Posttransplant lymphoproliferative disease in pediatric liver transplantation. Interplay between primary Epstein-Barr virus infection and immunosuppression

Management of Epstein-Barr Virus Infection and Post-Transplant Lymphoproliferative Disorder in Pediatric Liver Transplantation

With the advancement of immunosuppressive strategies, the outcome of liver transplantation during childhood has dramatically improved. On the other hand, Epstein–Barr virus (EBV) infection and associated post-transplant lymphoproliferative diseases (PTLD), such as malignant lymphoma, are serious complications that contribute to morbidity and mortality, and are still an important issue today. Recently, an early diagnosis by quantitative PCR and PET-CT testing, and treatment with rituximab (an anti-CD20 antibody) has been established, and long-term remission has been achieved in many cases. However, the optimal immunosuppression protocol after remission of PTLD needs to be determined, and it is hoped that a treatment for refractory PTLD (e.g., PTL-NOS) will be proposed.

A Bibliometric Analysis of the Landscape of Pediatric Liver Transplantation

Background

Nowadays, pediatric liver transplantation (PLT) has become an effective strategy for treating various acute or chronic end-stage liver diseases and inherited metabolic diseases. Many experts have already concluded the current challenges and future directions of PLT. However, no detailed analysis of the publication landscape has substantiated these proposed opinions.

Methods

This study presents a bibliometric review of the articles related to PLT between 1997 and 2020. A total of 3,084 publications were analyzed mainly by CiteSpace and VOSviewer.

Results

The field of PLT has evolved gradually in the past two decades. Articles increased at an average rate of 97 articles every 4 years. University of Pittsburgh (PITT) is the most prolific institution. The three most productive regions are North America, Europe, and East Asia. Currently, interdisciplinary studies on PLT are scarce. The main goal of PLT has shifted from survival rates to long-term outcome. The quality of life, living donor liver transplantation (LDLT), immunological biomarkers, perioperative hemodynamic management, expanding the indications of PLT, etc. are parts of the emerging research fronts. In the past two decades, articles that contain potentials that may lead to transformative discoveries are scarce, and obvious deficits can be seen in the field of new therapies.

Conclusions

Long-term outcome and good quality of life represent the principal direction of work concerning PLT. Deficits in new therapies align with the shortage of intellectual milestones, which indicate possible subsequent intellectual milestones may occur as innovations in therapies such as new immunosuppression therapies or liver cell transplantation.

Post-transplant Lymphoproliferative Disorder Following Cardiac Transplantation

Post-transplant lymphoproliferative disorder (PTLD) is a spectrum of lymphoid conditions frequently associated with the Epstein Barr Virus (EBV) and the use of potent immunosuppressive drugs after solid organ transplantation. PTLD remains a major cause of long-term morbidity and mortality following heart transplantation (HT). Epstein-Barr virus (EBV) is a key pathogenic driver in many PTLD cases. In the majority of PTLD cases, the proliferating immune cell is the B-cell, and the impaired T-cell immune surveillance against infected B cells in immunosuppressed transplant patients plays a key role in the pathogenesis of EBV-positive PTLD. Preventive screening strategies have been attempted for PTLD including limiting patient exposure to aggressive immunosuppressive regimens by tailoring or minimizing immunosuppression while preserving graft function, anti-viral prophylaxis, routine EBV monitoring, and avoidance of EBV seromismatch. Our group has also demonstrated that conversion from calcineurin inhibitor to the mammalian target of rapamycin (mTOR) inhibitor, sirolimus, as a primary immunosuppression was associated with a decreased risk of PTLD following HT. The main therapeutic measures consist of immunosuppression reduction, treatment with rituximab and use of immunochemotherapy regimens. The purpose of this article is to review the potential mechanisms underlying PTLD pathogenesis, discuss recent advances, and review potential therapeutic targets to decrease the burden of PTLD after HT.

Characteristics, management, and outcome of pediatric patients with post-transplant lymphoproliferative disease-A 20 years' experience from Austria

BACKGROUND

Management of pediatric post-transplantation lymphoproliferative disorder (PTLD) after hematopoietic stem cell (HSCT) and solid organ transplantation (SOT) is challenging.

AIM

This study of 34 PTLD patients up to 19-years old diagnosed in Austria from 2000 to 2018 aimed at assessing initial characteristics, therapy, response, and outcome as well as prognostic markers of this rare pediatric disease.

METHODS AND RESULTS

A retrospective data analysis was performed. Types of allografts were kidney (n = 12), liver (n = 7), heart (n = 5), hematopoietic stem cells (n = 4), lungs (n = 2), multi-visceral (n = 2), small intestine (n = 1), and vessels (n = 1). Eighteen/34 were classified as monomorphic PTLD, with DLBCL accounting for 15 cases. Polymorphic disease occurred in nine, and non-destructive lesions in six cases. One patient had a non-classifiable PTLD. Thirteen/34 patients are surviving event-free in first remission (non-destructive, n = 4/6; polymorphic, n = 4/9; monomorphic, n = 6/18). Fourteen/34 patients lacked complete response to first-line therapy, of whom seven died. Four/34 patients relapsed, of whom two died. In 3/34 patients, death occurred as a first event. The 5-year overall and event-free survival rates were 64% ± 9% and 35% ± 9% for the whole cohort. Among all parameters analyzed, only malignant disease as the indication for transplantation had a significantly poor influence on survival.

CONCLUSIONS

This study shows PTLD still to be a major cause of mortality following SOT or HSCT in children. A continued understanding of the molecular biology of the disease shall allow to decrease treatment intensity for lower risk patients and to identify patients who may benefit from newer therapy approaches to improve outcome and decrease morbidity.

Post-transplant eosinophilic gastrointestinal disorders and lymphoproliferative disorder in pediatric liver transplant recipients on tacrolimus

AIM

To examine and characterize post-transplant eosinophilic gastrointestinal disorders (PTEGID) and post-transplant lymphoproliferative disorder (PTLD) in pediatric liver transplant recipients.

METHODS

This is a single center retrospective study of all liver transplant recipients aged 0-18 years from 1999 to 2019 who received tacrolimus as their primary immunosuppressant. Demographic data and clinical/laboratory data including PTEGID, PTLD, liver transplant types, Epstein-Barr virus status, and blood eosinophil count were reviewed. Analysis was done with logistic regression and Mann-Whitney U test.

RESULTS

Ninety-eight pediatric liver transplant recipients were included with median age at transplantation of 3.3 years (IQR: 1.1-9.3). The major indication for transplantation was biliary atresia, 51 (52%) cases. Eight (8%) children had PTLD and 14 (14%) had PTEGID. Receiving liver transplantation at an age of ≤1 year was associated with developing PTEGID (OR = 11.9, 95% CI = 3.5-45.6, p < 0.001). Additionally, eosinophilic count of ≥500/μL was associated with having PTLD (OR = 10.7, 95% CI = 1.8-206.0, p = 0.030) as well as having at least one liver rejection (OR = 2.8, 95% CI = 1.2-7.0, p = 0.024). The frequency of food-induced anaphylaxis significantly increased post-transplantation (p = 0.023).

CONCLUSIONS

PTEGID and PTLD are common in this cohort and are associated with certain risk factors that help screen children to improve recipient survival. Further studies are needed to evaluate the clinical benefits of these findings.

