Quantitative EBV viral loads and immunosuppression alterations can decrease PTLD incidence in pediatric liver transplant recipients

Epstein-Barr virus infection and central nervous system involvement after orthoptic liver transplant

Epstein-Barr virus (EBV) infection presenting as encephalitis in seronegative adults in the context of solid organ transplantation is rarely reported. EBV seroconversion illnesses in the adult population after organ transplantation are quite uncommon. This report describes a case of encephalitis due to EBV infection after liver transplantation in an adult patient. The patient was seronegative for EBV pretransplant. She showed persistent viral replication indicated by high levels of EBV DNA in the serum, which raised concerns for future development of post-transplant lymphoproliferative disorder. The report discusses the management of such patients, awareness of EBV infection and earlier diagnosis by use of EBV PCR in adult immunocompromised individuals where infection may cause particular problems.

Posttransplant lymphoproliferative disease following liver transplantation

PURPOSE OF REVIEW

Despite contemporary immunosuppressive regimens, posttransplant lymphoproliferative disease (PTLD) remains a major complication after liver transplantation. This review highlights advances in the understanding of the pathophysiology, diagnosis, and management of PTLD in liver transplant recipients.

RECENT FINDINGS

The spectrum of PTLD after liver transplant ranges from polymorphic lymphoproliferation to high-grade monoclonal lymphoma and is usually related to outgrowth of lymphocytes infected with Epstein-Barr virus (EBV). Risk factors for PTLD include EBV-seronegativity of the recipient, young age, intensity of immunosuppression, and the first year posttransplant. Measurement of EBV load by quantitative polymerase chain reaction assays is an important aid in the surveillance and diagnosis of PTLD although the specificity for PTLD is only about 50% (specificity for EBV is ∼100%). In patients diagnosed with PTLD, management options include reduction of immunosuppression, rituximab, combination chemotherapy, and adoptive immunotherapy. Outcomes have improved because rituximab has been incorporated into treatment regimens, and immunotherapy approaches show promise.

SUMMARY

PTLD is a significant complication after liver transplantation, particularly in children. Advances in early detection approaches have aided in the diagnosis and management of PTLD, but further research to identify better predictive biomarkers is needed to improve risk-based treatment strategies.

Post-transplant lymphoproliferative disorders and Epstein-Barr virus DNAemia in a cohort of lung transplant recipients

BACKGROUND

Post-transplant lymphoproliferative disorders (PTLD) are serious complications in lung transplant recipients. No consensus on EBV DNAemia levels predictive of PTLD has been reached. In addition, in many instances EBV DNAemia is determined in patients with suggestive symptoms only.

METHODS

The characteristics of five patients with PTLD as well as the prevalence of EBV DNAmia in a cohort of 137 consecutive patients receiving lung transplantation are described.

RESULTS

Twenty-six out of 137 patients (18.9%) were excluded from the analysis because lost at follow-up or dead from PTLD-independent reasons within three months of transplantation. EBV DNA in peripheral blood mononuclear cells (PBMC) was determined in 83/111 patients (74.8%) because of potential PTLD-related symptoms, while 28 patients (25.2%) showed no symptoms and were not examined. EBV DNAemia was positive in 53/83 patients (63.8%), and negative in 30/83 patients (36.2%). PTLD was diagnosed in five (4.5%) patients at a median time of 270 (range 120-870) days following transplantation. All five PTLD (three large B-cell lymphomas, one Hodgkin lymphoma and one possible pre-neoplastic lesion) were potentially associated with EBV infection. However, only 3/5 patients with PTLD had detectable EBV DNAemia: < 1,000 copies EBV DNA/1 × 10⁵ PBMC in one patient and > 1,000 copies EBV DNA/1 × 10⁵ PBMC in two patients.

CONCLUSION

A systematic multidisciplinary (clinical, radiologic, virologic and histologic) approach is mandatory for the diagnosis and management of PTLD in lung transplant recipients, while monitoring of symptomatic patients only may provide an incomplete or late picture of the clinical problem. In addition, staining for EBV antigens and quantification of EBV DNA in biopsy specimens should always be performed to understand the role of EBV infection in the pathogenesis of PTLD.

