Epstein-Barr virus-related lymphoproliferation in children after liver transplant: role of immunity, diagnosis, and management

Development of an Improved Epstein-Barr Virus (EBV) Neutralizing Antibody Assay to Facilitate Development of a Prophylactic gp350-Subunit EBV Vaccine

No licensed vaccine is available for prevention of EBV-associated diseases, and robust, high-throughput bioanalytical assays are needed to evaluate immunogenicity of gp350 subunit-based candidate EBV vaccines. Here we have developed an improved EBV-GFP based neutralization assay for such a vaccine’s pre-clinical and clinical validation to measure EBV specific neutralizing antibodies in human donors. The supplementation of guinea pig complement of our previously published high-throughput EBV-GFP fluorescent focus (FFA)-based neutralization assay allowed the detection of complement-dependent neutralizing antibodies using a panel of heat-inactivated healthy human sera. Anti-gp350 antibody titers, which were evaluated using a previously optimized anti-gp350 IgG ELISA assay, were moderately correlated to the FFA-based neutralization titers. Overall, this improved high-throughput neutralization assay is capable of characterizing the serologic neutralizing antibody response to natural EBV infection, with applications in evaluating EBV antibody status in epidemiologic studies and immunogenicity of candidate gp350-subunit EBV vaccines in clinical studies.

Various initial presentations of Epstein-Barr virus infection-associated post-transplant lymphoproliferative disorder in pediatric liver transplantation recipients: Case series and literature review

PTLD is a rare but potentially life-threatening condition, which shows a higher prevalence in children than in adults. From 129 children who underwent LT, we reported 5 cases with biopsy-proven PTLD at a single teaching hospital. Four patients had shared clinical presentations including fever, lymphadenopathy, and splenomegaly. They were noted to be given a prolonged course of IS due to the management of comorbid complications such as acute cellular rejection or severe food allergy or eosinophilic gastrointestinal disease. The other one patient presented with upper gastrointestinal bleeding from gastric mass during an early post-transplantation period. Notably, hypoalbuminemia was noted in all reported patients. Similar to previous studies, both EBV serology mismatch between the donor and recipient with high EBV viral load were noted in all except one case, whose EBV serology was unknown before LT. At least one episode of CMV reactivation was also observed in 3 of 5 patients prior to the PTLD diagnosis. The histopathology revealed 1 of 5 early PTLD, 1 of 5 polymorphic PTLD, and 3 of 5 monomorphic PTLD. The treatment included IS withdrawal, chemotherapy, and/or rituximab. One patient died of multiorgan dysfunction, one remains in complete remission, and three patients are either still on treatment or await response evaluation. Even though most of our reported PTLD cases had shared manifestations with fever, lymphadenopathy, splenomegaly, EBV serology mismatch, and high EBV viral load, various initial presentations such as respiratory symptoms, hypoalbuminemia, and prolonged use of IS from other causes such as significant food allergy were noted.

Pediatric Gastrointestinal Posttransplant Lymphoproliferative Disorder: Incidence, Clinical Characteristics, and Impact of Major Surgical Interventions Upon Overall Survival

Posttransplant lymphoproliferative disorder (PTLD) is a severe complication of solid organ transplantation. A common site for PTLD development is the gastrointestinal (GI) tract. The purpose of this study was to evaluate the incidence, clinical features, and overall survival of pediatric patients with GI-PTLD, and to assess whether major surgical interventions increased mortality. Records of pediatric transplant patients who developed GI-PTLD between January 2000 and June 2015 were retrospectively reviewed at our institution. Of 814 patients who received solid organ transplants, 34 (4%) developed GI-PTLD. Lung and multiorgan transplants had the highest incidence of GI-PTLD (both 11%). Patients often had multisite GI involvement (47%). Within the first year of transplantation, 38% of the 34 patients developed GI-PTLD. Of the patients with Epstein-Barr Virus-positive disease, 12/22 (55%) presented in the first 12 months of transplantation, compared with only 1/12 (8%) of the patients with Epstein-Barr Virus-negative disease (P=0.002). Major surgical interventions were required in 41% of patients; overall survival rate for these surgical patients was 71%, compared with 60% for patients not requiring major surgical interventions (P=0.49). Despite multimodal treatments, overall survival remains poor for patients with GI-PTLD; however, major surgical intervention did not significantly impact overall survival in this cohort.

De Novo Malignancies After Liver Transplantation With 14 Cases at a Single Center

OBJECTIVE

To analyze the clinical characteristics, risk factors, and prevention of de novo malignant tumors after liver transplantation.

METHODS

Fourteen patients who underwent liver transplantation were identified as having de novo malignancies. The clinical characteristics and survival of these patients were retrospectively reviewed.

RESULTS

Fourteen cases of de novo malignancies after liver transplantation occurred for an incidence rate of 1.94% (14/722), including 11 men (78.6%, mean age, 48 y) and 3 women (21.4%, mean age, 50 y). The mean period from transplantation to cancer diagnosis was 55 ± 35 months. The distribution of tumor histologic types included colon cancer, lung cancer, esophageal cancer, nasopharyngeal cancer, liver cancer, parotid carcinoma, bone cancer, post-transplantation lymphoproliferative disorder, stomach cancer, bladder cancer, and laryngeal cancer. Twelve cases (85.7%) had hepatitis B. Five patients (35.7%) underwent operations, and the other 9 patients underwent chemotherapy or radiotherapy. During a mean follow-up period of 37 ± 26 months after the diagnosis of de novo malignancy, 8 patients (57.1%) died, with only 1 dying of causes not related to the de novo malignancy. The survival analysis showed 1-, 5-, and 7-year survival rates of 85.7%, 71.4%, and 42.9%, respectively.