What Animal Cancers teach us about Human Biology

Cancers in animals present a large, underutilized reservoir of biomedical information with critical implication for human oncology and medicine in general. Discussing two distinct areas of tumour biology in non-human hosts, we highlight the importance of these findings for our current understanding of cancer, before proposing a coordinated strategy to harvest biomedical information from non-human resources and translate it into a clinical setting. First, infectious cancers that can be transmitted as allografts between individual hosts, have been identified in four distinct, unrelated groups, dogs, Tasmanian devils, Syrian hamsters and, surprisingly, marine bivalves. These malignancies might hold the key to improving our understanding of the interaction between tumour cell and immune system and, thus, allow us to devise novel treatment strategies that enhance anti-cancer immunosurveillance, as well as suggesting more effective organ and stem cell transplantation strategies. The existence of these malignancies also highlights the need for increased scrutiny when considering the existence of infectious cancers in humans. Second, it has long been understood that no linear relationship exists between the number of cells within an organism and the cancer incidence rate. To resolve what is known as Peto's Paradox, additional anticancer strategies within different species have to be postulated. These naturally occurring idiosyncrasies to avoid carcinogenesis represent novel potential therapeutic strategies.

18F-FDG PET/CT for Evaluation of Post-Transplant Lymphoproliferative Disorder (PTLD)

Post-transplant lymphoproliferative disorders (PTLD) are a spectrum of heterogeneous lymphoproliferative conditions that are serious and possibly fatal complications after solid organ or allogenic hematopoietic stem cell transplantation. Most PTLD are attributed to Epstein-Barr virus reactivation in B-cells in the setting of immunosuppression after transplantation. Early diagnosis, accurate staging, and timely treatment are of vital importance to reduce morbidity and mortality. Given the often nonspecific clinical presentation and disease heterogeneity of PTLD, tissue biopsy and histopathological analysis are essential to establish diagnosis and most importantly, determine the subtype of PTLD, which guides treatment options. Advanced imaging modalities such as ¹⁸F-FDG PET/CT have played an increasingly important role and have shown high sensitivity and specificity in detection, staging, and assessing treatment response in multiple clinical studies over the last two decades. However, larger multicenter prospective validation is still needed to further establish the clinical utility of PET imaging in the management of PTLD. Significantly, new hybrid imaging modalities such as PET/MR may help reduce radiation exposure, which is especially important in pediatric transplant patients.

Medical care of liver transplant patients

INTRODUCTION

Liver transplantation is a life-changing event for patients and survival following transplantation has improved significantly since the first transplantation in 1967. Following liver transplantation, patients face a unique set of healthcare management decisions including transplantation-specific complications, recurrence of primary liver disease, as well as metabolic and malignancy concerns related to immunosuppression. As more patients with liver disease receive transplantation and live longer, understanding and managing these patients will require not only transplant specialist but also local subspecialist and primary care physicians.

AREAS COVERED

This review covers common issues related to the management of patients following liver transplantation including immunosuppression, liver allograft dysfunction, metabolic complications, as well as routine health maintenance such as immunizations and cancer screening.

EXPERT OPINION

Optimizing medical care for patients following liver transplant will benefit from ensuring all providers, not just transplant specialist, have a basic understanding of the common issues encountered in the post-transplant patient. This review provides an overview of common healthcare concerns and management options for patients following liver transplantation.

Post Transplant Lymphoproliferative Disorder risk factors in children: Analysis of a 23-year single-institutional experience

INTRODUCTION

PTLD is the most frequent malignancy following SOT in children and the second most common SOT complication in adults. However, factors determining outcomes in children are poorly understood due to its relative rarity.

METHODS

This study was performed at the University of Florida. Univariate and multivariate analyses were used to identify prognostic factors in pediatric patients diagnosed with PTLD.

RESULTS

We reviewed records of 54 pediatric (younger than 18 years old at diagnosis) patients diagnosed with PTLD from 1994 to 2017. The median follow-up was 28.8 months. The estimated 5-year survival rate was 87.6% (95% CI 74.3-94.2%). Univariate analysis showed that organ transplanted (specifically heart transplant), poor response to initial treatment, allograft rejection, and low Karnofsky score were statistically significant for negative prognostic factors in determining survival. Multivariate analysis determined progression in response to initial treatment and presence of allograft rejection as statistically significant prognostic factors affecting overall survival. We found no statistically significant impact of EBV serological status on PTLD prognosis.

CONCLUSIONS

Disease progression and allograft rejection were strong negative prognostic indicators in our study cohort. Close attention to graft status and development of therapies that protect the graft from rejection while bolstering anti-EBV immunity will be essential to further improving PTLD outcomes in children.

Co-infection of Cytomegalovirus and Epstein-Barr Virus Diminishes the Frequency of CD56dimNKG2A+KIR- NK Cells and Contributes to Suboptimal Control of EBV in Immunosuppressed Children With Post-transplant Lymphoproliferative Disorder

Post-transplant lymphoproliferative disorder (PTLD) is a rare but potentially life-threatening complication, frequently associated with Epstein-Barr virus (EBV), which develops after solid organ or stem cell transplantation. Immunosuppression received by transplant recipients has a significant impact on the development of PTLD by suppressing the function of T cells. The preferential proliferation of NKG2A-positive natural killer (NK) cells during primary symptomatic EBV infection known as infectious mononucleosis (IM) and their reactivity toward EBV-infected B cells point to a role of NK cell in the immune control of EBV. However, NK cell-mediated immune response to EBV in immunosuppressed transplant recipients who develop PTLD remains unclear. In this study, we longitudinally analyzed the phenotype and function of different NK cell subsets in a cohort of pediatric liver transplant patients who develop PTLD and compared them to those of children with IM. We found persistently elevated plasma EBV DNA levels in the PTLD patients indicating suboptimal anti-viral immune control. PTLD patients had markedly decreased frequency of CD56^dimNKG2A⁺Killer Immunoglobulin-like receptor (KIR)⁻ NK cells from the time of diagnosis through remission compared to those of IM patients. Whilst the proliferation of CD56^dimNKG2A⁺KIR⁻ NK cells was diminished in PTLD patients, this NK cell subset maintained its ability to potently degranulate against EBV-infected B cells. Compared to cytomegalovirus (CMV)-seropositive and -negative IM patients, PTLD patients co-infected with CMV and EBV had significantly higher levels of a CMV-associated CD56^dimNKG2C^hiCD57⁺NKG2A⁻KIR⁺ NK cell subset accumulating at the expense of NKG2A⁺KIR⁻ NK cells. Taken together, our data indicate that co-infection of CMV and EBV diminishes the frequency of CD56^dimNKG2A⁺KIR⁻ NK cells and contributes to suboptimal control of EBV in immunosuppressed children with PTLD.

Health-Related Quality of Life in Pediatric Liver Transplant Recipients

BACKGROUND

Health-related quality of life (HRQoL) of liver transplantation (LT) recipients has been widely studied because of increased patient longevity. However, studies in developing countries are scanty. We aimed to evaluate psychometric properties of the Thai version of the PedsQL Transplant Module and used it to determine the HRQoL in LT children.