Comparison of QIAsymphony automated and QIAamp manual DNA extraction systems for measuring Epstein-Barr virus DNA load in whole blood using real-time PCR

Automated and manual extraction systems have been used with real-time PCR for quantification of Epstein-Barr virus [human herpesvirus 4 (HHV-4)] DNA in whole blood, but few studies have evaluated relative performances. In the present study, the automated QIAsymphony and manual QIAamp extraction systems (Qiagen, Valencia, CA) were assessed using paired aliquots derived from clinical whole-blood specimens and an in-house, real-time PCR assay. The detection limits using the QIAsymphony and QIAamp systems were similar (270 and 560 copies/mL, respectively). For samples estimated as having ≥10,000 copies/mL, the intrarun and interrun variations were significantly lower using QIAsymphony (10.0% and 6.8%, respectively), compared with QIAamp (18.6% and 15.2%, respectively); for samples having ≤1000 copies/mL, the two variations ranged from 27.9% to 43.9% and were not significantly different between the two systems. Among 68 paired clinical samples, 48 pairs yielded viral loads ≥1000 copies/mL under both extraction systems. Although the logarithmic linear correlation from these positive samples was high (r(2) = 0.957), the values obtained using QIAsymphony were on average 0.2 log copies/mL higher than those obtained using QIAamp. Thus, the QIAsymphony and QIAamp systems provide similar EBV DNA load values in whole blood.

Epstein-Barr Virus-related post-transplant lymphoproliferative disorders: pathogenetic insights for targeted therapy

Post-transplant lymphoproliferative disorder (PTLD) is a spectrum of major, life-threatening lymphoproliferative diseases occurring in the post-transplant setting. The majority of PTLD is of B-cell origin and is associated with several risk factors, the most significant being Epstein-Barr virus (EBV) infection. EBV's in vitro transforming abilities, distinctive latency, clonality within the malignant cells and response to targeted therapies implicate a critical role in the biology of PTLD. This minireview focuses on EBV-related PTLD pathogenesis, in particular the interplay between aspects of the EBV life cycle and latency with nonviral factors resulting in the wide spectrum of histology and clinical presentations encountered in PTLD. With the increased prevalence of transplantation a rise in the incidence of PTLD may be expected. Therefore the importance of laboratory and animal models in the understanding of PTLD and the development of novel therapeutic approaches is discussed.

Monitoring infection with Epstein-Barr virus among seromismatch adult renal transplant recipients

Patients who undergo Epstein-Barr virus (EBV) seromismatch (D+/R-) transplants have a higher risk for the development of post-transplant lymphoproliferative disorder (PTLD). Adult renal transplant recipients at a single institution were prospectively monitored for EBV during the first year post-transplant. Over a 2-year period, 34 patients (7.78%) were identified as being EBV D+/R-recipients. Patients who developed symptoms or had persistent viremia were pre-emptively administered rituximab. Six recipients were discharged without monitoring on the protocol. Of those six, three (50%) developed PTLD and all three lost their grafts. Twenty (60.6%) of the 34 recipients developed viremia during the first year post-transplant. Of the recipients who became viremic, six (30%) received rituximab. None of the six who received rituximab-developed PTLD. We found that recipients who were not monitored on the protocol were more likely to have PTLD and graft loss compared to those who were (p = 0.008). Post-transplant monitoring of adults who undergo EBV D+/R-kidney transplants for viremia and symptoms associated with EBV infection may prompt intervention which reduces the incidence of PTLD within the first year. Use of rituximab in preventing PTLD among patients with primary EBV infection requires further prospective study to determine its overall safety and efficacy.

Asymptomatic high Epstein-Barr viral load carriage in pediatric renal transplant recipients

High viral load carriage of EBV is one of the risks for PTLD in transplant recipients. We reviewed retrospectively in pediatric renal transplant recipients with EBV seronegative. EBV loads in peripheral blood and EBV-CTLs were measured every 1-3 months in 13 patients after grafting. Immunosuppressants were reduced when the patients were considered to have persistent high EBV loads (>1000 copies/μgDNA for over six months). All showed primary EBV infection: six with asymptomatic persistent high EBV loads (group A) and seven with neither EBV-associated symptoms nor persistent high EBV loads (group B). No patient developed PTLD in either group. Chronic rejection occurred in one patient in group A after immunosuppressants' reduction. There was no difference in renal dysfunction rates between the two groups. The maximum and increase rates in EBV loads were significantly higher in group A. The CTLs' percentage was significantly lower in group A when EBV loads first rose above 100 copies/μg DNA. This study suggests the possibility that EBV loads and CTLs' monitoring may be useful for avoidance of PTLD, as patients with asymptomatic persistent high EBV loads had higher EBV loads and lower percentages of CTLs.

