Epstein-Barr virus and post-transplant lymphoproliferative disease

There is convincing evidence that Epstein-Barr virus (EBV) is associated with post-transplant lymphoproliferative disease (PTLD). Primary EBV infection following transplantation occurs in as many as 90% of cases of PTLD in children and pretransplant EBV seronegativity is a recognized risk factor for developing PTLD. Other risk factors include young age at the time of transplant, the type of transplant that the recipient receives and the type and intensity of immunosuppression. The clinical presentation is often nonspecific and tissue biopsy is necessary to establish the diagnosis. There appears to be a correlation between PTLD and EBV viral load measured by polymerase chain reaction (PCR) of the peripheral blood and quantitative PCR may be a useful guide in the management of PTLD. Antiviral drugs and cytomegalovirus-immunoglobulin G may have a role in preventing PTLD. Because PTLD results from functional over-immunosuppression, the initial treatment is reduction of immunosuppression. Antiviral agents, interferon, immuno-based monoclonal therapy, cell-based therapy and chemotherapy also have a potential role in treating this disorder. At the present time there is no standardized approach to the evaluation and treatment of PTLD.     

Asymptomatic small bowel intussusception associated with post-transplant lymphoproliferative disease

Abstract:  A 2-yr-old boy who had undergone orthotopic liver transplantation for biliary atresia 6 months prior presented with generalized lymphadenopathy. Physical exam revealed lymphadenopathy only; the patient had no gastrointestinal signs or symptoms. CT was used to evaluate the patient's lymphadenopathy. The findings were consistent with PTLD, and an incidental intussusception causing small bowel obstruction was found. The intussusception was successfully managed expectantly, and the patient's PTLD responded to administration of rituximab. The etiology, diagnosis and management of intussusception is discussed.     

Differentiation of EBV-induced post-transplant Hodgkin lymphoma from Hodgkin-like post-transplant lymphoproliferative disease

Abstract:  The development of lymphomas after SOT is a well-known complication of the immunosuppressive therapy necessary to prevent graft rejection. Epstein-Barr virus plays a central role in the pathogenesis of lymphomas because of its ability to transform infected cells. Differentiating PTLD from malignant lymphomas, especially HL can be challenging. We report on two patients, who developed EBV-associated lymphomas several years after SOT. A histological examination of lymph nodes led to a diagnosis of HL in both patients, who were started on chemotherapy according to current treatment protocols. A rapid and complete remission in one patient prompted us to analyze the expression pattern of EBV-latency genes. In this patient, the EBV expression profile revealed a latency type III suggesting the diagnosis of Hodgkin-like PTLD. The other patient required six courses of chemotherapy plus radiotherapy to reach a complete remission. In his tumor cells, a restricted EBV-latency type II pattern was found, suggesting a diagnosis of classical HL. These two cases demonstrate that in post-transplant lymphomas with histological features of HL, an analysis of the expression pattern of EBV proteins might aid in the differentiation between PTLD and HL.     

Childhood post-transplant lymphoproliferative disorder

Post-transplant lymphoproliferative disorders (PTLDs) are a heterogeneous group of neoplasms that occur as a serious complication of haematopoetic stem cell or solid organ transplantation. They are Epstein Barr virus (EBV) driven in over 90% of the cases. Incidence of PTLD varies from 1 to 20 % depending on the organ transplanted, the intensity of immunosuppression and the recipient's pre transplant EBV status. The pathology of PTLD varies from polymorphic to monomorphic/monoclonal disease which is indistinguishable from a high-grade lymphoma. The clinical course varies from indolent to rapidly progressive, fulminant disease. Over two thirds to 90% of PTLDs are of B cell origin. The current standard of treatment involves reduction of immunosuppressive drugs and if that is not sufficient, use of anti CD20 monoclonal antibody (Rituximab) alone or in combination with conventional chemotherapy. This review offers an overview for healthcare professionals looking after children and young people who may be at risk of or have PTLD. It discusses the pathophysiology, the risk factors, classification and diagnosis of PTLD. It also summarises the current approach to management and monitoring strategies.     

Sirolimus for pediatric liver transplant recipients with post-transplant lymphoproliferative disease and hepatoblastoma

