Surveillance of active human cytomegalovirus infection in hematopoietic stem cell transplantation (HLA sibling identical donor): search for optimal cutoff value by real-time PCR

<p>Abstract</p> <p>Background</p> <p>Human cytomegalovirus (CMV) infection still causes significant morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Therefore, it is extremely important to diagnosis and monitor active CMV infection in HSCT patients, defining the CMV DNA levels of virus replication that warrant intervention with antiviral agents in order to accurately prevent CMV disease and further related complications.</p> <p>Methods</p> <p>During the first 150 days after allogeneic HSTC, thirty patients were monitored weekly for active CMV infection by <it>pp65 </it>antigenemia, nested-PCR and real-time PCR assays. Receiver operating characteristic (ROC) plot analysis was performed to determine a threshold value of the CMV DNA load by real-time PCR.</p> <p>Results</p> <p>Using ROC curves, the optimal cutoff value by real-time PCR was 418.4 copies/10⁴PBL (sensitivity, 71.4%; specificity, 89.7%). Twenty seven (90%) of the 30 analyzed patients had active CMV infection and two (6.7%) developed CMV disease. Eleven (40.7%) of these 27 patients had acute GVHD, 18 (66.7%) had opportunistic infection, 5 (18.5%) had chronic rejection and 11 (40.7%) died - one died of CMV disease associated with GVHD and bacterial infection.</p> <p>Conclusions</p> <p>The low incidence of CMV disease in HSCT recipients in our study attests to the efficacy of CMV surveillance based on clinical routine assay. The quantification of CMV DNA load using real-time PCR appears to be applicable to the clinical practice and an optimal cutoff value for guiding timely preemptive therapy should be clinically validated in future studies.</p

Management of Epstein-Barr virus (EBV) reactivation after allogeneic stem cell transplantation by simultaneous analysis of EBV DNA load and EBV-specific T cell reconstitution

BACKGROUND: Epstein-Barr virus (EBV) reactivation is a frequent event after allogeneic stem cell transplantation and may progress to life-threatening lymphoproliferative disease (EBV-LPD) in the absence of adequate EBV-specific T cell immunity. Quantification of EBV DNA load in asymptomatic individuals who are at risk is a useful (although not entirely predictive) indicator of progression to EBV-LPD and guide for preemptive treatment with CD20 antibodies. METHODS: With the aim of improving the identification of patients at risk, we retrospectively analyzed, within a cohort of 25 consecutive allogeneic stem cell transplant recipients at risk for EBV-LPD, the pattern of T cell reconstitution during EBV reactivation in all preemptively treated patients (8 patients). RESULTS: In 6 of 8 cases, a significant T cell reconstitution (i.e., a CD3+ T cell count of &gt;300 cells/microL) was documented during EBV reactivation, which included an expansion of EBV-specific memory T cells, as shown by human leukocyte antigen class I tetramer analysis. Additional evidence for the antiviral potential of this T cell reconstitution was obtained prospectively from a cohort of 14 consecutive allogeneic stem cell transplant recipients at risk for EBV-LPD. EBV reactivation occurred in 3 patients. Preemptive treatment was successfully withheld for 2 of these patients in light of concurrent (EBV-specific) T cell recovery. CONCLUSION: We conclude that analysis of the level of (EBV-specific) T cell reconstitution during EBV reactivation is an important second parameter, in addition to quantification of EBV DNA load, that will be instrumental in a more accurate definition of patients at risk for EBV-LPD who, given their immunoincompetence, will be most certainly dependent on preemptive interventions