Malignancies following lung transplantation

Malignancy is an important complication of thoracic organ transplantation and is associated with significant morbidity and mortality. Lung transplant recipients are at greater risk for cancer than immunocompetent persons, with cancer-specific incidence rates up to 60-fold higher than the general population. The increased risk for cancer is attributed to neoplastic properties of immunosuppressive medications, oncogenic viruses, and cancer-specific risk factors. This article addresses the epidemiology, presentation, and treatment of the most common malignancies after lung transplantation, including skin cancer, posttransplant lymphoproliferative disorder, and bronchogenic carcinoma.

Infections in pediatric transplant recipients: not just small adults

Transplantation increasingly is being used as treatment for children with end-stage organ diseases, hematopoietic rescue from therapy used to treat malignancies, and as cure for primary immune deficiencies. This article reviews some of the major concepts regarding infections that complicate pediatric transplantation, highlighting differences in epidemiology, evaluation, treatment and prevention for children compared with adult recipients.

Epstein-Barr virus-related lymphoproliferative disorder induced by equine anti-thymocyte globulin therapy

Post-transplant lymphoproliferative disorder (PTLD) is generally caused by an uncontrolled B-cell proliferation induced by Epstein-Barr virus (EBV) in the setting of impaired EBV-specific T-cell immunity. PTLD has been described in allogeneic hematopoietic stem cell transplant (HSCT) and rarely in autologous HSCT. Anti-thymocyte globulin (ATG) is being increasingly utilized for acute rejection in organ transplantation, severe autoimmune diseases and aplastic anemia. Mainly, the use of rabbit ATG has been associated with PTLD, which is considered to be more immunosuppressive than equine ATG. The sole administration of equine ATG has rarely been associated with PTLD. Due to the increased use of these potent and novel immunosuppressive agents, it is paramount to be aware of these complications. We present a 55-year-old man with an autologous HSCT who presented with an unusual case of monoclonal plasmacytic PTLD. His lymphoproliferative disorder occurred 3 years after his HSCT and 1 month after the use of equine ATG administered for severe aplastic anemia. We review current concepts of EBV-PTLD, including risk factors, the potential for preemptive therapy and various management strategies.

Using Epstein-Barr viral load assays to diagnose, monitor, and prevent posttransplant lymphoproliferative disorder

Epstein-Barr virus (EBV) DNA measurement is being incorporated into routine medical practice to help diagnose, monitor, and predict posttransplant lymphoproliferative disorder (PTLD) in immunocompromised graft recipients. PTLD is an aggressive neoplasm that almost always harbors EBV DNA within the neoplastic lymphocytes, and it is often fatal if not recognized and treated promptly. Validated protocols, commercial reagents, and automated instruments facilitate implementation of EBV load assays by real-time PCR. When applied to either whole blood or plasma, EBV DNA levels reflect clinical status with respect to EBV-related neoplasia. While many healthy transplant recipients have low viral loads, high EBV loads are strongly associated with current or impending PTLD. Complementary laboratory assays as well as histopathologic examination of lesional tissue help in interpreting modest elevations in viral load. Circulating EBV levels in serial samples reflect changes in tumor burden and represent an effective, noninvasive tool for monitoring the efficacy of therapy. In high-risk patients, serial testing permits early clinical intervention to prevent progression toward frank PTLD. Restoring T cell immunity against EBV is a major strategy for overcoming PTLD, and novel EBV-directed therapies are being explored to thwart virus-driven neoplasia.

