Pattern analysis of Epstein-Barr virus viremia and its significance in the evaluation of organ transplant patients suspected of having posttransplant lymphoproliferative disorders

The IPTA Nashville Consensus Conference on Post-Transplant lymphoproliferative disorders after solid organ transplantation in children: III - Consensus guidelines for Epstein-Barr virus load and other biomarker monitoring

The International Pediatric Transplant Association convened an expert consensus conference to assess current evidence and develop recommendations for various aspects of care relating to post-transplant lymphoproliferative disorders after solid organ transplantation in children. In this report from the Viral Load and Biomarker Monitoring Working Group, we reviewed the existing literature regarding the role of Epstein-Barr viral load and other biomarkers in peripheral blood for predicting the development of PTLD, for PTLD diagnosis, and for monitoring of response to treatment. Key recommendations from the group highlighted the strong recommendation for use of the term EBV DNAemia instead of "viremia" to describe EBV DNA levels in peripheral blood as well as concerns with comparison of EBV DNAemia measurement results performed at different institutions even when tests are calibrated using the WHO international standard. The working group concluded that either whole blood or plasma could be used as matrices for EBV DNA measurement; optimal specimen type may be clinical context dependent. Whole blood testing has some advantages for surveillance to inform pre-emptive interventions while plasma testing may be preferred in the setting of clinical symptoms and treatment monitoring. However, EBV DNAemia testing alone was not recommended for PTLD diagnosis. Quantitative EBV DNAemia surveillance to identify patients at risk for PTLD and to inform pre-emptive interventions in patients who are EBV seronegative pre-transplant was recommended. In contrast, with the exception of intestinal transplant recipients or those with recent primary EBV infection prior to SOT, surveillance was not recommended in pediatric SOT recipients EBV seropositive pre-transplant. Implications of viral load kinetic parameters including peak load and viral set point on pre-emptive PTLD prevention monitoring algorithms were discussed. Use of additional markers, including measurements of EBV specific cell mediated immunity was discussed but not recommended though the importance of obtaining additional data from prospective multicenter studies was highlighted as a key research priority.

Post-Transplant Lymphoproliferative Disorders

Post-transplant lymphoproliferative disorders (PTLDs) are a heterogenous set of unregulated lymphoid cell proliferations after organ or tissue transplant. A majority of cases are associated with the Epstein-Barr virus and higher intensity of pharmacologic immunosuppression. The clinical presentations are numerous. The diagnosis is ideally by histology, except in cases where the tumor is inaccessible to biopsy. While some pre-emptive therapies and treatment strategies are available have reasonable success are available, they do not eliminate the high morbidity and significant mortality after PTLD.

Characteristics and Outcome of Post-Transplant Lymphoproliferative Disorders After Solid Organ Transplantation: A Single Center Experience of 196 Patients Over 30 Years

Post-transplant lymphoproliferative disorder (PTLD) is a rare but life-threatening complication after transplantation. In this retrospective, monocentric study we aimed to collect real life data regarding PTLD and determine the role of Epstein Barr Virus (EBV) status and year of diagnosis on prognosis. We identified 196 biopsy-proven PTLD after solid organ transplantation (SOT) diagnosed at the University Hospitals Leuven (Belgium) from 1989 to 2019. EBV status was positive in 61% of PTLD. The median overall survival (OS) was 5.7 years (95% CI: 2.99-11.1). Although EBV positivity was not significantly correlated with OS in multivariate analyses (HR: 1.44 (95% CI: 0.93-2.24); p = 0.10), subgroup analysis showed a significantly better median OS for EBV negative post-transplant diffuse large B-cell lymphoma (DLBCL) compared to EBV positive post-transplant DLBCL (8.8 versus 2.5 years respectively; p = 0.0365). There was a significant relation between year of PTLD diagnosis and OS: the more recent the PTLD diagnosis, the lower the risk for death (adjusted HR: 0.962 (95% CI: 0.931-0.933); p = 0.017). In conclusion, the prognosis of PTLD after SOT has improved in the past decades. Our analysis shows a significant relation between EBV status and OS in post-transplant DLBCL.

Probable posttransplant lymphoproliferative disorder after pediatric living donor liver transplantation: Is a biopsy still needed?