CONCLUSIONS

De novo malignancies after organ transplantation have been suggested to be a major cause of late mortality. De novo malignancy after orthotopic liver transplantation was found to be related to smoking, sex, and low immune function due to immunosuppressive agents. Solid tumors should be removed, and the patient should receive chemotherapy or radiotherapy as early as possible. Early diagnosis and treatment are very important for improving the prognosis.

Malignancies After Heart Transplant

Along with graft vasculopathy, malignancies comprise a major complication after heart transplant, with a rate of occurrence of 39.1% in 10 years. Skin cancers and posttransplant lymphoproliferative disorder are more common in adults, whereas lymphoma is more often shown in children. A major cause of malignancies after heart transplant is the use of increased doses of prophylactics needed during immunosuppressive therapy. Data, however, are scarce regarding the association between a particular immunosuppressive drug and a posttransplant malignancy. Compared with the general population, recipients have a higher incidence of malignancies after heart transplant, with an early onset and more aggressive disease. Solid tumors known to occur in heart transplant recipients include lung cancer, bladder and prostate carcinoma, adenocarcinoma of the oral cavity, stomach cancer, and bowel cancer, although the incidence is rare. The risk factors for development of a malignancy after heart transplant are the same as for the nontransplant population.

Post-transplant lymphoproliferative disorders: from epidemiology to pathogenesis-driven treatment

Post-transplant lymphoproliferative disorders (PTLDs) represent the most severe complication of both solid organ and hematopoietic stem cell transplantation. The Epstein-Barr Virus (EBV) is the main driver of PTLD, particularly those occurring early after transplantation. EBV-driven malignancies are associated with selective expression of latent viral proteins, but uncontrolled lytic replication may favor early phases of cell transformation. Besides immunodepression, persistent immune activation and chronic inflammation play an important role in both virus reactivation and expansion of EBV-infected B cells. EBV-induced immortalization requires the expression of telomerase. TERT, the rate-limiting component of the telomerase complex, is central in the switch from the lytic to the latent viral program, and TERT inhibition induces the EBV lytic cycle and cell death. Immunotherapy and combination of EBV lytic cycle inducers with antiviral drugs are promising strategies to improve the treatment of PTLD patients. This review is aimed at providing an update on the intriguing association between EBV and PTLD, mainly focusing on cases arising after kidney and liver transplantation, which account for the vast majority of transplants.

Identifying predictive factors for posttransplant lymphoproliferative disease in pediatric solid organ transplant recipients with Epstein-Barr virus viremia

Epstein-Barr virus (EBV) viremia (EV) in pediatric solid organ transplant (SOT) recipients is a significant risk factor for posttransplant lymphoproliferative disease (PTLD) but not all patients with EV develop PTLD. We identify predictive factors for PTLD in patients with EV. We conducted a retrospective chart review of all pediatric SOT recipients (0 to 21 y) at a single institution between 2001 and 2009. A total of 350 pediatric patients received a SOT and 90 (25.7%) developed EV. Of EV patients, 28 (31%) developed PTLD. The median age at transplant was 11.5 months in the PTLD group and 21.5 months in the EV-only group (P=0.003). Twenty-three (37%) EV-only patients had immunosuppression increased before EV, compared with 28 (100%) of PTLD patients (P<0.001). The median peak EBV level was 3212 EBV copies/10 lymphocytes for EV-only and 8392.5 EBV copies/10 lymphocytes for PTLD (P=0.005). All patients who developed PTLD had ≥1 clinical symptoms. Younger age at transplant, increased immunosuppression before EV, higher peak EBV level, and presence of clinical symptoms have predictive value in the development of PTLD in SOT patients with EV.

Prevention and treatment for Epstein-Barr virus infection and related cancers

Epstein-Barr virus (EBV) was the first herpes virus described as being oncogenic in humans. EBV infection is implicated in post-transplant lymphoproliferative diseases (PTLD) and several other cancers in non-immunocompromised patients, with more than 200,000 new cases per year. While prevention of PTLD is improving, mainly based on EBV monitoring and preemptive tapering of immunosuppression, early diagnosis remains the best current option for the other malignancies. Significant progress has been achieved in treatment, with decreased mortality and morbidity, but some challenges are still to face, especially for the more aggressive diseases. Possible prevention by EBV vaccination would be a more global approach of this public health problem, but further active research is needed before this goal could be reached.