The changing face of post-transplant lymphoproliferative disease in the era of molecular EBV monitoring

Pediatric PTLD is often associated with primary EBV infection and immunosuppression. The aim was to retrospectively review the spectrum of histologically documented PTLD for two time intervals differentiated by changes in use of molecular EBV monitoring. Eleven of 146 patients (7.5%) in 2001-2005 (Era A) and 10 of 92 (10.9%) in 1993-1997 (Era B) were diagnosed with PTLD. The median age at liver transplantation (0.8 and 0.9 yr, respectively) and the median duration between liver transplant and diagnosis of PTLD (0.6 and 0.7 yr, respectively) were similar in both eras. However, patients in Era A presented with significantly less advanced histological disease compared to patients in Era B (p=0.03). Specifically, nine patients (82%) in Era A had Pl hyperplasia/polymorphic PTLD, whereas in Era B, six had advanced histological disease (five monomorphic and one unclassified). Three transplant recipients in Era B died secondary to PTLD, whereas there were no PTLD-related deaths in Era A (p=0.03). Heightened awareness of risk for PTLD, alterations in baseline immunosuppression regimens, implementation of molecular EBV monitoring, pre-emptive reduction in immunosuppression and improved therapeutic options may have all contributed to a milder PTLD phenotype and improved clinical outcomes.

Diagnosis of post-transplant lymphoproliferative disorder in solid organ transplant recipients - BCSH and BTS Guidelines

A joint working group established by the Haemato-oncology subgroup of the British Committee for Standards in Haematology (BCSH) and the British Transplantation Society (BTS) has reviewed the available literature and made recommendations for the diagnosis and management of post-transplant lymphoproliferative disorder (PTLD) in adult recipients of solid organ transplants. This review details the risk factors predisposing to development, initial features and diagnosis. It is important that the risk of developing PTLD is considered when using post transplant immunosuppression and that the appropriate investigations are carried out when there are suspicions of the diagnosis. These must include tissue for histology and computed tomography scan to assess the extent of disease. These recommendations have been made primarily for adult patients, there have been some comments made with regard to paediatric practice.

Infections after living donor liver transplantation in children

The aim of this study was to evaluate the infectious complications after living donor liver transplantation (LDLT) in children. We enrolled 95 children (38 boys and 57 girls) who underwent LDLT from 1994 to 2004. The median age was 22 months (range, 6 months to 15 yr). We retrospectively investigated the proven episodes of bacterial, viral, and fungal infection. There occurred 150 infections in 67 (70%) of 95 patients (1.49 infections/patient); 74 in 43 patients were bacterial, 2 in 2 were fungal, and 74 in 42 were viral. The most common sites of bacterial infection were the bloodstream (33%) and abdomen (25%). Most of the bacterial infections occurred within the first month after LDLT. Bacterial and fungal infections did not result in any deaths. The most common causes of viral infection were Epstein-Barr virus in 37 patients and cytomegalovirus in 18. Seven of the 14 deaths after LDLT were associated with viral infection. Our study suggests that infection is one of the important causes of morbidity and mortality after LDLT. Especially careful monitoring and management of viral infections is crucial for improving the outcome of LDLT in children.

Posttransplant lymphoproliferative diseases

The risk of developing cancer after solid organ transplantation (SOT) is about 5- to 10-fold greater than that of the general population. The cumulative risk of cancer rises to more than 50% at 20 years after transplant and increases with age, and so children receiving transplants are at high risk of developing a malignancy. Posttransplant lymphoproliferative disease (PTLD) is the most common cancer observed in children following SOT, accounting for half of all such malignancies. PTLD is a heterogeneous group of disorders with a wide spectrum of pathologic and clinical manifestations and is a major contributor to long-term morbidity and mortality in this population. Among children, most cases are associated with Epstein-Barr virus infection. This article reviews the pathology, immunobiology, epidemiology, and clinical aspects of PTLD, underscoring the need for ongoing systematic study of complex biologic and therapeutic questions.

