Torquetenovirus viremia kinetics after autologous stem cell transplantation are predictable and may serve as a surrogate marker of functional immune reconstitution.
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.
Focosi
Daniele
D
Division of Hematology, Azienda Ospedaliera Universitaria Pisana Santa Chiara, Pisa, Italy.
Maggi
Fabrizio
F
Albani
Melania
M
Macera
Lisa
L
Ricci
Valentina
V
Gragnani
Silvia
S
Di Beo
Serena
S
Ghimenti
Massimo
M
Antonelli
Guido
G
Bendinelli
Mauro
M
Pistello
Mauro
M
Ceccherini-Nelli
Luca
L
Petrini
Mario
M
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
D015415:Biomarkers; D012367:RNA, Viral