METHODS

We included children aged 2 to 18 years who underwent LT more than 1 year previously. The phase 1 study included a cognitive interview with 20 LT children and their parents using the Thai version of PedsQL Transplant Module and revised the module accordingly. Then, the finalized version was evaluated for psychometric properties in 50 LT children. In phase 2, HRQoL was evaluated in 52 LT children who did not participate in the phase 1 study.

RESULTS

In the Thai PedsQL Transplant Module, both parent report and child self-report had good internal consistency (α = 0.94 and 0.93, respectively) and substantial reliability (interclass correlation coefficient = 0.82 and 0.77, respectively). Median HRQoL scores from the parent report and child self-report were 80 (interquartile range [IQR], 70, 88) and 77 (IQR, 71, 88), respectively. From the parent report, lower HRQoL was associated with opportunistic viral infection (P = .004) and correlated with a greater number of immunosuppressive agents (ρ = -0.346, P = .014). However, none of these factors were significant according to the child self-report.

CONCLUSIONS

The Thai PedsQL Transplant Module has satisfactory psychometric properties. Post-LT children have good HRQoL. To improve their HRQoL, specific attention should be focused on managing viral infection and optimizing immunosuppressive therapy.

De novo malignancies after liver transplantation: The effect of immunosuppression-personal data and review of literature

BACKGROUND

Immunosuppression has undoubtedly raised the overall positive outcomes in the post-operative management of solid organ transplantation. However, long-term exposure to immunosuppression is associated with critical systemic morbidities. De novo malignancies following orthotopic liver transplants (OLTs) are a serious threat in pediatric and adult transplant individuals. Data from different experiences were reported and compared to assess the connection between immunosuppression and de novo malignancies in liver transplant patients.

AIM

To study the role of immunosuppression on the incidence of de novo malignancies in liver transplant recipients.

METHODS

A systematic literature examination about de novo malignancies and immunosuppression weaning in adult and pediatric OLT recipients was described in the present review. Worldwide data were collected from highly qualified institutions performing OLTs. Patient follow-up, immunosuppression discontinuation and incidence of de novo malignancies were reported. Likewise, the review assesses the differences in adult and pediatric recipients by describing the adopted immunosuppression regimens and the different type of diagnosed solid and blood malignancy.

RESULTS

Emerging evidence suggests that the liver is an immunologically privileged organ able to support immunosuppression discontinuation in carefully selected recipients. Malignancies are often detected in liver transplant patients undergoing daily immunosuppression regimens. Post-transplant lymphoproliferative diseases and skin tumors are the most detected de novo malignancies in the pediatric and adult OLT population, respectively. To date, immunosuppression withdrawal has been achieved in up to 40% and 60% of well-selected adult and pediatric recipients, respectively. In both populations, a clear benefit of immunosuppression weaning protocols on de novo malignancies is difficult to ascertain because data have not been specified in most of the clinical experiences.

CONCLUSION

The selected populations of tolerant pediatric and adult liver transplant recipients greatly benefit from immunosuppression weaning. There is still no strong clinical evidence on the usefulness of immunosuppression withdrawal in OLT recipients on malignancies. An interesting focus is represented by the complete reconstitution of the immunological pathways that could help in decreasing the incidence of de novo malignancies and may also help in treating liver transplant patients suffering from cancer.

Renal transplantation and predisposition to opportunistic infections

PURPOSE OF REVIEW

Infections represent a significant source of morbidity and mortality after kidney transplantation in children. We review recent advances in epidemiology, assessment, prevention and treatment for several different infections.

RECENT FINDINGS

Infections, such as bacterial urinary tract infection or opportunistic viral infection remain common, may be increasing and represent a large proportion of hospitalization. Extended antiviral agent use reduces the incidence of cytomegalovirus disease but its efficacy to reduce Epstein-Barr virus disease remains controversial. Human herpesvirus-6 and hepatitis E virus represent new infections to keep in mind. Ureteral stenting increases the rate of early UTI. Several new vaccines are now available, but rates of complete vaccination pretransplant are low.

SUMMARY

Infections remain a critical posttransplant issue associated with significant medical burdens. Emerging data on associated risk factors, assessment of and treatment for infections provide clinicians with new knowledge.

Post-transplantation lymphoproliferative disease in pediatric liver recipients in Taiwan

BACKGROUND

Post-transplantation lymphoproliferative disorder (PTLD) is a heterogeneous, potentially life-threatening complication after liver transplantation in children. In this study, the disease characteristics, outcomes, and prognostic factors of PTLD were investigated.

METHODS

A retrospective, observational study was conducted on 16 pediatric liver transplant (LT) recipients who developed PTLD between February 2001 and December 2013 at a tertiary referral center in Taiwan. The disease characteristics and treatment outcomes of the patients were analyzed.

RESULTS

The median time from liver transplantation to the development of PTLD was 8 months. Early onset (<1 year post-transplantation) PTLD constituted 62.5% of the cases. PTLD location was frequently extranodal (81.3%) and mostly involved the gastrointestinal tract (68.8%). Histopathologic findings showed polymorphic PTLD in six cases (37.5%), diffuse large B-cell lymphoma in five cases (31.3%), and Burkitt's PTLD in two cases (12.5%). Early lesions in PTLD, T-cell lymphoma, and Hodgkin's lymphoma were observed in one case each (6.3%). Overall survival at 1- and 5-years post-PTLD diagnosis was 87.5% and 79.5%, respectively. St Jude's classification stage IV disease was associated with poor survival (hazard ratio [HR] = 13.37, P = 0.037). Two patients (12.5%) had chronic rejection after the treatment for PTLD and one patient (6.3%) developed graft failure.

CONCLUSION

PTLD is a major complication in pediatric LT recipients, but long-term survival is possible in most cases with an adequate treatment strategy. Stage IV disease is a major risk factor for poor survival in pediatric PTLD patients. During the management of PTLD, the possibility of chronic rejection and even graft failure should be considered.

A review of adenotonsillar hypertrophy and adenotonsillectomy in children after solid organ transplantation

OBJECTIVE

Paediatric solid organ transplantation is an increasingly successful treatment. Improved survival is paralleled by increased secondary complications of immunosuppression, including post-transplant lymphoproliferative disease (PTLD). PTLD frequently presents in Waldeyer's lymphatic ring. Adenotonsillar hypertrophy (ATH) is common in children, however in children after transplant, ATH may indicate PTLD. We review the literature on ATH and the role of adenotonsillectomy in children after transplantation.

METHODS

A comprehensive literature search was performed on the 26 th September 2017 of Ovid Medline (1996-September 2017), Embase (1996-2017) and EBM reviews (Cochrane database of systematic reviews 2005-September 20 th 2017). Results were limited to English language publications within the last 20 years. Abstracts were screened for relevance to PTLD and ATH in the paediatric solid organ transplantation population. Screening of the bibliographies identified further articles.

RESULTS

85 unique articles were screened to yield 18 relevant publications. 10 were retrospective studies and 8 were prospective studies.

CONCLUSION

In children, we report a PTLD incidence of up to 15%, with up to 63% of cases presenting in the head and neck. Histological examination of adenotonsillectomy specimens found PTLD in a mean 5.7% (range 0-39%). We found a lack of prospective studies into this topic and further high quality research is needed. Clinical assessment of ATH in children after transplantation and when to perform a diagnostic adenotonsillectomy remains challenging. Children with ATH warrant prompt further investigation and support from colleagues in transplantation and oncology is required. .