Posttransplant lymphoproliferative disorder (PTLD) is a complication of solid organ transplantation and is associated with Epstein-Barr virus (EBV). Recently, EBV-related PTLD was defined as probable PTLD or proven PTLD. Probable PTLD involves significant lymphadenopathy, hepatosplenomegaly, or other end-organ manifestations, without a histological diagnosis, together with significant EBV DNAemia. Proven PTLD is the detection of EBV-encoded proteins in a tissue specimen, together with symptoms and/or signs originating from the affected organ. Probable PTLD after pediatric liver transplantation has not been well documented. Therefore, here, we aimed to describe cases of five pediatric patients with probable PTLD after liver transplantation, who were successfully treated with preemptive immunosuppression reduction with or without rituximab. All five patients (age range, 1-4 years; two girls and three boys) had EBV DNAemia. Three patients developed probable PTLD within 12 months of transplantation. Further, three patients had a significantly high EBV viral load, but the other two patients with lymphadenopathy and end-organ manifestation had a relatively low EBV viral load. Early onset pediatric PTLD with significant EBV DNAemia is almost universally EBV-related. Biopsy was not performed in any patient due to the relative inaccessibility of the lesion and young age of the patients. If the patient's symptoms are too mild, if excisional biopsy is too difficult to perform, or if the patient is too sick to undergo an invasive procedure, initiating preemptive treatment without a histological diagnosis could be the treatment option.

Co-Occurrence of EBV-Positive Mucocutaneous Ulcer (EBV-MCU) and CLL/SLL in the Head and Neck Region

EBV-positive mucocutaneous ulcer (EBV-MCU) was classified as a rare new entity of the lymphoproliferative B-cell diseases by the WHO in 2017 and must be distinguished from head and neck squamous cell carcinoma by early biopsy. The aim of the study is to raise awareness of the disease and to give a review of the current literature and a recommendation for EBV-MCU management. All EBV-MCU cases of the head and neck region published so far were included. We also report a case of a pharyngeal EBV-MCU in an 89-year-old patient who was immunosuppressed by chronic lymphatic leukaemia/small lymphocytic lymphoma (CLL/SLL). In contrast to all previously described cases, histopathology showed a co-infiltration of EBV-MCU and CLL/SLL. A total of 181 cases were identified on PubMed and summarised. EBV-MCU was predominantly caused by immunosuppressive drug therapy. Complete remission could be achieved in 68% of cases and was mainly attributed to a reduction of the immunosuppressive therapy alone (72%). However, some severe cases require more aggressive treatment. Regarding the various histopathologic similarities to other lymphoproliferative disorders, the diagnosis of EBV-MCU can be misleading, with a great impact on patient care and treatment. This diagnosis must be made with caution and requires a combination of clinical, morphological and immunophenotypic features.

Role of Cytomegalovirus in the Development of Posttransplant Lymphoproliferative Disorders With or Without Epstein-Barr Virus Infection

OBJECTIVES

Many studies have revealed the role of Epstein-Barr virus infection, in combination with chronic immunosuppression, as the main factor in the development of posttransplant lymphoproliferative disorder malignancy. Although many studies have been published on other confounding factors involved in posttransplant lymphoproliferative disorders, the role of coinfection with both cytomegalovirus and Epstein-Barr virus has not been investigated. We evaluated the role of cytomegalovirus infection as a risk factor in transplant recipients who were simultaneously infected with Epstein-Barr virus.

MATERIALS AND METHODS

In the current retrospective study, 143 recipients of various solid-organ transplants at Namazi Hospital from April 2018 to March 2019 were assessed for coinfection with cytomegalovirus and Epstein-Barr virus with the TaqMan real-time polymerase chain reaction assay. We collected clinical and pathology details from their medical records.

RESULTS

Of the 143 patients, 81 (57%) were male. Children under 5 years old were the largest group with 32% prevalence, and the most common organ transplant in this study was liver transplant. The prevalence of cytomegalovirus and Epstein-Barr virus coinfection was 12.6% (18/143 patients), of whom 50% experienced posttransplant lymphoproliferative disorder (9/18 patients) during 18 months after transplant. The incidence of posttransplant lymphoproliferative disorder was significantly higher among patients coinfected with cytomegalovirus and Epstein-Barr virus than among patients without coinfection. We observed a significant correlation between cytomegalovirus viral loads, as well as Epstein-Barr virus genome load, in posttransplant lymphoproliferative disorder development.