Measuring T-cell responses against LCV and CMV in cynomolgus macaques using ELISPOT: potential application to non-clinical testing of immunomodulatory therapeutics

A number of immunomodulatory therapeutics increase the risk of disease associated with latent herpesviruses such as cytomegalovirus (CMV) and Epstein-Barr virus (EBV), a member of the lymphocryptovirus (LCV) family that infects humans. The diseases associated with loss of immunity to these viruses can have major impacts on patients as well as on the commercial viability of the immunomodulatory therapeutics. In an effort to develop non-clinical methods for measuring effects on anti-viral immunity, we have developed an interferon (IFN)-γ enzyme-linked immunosorbent spot (ELISPOT) assay to quantify the number of CMV or LCV-reactive T-cells in peripheral blood of cynomolgus macaques. After optimization of various parameters, the IFN-γ ELISPOT assay was characterized for specificity, intra-assay, monkey-to-monkey, and longitudinal variability and sensitivity to immunosuppression. The results show that nearly all animals have detectable responses against both CMV and LCV and responses were derived from T-cells specific to the virus of interest. Analyses of variability show assay reproducibility (≤23% CV), and that variability over time in anti-viral responses in individual animals (larger for LCV than for CMV) was ∼2-fold in most animals over a 3-month time period, which is predicted to allow for detection of drug-induced changes when using group sizes typical of non-clinical studies. In addition, the IFN-γ ELISPOT assay was capable of detecting decreases in the numbers of CMV and LCV reactive T-cells induced by immunosuppressive drugs in vitro. This assay may allow for non-clinical assessment of the effects of immunomodulatory therapeutics on anti-viral T-cell immunity in monkeys, and may help determine if therapeutics increase the risk of reactivating latent viral infections.

Post-transplant lymphoproliferative disorders in liver transplant recipients: a clinicopathological study

BACKGROUND AND AIMS

Complications after liver transplantation are major factors that determine the prognosis of patients. In this study, we aimed at investigating an important though less frequently occurring complication, post-transplant lymphoproliferative disorders (PTLD), in a single institution after liver transplantation.

METHODS

15 cases with a diagnosis of PTLD in post-liver transplant patients were retrieved from our archive and the clinicopathological features reviewed.

RESULTS

The overall incidence of PTLD was 2.3% (n=15/658), and the incidence was much higher in the paediatric than the adult age groups, being 11.1% (9/81) and 1% (6/577), respectively. The median time of presentation was 16 months after transplantation (occurrence time ranging from 2 to 87 months after transplantation). Lymph nodes, gastrointestinal tract and graft liver were the commonest sites of involvement. 11 cases were classified as monomorphic PTLD according to WHO classification and the majority (n=10/11) of them were of B cell differentiation. 12 of the total 15 PTLD cases showed a positive result for Epstein-Barr virus-encoded RNAs with in situ hybridisation. Eight patients were alive at the time of review, and two of them suffered from recurrence of the PTLD. Among the seven patients who died, six succumbed within 1 year from the diagnosis of PTLD.

CONCLUSIONS

Despite its relative rarity as a complication for liver transplantation, PTLD imposes significant effects on the morbidity, mortality and treatment implications in postliver transplant patients. The clinicopathological data would hopefully provide better insight into the surveillance and management for susceptible patients.

Diverse IgG serum response to novel glycopeptide epitopes detected within immunodominant stretches of Epstein-Barr virus glycoprotein 350/220: diagnostic potential of O-glycopeptide microarrays

The Epstein-Barr virus (EBV) envelope glycoprotein 350/220 (gp350/220) is the most abundant molecule on the viral surface and it is responsible for the initial viral attachment to cell surface of the host. As many other viral envelope proteins, it is highly glycosylated, not least with O-linked glycans, most of which essential for EBV life cycle. EBV gp350/220 is also a primary target for neutralizing antibodies in the human hosts and a promising candidate for an EBV vaccine. Here we showed that recombinant GalNAc transferases can glycosylate scan peptides of the EBV gp350/220 envelope protein immobilized on microarray glass slides. We also identified serum IgG antibodies to a selection of peptides and O-glycopeptides, whereas sera from EBV-IgG negative individuals remained negative. We here describe novel glycopeptide epitopes present within immunodominant stretches of EBV gp350/220 and demonstrate a remarkable variability between individual samples with respect to their reactivity patterns to peptides and glycopeptides. The study provides additional insights into the complex B-cell response towards the EBV gp350/220 envelope protein, which may have implications for diagnostic and vaccine developments.

Long-term outcome after liver transplantation

Liver transplantation is a life-saving therapy for patients with end-stage liver disease, acute liver failure, and liver tumors. Over the past 4 decades, improvements in surgical techniques, peritransplant intensive care, and immunosuppressive regimens have resulted in significant improvements in short-term survival. Focus has now shifted to addressing long-term complications and improving quality of life in liver recipients. These include adverse effects of immunosuppression; recurrence of the primary liver disease; and management of diabetes, hypertension, dyslipidemia, obesity, metabolic syndrome, cardiovascular disease, renal dysfunction, osteoporosis, and de novo malignancy. Issues such as posttransplant depression, employment, sexual function, fertility, and pregnancy must not be overlooked, as they have a direct impact on the liver recipient's quality of life. This review summarizes the latest data in long-term outcome after liver transplantation.

Radiofrequency ablation in the treatment of liver tumors in children

Hepatoblastoma and liver metastasis of Wilms' tumors are rare hepatic tumors in children. Treatment of both tumors consists of a combination of chemotherapy and liver surgery. Radiofrequency ablation (RFA) is frequently used for the treatment of adult liver tumors but is rarely mentioned as a treatment option in pediatric liver tumors. We present a patient with hepatoblastoma and 1 with liver metastasis from a Wilms' tumor. Both patients were treated according to the latest protocols except that surgery included use of RFA. Both are well and recurrence free 8 and 3 years after surgery. Radiofrequency ablation may be a good addition to the existing arsenal of treatment modalities for pediatric liver tumors.

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.

Epstein-Barr virus: Silent companion or causative agent of chronic liver disease?