Risk factors and long-term outcomes of pediatric liver transplant recipients with chronic high Epstein-Barr virus loads

BACKGROUND

Serial monitoring of Epstein-Barr virus (EBV) reveals that certain pediatric liver transplant (LT) recipients exhibit high EBV loads for long periods. We investigated the incidence and risk factors of chronic high EBV (CHEBV) loads (continuous EBV DNA >10 000 IU/mL of whole blood for ≥6 months) and long-term outcomes.

METHODS

This single center, retrospective observational study investigated pediatric LT recipients who survived ≥6 months. We quantitated EBV DNA weekly during hospitalization and subsequently every 4 or 6 weeks at the outpatient clinic. Tacrolimus was maintained at a low trough level (<3 ng/mL, EBV DNA load >5000 IU/mL).

RESULTS

Thirty-one of 77 LT recipients developed CHEBV. Univariate analysis revealed that age <2 years and body weight <10 kg upon LT, operation time <700 minutes, warm ischemia time (WIT) >35 minutes, graft-to-recipient weight ratio (GRWR) >2.7%, and preoperative EBV seronegativity were significantly associated with the development of CHEBV loads. Multivariate analysis identified significant associations of CHEBV with WIT >35 minutes, GRWR >2.7%, and preoperative seronegative. None of the recipients developed post-transplantation lymphoproliferative disorder. Survival rates of patients with and without CHEBV loads were not significantly different.

CONCLUSIONS

A significant number of pediatric LT recipients developed CHEBV loads. Long WIT, high GRWR, and preoperative EBV seronegativity were significantly associated with the development of CHEBV loads. Although the long-term outcomes of patients with or without CHEBV loads were not significantly different, further studies of more subjects are warranted.

No effect of treatment with intravenous ganciclovir on Epstein-Barr virus viremia demonstrated after pediatric liver transplantation

EBV after pediatric LT is a risk factor for PTLD. We wanted to evaluate the effect of intravenous ganciclovir on EBV viremia and to identify risk factors for chronic EBV viremia. All pediatric patients who underwent LT in Norway from 2002 until 2015 were reviewed. Twenty-two of 38 patients with viremia were treated with intravenous ganciclovir for a median of 22 (21-38) days. Treated and untreated patients were not different with respect to EBV seroconversion prior to transplantation or age at transplantation, but treated patients had significantly earlier viremia after transplantation (P=.005). There was no difference in the proportion of patients with reduction in virus load in patients treated with ganciclovir compared to untreated patients at 8 weeks. After 1 year, five of 19 patients treated with ganciclovir and six of 14 untreated patients had reduced virus load compared to start of viremia (P=.27). In conclusion, treatment with intravenous ganciclovir did not change the proportion of patients with reduction in EBV load at 8 weeks and 1 year after viremia. Younger age at transplantation, short time from transplantation to viremia, and lack of EBV seroconversion prior to transplantation were significant predictors of chronic EBV viremia.

Post-transplant lymphoproliferative disorder after solid-organ transplant in children

The post-transplant lymphoproliferative disorders (PTLD) are a diverse group of potentially life-threatening conditions affecting organ transplant recipients. PTLD arises in the setting of an attenuated host immunologic system that is manipulated to allow a foreign graft but then fails to provide adequate immune surveillance of transformed malignant or premalignant lymphocytes. The diversity of biological behavior and clinical presentation makes for a challenging clinical situation for those involved in the care of children with PTLD occurring after solid-organ transplantation. This review details a large transplant center's multidisciplinary approach to monitoring for PTLD and systematic approach to intervention, which has been essential for early recognition and successful treatment.

The Role of Antiviral Prophylaxis for the Prevention of Epstein-Barr Virus-Associated Posttransplant Lymphoproliferative Disease in Solid Organ Transplant Recipients: A Systematic Review

The role of antiviral prophylaxis for the prevention of posttransplant lymphoproliferative disease (PTLD) remains controversial for solid organ transplantation (SOT) recipients who are seronegative for Epstein-Barr virus (EBV) but who received organs from seropositive donors. We performed a systematic review and meta-analysis to address this issue. Two independent assessors extracted data from studies after determining patient eligibility and completing quality assessments. Overall, 31 studies were identified and included in the quantitative synthesis. Nine studies were included in the direct comparisons (total 2366 participants), and 22 were included in the indirect analysis. There was no significant difference in the rate of EBV-associated PTLD in SOT recipients among those who received prophylaxis (acyclovir, valacyclovir, ganciclovir, valganciclovir) compared with those who did not receive prophylaxis (nine studies; risk ratio 0.95, 95% confidence interval 0.58-1.54). No significant differences were noted across all types of organ transplants, age groups, or antiviral use as prophylaxis or preemptive therapy. There was no significant heterogeneity in the effect of antiviral prophylaxis on the incidence of PTLD. In conclusion, the use of antiviral prophylaxis in high-risk EBV-naive patients has no effect on the incidence of PTLD in SOT recipients.

Post-transplant lymphoproliferative disorder of the pediatric airway: Presentation and management

OBJECTIVE

Post-transplant lymphoproliferative disorder (PTLD) is a rare complication of immunosuppression with little consensus on its evaluation and management. The purpose of this contemporary review is to describe a pediatric patient with PTLD of the airway and review the literature to provide multidisciplinary recommendations regarding management.

DATA SOURCES

Retrospective chart and literature review.

REVIEW METHODS

A pediatric patient with PTLD of the airway is described. An extensive literature search to review the existing data on pediatric PTLD of the upper airway was also performed.

RESULTS

A pediatric patient with mixed fetal/embryonal hepatoblastoma developed laryngo-tracheal PTLD following liver transplantation. Diagnostic positron emission tomography (PET) scan demonstrated multiple sites of abnormal fluorodeoxyglucose (FDG) uptake within the larynx, distal esophagus, cervical lymph nodes, and abdomen concerning for PTLD. Laryngeal biopsy demonstrated Epstein-Barr virus (EBV) positive cells confirming the diagnosis. Rituximab therapy and reduction of immunosuppression resulted in resolution of his laryngeal disease in 3 months. An extensive literature search to review the existing data on pediatric PTLD of the larynx and trachea revealed 14 reported cases.

CONCLUSIONS

PTLD of the pediatric airway is an EBV-associated disease that requires a high index of suspicion as patients can often present with non-specific signs and symptoms but progress to have significant airway compromise. Evaluation consists of peripheral blood polymerase chain reaction (PCR) assays, biopsy, and PET/CT imaging. Management options include reduction of immunosuppression and/or systemic therapies.

Sinonasal Posttransplant Lymphoproliferative Disorder in Pediatric Lung Transplant Patients

OBJECTIVE: To evaluate sinonasal manifestations of posttransplant lymphoproliferative disorder (PTLD) in the pediatric lung transplant population.

STUDY DESIGN AND METHODS: Case series of children less than 18 years presenting with PTLD after pulmonary transplantation at St Louis Children's Hospital between Jan 1, 1990 and Dec 31, 2003.