CONCLUSIONS

Coinfection with cytomegalovirus and Epstein-Barr virus, as well as the genome load of each virus, can serve as a strong predictive factor of posttransplant lymphoproliferative disorder in solidorgan transplant recipients.

Viral infections in lung transplantation

Viral infections account for up to 30% of all infectious complications in lung transplant recipients, remaining a significant cause of morbidity and even mortality. Impact of viral infections is not only due to the direct effects of viral replication, but also to immunologically-mediated lung injury that may lead to acute rejection and chronic lung allograft dysfunction. This has particularly been seen in infections caused by herpesviruses and respiratory viruses. The implementation of universal preventive measures against cytomegalovirus (CMV) and influenza (by means of antiviral prophylaxis and vaccination, respectively) and administration of early antiviral treatment have reduced the burden of these diseases and potentially their role in affecting allograft outcomes. New antivirals against CMV for prophylaxis and for treatment of antiviral-resistant CMV infection are currently being evaluated in transplant recipients, and may continue to improve the management of CMV in lung transplant recipients. However, new therapeutic and preventive strategies are highly needed for other viruses such as respiratory syncytial virus (RSV) or parainfluenza virus (PIV), including new antivirals and vaccines. This is particularly important in the advent of the COVID-19 pandemic, for which several unanswered questions remain, in particular on the best antiviral and immunomodulatory regimen for decreasing mortality specifically in lung transplant recipients. In conclusion, the appropriate management of viral complications after transplantation remain an essential step to continue improving survival and quality of life of lung transplant recipients.

Malignancies after pediatric solid organ transplantation

As life expectancy among pediatric solid organ transplant recipients (SOTRs) improves, the risk of comorbid conditions such as malignancy post-transplantation has also increased. SOTRs are at elevated risks of post-transplantation lymphoproliferative disorders (PTLDs), and skin and solid cancers. PTLDs typically occur early following transplantation, while skin and solid cancers frequently arise in young adulthood (25-40 years). By 30 years following transplantation, 26-41% of pediatric SOTRs have developed cancer. Different risk factors exist for PTLD, and skin and solid cancers, which are modified by cumulative immunosuppression, infections, transplanted organ, and the underlying disease process associated with initial organ failure (e.g., kidney failure). Optimal cancer treatment strategies depend on the specific cancer type, stage, and patient comorbidities. Immunosuppression reduction may be beneficial for certain cancers but must be considered against the risks of acute and chronic rejection and allograft loss. Lifestyle counseling regarding smoking avoidance and sun protection, as well as human papillomavirus vaccination, is an important aspect of cancer prevention. Currently, no cancer screening guidelines exist specifically for pediatric SOTRs. Adult population screening guidelines have not been validated in transplant populations. Therefore, an individualized approach should be taken to cancer screening for pediatric SOTRs, accounting for other cancer risk factors.

Biomarkers for PTLD diagnosis and therapies

Post-transplant lymphoproliferative disorder (PTLD) represents a spectrum of lymphoproliferative disorders and is a serious complication of pediatric transplantation. The majority of PTLD are associated with Epstein Barr virus (EBV) and the characteristic EBV+ B cell lymphomas are the leading post-transplant malignancy in children. EBV+ PTLD remains a formidable issue in pediatric transplantation and is thought to result from impaired immunity to EBV as a result of immunosuppression. However, the key viral and immune factors that determine whether EBV+ PTLD develops remain unknown. Recently, there has been much interest in developing biomarkers in order to improve and achieve more personalized approaches, in the clinical diagnosis, management, and treatment of EBV+ PTLD. Here, we review the status of immune-, viral-, and B cell lymphoma-derived candidates for biomarkers of EBV+ PTLD.