Sirolimus is a promising immune suppressive agent, with the potential to reduce calcineurin inhibitor associated nephrotoxicity, halt progression of chronic rejection and prevent tumor proliferation. The aim of this study was to review the experience using sirolimus in pediatric liver transplant recipients at a single center. Database and medical charts of all pediatric liver transplant recipients receiving sirolimus at the Hospital for Sick Children in Toronto were reviewed. Eight patients received sirolimus between October, 2000 and September, 2002. Indications for using sirolimus were post-transplant lymphoproliferative disease (PTLD) (n = 6) and hepatoblastoma (n = 2). Two patients with PTLD concurrently had renal impairment and chronic rejection. Sirolimus dosages ranged between 1.5 and 5 mg once daily. Median duration of follow-up was 17 months. Persistently elevated liver transaminase levels in the two children with chronic rejection decreased during sirolimus therapy. Recurrence of PTLD occurred in one patient. Two patients were diagnosed with acute cellular rejection after transition to maintenance sirolimus monotherapy. Resolution of adverse effects including mouth sores (n = 3), leg swelling (n = 2) and hyperlipidemia (n = 3) occurred either spontaneously or with dose reduction. Sirolimus was discontinued in four patients because of persisting bone marrow suppression, interstitial pneumonitis, life-threatening sepsis and refractory diarrhea. Children with PTLD or hepatoblastoma may benefit from immune suppression with sirolimus after liver transplantation. Further multi-center, prospective, randomized controlled trials will be instrumental to further the knowledge of long-term efficacy, safety and tolerability of sirolimus for selected children following liver transplantation.     

Epstein-Barr virus-associated post-transplant lymphoproliferative disease after bone marrow transplantation mimicking graft-versus-host disease

In contrast to solid organ transplantation (Tx), the incidence of post-transplant lymphoproliferative disease (PTLD) after hematopoietic stem cell Tx (HSCT) is generally low. This risk, however, is significantly elevated in patients receiving human leukocyte antigen (HLA) mis-matched or T-cell-depleted grafts, or after treatment for severe graft-versus-host disease (GvHD). An 18-yr-old patient with positive Epstein-Barr virus (EBV) serology received a fully matched, unmanipulated bone marrow graft from an unrelated EBV-positive donor for treatment of acute myeloid leukemia (AML) in second complete remission. GvHD prophylaxis was performed with cyclosporin A (CsA) and a short course of methotrexate. Four months after Tx, the patient developed ulcerative tonsillitis that was unresponsive to antibiotic treatment. Diarrhea appearing simultaneously was interpreted as gastrointestinal GvHD and steroids were added to CsA. A few days later the patient was admitted to hospital because of generalized seizure and pneumonia. Despite reduction of immunosuppression, intensification of anti-viral treatment, and subsequent mechanical ventilation, the patient died of acute respiratory distress 6 days later. Autopsy demonstrated disseminated EBV-induced, multi-nodular lymphoma infiltration of the entire colon but no signs of GvHD. Moreover, both lungs, paratracheal lymph nodes, kidneys, thyroid gland, and liver were infiltrated with large B-cell non-Hodgkin's lymphomas. This case underlines the rapid and aggressive course of EBV-induced disseminated PTLD after HSCT, initially mimicking intestinal GvHD because of massive colonic lymphoma infiltration. Tissue biopsies should be performed early for establishing correct diagnosis, thus enabling specific therapy, e.g. infusion of donor leukocytes with cytotoxic T-lymphocytes.     

移植后淋巴增殖性疾病一例

患儿男,10岁,2005年12月因反复皮肤出血点、发热1月余,经我院骨髓检查诊断为重型再生障碍性贫血.骨髓涂片提示:造血机能低下,粒系增生低下,红系增生低下,淋巴细胞相对增生活跃,颗粒巨核1.     

Graft rejection in pediatric liver transplant patients with Epstein-Barr viremia and post-transplant lymphoproliferative disease

Treatment of primary EV and PTLD in pediatric LT recipients (pLT) involves IS reduction/cessation. Retrospective review of pLT at our institution from 2001-2009 was conducted to characterize risk factors for GR after EV/ PTLD. Of 184 pLT, EV occurred in 61 (33%) at mean 16.5 m (0-82) and PTLD in 18 (9.8%) at mean 17.7 m (3-78) post-LT. Median age at pLT was 11 m (1-245 m) and follow-up six yr. For EV, 86% underwent IS reduction and 51% received antivirals. GR occurred in 12 (27.9%) with EV and 15 (83.3%) after PTLD diagnosis (relative risk of GR for PTLD 2.98). GR treated with methylprednisolone bolus in half and/or oral IS in half. Following GR therapy, four had PTLD relapses, no graft loss and one EV patient required re-transplantation. GR history before EV was a risk factor for GR after EV (p = 0.024). GR at any point after pLT was a risk factor for PTLD (p = 0.001). Children with EV and GR prior to EV should be monitored closely for GR after IS reduction and GR is a significant risk factor for PTLD. Most children with PTLD eventually developed GR.     