RESULTS: Two hundred eighty-two lung transplants were performed in 246 children. Thirty-two cases of histopathologically confirmed PTLD were identified with 8 (25%) presenting in the head and neck. Sinonasal PTLD was the most common site of head and neck involvement (63%), with 40% of patients presenting with occult disease. All patients with sinonasal PTLD had longstanding nasal polyposis related to cystic fibrosis ( P = 0.07).

CONCLUSIONS: This is, to our knowledge, the first report identifying an increased frequency of sinonasal PTLD after pediatric pulmonary transplantation, particularly in children with cystic fibrosis and associated nasal polyposis. Because sinonasal PTLD may be asymptomatic, this region should receive close scrutiny on surveillance evaluations.

Incidence, risk factors and outcomes of de novo malignancies post liver transplantation

Liver transplantation (LT) is associated with a 2 to 7 fold higher, age and gender adjusted, risk of de novo malignancy. The overall incidence of de novo malignancy post LT ranges from 2.2% to 26%, and 5 and 10 years incidence rates are estimated at 10% to 14.6% and 20% to 32%, respectively. The main risk factors for de novo malignancy include immunosuppression with impaired immunosurveillance, and a number of patient factors which include; age, latent oncogenic viral infections, tobacco and alcohol use history, and underlying liver disease. The most common cancers after LT are non-melanoma skin cancers, accounting for approximately 37% of de novo malignancies, with a noted increase in the ratio of squamous to basal cell cancers. While these types of skin cancer do not impact patient survival, post-transplant lymphoproliferative disorders and solid organ cancer, accounting for 25% and 48% of malignancies, are associated with increased mortality. Patients developing these types of cancer are diagnosed at more advanced stages, and their cancers behave more aggressively compared with the general population. Patients undergoing LT for primary sclerosing cholangitis (particularly with inflammatory bowel disease) and alcoholic liver disease have high rates of malignancies compared with patients undergoing LT for other indications. These populations are at particular risk for gastrointestinal and aerodigestive cancers respectively. Counseling smoking cessation, skin protection from sun exposure and routine clinical follow-up are the current approach in practice. There are no standardized surveillance protocol, but available data suggests that regimented surveillance strategies are needed and capable of yielding cancer diagnosis at earlier stages with better resulting survival. Evidence-based strategies are needed to guide optimal surveillance and safe minimization of immunosuppression.

Lowered Immune Cell Function in Liver Recipients Recovered From Posttransplant Lymphoproliferative Disease Who Developed Graft Tolerance

Tolerance after treatment and recovery from posttransplant lymphoproliferative disease (PTLD) have been described but little is known about the immunology. The objective of this study is to evaluate the immunity of pediatric recipients who recovered from PTLD.

Viral surveillance and subclinical viral infection in pediatric kidney transplantation

The more potent immunosuppressive therapy that has successfully reduced the incidence of acute rejection and improved graft outcomes has also resulted in a higher incidence of viral complications. Sensitive molecular methods now allow for the detection of subclinical viral infection, which is increasingly recognized due to the adoption of routine post-transplant viral surveillance protocols. The goal of viral surveillance is the detection of subclinical viral infection that triggers an intervention; one that either prevents progression to viral disease or leads to early diagnosis of viral disease, which is associated with improved outcomes. Knowledge of the epidemiology and natural history of subclinical viral infection and viral disease, as well as patient-specific risk factors, is required to establish the optimal surveillance schedule which achieves the goal of early diagnosis. Evidence that detection of subclinical viral infection can impact viral disease is variable depending on the virus. This review will summarize the current data on the role of viral surveillance for BK virus (BKV), cytomegalovirus (CMV), and the Epstein-Barr virus (EBV) in the pediatric kidney transplant population.

Post-transplant lymphoproliferative disorders

Post-transplant lymphoproliferative disorders (PTLD) are a serious complication after solid organ or allogeneic hematopoietic stem cell transplantation and include a range of diseases from benign proliferations to malignant lymphomas. Risk factors for developing PTLD include Epstein-Barr virus (EBV) infection, recipient age, transplanted organ, type of immunosuppression, and genetics. Uncontrolled proliferation of EBV-infected B cells is implicated in EBV-positive PTLD, whereas the pathogenesis of EBV-negative PTLD may be similar to non-Hodgkin's lymphoma in the general population. The World Health Organization (WHO) classifies PTLD into four categories: early lesions, polymorphic PTLD, monomorphic PTLD, and classical Hodgkin's lymphoma (cHL). Treatment is aimed at cure of PTLD, while maintaining transplanted organ function. However, there are no established guidelines for the treatment of PTLD. Immune suppression reduction (ISR) is the first line of treatment in most cases, with more recent data suggesting early use of rituximab. In more aggressive forms of PTLD, upfront chemotherapy may offer a better and more durable response. Sequential therapy using rituximab followed by chemotherapy has demonstrated promising results and may establish a standard of care. Novel therapies including anti-viral agents, adoptive immunotherapy, and monoclonal antibodies targeting cytokines require further study in the prevention and treatment of PTLD.

Posttransplantation lymphoproliferative disease: proposed imaging classification

Posttransplantation lymphoproliferative disease (PTLD) is the second most common tumor in adult transplant recipients. Most cases of PTLD are attributed to Epstein-Barr virus. Decreased levels of immunosurveillance against this tumor virus as a result of immunosuppressive regimens are thought to account for most cases of PTLD. Histologically, PTLD ranges from relatively benign lymphoid hyperplasia to poorly differentiated lymphoma, and tissue sampling is required to establish the subtype. The frequency of PTLD varies depending on the type of allograft and immunosuppressive regimen. PTLD has a bimodal manifestation, with most cases occurring within the first year after transplantation and a second peak occurring 4-5 years after transplantation. Patients are often asymptomatic or present with nonspecific symptoms, and a mass visible at imaging may be the first clue to the diagnosis. Imaging plays an important role in identifying the presence of disease, guiding tissue sampling, and evaluating response to treatment. The appearance of PTLD at imaging can vary. It may be nodal or extranodal. Extranodal disease may involve the gastrointestinal tract, solid organs, or central nervous system. Solid organ lesions may be solitary or multiple, infiltrate beyond the organ margins, and obstruct organ outflow. Suggestive imaging findings should prompt tissue sampling, because knowledge of the PTLD subtype is imperative for appropriate treatment. Treatment options include reducing immunosuppression, chemotherapy, radiation therapy, and surgical resection of isolated lesions.

Prevention of Posttransplant Lymphoproliferative Disorder in Pediatric Patients With a Liver Transplant

OBJECTIVES

This study sought to evaluate in pediatric liver transplant recipients the effects of hybrid antiviral therapy on the rate of posttransplant lymphoproliferative disorder.

MATERIALS AND METHODS

All pediatric patients (87 cases) who had undergone a liver transplant between April 2011 and March 2012 took part in the study and received hybrid antiviral treatment (case group). Epstein-Barr virus polymerase chain reaction was monitored intermittently. The results were compared to those of a historical control group including 117 pediatric patients who received a liver transplant between April 2009 and March 2011. Follow-up was 27 to 47 months in the control group and 12 to 26 months in the case group.