The Epstein-Barr virus (EBV) has an important and multifaceted role in liver pathology. As a member of the herpes virus family, EBV establishes a persistent infection in more than 90% of adults. Besides acute hepatitis during primary infection, many clinical syndromes of interest for the hepatologist are associated with EBV infection. The role of EBV in the evolution of chronic hepatitis from hepatotropic viruses is considered. Chronic EBV-associated hepatitis is suspected in immunocompetent adults with compatible serology, suggestive histology and detection of the viral genome in the liver and/or increase of specific circulating cytotoxic T-lymphocytes. EBV is the main cause of post-transplant lymphoproliferative disorders which occur in up to 30% of cases. EBV-driven lymphoproliferative diseases are also recognized in non-immunocompromised patients and liver is involved in up to a third of the cases. Directly implicated in the pathogenesis of different tumors, EBV has a disputable role in hepatocellular carcinoma carcinogenesis. Further research is required in order to establish or reject the role of EBV in human liver cancer. This paper attempts to discuss the range of EBV-associated chronic liver diseases in immunocompetent patients, from mild, self-limiting mononuclear hepatitis to liver cancer.

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.

CNS or bone marrow involvement as risk factors for poor survival in post-transplantation lymphoproliferative disorders in children after solid organ transplantation

PURPOSE

To identify prognostic factors of survival in pediatric post-transplantation lymphoproliferative disorder (PTLD) after solid organ transplantation.

PATIENTS AND METHODS

A multicenter, retrospective case analysis of 55 pediatric solid organ graft recipients (kidney, liver, heart/lung) developing PTLD were reported to the German Pediatric-PTLD registry. Patient charts were analyzed for tumor characteristics (histology, immunophenotypes, cytogenetics, Epstein-Barr virus [EBV] detection), stage, treatment, and outcome. Probability of overall and event-free survival was analyzed in defined subgroups using univariate and Cox regression analyses.

RESULTS

PTLD was diagnosed at a median time of 29 months after organ transplantation, with a significantly shorter lag time in liver (0.83 years) versus heart or renal graft recipients (3.33 and 3.10 years, respectively; P = .001). The 5-year overall and event-free survival was 68% and 59%, respectively, with 59% of patients surviving 10 years. Stage IV disease with bone marrow and/or CNS involvement was associated independently with poor survival (P = .0005). No differences in outcome were observed between early- and late-onset PTLD, monomorphic or polymorphic PTLD, and EBV-positive or EBV-negative PTLD, respectively. Patients with Burkitt or Burkitt-like PTLD and c-myc translocations had short survival (< 1 year).

CONCLUSION

Stage IV disease is an independent risk factor for poor survival in pediatric PTLD patients. Prospective multicenter trials are needed to delineate additional risk factors and to assess treatment approaches for pediatric PTLD.

Successful prolonged rituximab treatment for post-transplant lymphoproliferative disorder following living donor liver transplantation in a child

PTLD is a serious complication of immunosuppression in solid organ transplant recipients. The incidence of PTLD is significantly higher in pediatric recipients than in adult because children are often EBV-seronegative and they may develop primary EBV infection after transplantation. We herein describe a case of GI-PTLD who achieved a complete remission by prolonged rituximab, a chimeric monoclonal antibody against CD20, mono-therapy. A one-yr-old female underwent a LDLT for liver failure after having previously undergone the Kasai procedure for biliary atresia. At sixty days following the transplantation, GI-PTLD developed. Withdrawal of immunosuppression and a surgical resection were thus performed. A histopathological examination of tumor revealed atypical medium to large cell lymphoid proliferation with strong CD20 immunopositivity indicating their B-cell origin. Polymorphic PTLD was diagnosed. Rituximab was administered at a dose of 375 mg/m2 once a week, and the monotherapy resulted in a complete remission after 34 administrations. Based on this case, rituximab appears to be beneficial as a first-line therapy for PTLD.

Severe cold agglutinin disease caused by recurrent monomorphic Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disorder (PTLD), clonally related to an EBV-negative plasmacytic hyperplasia in a pediatric multivisceral organ transplant recipient

PTLD represent major post-transplant complications. The major etiologic factor is EBV. Association with cold agglutinin disease has not been described so far. We report a three-yr-old girl who developed oligoclonal EBV-negative plasmacytic hyperplasia as well as Coombs test-positive anemia one yr after multivisceral organ transplantation, performed after subtotal bowel resection for colointestinal aganglionosis and liver cirrhosis resulting from long-term parenteral nutrition. The patient was treated for plasmacytic hyperplasia with cyclophosphamide and prednisolone and achieved clinical remission. One yr later PTLD progressed possibly driven by EBV to DLBCL. The migration patterns of the amplified Ig heavy chain genes demonstrated a probable clonal relationship of the DLBCL to a clone almost present in the plasmacytic hyperplasia. This progression was accompanied by a rapid rise of cold agglutinin titers with symptoms of severe cold agglutinin disease, leading to right femoral and extern iliac vein thromboses requiring partial leg amputation. After four cycles of rituximab, cyclophosphamide, and prednisolone, the patient achieved complete PTLD remission and the cold agglutinins disappeared. Summarizing, PTLD may be accompanied by cold agglutinin disease, and both may be successfully treated by immuno-chemotherapy. The appearance of cold agglutinins in transplant patients may indicate PTLD development.