Epstein-Barr viral load monitoring for diagnosing post-transplant lymphoproliferative disorder in pediatric liver transplant recipients

This study aimed to investigate the incidence of PTLD in pediatric liver transplant recipients and the risk factors for the development of PTLD. We also determined clinically useful quantitative EBV PCR parameters for aiding in the diagnosis of EBV-associated PTLD in the pediatric liver transplant recipients at our institute. We reviewed children < 18 years old who had undergone liver transplantations and quantitative analysis of whole blood EBV load at our institute from January 2006 to March 2015. A total of 142 liver transplant recipients were included, and their median age was 1.5 years. Clinically significant high-level EBV DNAemia ≥ 10 000 copies/mL at least twice was observed in 53.5% and PTLD occurred in 9.9%. Among PTLD group, graft failure and mortality rate were as high as 21.4% and 14.3%, respectively. Deceased donor, presence of high-level EBV DNAemia, and primary CMV infection following transplant were associated with an increased risk for PTLD in the multivariate analysis. The peak titer at 10 875 copies/mL could be used as a cutoff value with a sensitivity of 92.9% and a specificity of 37.9%; the rate of increase in EBV load suggested a sensitivity of 64.3% and a specificity of 70.9% at the cutoff value of 44 000 copies/mL/week. In conclusion, the incidence of PTLD following liver transplant in children was as high as 10%. PTLD is associated with significant morbidity and mortality. Close monitoring of EBV DNAemia is crucial for the early diagnosis and proper treatment of PTLD in pediatric liver transplant recipients.

Post-transplantation lymphoproliferative disorders: Current concepts and future therapeutic approaches

Transplant recipients are vulnerable to a higher risk of malignancy after solid organ transplantation and allogeneic hematopoietic stem-cell transplant. Post-transplant lymphoproliferative disorders (PTLD) include a wide spectrum of diseases ranging from benign proliferation of lymphoid tissues to frank malignancy with aggressive behavior. Two main risk factors of PTLD are: Firstly, the cumulative immunosuppressive burden, and secondly, the oncogenic impact of the Epstein-Barr virus. The latter is a key pathognomonic driver of PTLD evolution. Over the last two decades, a considerable progress has been made in diagnosis and therapy of PTLD. The treatment of PTLD includes reduction of immunosuppression, rituximab therapy, either isolated or in combination with other chemotherapeutic agents, adoptive therapy, surgical intervention, antiviral therapy and radiotherapy. In this review we shall discuss the prevalence, clinical clues, prophylactic measures as well as the current and future therapeutic strategies of this devastating disorder.

Post-transplant lymphoproliferative disorders, Epstein-Barr virus infection, and disease in solid organ transplantation: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

PTLD with the response-dependent sequential use of RIS, rituximab, and cytotoxic chemotherapy is recommended. Evidence gaps requiring future research and alternate treatment strategies including immunotherapy are highlighted.

Comprehensive review of post-organ transplant hematologic cancers

A higher risk for a variety of cancers is among the major complications of posttransplantation immunosuppression. In this part of a continuing series on cancers posttransplantation, this review focuses on the hematologic cancers after solid organ transplantation. Posttransplantation lymphoproliferative disorders (PTLDs), which comprise the great majority of hematologic cancers, represent a spectrum of conditions that include, but are not limited to, the Hodgkin and non-Hodgkin lymphomas. The oncogenic Epstein-Barr virus is a key pathogenic driver in many PTLD cases, through known and unknown mechanisms. The other hematologic cancers include leukemias and plasma cell neoplasms (multiple myeloma and plasmacytoma). Clinical features vary across malignancies and location. Preventive screening strategies have been attempted mainly for PTLDs. Treatments include the chemotherapy regimens for the specific cancers, but also include reduction of immunosuppression, rituximab, and other therapies.

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.

Peripheral Blood Epstein-Barr Viral Nucleic Acid Surveillance as a Marker for Posttransplant Cancer Risk

Several viruses, such as Epstein-Barr virus, are now known to be associated with several human cancers, but not all patients with these viral infections develop cancer. In transplantation, such viruses often have a prolonged time gap from infection to cancer development, and many are preceded by a period of circulating and detectable nucleic acids in the peripheral blood compartment. The interpretation of a viral load as a measure of posttransplant risk of developing cancer depends on the virus, the cancer and associated pathogenic factors. This review describes the current state of knowledge regarding the utility and limitations of peripheral blood nucleic acid testing for Epstein-Barr virus in surveillance and risk prediction for posttransplant lymphoproliferative disorders.

Role of multimodality imaging in the diagnosis of lymphoproliferative malignancies and hematologic disorders of the kidneys

Lymphoproliferative and hematologic disorders of the kidney may present with focal or diffuse renal parenchymal involvement in clinical practice. Radiologic findings of lymphoproliferative and hematologic disorders of the kidney may mimick primary neoplastic and inflammatory disorders of the kidney. All cross-sectional imaging modalities including ultrasonography, computed tomography, and magnetic resonance imaging may be used in the diagnosis of these diseases. Percutaneous biopsy may be used in problematic cases for definitive diagnosis.