RESULTS

Posttransplant lymphoproliferative disorder occurred in 12 patients in control group (10.2%) and 5 patients in case group (5.7%) (P = .249). Of 12 cases of posttransplant lymphoproliferative disorder, death occurred in 5 cases in the control group (41.7%), while no posttransplant lymphoproliferative disorder-associated death was seen in the case group (P = .086).

CONCLUSIONS

Although hybrid antiviral treatment did not result in a statistically significant decrease in posttransplant lymphoproliferative disorder and posttransplant lymphoproliferative disorder-associated mortality rates, considering the limited number of posttransplant lymphoproliferative disorder cases in this study, this decrease may be interpreted as noticeable, and we advise using this strategy for pediatric patients undergoing a liver transplant.

Pediatric heart transplantation-indications and outcomes in the current era

Pediatric heart transplantation (HTx) remains an important treatment option in the care of children with end-stage heart disease, whether it is secondary to cardiomyopathy or congenital heart disease (CHD). As surgical outcomes for CHD have improved, the indications for pediatric HTx have had to be dynamic, not only for children with CHD but also for the growing population of adults with CHD. As the field of pediatric HTx has evolved, the outcomes for children undergoing HTx have improved. This is undoubtedly due to the continued research efforts of both single-center studies, as well as research collaboratives such as the International Society for Heart and Lung Transplantation (ISHLT) and the Pediatric Heart Transplant Study (PHTS) group. Research collaboratives are increasingly important in pediatric HTx as single center studies for a limited patient population may not elicit strong enough evidence for practice evolution. Similarly, complications that limit the long term graft survival may occur in a minority of patients thus pooled experience is essential. This review focuses on the indications and outcomes for pediatric HTx, with a special emphasis on studies generated by these research collaboratives.

Pediatric heart transplantation-indications and outcomes in the current era

Pediatric heart transplantation (HTx) remains an important treatment option in the care of children with end-stage heart disease, whether it is secondary to cardiomyopathy or congenital heart disease (CHD). As surgical outcomes for CHD have improved, the indications for pediatric HTx have had to be dynamic, not only for children with CHD but also for the growing population of adults with CHD. As the field of pediatric HTx has evolved, the outcomes for children undergoing HTx have improved. This is undoubtedly due to the continued research efforts of both single-center studies, as well as research collaboratives such as the International Society for Heart and Lung Transplantation (ISHLT) and the Pediatric Heart Transplant Study (PHTS) group. Research collaboratives are increasingly important in pediatric HTx as single center studies for a limited patient population may not elicit strong enough evidence for practice evolution. Similarly, complications that limit the long term graft survival may occur in a minority of patients thus pooled experience is essential. This review focuses on the indications and outcomes for pediatric HTx, with a special emphasis on studies generated by these research collaboratives.

Hepatic transplantation: postoperative complications

Advances in surgical techniques and immunosuppression have made orthotopic liver transplantation a first-line treatment for many patients with end-stage liver disease. The early detection and treatment of postoperative complications has contributed significantly to improved graft and patient survival with imaging playing a critical role in detection. Complications that can lead to graft failure or patient mortality include vascular abnormalities, biliary abnormalities, allograft rejection, and recurrent or post-transplant malignancy. Vascular abnormalities include stenosis and thrombosis of the hepatic artery, portal vein, and inferior vena cava, as well as hepatic artery pseudoaneurysm, arteriovenous fistula, and celiac stenosis. Biliary abnormalities include strictures, bile leak, obstruction, recurrent disease, and infection. While imaging is not used to diagnose allograft rejection, it plays an important role in identifying complications that can mimic rejection. Ultrasound is routinely performed as the initial imaging modality for the detection and follow-up of both early and delayed complications. Cholangiography and magnetic resonance cholangiopancreatography are used to characterize biliary complications and computed tomography is used to confirm abnormal findings on ultrasound or for the evaluation of postoperative collections. The purpose of this article is to describe and illustrate the imaging appearances and management of complications associated with liver transplantation.

The Role of mTOR Inhibitors in Liver Transplantation: Reviewing the Evidence

Despite the success of liver transplantation, long-term complications remain, including de novo malignancies, metabolic syndrome, and the recurrence of hepatitis C virus (HCV) and hepatocellular carcinoma (HCC). The current mainstay of treatment, calcineurin inhibitors (CNIs), can also worsen posttransplant renal dysfunction, neurotoxicity, and diabetes. Clearly there is a need for better immunosuppressive agents that maintain similar rates of efficacy and renal function whilst minimizing adverse effects. The mammalian target of rapamycin (mTOR) inhibitors with a mechanism of action that is different from other immunosuppressive agents has the potential to address some of these issues. In this review we surveyed the literature for reports of the use of mTOR inhibitors in adult liver transplantation with respect to renal function, efficacy, safety, neurological symptoms, de novo tumors, and the recurrence of HCC and HCV. The results of our review indicate that mTOR inhibitors are associated with efficacy comparable to CNIs while having benefits on renal function in liver transplantation. We also consider newer dosing schedules that may limit side effects. Finally, we discuss evidence that mTOR inhibitors may have benefits in the oncology setting and in relation to HCV-related allograft fibrosis, metabolic syndrome, and neurotoxicity.

Epstein-Barr DNA serology and positron-emission tomography imaging of the head and neck in pediatric transplant recipients

OBJECTIVES/HYPOTHESIS

Epstein-Barr virus (EBV) infection is a potential precursor of post-transplantation lymphoproliferative disorder (PTLD) in the pediatric transplant patient. Positron-emission tomography (PET) imaging is increasingly utilized in this population to monitor for neoplasia and PTLD. We assess the association between EBV serum titers and Waldeyer's ring and cervical lymph node PET positivity in the pediatric transplant recipient.

STUDY DESIGN

Retrospective analysis of EBV serology and PET imaging results in pediatric orthotopic liver transplantation (OLT) recipients.

METHODS

Imaging results and laboratory data were reviewed for all pediatric OLT recipients from January 2005 to July 2011 at a single institution. Charts were evaluated for PET positivity at Waldeyer's ring or cervical lymphatics, and for EBV serology results. Demographic data extracted include patient sex and age at transplantation.

RESULTS

A total of 122 pediatric OLT recipients were reviewed. Twelve patients (10%) underwent PET imaging. Overall, four patients (33%) had evidence of PET positivity at Waldeyer's ring or cervical lymphatics. Five patients (42%) had positive EBV serology. There was a significant association between PET imaging results and EBV DNA serology results (P = .01).

CONCLUSIONS

PTLD surveillance in the pediatric transplant recipient is an important component of long-term care in this population. Although PET imaging is a new modality in monitoring pediatric transplant recipients for early signs of PTLD, an association between EBV serology and PET imaging results appears to exist. With increased implementation, PET imaging will likely prove valuable in its ability to monitor the transplant recipient at risk for PTLD.

Decreasing incidence of symptomatic Epstein-Barr virus disease and posttransplant lymphoproliferative disorder in pediatric liver transplant recipients: report of the studies of pediatric liver transplantation experience

Posttransplant lymphoproliferative disorder (PTLD) causes significant morbidity and mortality in pediatric recipients of liver transplantation (LT).