Epstein–Barr virus infection as a complication of transplantation of a nerve allograft from a living related donor

✓Reconstruction of extensive nerve defects is hampered by the amount of autogenous nerve tissue available for transplantation and by donor site morbidity. Nerve allografts, being of foreign origin and potentially unlimited in supply, provide a solution to these problems. Studies have shown that nerve allotransplants require immunosuppression only until end-organ connections are made and that immunosuppressant therapy may be subsequently discontinued with no negative effect on functional outcome. Also, recent experimental and clinical focus has been on shorter periods of immunosuppression in order to reduce risk, even stopping immunosuppression after regeneration has reached the distal suture line rather than before recovery of end-organ connections. In the pediatric population, the increased disease burden and increased potential for nerve regeneration as well as the frequent availability of a living related donor make allografts all the more attractive as solutions to nerve reconstructive problems. Nevertheless, the risks of immunosuppression must not be underemphasized, and they deserve more attention in the current nerve transplantation literature.

The authors report on a child who, at the age of 1 year, received a nerve allograft from a living related donor who was positive for Epstein–Barr virus (EBV). The child quickly developed a symptomatic EBV infection concurrent with immunosuppressant drug therapy. The immunosuppression regimen was stopped prematurely, and the patient suffered only a short illness, but the EBV infection could have developed into a life-threatening posttransplant lymphoproliferative disorder (PTLD). The patient is consequently predisposed to develop PTLD and will have to be monitored for the rest of his life. This case highlights the importance of considering the potentially fatal risks associated with this elective procedure. Future studies are needed to quantify and minimize this complication. Nevertheless, it should be weighed against the potential functional benefit from using nerve allografts.

Presentation and early detection of post-transplant lymphoproliferative disorder after solid organ transplantation

Post-transplant lymphoproliferative disorder (PTLD) is a serious and still frequently observed complication of solid organ transplantation. Despite the recent introduction of anti B-cell monoclonal antibody therapy (rituximab) for treatment of PTLD, mortality rates remain high. Because PTLD often presents in a nonspecific way in clinically unsuspected patients, it is a major challenge to diagnose PTLD at an early stage. Epstein-Barr virus (EBV)-DNA load monitoring is a promising tool for the identification of patients at risk for PTLD development. However, there are some limitations of this method, and not all patients at risk for PTLD can be identified by EBV-DNA measurements alone. Therefore, it is of major importance to recognize early clinical signs and symptoms of PTLD. In this review, risk factors for PTLD development, disease presentation, and methods for early detection will be discussed. Special attention is given to allograft and digestive tract localization and the relation with time of onset of PTLD. The value and pitfalls of EBV-DNA load monitoring are discussed. In addition, because fluorodeoxyglucose (FDG)-positron emission tomography (PET) has shown to be a powerful tool for staging and response evaluation of malignant lymphoma, the role of FDG-PET for early diagnosis and staging of PTLD is addressed.

Epstein-Barr virus-DNA load monitoring late after lung transplantation: a surrogate marker of the degree of immunosuppression and a safe guide to reduce immunosuppression

BACKGROUND

Posttransplant lymphoproliferative disease (PTLD) is a serious complication after lung transplantation and its relation with Epstein-Barr virus (EBV) is well recognized. It has been postulated that preemptive reduction of immunosuppression guided by EBV-DNA load may lead to a significantly lower incidence of PTLD, because of the reconstitution of T-cell control. In this report, we describe the feasibility of this approach in terms of safety with regard to the risk of acute as well as chronic allograft rejection in 75 lung transplant recipients transplanted between 1990 and 2001 and followed for this study from June 1, 2001 until January 1, 2006.

METHODS

From all patients visiting our outpatient clinic, EBV-DNA load was measured at least twice a year during the study period. In patients with positive results, measurements were repeated every two to four weeks. EBV reactivation was defined as two consecutive EBV-DNA load measurements with a rising trend; with the last measurement exceeding 10.000 copies/mL under stable immunosuppression. In such case, immunosuppression was reduced.

RESULTS

EBV reactivation was observed in 26/75 patients (35%). One (1.5%) of these patients developed PTLD during the study period. Acute rejection, acceleration of chronic allograft rejection, or worse survival were not observed after reduction of immunosuppression.

CONCLUSIONS

Preemptive reduction of immunosuppression after lung transplantation guided by EBV-DNA load appears to be a safe approach for the prevention of PTLD in lung transplant recipients late after transplantation.

Sustained Epstein-Barr virus detection in paediatric liver transplantation. Insights into the occurrence of late PTLD

Epstein-Barr virus (EBV) infection is the main cause of post-transplant lymphoproliferative disease (PTLD). Little is known on chronic carrier state and its relation with late PTLD. We aimed to study EBV infection in the long-term after paediatric liver transplantation (OLT). We conducted a retrospective review of 34 children monitored for a median of 5.8 years (range 1.5-17.7). 21 were IgG seronegative (group A) and 13 seropositive (group B) before OLT. Primary infection was the appearance of VCA-IgM or VCA-IgG or Real-Time Polymerase Chain Reaction (RT-PCR) in patients previously IgG seronegative; positive VCA-IgM or EA-IgG or RT-PCR lasting longer than 6 months was defined sustained viral detection (SVD). 18/21 patients of group A had a primary infection at a median time of 3 months after transplant (0.5-60). 14/18 of group A and 0/13 of group B had a SVD (P < 0.0001). Viral loads greater than 500 copies/10(5) mononuclear cells occurred in 12/18 patients in group A and 0/13 patients in group B (P < 0.0001). The 3 patients who developed late PTLD (median time after OLT 47 months, range 15-121) were from group A, and presented with SVD before developing PTLD. In conclusion, EBV infection in seronegative patients at OLT is associated with greater viral loads and sustained viral detection. Late PTLD occurred only in naïve patients with markers of SVD. Three to 4 monthly long-term monitoring of EBV in pre-OLT naïve patients might help preventing the occurrence of late PTLD.

