:Infant; D008297:Male; D009017:Morbidity; D030361:Papillomavirus Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000276:immunology; D012189:Retrospective Studies; D012307:Risk Factors; D017735:Virus Latency / Q000276:immunology*
chemical_list: D000998:Antiviral Agents; D004279:DNA, Viral