Acute cellular rejection and Epstein-Barr virus-related post-transplant lymphoproliferative disorder in a pediatric lung transplant with low viral load

We report the case of an 18-year-old male who underwent bilateral lung transplantation for end-stage cystic fibrosis. No Epstein-Barr virus (EBV) or cytomegalovirus serology mismatch was detected on pre-transplant evaluation (donor and recipient were both positive). Two months after lung transplantation a computed tomography scan showed multiple nodules throughout both lungs. At that time a low EBV DNA blood level was detected (<300 copies/100,000 lymphomonocytes). Scheduled follow-up transbronchial biopsy (TBB) revealed a prevalent finding characterized by perivascular lymphoid infiltrates with endothelitis. Extensive tissue coagulative necrosis with peripheral areas of dense aggregates of larger lymphoid cells were detected in the trans-thoracic fine needle core biopsy (FNCB) performed on the largest nodule. The immunophenotypic profile characterized the perivascular lymphoid cells in TBB as mainly composed of T lymphocytes (CD3 positive) while the larger number of lymphocytes in FNCB as B cells (CD20 positive). In situ hybridization for EBV (EBER mRNA) was negative in TBB while it was positive in many lymphocytes of the FNCB. Real-time polymerase chain reaction (PCR) for EBV was performed on paraffin-embedded FNCB and detected a high quantity of EBV genomes (1260 copies/cell). IgH gene rearrangement using a fragment size PCR technique revealed a monoclonal B-cell population in FNCB. Morphological and molecular findings suggest a final diagnosis of acute cellular rejection and a post-transplant lymphoproliferative disorder (PTLD) EBV-related in a lung transplant recipient with a low EBV DNA blood level. A possible coexistence of PTLD and acute rejection should be considered both for diagnosis and treatment. EBV PCR in the peripheral blood is a useful screening tool in transplant recipients; however, rare cases with PTLD may not have detectable levels of EBV DNA. This aspect should be taken into consideration to avoid false negatives.

KDIGO clinical practice guideline for the care of kidney transplant recipients

The 2009 Kidney Disease: Improving Global Outcomes (KDIGO) clinical practice guideline on the monitoring, management, and treatment of kidney transplant recipients is intended to assist the practitioner caring for adults and children after kidney transplantation. The guideline development process followed an evidence-based approach, and management recommendations are based on systematic reviews of relevant treatment trials. Critical appraisal of the quality of the evidence and the strength of recommendations followed the Grades of Recommendation Assessment, Development, and Evaluation (GRADE) approach. The guideline makes recommendations for immunosuppression, graft monitoring, as well as prevention and treatment of infection, cardiovascular disease, malignancy, and other complications that are common in kidney transplant recipients, including hematological and bone disorders. Limitations of the evidence, especially on the lack of definitive clinical outcome trials, are discussed and suggestions are provided for future research.

How I treat EBV lymphoproliferation

Epstein-Barr virus (EBV)-associated B-cell lymphoproliferation is a life-threatening complication after hematopoietic stem cell or solid organ transplantation resulting from outgrowth of EBV-infected B cells that would normally be controlled by EBV-cytotoxic T cells. During the past decade, early detection strategies, such as serial measurement of EBV-DNA load in peripheral blood samples, have helped to identify high-risk patients and to diagnose early lymphoproliferation. Treatment options include manipulation of the balance between outgrowing EBV-infected B cells and the EBV cytotoxic T lymphocyte response and targeting the B cells with monoclonal antibodies or chemotherapy. Major challenges remain for defining indications for preemptive therapies and integrating novel and conventional therapies.

Towards minimizing immunosuppression in pediatric liver transplant recipients

Immunosuppression regimens after liver transplantation focus mainly on preventing rejection and subsequent graft loss. However, in children, morbidity and mortality rates from infections exceed those from rejection after transplant, and immunosuppression can hinder growth, renal function, and graft tolerance. We hypothesized that early steroid withdrawal, with a primary aim of TAC monotherapy would yield no penalty in terms of rejection and graft loss, while reducing risks of infection and maximizing growth. We prospectively evaluated 64 consecutive pediatric liver transplant recipients. One yr patient/graft survival was 93/90%, respectively. At one yr post-transplant, 75.4% of patients were on TAC monotherapy. No deaths or graft losses were caused by infection. Sixty-one percent of patients had at least one episode of rejection, most within three months following transplant and 3.8% were treated for chronic rejection. One non-compliant adolescent died from chronic rejection. CMV, EBV, and lymphoproliferative disease rates were 3.1%, 5.3%, 1.8%, respectively. Pretransplant and one yr post-transplant glomerular filtration rates were unchanged. One yr improved catch-up growth was observed. We conclude that immunosuppression minimization after pediatric liver transplant yields no serious complications from rejection, and might confer advantages with respect to infection, renal function, growth, and is deserving of wider application and study.