OBJECTIVE

Describe the incidence of PTLD and symptomatic Epstein-Barr virus (SEBV) disease in a large multicenter cohort of children who underwent LT with a focus on the risk factors and changes in incidence over time. SEBV and PTLD were prospectively determined in 2283 subjects who had undergone LT for the first time with at least 1 year of follow-up in the Studies of Pediatric Liver Transplantation database. SEBV was defined with specific criteria, and PTLD required tissue confirmation. The incidence of SEBV and PTLD was determined with a Kaplan-Meier analysis. Univariate and multivariate modeling of risk factors was performed with standard methods. SEBV occurred in 199 patients; 174 (87.4%) were EBV-negative at LT. Seventy-five patients developed PTLD, and 64 (85.3%) of these patients were EBV-negative at LT. Among the 2048 patients with at least 2 years of follow-up, 8.3% developed SEBV by the second year after LT, and 2.8% developed PTLD. There were lower rates of SEBV (5.9% versus 11.3%, P < 0.001) and PTLD (1.7% versus 4.2%, P = 0.001) in 2002-2007 versus 1995-2001. In 2002-2007, tacrolimus and cyclosporine trough blood levels in the first year after LT were significantly lower, and fewer children were receiving steroids. Biliary atresia, and recipient EBV status were correlated. In a multivariate analysis, era of LT, recipient EBV status, and frequent rejection episodes were associated with SEBV and PTLD. The incidence of SEBV and PTLD is decreasing in pediatric LT recipients concomitantly with a reduction in immunosuppression. Younger recipients and those with multiple rejections remain at higher risk for SEBV and PTLD.

More benign lymphoproliferative disease after liver transplant in infants

CONTEXT-Despite the high frequency of liver transplants in infants, few data are available on the characteristics of posttransplant lymphoproliferative disorders in liver transplant patients (PTLD). OBJECTIVE-To analyze special features and behavior of PTLD arising after liver transplant in infants. METHODS-A comprehensive search of the literature was conducted for the available data on PTLD in infant liver transplant recipients through PubMed and Google scholar. An infant was defined as a liver recipient who was less than 2 years old at the time of transplant. Overall, 205 cases of PTLD were found in 24 reports, and the 100 infants with PTLD were compared with children and adults with PTLD. RESULTS-PTLD lesions in infants were more likely to be polymorphic whereas monomorphic lesions were more prevalent among older patients (P= .05). Remission rates, metastasis frequency, and organ involvement did not differ significantly between the groups. Survival analysis showed that the infants had a significantly better outcome than did older patients (P= .05). CONCLUSION-PTLD is more benign and may have a better outcome in infant liver transplant recipients than in older recipients. A prospective multicenter approach is needed for future research studies.

Posttransplant Lymphoproliferative Disorder after Cardiac Transplantation in Children: Life Threatening Complications Associated with Chemotherapy Combined with Rituximab

Despite the excellent long-term survival currently achieved in pediatric heart transplant recipients, posttransplant lymphoproliferative disorders (PTLDs) are one of the most important causes of morbidity and mortality after heart transplantation (HTx), especially in children. Timely and accurate diagnosis based on histological examination of biopsy tissue is essential for early intervention for PTLD. Chemotherapy is indicated for patients with poor response to reduction of immunosuppressive medication and for highly aggressive monomorphic PTLD. The use of rituximab in combination with chemotherapy is effective to suppress B cell type PTLD (B-PTLD). However, PTLD relapses frequently and the outcome is still poor. Although everolimus (EVL) has been reported to inhibit growth of human Epstein-Barr-virus- (EBV-) transformed B lymphocytes in vitro and in vivo, EVL has several side effects, such as delayed wound healing and an increase in bacterial infection. During combined treatment of chemotherapy and rituximab, B-PTLDs are sometimes associated with life-threatening complications, such as intestinal perforation and cardiogenic shock due to cytokine release syndrome. In HTx children especially treated with EVL, stoma should be made to avoid reoperation or sepsis in case of intestinal perforation. In cases with cardiac graft dysfunction possibly due to cytokine release syndrome by chemotherapy with rituximab for PTLD, plasma exchange is effective to restore cardiac function and to rescue the patients.

Epstein-Barr and other herpesvirus infections in patients with early onset type 1 diabetes treated with daclizumab and mycophenolate mofetil

BACKGROUND

We assessed the morbidity of herpesviruses in patients with type 1 diabetes mellitus (T1D) enrolled in immunosuppressive treatment studies.

METHODS

Epstein-Barr virus (EBV), cytomegalovirus (CMV), herpes simplex virus (HSV), and varicella zoster virus (VZV) infections were monitored in 126 participants of a randomized, double-blind, placebo-controlled study of daclizumab (DZB) and mycophenolate mofetil (MMF) including DZB(+)MMF(+), DZB(-)MMF(+), DZB(+)MMF(-), and DZB(-)MMF(-). During the 2-year follow-up, herpesviral infections were monitored clinically, by serology and blood DNA polymerase chain reaction.

RESULTS

Among 57 baseline EBV-seronegative participants, 9 developed EBV primary infections, including 2 with infectious mononucleosis syndrome. There were no appreciable differences in the course of the primary EBV infections across treatment groups. Among 69 baseline EBV-seropositive participants, 22 had virologic reactivations, including 1 symptomatic DZB(-)MMF(+) subject. Compared with 7 DZB(-)MMF(-) EBV reactivators, the 9 DZB(+)MMF(+) reactivators tended to have more prolonged viremia (11.4 vs 4.4 months; P = .06) and higher cumulative viral burden (14.2 vs 12.5 log EBV copies/mL; P = .06). Four of 85 baseline CMV-seronegative subjects developed asymptomatic primary CMV infections. There were no CMV reactivations. Of 30 baseline HSV-seropositive subjects, 8 developed ≥1 episode of herpes labialis; 1 subject had a primary HSV infection; and 1 subject without baseline serology information had a new diagnosis of genital HSV. There were no significant differences in the incidence of HSV recurrences across treatment groups. Of 100 baseline VZV-seropositive subjects, 1 DZB(-)MMF(-) subject developed herpes zoster and 1 DZB(-)MMF(+) subject had Bell's palsy possibly related to VZV.

CONCLUSIONS

The use of DZB alone or in combination with MMF was not associated with increased morbidity due to herpesviruses.

CLINICAL TRIALS REGISTRATION

NCT00100178.

The Seville expert workshop for progress in posttransplant lymphoproliferative disorders

: Posttransplant lymphoproliferative disorders (PTLDs) are associated with significant morbidity and mortality among solid-organ transplant patients, but approaches to diagnosis and management vary considerably. An international multidisciplinary panel evaluated current understanding of risk factors and classification systems and developed recommendations to aid in PTLD prevention. We considered evidence on PTLD risk factors including Epstein-Barr virus serostatus and immunosuppression and identified knowledge gaps for future research. Recommendations address prophylactic and preemptive strategies to minimize PTLD development, including modulation of immunosuppression and antiviral drug regimens. Finally, new classification criteria were outlined that may help facilitate standardized reporting and improve our understanding of PTLD.

