title: Torquetenovirus viremia kinetics after autologous stem cell transplantation are predictable and may serve as a surrogate marker of functional immune reconstitution.
abstract: BACKGROUND
  It is common experience that retreating patients too early after a course of intensive chemotherapy predisposes to opportunistic infections despite apparently normal lymphocyte levels.
  
  
  OBJECTIVE
  The extent of replication of persistent viruses that cause no obvious disease (and hence need no treatment) might better define when a patient has recovered from functional immune deficiency.
  
  
  METHODS
  We used real-time polymerase chain reaction to monitor the kinetics of plasma torquetenovirus (TTV) viremia in hematological patients undergoing autologous hematopoietic stem cell transplantation as support to high-dose chemotherapy (HSCT).
  
  
  RESULTS
  Independently from underlying hematological disease and therapeutic regimen, TTV viremia increased post-HSCT, and this increase paralleled the increase of circulating CD8(+)CD57(+) T lymphocytes, known to represent an indirect marker of functional immune deficiency. Subsequently, within a matter of months, TTV levels returned to baseline values, at a pace that appeared to be constant over time.
  
  
  CONCLUSIONS
  Monitoring of TTV viremia represents a unique opportunity to follow functional immune reconstitution in immunosuppressed patients. Also, the size of the TTV viremia increases resulting from immunosuppressive treatments might be of guidance in determining the appropriate time interval before delivery of a next course of therapy.
authors.affiliation: Division of Hematology, Azienda Ospedaliera Universitaria Pisana Santa Chiara, Pisa, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Focosi
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Maggi
authors.forename: Melania
authors.initials: M
authors.lastname: Albani
authors.forename: Lisa
authors.initials: L
authors.lastname: Macera
authors.forename: Valentina
authors.initials: V
authors.lastname: Ricci
authors.forename: Silvia
authors.initials: S
authors.lastname: Gragnani
authors.forename: Serena
authors.initials: S
authors.lastname: Di Beo
authors.forename: Massimo
authors.initials: M
authors.lastname: Ghimenti
authors.forename: Guido
authors.initials: G
authors.lastname: Antonelli
authors.forename: Mauro
authors.initials: M
authors.lastname: Bendinelli
authors.forename: Mauro
authors.initials: M
authors.lastname: Pistello
authors.forename: Luca
authors.initials: L
authors.lastname: Ceccherini-Nelli
authors.forename: Mario
authors.initials: M
authors.lastname: Petrini
mesh_terms: D015415:Biomarkers; D006801:Humans; D016867:Immunocompromised Host; D007165:Immunosuppression Therapy / Q000009:adverse effects*; D010949:Plasma / Q000821:virology; D012367:RNA, Viral / Q000097:blood; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D033581:Stem Cell Transplantation / Q000009:adverse effects*; D022783:Torque teno virus / Q000302:isolation & purification*; D014182:Transplantation, Autologous / Q000009:adverse effects*; D014766:Viremia
chemical_list: D015415:Biomarkers; D012367:RNA, Viral