Current issues in pediatric transplantation

Pediatric solid organ transplantation is so successful that >80% of children will survive to become teenagers and adults. Therefore, it is essential that these children maintain a good quality life, free of significant long-term side effects. While intensive immunosuppressive regimens (containing CsA, tacrolimus, MMF, and steroids) effectively reduce acute or chronic rejection, they can produce long-term side effects including viral infection, renal dysfunction, hypertension, and stunting. The development of effective methods of diagnosis, prevention, and treatment of CMV means that this is no longer a significant cause of mortality, but morbidity remains high. In contrast, infection rates of EBV remain high in EBV-negative pre-transplant patients. However, pre-emptive reduction of immunosuppression or treatment with rituximab or adoptive T-cell therapy is effective in preventing/treating post-transplant lymphoproliferative disease. Recent protocols have concentrated on reducing CsA immunosuppression, to prevent unacceptable cosmetic effects, and to reduce the hypertension, hyperlipidemia, and nephrotoxicity. Both CsA and tacrolimus cause a 30% reduction in renal function, with 4-5% of patients developing severe chronic renal failure. The use of IL-2 inhibitors for induction therapy with low-dose calcineurin inhibitors, in combination with renal-sparing drugs such as MMF or sirolimus for maintenance immunosuppression, should prevent significant renal dysfunction in the future. The concept of steroid-free immunosuppression with IL-2 inhibitors, tacrolimus, and MMF is an attractive option, which may reduce stunting and renal dysfunction. However, these regimens may be associated with the increased development of de-novo autoimmune hepatitis in 2-3% of children. The most important challenge to long-term survival in transplanted children is the management of non-adherence and other adolescent issues, particularly when transferring to adult units, as this is the time when many successful transplant survivors lose their grafts.

Circulating Epstein-Barr virus (EBV) in HIV-infected patients and its relation with primary brain lymphoma

OBJECTIVE

To analyze Epstein-Barr virus (EBV) load at different HIV infection stages and its relation with brain lymphoma.

DESIGN

A cross-sectional study was conducted on 172 HIV-infected individuals: 62 asymptomatic HIV carriers (group A), 30 HIV progressors (group B), 73 AIDS patients (group C), seven AIDS patients with brain lymphoma (group C-BL); and 26 blood donors (group BD) as healthy carriers. EBV load was measured in peripheral blood mononuclear cells (PBMC) and plasma samples using a semi-quantitative PCR method.

RESULTS

PBMC-EBV levels in HIV-infected patients were higher than in the blood donors (p<0.05). No differences in PBMC-EBV loads were found in groups A, B, or C (p>0.05), while the C-BL group had significantly lower levels (p<0.05). Similar PBMC-EBV loads were seen in HIV-infected patients with CD4+ T cell counts higher than 50/mm(3) (p>0.05), while significantly lower levels were found in cases with less than 50 cells/mm(3) (p<0.05). In all HIV-infected patients, plasma-EBV load was lower than, or similar to, PBMC-EBV load, unlike 2/7 HIV-positive brain lymphoma patients.

CONCLUSIONS

During HIV infection PBMC-EBV load rises in comparison to healthy carriers, but decreases when immunosuppression progresses and CD4+ T cell count becomes <50/mm(3). Circulating EBV is mainly cell-associated in the HIV-infected population. Neither PBMC-EBV nor plasma-EBV loads would be useful to diagnose brain lymphoma in AIDS patients.

Infections in pediatric solid organ transplant recipients

Despite the progress made in graft and patient survival in recent years, infectious complications remain a major source of morbidity and mortality in pediatric solid organ transplant recipients. The risk of infection after transplant is determined by the interaction of several factors, including age, type of organ transplanted, type and intensity of immunosuppression, environmental exposures, and the consequences of invasive procedures. Compared with adult transplant recipients, children are at higher risk of developing primary infection with various organisms after transplantation, as they often lack previous immunity from natural exposure to many microbes and often have not completed their primary immunization series at the time of transplantation. This article provides an overview of the risk factors, timing, and types of infectious complications associated with organ transplantation in children.

Use of cytokine polymorphisms and Epstein-Barr virus viral load to predict development of post-transplant lymphoproliferative disorder in paediatric liver transplant recipients

OBJECTIVE

Currently there are no tests to accurately identify paediatric liver transplant patients at risk for post-transplant lymphoproliferative disorder (PTLD). Herein we describe the use of cytokine polymorphisms and real-time quantitative polymerase chain reaction (qPCR) Epstein-Barr virus (EBV) viral load to identify patients at risk for PTLD development.