Low-dose chemotherapy and rituximab for posttransplant lymphoproliferative disease (PTLD): a Children's Oncology Group Report

Optimal therapy for posttransplant lymphoproliferative disease (PTLD) remains problematic. A phase II trial adding rituximab to a low-dose cyclophosphamide and prednisone regimen was conducted for pediatric patients with Epstein-Barr virus (EBV) (+), CD20 (+) PTLD. Fifty-five patients were enrolled. Toxicity was similar for cycles of therapy containing rituximab versus those without. The complete remission (CR) rate was 69% (95% confidence interval (CI); 57%-84%). Of 12 patients with radiographic evidence of persistent disease at the end of therapy, eight were in CR 28 weeks later without further PTLD therapy. There were 10 deaths, 3 due to infections while receiving therapy and 7 from PTLD. The 2-year event-free survival (alive with functioning original allograft and no PTLD) was 71% (95% CI: 57%-82%) and overall survival was 83% (95% CI: 69%-91%) with median follow-up of 4.8 years. Due to small numbers, we were unable to determine significance of tumor histology, stage of disease, allograft type or early response to treatment on outcome. These data suggest rituximab combined with low-dose chemotherapy is safe and effective in treating pediatric with EBV (+) PTLD following solid-organ transplantation.

Burden of de novo malignancy in the liver transplant recipient

Recipients of liver transplantation (LT) have a higher overall risk (2-3 times on average) of developing de novo malignancies than the general population, with standardized incidence ratios ranging from 1.0 for breast and prostate cancers to 3-4 for colon cancer and up to 12 for esophageal and oropharyngeal cancers. Aside from immunosuppression, other identified risk factors for de novo malignancies include the patient's age, a history of alcoholic liver disease or primary sclerosing cholangitis, smoking, and viral infections with oncogenic potential. Despite outcome studies showing that de novo malignancies are major causes of mortality and morbidity after LT, there are no guidelines for cancer surveillance protocols or immunosuppression protocols to lower the incidence of de novo cancers. Patient education, particularly for smoking cessation and excess sun avoidance, and regular clinical follow-up remain the standard of care. Further research in epidemiology, risk factors, and the effectiveness of screening and management protocols is needed to develop evidence-based guidelines for the prevention and treatment of de novo malignancies.

Effective control of Epstein-Barr virus infection following pediatric liver transplantation by monitoring of viral DNA load and lymphocyte surface markers

EBV-associated PTLD is a serious complication of liver transplantation. We performed periodical molecular EBV monitoring in 140 consecutive pediatric patients who had living-related liver transplantation in the National Center for Child Health and Development, Tokyo. Sixty-three of the 140 patients showed elevation of EBV DNA level to >10(2) copies/μg DNA and were further examined immunologically by flow cytometry, and the dose of tacrolimus and/or cyclosporine A was adjusted according to the results. The decrease in CD4/CD8 ratio and the increase in the number of HLA-DR(+) CD8(+) cells were observed in parallel with the decrease in EBV DNA load and in the number of CD19(+) CD23(+) cells following the reduction in immunosuppressive drugs. Analysis with HLA tetramers in a patient demonstrated a dramatic increase in the number of CD8(+) T cells specific to the EBV latent protein LMP2 accompanying the decline of EBV DNA load, suggesting that T cells of this specificity were actually involved in the control of EBV infection. No clinically apparent PTLD has developed in the 140 recipients, suggesting that our program of EBV control by molecular EBV monitoring coupled with lymphocyte phenotype analyses is effective in controlling EBV infection in pediatric liver transplant recipients.

Early bedside detection of ischemia and rejection in liver transplants by microdialysis

This study was performed to explore whether lactate, pyruvate, glucose, and glycerol levels sampled via microdialysis catheters in the transplanted liver could be used to detect ischemia and/or rejection. The metabolites were measured at the bedside every 1 to 2 hours after the operation for a median of 10 days. Twelve grafts with biopsy-proven rejection and 9 grafts with ischemia were compared to a reference group of 39 grafts with uneventful courses. The median lactate level was significantly higher in both the ischemia group [5.8 mM (interquartile range = 4.0-11.1 mM)] and the rejection group [2.1 mM (interquartile range = 1.9-2.4 mM)] versus the reference group [1.5 mM (interquartile range = 1.1-1.9 mM), P < 0.001 for both]. The median pyruvate level was significantly increased only in the rejection group [185 μM (interquartile range = 155-206 μM)] versus the reference group [124 μM (interquartile range = 102-150 μM), P < 0.001], whereas the median lactate/pyruvate ratio and the median glycerol level were increased only in the ischemia group [66.1 (interquartile range = 23.9-156.7) and 138 μM (interquartile range = 26-260 μM)] versus the reference group [11.8 (interquartile range = 10.6-13.6), P < 0.001, and 9 μM (interquartile range = 9-24 μM), P = 0.002]. Ischemia was detected with 100% sensitivity and greater than 90% specificity when a positive test was repeated after 1 hour. In 3 cases of hepatic artery thrombosis, ischemia was detected despite normal blood lactate levels. Consecutive pathological measurements for 6 hours were used to diagnose rejection with greater than 80% sensitivity and specificity at a median of 4 days before the activity of alanine aminotransferase, the concentration of bilirubin in serum, or both increased. In conclusion, bedside measurements of intrahepatic lactate and pyruvate levels were used to detect ischemia and rejection earlier than current standard methods could. Discrimination from an uneventful patient course was achieved. Consequently, intrahepatic graft monitoring with microdialysis may lead to the earlier initiation of graft-saving treatment.

Associations between EBV serostatus and organ transplant type in PTLD risk: an analysis of the SRTR National Registry Data in the United States

In a prior multiorgan transplant database study, recipient Epstein-Barr virus (EBV) seronegativity was not associated with increased risk for posttransplant lymphoproliferative disorders (PTLD) in liver transplants (LTX), at variance with prior single center reports and with data from kidney and heart transplants (KTX and HTX). The Scientific Registry of Transplant Recipients (SRTR) in the United States is the only other registry with data on the required variables for comparison.Our study set comprised 112 756 KTX (580 PTLDs; 0.51%), 13 937 HTX (140 PTLDs; 1.0%) and 40 437 LTX (383 PTLDs; 0.95%) performed January 2003 onward. The unadjusted hazard ratio (HR) for PTLD if recipient EBV seronegative was 5.005 for KTX, 6.528 for HTX and 2.615 for LTX (p < 0.001 for all). In models adjusted for multiple covariates, the adjusted HR was 3.583 (p < 0.001) for KTX, 4.037 (p < 0.001) for HTX, 1.479 (p = 0.03) for LTX. Interaction models using EBV seropositive KTX as reference group showed significantly higher risk for all other EBV seronegative organ transplant groups and also for EBV seropositive LTX (AHR 2.053, p < 0.0001).Recipient EBV seronegativity is still significantly associated with risk for PTLD in LTX, though less so because of higher baseline risk in the EBV seropositive LTX group.

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.

Epstein-Barr virus infection in transplant recipients: Summary of a workshop on surveillance, prevention and treatment

Diseases caused by the Epstein-Barr virus are of great significance among organ transplant recipients. One of these diseases, post-transplant lymphoproliferative disease, is a major complication among organ transplant recipients. Management of this entity is problematic due to the difficulties with laboratory surveillance, diagnosis, prevention and treatment. A group of Canadian and American experts was assembled to discuss these aspects of Epstein-Barr virus diseases in Canadian organ transplant recipients. This report summarizes the relevant background literature and levels of evidence in relation to the outcomes of the deliberations and recommendations by the expert panel.