Asymptomatic Epstein-Barr Virus Shedding in the Urine of Kidney Transplant Recipients: Case Reports and Review of the Literature

Epstein-Barr virus (EBV) is associated with a wide range of malignancies and complications like post-transplant lymphoproliferative disorder (PTLD). To suppress active EBV infection in transplant recipients, who are at a heightened risk of developing PTLD, EBV DNAemia monitoring has been recommended. Quantitative multiplex real time polymerase chain reaction (QMRTPCR) offered the advantage of detection of more than one target in the same sample. We present four cases of kidney transplant recipient who were admitted for rising serum creatinine between 9 and 20 months post-transplant with a suspicion of BKV-associated nephropathy. All but one patient had unusual sonography findings in their genitourinary tracts and were positive for urinary culture for bacteria. Using a commercial QMRTPCR that could detect and quantitate BKV, EBV and cytomegalovirus simultaneously, all patients were positive for EBV in their urine for the levels between 2500 and 8×10⁸ U/mL. None of the patients had any symptoms regarding this finding. On following up survey 3 month post discharge from hospital, all patients were negative for plasma and urine EBV. Absent of EBV DNAemia together with alternating phases of detectable EBV in urine might reflect the presence of functionally efficient central/effector memory T cells against EBV. The significance of this finding in immunocompromized patients necessitates prospective longitudinal studies.

Epstein-Barr virus and renal transplantation

Epstein-Barr virus (EBV) is a gamma herpesvirus associated with diseases ranging from asymptomatic viremia to post-transplant malignancies in kidney transplant recipients. EBV specifically is associated with post-transplantation lymphoproliferative disorder (PTLD), in kidney transplant recipients, with increased risk in EBV seronegative patients with EBV seropositive donors on intensified immunosuppression. The diagnosis of PTLD relies on clinical suspicion plus tissue biopsy with polymerase chain reaction (PCR) testing of blood currently used for risk determination in high-risk recipients. Therapeutic strategies for PTLD include reduction of immunosuppression, chemotherapy and rituximab, and consideration of sirolimus-based immunosuppression. Antivirals such as ganciclovir are used to prevent reactivation of cytomegalovirus and other herpes viruses but are not onco-therapeutic. Radiation therapy or surgery is indicated for bulky, disseminated or recalcitrant disease. Prognosis varies depending on the type of malignancy identified and stage of disease.

Imaging features of haematological malignancies of kidneys

Haematological malignancies are relatively uncommon neoplasms of kidneys. Nevertheless, the incidence of these neoplasms is increasing, partly due to more widespread use of computed tomography and magnetic resonance imaging. This article discusses the clinical and imaging features of renal lymphoma, leukaemia, extra-osseous multiple myeloma, and post-transplant lymphoproliferative disorder. Although there is overlap of imaging features with other more common malignancies, such as transitional and renal cell cancers, the combination of imaging findings and the appropriate clinical picture should allow the radiologist to raise a provisional diagnosis of a haematological neoplasm. This has management implications including the preference for image-guided core biopsies and a shift towards medical rather than surgical therapy.

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.

Endoscopic features of gastro-intestinal lymphomas: From diagnosis to follow-up

Many progresses have been done in the management of gastrointestinal (GI) lymphomas during last decades, especially after the discovery of Helicobacter pylori-dependent lymphoma development. The stepwise implementation of new endoscopic techniques, by means of echoendoscopy or double-balloon enteroscopy, enabled us to more precisely describe the endoscopic features of GI lymphomas with substantial contribution in patient management and in tailoring the treatment strategy with organ preserving approaches. In this review, we describe the recent progresses in GI lymphoma management from disease diagnosis to follow-up with a specific focus on the endoscopic presentation according to the involved site and the lymphoma subtype. Additionally, new or emerging endoscopic technologies that have an impact on the management of gastrointestinal lymphomas are reported. We here discuss the two most common subtypes of GI lymphomas: the mucosa-associated lymphoid tissue and the diffuse large B cell lymphoma. A general outline on the state-of-the-art of the disease and on the role of endoscopy in both diagnosis and follow-up will be performed.