METHODS

Between 2001 and 2004, approximately 1047 patient samples were collected for qPCR for EBV in 59 patients. EBV viral load was reported in three groups: low EBV (<4,000 copies/microg DNA), high EBV/no PTLD (>4000 copies/microg DNA) and biopsy-proven PTLD. All 59 patients also had cytokine polymorphism genotyping performed for six cytokine polymorphisms (transforming growth factor (TGF)-beta, tumor necrosis factor (TNF)-alpha, interleukins (IL)-6, IL-10, IL-2, and interferon (IFN)-gamma) from DNA isolated from peripheral blood mononuclear cells. Positive predictive value (PPV) and negative predictive value (NPV) were calculated using qPCR and cytokine polymorphism results. Data are reported as a mean +/- standard error of the mean.

RESULTS

There were 35 males and 24 females with a mean follow-up of 34.9 months. EBV viral load had a PPV and NPV of 29 and 95%, respectively. The low IFN-gamma (A/A) polymorphism was found to be present in 4/6 PTLD patients (67%) and only 17/53 (33%) non-PTLD patients. When the low A/A IFN-gamma polymorphism was combined with EBV viral load for prediction of PTLD, PPV and NPV were 57 and 93%, respectively.

DISCUSSION

Use of cytokine genotyping in conjunction with qPCR for EBV viral load can significantly improve the predictive value of diagnostic tests for identification of patients at high risk for PTLD.

Liver transplantation for inborn errors of liver metabolism

Liver transplantation brings complete recovery from end-stage liver disease, and full correction of liver based inborn errors of metabolism.

Pediatric liver transplantation

In the past two decades, pediatric liver transplantation has become the state-of-the-art operation with anticipated success and limited mortality. The future success of pediatric liver transplantation will require thoughtful solutions to the delicate balance of risk to donors and recipients, the complex needs of the acute postoperative patient, and the long-term challenges of chronic immunosuppression in these previously unsalvageable patients.

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

Epstein-Barr virus (EBV) is a common viral infection in pediatric liver transplant patients and can lead to development of post-transplant lymphoproliferative disorder (PTLD). Differing studies have used immunosuppression reduction, antiviral medications or i.v. CMV-immunogloublin for EBV prevention and treatment. The purpose of this study was to determine whether implementation of a protocol for frequent EBV monitoring and EBV viral load-driven immunosuppression reduction could decrease the incidence of PTLD in our patient population. All data were prospectively collected between 2001 and 2004 at a single institution. Seventy-three patients were entered into the study. Patients were divided into a historical control group (pre-2001, 30 patients) and a treatment group (post-2001, 43 patients). Approximately 1271 blood samples of 73 patients were collected between 2001 and 2004. Eleven out of 43 patients received immunosuppression tapering due to high EBV viral loads (>4000 copies/microg DNA). One patient developed allograft rejection after immunosuppression modulation. Prior to 2001, the incidence of PTLD at our institution was 16%. After instituting a protocol for EBV monitoring, the incidence of PTLD decreased to 2% (p-value<0.05). These findings illustrate that frequent EBV viral load monitoring and preemptive immunosuppression modulation have an integral role in preventing PTLD in the pediatric liver transplant population.

Monitoring of Epstein-Barr viral load in pediatric heart and lung transplant recipients by real-time polymerase chain reaction

BACKGROUND

Elevation in Epstein-Barr virus (EBV) load measured in peripheral blood has been proposed as a marker for development of post-transplant lymphoproliferative disease (PTLD), but there are few published data examining this relationship. We report the longitudinal surveillance of EBV for all recipients of heart (HTx), heart-lung (HLTx) and lung (LTx) transplants at our institution.

METHODS

The study population included all patients transplanted between January 2003 and July 2004. EBV load was serially measured in peripheral blood by real-time polymerase chain reaction (PCR). Results were correlated with recipient pre-transplant EBV status and development of PTLD.

RESULTS

Forty-four transplant operations were performed, including 33 HTx, 6 HLTx and 5 LTx. Thirty-two (73%) of the patients were EBV seropositive pre-transplant. Nineteen (44%) pediatric recipients developed EB viremia, including 17 HTx, 1 HLTx and 1 LTx. Eleven (58%) of these patients were EBV seropositive pre-transplant. EBV was first detected at a median of 30.5 days (range 2 to 81) post-transplant. The median peak EBV load in that group was 10,099 copies/ml (range 5,935 to 255,466) whole blood. One patient with cystic fibrosis post-LTx developed PTLD localized in the colon. This patient was EBV seronegative pre-transplant; peak EBV load was 14,513 copies/ml. Acute infectious mononucleosis was seen in 1 case. Positive pre-transplant EBV status did not predict post-transplant EB viremia (positive predictive value 0.03).

CONCLUSIONS

Contrary to earlier reports, our data demonstrate that a high EBV load does not lead to PTLD early post-transplant. These results do not support the practice of pre-emptively reducing immunosuppression in patients with raised EBV load.

Tacrolimus and steroids versus ciclosporin microemulsion, steroids, and azathioprine in children undergoing liver transplantation: randomised European multicentre trial

BACKGROUND

Results of studies in adult recipients of liver allograft suggest that tacrolimus is more efficacious than ciclosporin microemulsion in the prevention of acute rejection. We aimed to compare these drugs in children undergoing liver transplantation.

