EBV Conference 2008 Guangzhou - Baylor College of Medicine

159 (RegID: 1355; 1383)
Floor Pietersma
Institution: University Medical Center Utrecht
e-mail: f.pietersma@umcutrecht.nl
HIGH PERFORIN EXPRESSION ON T CELLS: A PROGNOSTIC MARKER FOR SEVERITY
OF HERPESVIRUS REACTIVATION EARLY AFTER STEM CELL TRANSPLANTATION
F. Pietersma (1), R. Jacobi (1), L. Ran (1), N. Nanlohy (1), R. Schuurman (2), M. Minnema (3), E. Meijer
(4) and D. van Baarle (1)
(1) Department of Immunology, (2) Department of Virology, (3) Department of Hematology, University
Medical Center Utrecht, Utrecht, the Netherlands
(4) Department of Hematology, Erasmus Medical Center, Rotterdam, the Netherlands
Posterabstract:
Viral reactivations are a major complication after stem cell transplantation (SCT). Due to the
immunosuppressed state of the transplant recipient, reactivation with Epstein-Barr virus (EBV) cannot be
adequately controlled by the immune system and can lead to uncontrolled lymphoproliferation and
subsequent post-transplant lymphoproliferative disease (PTLD). Cytomegalovirus (CMV) infection or
reactivation is also a major cause of morbidity and mortality following SCT. Since EBV and CMV
reactivations frequently coincide in SCT recipients we classified patients as with or without herpesvirus
reactivation based upon their peak viral load of either virus. Detection of reactivation and subsequent
pre-emptive therapy relies on frequent viral load detection after stem cell transplantation. Additional virus
specific T-cell reconstitution data can increase the predictive value for viral complications following
transplantation. Here we studied perforin expression in CD8+ T cells, used as a measure for cytotoxic
T-cell capacity, in relation to occurrence of viral reactivation. In a prospective study we followed 40
individuals during the first 3 month post transplantation and measured viral load levels in combination
with intracellular perforin expression in CD8+ T cells. Median intracellular perforin levels in CD8+ T
cells throughout 3 months post SCT are higher in patients with herpesvirus reactivations (4,9% of CD8+ T
cells versus 2,3% of CD8+ T cells, p=0,001). Perforin levels increase with reactivation severity, patients
with low viral loads had median perforin levels of 3,9% compared to 10,7% in patients with viral loads
exceeding 1000 copies/ml. Patients with viral reactivations exceeding 1000 copies/ml in plasma reached
high percentages of intracellular perforin in CD8+ T cells much more often and much faster than patients
with low (viral load below 1000 copies/ml) or without reactivation. In all cases perforin expression
preceded high viral loads making perforin an easy to use prognostic marker to identify patients at risk of
severe viral reactivations.
EBV Conference 2008 Guangzhou
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