Interlaboratory comparison of epstein-barr virus viral load assays

To assess interlaboratory variability in qualitative and quantitative Epstein-Barr virus (EBV) viral load (VL) testing, we distributed a panel of samples to 28 laboratories in the USA, Canada and Europe who performed testing using commercially available reagents (n = 12) or laboratory-developed assays (n = 18). The panel included two negatives, seven constructed samples using Namalwa and Molt-3 cell lines diluted in plasma (1.30-5.30 log(10) copies/mL) and three clinical plasma samples. Significant interlaboratory variation was observed for both actual (range 1.30-4.30 log(10) copies/mL) and self-reported (range, 1.70-3.30 log(10) copies/mL) lower limits of detection. The variation observed in reported results on individual samples ranged from 2.28 log(10) (minimum) to 4.14 log(10) (maximum). Variation was independent of dynamic range and use of commercial versus laboratory-developed assays. Overall, only 47.0% of all results fell within acceptable standards of variation: defined as the expected result +/- 0.50 log(10). Interlaboratory variability on replicate samples was significantly greater than intralaboratory variability (p < 0.0001). Kinetics of change in VL appears more relevant than absolute values and clinicians should understand the uncertainty associated with absolute VL values at their institutions. The creation of an international reference standard for EBV VL assay calibration would be an initial important step in quality improvement of this laboratory tool.

Unusual case of Epstein-Barr virus DNA tissue positive: blood negative in a patient with post-transplant lymphoproliferative disorder

Detection of PTLD uses PCR to detect circulating EBV DNA in the blood or in situ hybridization to identify EBV DNA in tissue biopsies. EBV DNA was detected in the tissue section using both real-time PCR and in situ hybridization. We report an unusual presentation of PTLD with no detectable EBV DNA in the blood using EBER-1 and EBNA-1 PCR assays. This report suggests that the use of EBV-PCR for the early detection of PTLD in blood samples may not be 100% effective in detecting disease.

Improving long-term outcomes after liver transplantation in children

The objective was to review the current state of knowledge and recommend future research directions related to long-term outcomes for pediatric liver transplant recipients. A 1-day Clinical Research Workshop on Improving Long-Term Outcomes for Pediatric Liver Transplant Recipients was held on February 12, 2007, in Washington, DC. The speaker topics were germane to research priorities delineated in the chapters on Pediatric Liver Diseases and on Liver Transplantation in the Trans-NIH Action Plan for Liver Disease Research. Issues that compromise long-term well-being and survival but are amenable to existing and new research efforts were presented and discussed. Areas of research that further enhanced the research priorities in the Action Plan for Liver Disease Research included collection of longitudinal data to define emerging trends of clinical challenges; identification of risk factors associated with long-term immunosuppression complications; development of tolerance-inducing regimens; definition of biomarkers that reflect the level of clinical immunosuppression; development of instruments for the measurement of health wellness; identification of risk factors that impede growth and intellectual development before and after liver transplantation and identification of barriers and facilitators that impact nonadherence and transition of care for adolescents.

EBV-associated lymphoproliferative disorders: classification and treatment

Since its discovery as the first human tumor virus, Epstein-Barr virus (EBV) has been implicated in the development of a wide range of B-cell lymphoproliferative disorders, including Burkitt's lymphoma, classic Hodgkin's lymphoma, and lymphomas arising in immunocompromised individuals (post-transplant and HIV-associated lymphoproliferative disorders). T-cell lymphoproliferative disorders that have been reported to be EBV associated include a subset of peripheral T-cell lymphomas, angioimmunoblastic T-cell lymphoma, extranodal nasal type natural killer/T-cell lymphoma, and other rare histotypes. EBV encodes a series of products interacting with or exhibiting homology to a wide variety of antiapoptotic molecules, cytokines, and signal transducers, hence promoting EBV infection, immortalization, and transformation. However, the exact mechanism by which EBV promotes oncogenesis is an area of active debate. The focus of this review is on the pathology, diagnosis, classification, and pathogenesis of EBV-associated lymphomas. Recent advances in EBV cell-based immunotherapy, which is beginning to show promise in the treatment of EBV-related disorders, are discussed.