METHODS

This 12-month multicentre, open-label, parallel-group, randomised study compared a dual tacrolimus regimen (tacrolimus/corticosteroids, n=93) with a triple ciclosporin microemulsion regimen (ciclosporin microemulsion/corticosteroids/azathioprine, n=92) in children who had had liver transplants (age < or =16 years, bodyweight < or =40 kg). Initial oral daily doses were 0.30 mg/kg for tacrolimus and 10 mg/kg for ciclosporin microemulsion. Primary endpoint was the incidence of and time to first histologically proven acute rejection. We excluded patients from analysis if they did not receive the study drug, or were given incorrect medication. Otherwise patients were analysed in accordance with their random treatment allocation, irrespective of whether they switched medication during the trial.

FINDINGS

Median age was 22 months (IQR 9-56) in the tacrolimus group and 17 months (9-54) in the ciclosporin microemulsion group. We noted no difference between treatment groups with respect to patient survival (93.4% vs 92.2%; p=0.77) or graft survival (92.3% vs 85.4%; p=0.16) at month 12 after transplant. The acute rejection free rate at study end (Kaplan-Meier method) was 55.5% for patients on tacrolimus and 40.2% for patients on ciclosporin microemulsion (p=0.0288). The Kaplan-Meier estimate of patients free from corticosteroid-resistant acute rejection at study end was 94.0% for tacrolimus-treated patients and 70.4% for ciclosporin-microemulsion-treated patients (p<0.0001). Overall, incidence of adverse events did not differ between groups.

INTERPRETATION

Tacrolimus is a safe and effective treatment for the prevention of rejection after liver transplantation in children.

Epstein-Barr Virus (EBV) DNA in Plasma Is Not Encapsidated in Patients With EBV-Related Malignancies

Epstein-Barr Virus (EBV), a ubiquitous gamma herpes virus, infects more than 95% of the human population before adulthood. Life-long persistence, usually without adverse health consequences, relies on a balance between viral latency, viral replication, and host immune response. Patients with EBV-related disease often have high levels of EBV DNA in their plasma. This study addresses whether this circulating, cell-free EBV DNA is encapsidated in virions or exists as naked genomes. First, an assay was developed, combining DNase I and quantitative real-time PCR, to discriminate encapsidated from naked EBV DNA. EBV DNA was almost always naked in the plasma of AIDS-related lymphoma patients (n = 11) and immunosuppressed/posttransplantation patients (n = 8). In contrast, infectious mononucleosis patients (n = 30) often had a mixture of encapsidated and naked EBV DNA. These findings may be important in understanding how viral load relates to disease status and in predicting response to nucleoside analogs and other antiviral therapies.

Complete immunosuppressive withdrawal as a uniform approach to post-transplant lymphoproliferative disease in pediatric liver transplantation

Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disease (PTLD) in pediatric liver transplant recipients is associated with a high mortality (up to 60%) and the younger age groups, who are predominantly EBV-naïve, are at highest risk for development of this disease. The aim of this study is to assess, in this high-risk group, patient outcome and graft loss to rejection when complete withdrawal of immunosuppressive agents (IMS) is instituted as the mainstay of treatment in addition to the use of standard therapy. A retrospective analysis of 335 pediatric patients whose liver transplants were performed by our team between September 1988 and September 2002, was carried out through review of computer records, database and patient charts. Fifty patients developed either EBV or PTLD; 80% were < or =2 yr of age. Of these 50 patients, 19 had a positive tissue diagnosis for PTLD and 31 were diagnosed with EBV infection, 14 of whom had positive tissue for EBV. Fifty-eight percent of patients who developed PTLD and 51.6% of patients with EBV received antibody for induction or treatment of rejection prior to onset of disease. Forty-six patients (92%) received post-transplant antiviral prophylaxis with ganciclovir or acyclovir. Antiviral treatment included ganciclovir in 76%, acyclovir in 20% and Cytogam (in addition to one of the former agents) in 44%. In those with PTLD, treatment included chemotherapy (n = 1), Rituximab (n = 2), and ocular radiation (n = 1). IMS was stopped in all patients with PTLD and in 19 with EBV infection and was held as long as there was no allograft rejection. Eight patients have remained off IMS for a mean of 1535.5 +/- 623 days. Of the 21 patients who were restarted on IMS for acute rejection, 18 responded to steroids and/or reinstitution of low-dose calcineurin inhibitors. The mean time to rejection while off IMS in this group was 107.43 +/- 140 days (range: 7-476). Two patients were re-transplanted for chronic rejection; one had chronic rejection that existed prior to discontinuing IMS. The mortality rate in our series was 31.6% in those with PTLD and 6% in those with EBV disease. The cause of death was related to PTLD or sepsis in all cases; no deaths were due to graft loss from acute or chronic rejection. PTLD is associated with high mortality in the pediatric population. Based on this report, we advocate aggressive management of PTLD that is composed of early cessation of IMS, the use of antiviral therapy, and chemotherapy when indicated. Episodes of rejection that occur after stopping IMS can be successfully treated with standard therapy without graft loss to acute rejection.

Liver transplantation in neonates

Orthotopic liver transplantation (OLT) has evolved over the past two decades to become the standard of care for end-stage liver disease in infants and children. Technical advances, particularly the use of technical variant allografts, have permitted extension of OLT into a much younger and smaller population than previously possible. Major centers around the world now routinely perform OLT in infants with survival success equivalent to that in older children and adults. We are beginning to see a small population of school-aged children who were infant OLT recipients. The further extension of OLT into neonates is more recent, with only a few pediatric centers reporting survival success. Very little is known about this frontier of transplantation. Our intent is to provide an overview of neonatal OLT using all available data and our experience in the field.