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.
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).
In 6 of 8 cases, a significant T cell reconstitution (i.e., a CD3+ T cell count of >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.
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.
"The importance of virus-specific T cells has been also demonstrated with regard to other viruses such as adenovirus (15–18), EB virus (19–21), BK virus (22–25), and JC virus (26, 27). Recently, banked third party virus-specific T cells were reported to be safe and effective for the treatment of viral disease after allogeneic HSCT, which circumvents a major obstacle to the wider use of virus-specific T cells, in particular in patients after cord blood transplant (28). "
[Show abstract][Hide abstract] ABSTRACT: The clinical outcome after allogeneic hematopoietic stem cell transplantation (HSCT) has been significantly improved during the last decades with regard to the reduction in organ failure, infection, and severe acute graft-versus-host disease. However, severe complications due to infectious diseases are still one of the major causes of morbidity and mortality after allogeneic HSCT, in particular in patients receiving haploidentical HSCT or cord blood transplant due to a slow and often incomplete immune reconstitution. In order to improve the immune control of pathogens without an increased risk of alloreactivity, adoptive immunotherapy using highly enriched pathogen-specific T cells offers a promising approach. In order to identify patients who are at high risk for infectious diseases, several monitoring assays have been developed with potential for the guidance of immunosuppressive drugs and adoptive immunotherapy in clinical practice. In this article, we aim to give a comprehensive overview regarding current developments of T-cell monitoring techniques focusing on T cells against viruses and fungi. In particular, we will focus on rather simple, fast, non-labor-intensive, cellular assays which could be integrated in routine clinical screening approaches.
Frontiers in Immunology 09/2013; 4:276. DOI:10.3389/fimmu.2013.00276
"In the search for additional markers for predicting post-transplant lymphoproliferative disease, the determination of anti-EBV-specific T cell response as well as B lymphocytes should be taken into account. The results of several studies suggest that, in the future, the virus load measurement might be assisted by monitoring the EBV-specific immune response [Meij et al., 2003, Clave et al., 2004, Annels et al., 2006]. The authors measured the anti-EBV-specific T cell response in correlation to EBV load and the occurrence of EBV reactivation and lymphoproliferation, respectively in patients after allogeneic stem cell transplantation. "
[Show abstract][Hide abstract] ABSTRACT: Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disease is a life-threatening complication following hematopoietic stem cell transplantation. A quantitative polymerase chain reaction to evaluate EBV-genome copy numbers based on a nested polymerase chain reaction and an end-point dilution was used. Applying this assay EBV load was prospectively screened weekly in 123 patients after transplantation. The results demonstrate that EBV reactivations with more than 1,000 EBV-genome copies measured in 10(5) peripheral blood mononuclear cells were observed in 31 patients (25.2%). Three patients developed lymphoproliferative disease with extremely high EBV-genome copies in peripheral blood mononuclear cells (>100,000 copies/10(5) cells) and plasma. After combined antiviral and immune therapy two of three patients showed a dramatic decrease of EBV load and survived, while the third patient died of lymphoma. A subclinical EBV reactivation was observed in 24 cases (19.5%) with EBV-genome copies in 10(5) peripheral blood mononuclear cells ranging between 2,500 and mostly 10,000. After reduction of immunosuppression the EBV levels normalized. In four patients, the high copy number of > or =80,000 copies/10(5) peripheral blood mononuclear cells and plasma positivity prompted us to start pre-emptive therapy with rituximab and cidofovir for prevention of lymphoproliferative disease. After drug administration the high EBV load was reduced remarkably. Ninety-two patients (74.8%) who had < or =1,000 copies/10(5) peripheral blood mononuclear cells did not develop EBV-associated lymphoproliferative disease. In conclusion, monitoring of EBV load is a sensitive and useful parameter in the surveillance of EBV reactivation for early intervention in EBV-associated lymphoproliferative disease as well as for follow-up of the efficacy of therapy.
Journal of Medical Virology 03/2008; 80(3):441-54. DOI:10.1002/jmv.21096 · 2.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We derive estimators for the multiple lag process, a generalization of the lag process, via spectral representations of stationary processes by complex random spectral measures. We present estimators of transfer functions for the multiple lag model with a given vector of lags and derive a multiple-lag (quadratic) coherence which can be maximized to choose the best vector of lags in the minimum mean squared error sense from a given set of lag vectors. We also demonstrate the estimation scheme by a simulation example and point out possible applications for the multiple-lag model in speech processing
Acoustics, Speech, and Signal Processing, 1995. ICASSP-95., 1995 International Conference on; 06/1995
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