Efficacy and safety of valganciclovir in liver-transplanted children infected with Epstein-Barr virus

Epstein-Barr virus (EBV) infection after liver transplantation (LT) is associated with increased risk of posttransplant lymphoproliferative disorder (PTLD). Lowering immunosuppression is the current method to prevent PTLD in LT children with a high viral load. The aim of this study was to assess the efficacy and safety of valganciclovir (VGCV) in children with EBV infection after LT. Forty-seven children showing detectable EBV-DNA (72% asymptomatic) were treated with VGCV (520 mg/sqm twice daily) with no immunosuppression decrease (except in 4 cases). VGCV treatment started 17 months (median) after the onset of EBV infection. A 30-day treatment applied to 26 patients led to undetectable EBV-DNA in 11/32 courses (34.3%), with 82% relapsing. A long VGCV treatment (median: 8 months) achieved undetectable EBV-DNA in 20/42 (47.6%), 60% of whom maintained response off therapy. There were no new PTLD cases. Symptoms worsened in 1 (2.1%) in whom PTLD was suspected but not confirmed in liver and jejunum biopsies. Factors associated with achievement of undetectable EBV-DNA were a longer time from LT and a lower rate of intervening infections in comparison with nonresponders. The safety profile for VGCV was excellent. Graft rejection occurred in 6%. In conclusion, in 47 LT children with a sustained increased EBV load treated with VGCV and unchanged immunosuppression, PTLD was suspected in 1 child (2.1%). A viral load decrease could be achieved as EBV-DNA was undetectable in 47% of patients under prolonged treatment.

Laboratory assays for Epstein-Barr virus-related disease

Epstein-Barr virus (EBV) infects various cell types in a wide spectrum of benign and malignant diseases. Laboratory tests for EBV have improved and are increasingly used in diagnosis, prognosis, prediction, and prevention of diseases ranging from infectious mononucleosis to selected subtypes of lymphoma, sarcoma, and carcinoma. Indeed, the presence of EBV is among the most effective tumor markers supporting clinical management of cancer patients. In biopsies, localization of EBER transcripts by in situ hybridization remains the gold standard for identifying latent infection. Other RNA- and protein-based assays detect lytic viral replication and can distinguish carcinoma-derived from lymphocyte-derived EBV in saliva or nasopharyngeal brushings. Analysis of blood using EBV viral load and serology reflects disease status and risk of progression. This review summarizes prior research in the context of basic virologic principles to provide a rational strategy for applying and interpreting EBV tests in various clinical settings. Such assays have been incorporated into standard clinical practice in selected settings such as diagnosis of primary infection and management of patients with immune dysfunction or nasopharyngeal carcinoma. As novel therapies are developed that target virus-infected cells or overcome the adverse effects of infection, laboratory testing becomes even more critical for determining when intervention is appropriate and the extent to which it has succeeded.

EBV PCR in the diagnosis and monitoring of posttransplant lymphoproliferative disorder: results of a two-arm prospective trial

While EBV PCR is used in the management of PTLD, the optimal primer set, relative importance of intracellular versus free plasma EBV, and the baseline profile in an organ transplant population remains unclear. We performed a prospective 2-arm trial utilizing an EBV PCR panel measuring LMP-1, EBER-1 and EBNA-1 in both free plasma as well as intracellular whole blood. Control Arm A consisted of 31 lung transplant patients and Arm B consisted of 35 transplant patients being evaluated for possible PTLD. In Arm A, 1/31 (3%) patients developed a transient plasma EBV load. Thirteen of 31 (42%) had detectable intracellular EBV. In Arm B, 17 (49%) patients were diagnosed with PTLD. Thirteen (76%) had EBV-positive PTLD with 12/13 (92%) having detectable EBV by PCR. The EBV PCR panel had a high sensitivity (92%), specificity (72%), positive predictive value (PPV) (71%) and negative predictive value (NPV) (93%) for diagnosing EBV-positive PTLD and followed patients' clinical course well (p < 0.001). Comparing the individual PCR assays, plasma EBNA PCR was superior with high sensitivity (77%), specificity (100%), PPV (100%) and NPV (86%). We conclude that EBV PCR is a useful test for managing PTLD patients. While plasma EBNA PCR is the best single assay for diagnosing and monitoring PTLD, the complete PCR panel is superior for ruling out its presence.

Outcomes following liver transplantation

As the field of Liver Transplantation has matured, survival alone is no longer an acceptable single metric of success. This chapter explores the impact of the PELD system for donor organ allocation, surgical modification of donor organs, living donation, and long-term transplant-related complications on overall quality of life and outcome. Strategies to improve survival, overall outcome, and health-related quality of life in long-term recipients are outlined.

Multicenter comparison of different real-time PCR assays for quantitative detection of Epstein-Barr virus

Quantification of Epstein-Barr virus (EBV) in peripheral blood is important for the diagnosis and management of serious EBV diseases, including posttransplant lymphoproliferative disorder. A variety of PCR-based methods are currently in use; however, there is little information on their comparability. This study assessed the relative performance of different quantitative assays. A multicenter comparative study was performed at eight sites using three panels consisting of serial dilutions of quantified EBV DNA and extracts from a total of 19 whole-blood specimens. Samples were distributed and tested blindly. Instrumentation, probe chemistries, amplification targets, and other test-related aspects varied considerably between laboratories. Each laboratory's calibration curve indicated strong evidence of a consistent log-linear relationship between viral load and cycle threshold, suggesting that intralaboratory tracking of a given patient would yield similar relative quantitative trends among the participating test sites. There was strong concordance among laboratories with respect to qualitative test results; however, marked quantitative discordance was seen. For most samples, the across-laboratory interquartile range of the reported viral load (in copies/microl) was roughly 0.6 log-units, and for one sample the overall range was approximately 4.2 log-units. While intralaboratory tracking of patients may yield similar results, these data indicate a need for caution when attempting to compare clinical results obtained at different institutions and suggest the potential value to be gained by more standardized testing methodology.

Epstein-Barr virus DNA load and seroconversion in pediatric renal transplantation with tacrolimus immunosuppression

EBV infection is one of major complications arising in pediatric patients who have undergone renal transplantation. A strong correlation between the grade of immunosuppression and the development of PTLD, one of the most severe EBV-associated diseases, has been recognized. In this study, we monitored the serologic profile in conjunction with peripheral blood EBV-DNA load of 32 children who underwent renal transplantation with tacrolimus as an immunosuppressant. Six patients were EBV-seronegative (EBV-) before the transplantation, and the mean DNA load in the EBV- group was significantly higher than that in the EBV-seropositive (EBV+) group. Seroconversion occurred in five of these patients in a mean period of 22 weeks after the transplantation. The EBV-DNA load in the EBV+ group was maintained at a low level for a year, whereas it increased rapidly to over 1 x 10(5) copies/mL in two patients in the EBV- group three to seven months after the transplantation, which corresponds to the timing of seroconversion, and one of them developed PTLD. These observations suggest that the close monitoring of the EBV-DNA load, along with longitudinal observation of seroconversion, is essential in pediatric renal transplantation, particularly for younger children who are more likely to be EVB-.

Strategies for Epstein–Barr virus monitoring, detection and therapy in post-transplant lymphoproliferative disorder

Epstein–Barr virus (EBV) is a significant cause of morbidity and mortality in solid-organ transplant (SOT) recipients. The most serious complication of EBV infection in this population is post-transplant lymphoproliferative disorder (PTLD). EBV-viral load monitoring can be used to predict those SOT patients at high risk of PTLD, particularly those who are EBV seronegative prior to transplant. Surveillance EBV-load monitoring to inform pre-emptive reduction of immunosuppression has contributed to the decrease in the incidence of PTLD in SOT recipients. The use of the anti-CD20 antibody, rituximab, as a therapeutic agent is increasing, with anecdotal reports of positive outcomes. However, experience to date suggests that the use of this agent may not prevent recurrence of the tumor or improve cell-mediated immune responses to EBV. Future investigation of EBV-specific T-cell responses as an adjunct to monitoring, and the adoptive transfer of EBV-specific cytotoxic T lymphocytes appear likely in future attempts as a means to limit the consequences of EBV infection in the SOT population.