Hodgkin's lymphoma after post-transplant lymphoproliferative disease in a renal transplant recipient

Lymphoid malignancies such as post-transplant lymphoproliferative disease (PTLD) are a major complication of solid organ transplantation. Hodgkin's lymphoma (HL) is not part of the typical spectrum of PTLD, but has rarely been reported as a separate complication. We report a case of HL occurring after previous PTLD in a renal transplant recipient. A 9-yr-old girl with end-stage autosomal recessive polycystic kidney disease received a cadaveric renal transplant at 1 yr of age. She developed polymorphic PTLD localized to the bone marrow at 6 yr post-transplant. She was treated with reduction of immunosuppression and alpha-interferon. No chemotherapy or anti-B cell antibody was administered. The PTLD resolved and kidney graft function remained stable. At 9 yr post-transplant, she presented again with fever of 2 wk duration, associated with enlarged lymph nodes at multiple sites. A lymph node biopsy revealed the presence of classic Reed Sternberg cells positive for CD15, CD30 and EB RNA. She was treated with standard combination chemotherapy for HL with COPP/ABV. All immunosuppressive agents were discontinued except for low dose prednisone. The patient had an excellent response, with resolution of her lymphadenopathy and maintenance of stable graft function. RS like cells have been reported in the setting of PTLD, but these cells possess an activated B cell phenotype, are EBV negative and CD15 negative. True HL following PTLD has been reported in only three previous cases, with good response to standard chemotherapy in each.     

Low-dose immunosuppression reduces the incidence of post-transplant lymphoproliferative disease in pediatric liver graft recipients

OBJECTIVES: In pediatric solid organ transplantation, the Epstein-Barr virus (EBV)-related lymphoproliferative disorders (PTLD) still play a major role in post-transplant morbidity and mortality. The aim of the study was to determine the incidence of PTLD in pediatric patients with liver transplant who receive low-dose immunosuppression protocols. METHODS: All pediatric patients (n = 269) received a dual immunosuppression therapy consisting of cyclosporine A (initial trough levels, 170-200 microg/L; trough levels for maintenance immunosuppression after 1 year, 80-100 microg/L) and prednisolone (starting dose, 60 mg/m2). Steroids were reduced to 30 mg/m2 after 1 week, followed by a weekly tapering to 5 mg/m2. Seventy-seven of 269 patients were switched to tacrolimus therapy. The authors evaluated the significance of EBV-DNA monitoring by quantitative polymerase chain reaction in identifying patients at risk for PTLD. RESULTS: Patient survival was 90.3%; graft survival was 85.9%. Eight patients lost their grafts because of chronic rejection. The incidence of PTLD was low (0.7%), although a significant EBV viral load was found in 42.4% of the patients. One third of the patients with a viral load of 3,000 genomes/10(5) cells or greater had clinical signs of EBV infection. CONCLUSIONS: The authors conclude that low-dose immunosuppressive protocols significantly reduce the incidence of PTLD. In patients treated with that regimen, the monitoring of EBV viral load seems not to be helpful. It can be assumed that low-dose immunosuppression does not suppress EBV-specific cytotoxic CD8+ T cells, thus allowing the host to control EBV infection without the risk of PTLD. Our low-dose immunosuppression protocol did not increase the risk of chronic rejection.     

Rapid response to rituximab in a pediatric liver transplant recipient with post-transplant lymphoproliferative disease and maintenance with sirolimus monotherapy

A 12-yr-old girl with end-stage renal disease secondary to primary hyperoxaluria type I received a living related (left lateral segment) liver transplant from her brother as the first step of a staged liver and kidney transplant. Renal transplantation was planned for a later date from the same donor. Nine weeks after transplantation she developed polymorphic PTLD of the tonsils and adenoids. Initial treatment with surgical resection and withdrawal of immunosuppression was insufficient as she developed recurrence of the PTLD lesion 1 wk after surgical resection and reduction of immunsuppression. Treatment with the chimeric monoclonal anti CD20 antibody, rituximab (Mabthera, Hoffman-La Roche AG, Grenzach-Whylen, Germany), resulted in quick response and complete recovery from PTLD within 2 wk, with no recurrence up to 8 months after treatment. Rejection prophylaxis was successfully achieved with Sirolimus (Rapamune, Wyeth Pharmaceuticals Inc., Philadelphia, PA, USA) monotherapy, with no episodes of acute rejection.     

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

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

Successful treatment of a child with late-onset T-cell post-transplant lymphoproliferative disorder/lymphoma

We report a novel regimen for refractory post-transplant T-cell lymphoma (PTL). Our patient presented with non-Epstein-Barr virus (EBV) related, T-cell post-transplant lymphoproliferative disease (PTLD) 3.5 years after liver transplantation. Initially diagnosed as polyclonal PTLD, the disease progressed to a monoclonal, T-cell PTL that was refractory to several chemotherapy regimens but responded to a regimen consisting of fludarabine, cyclophosphamide, cytarabine, and alemtuzumab. Consolidation therapy included high-dose chemotherapy, autologous hematopoietic stem cell rescue, and radiation therapy. She remains in remission 2.5 years later. T-cell PTL is a rare disease with a poor prognosis; this regimen provides a novel, potentially curative approach for its treatment.     

Native kidney post-transplant lymphoproliferative disorder in a non-renal transplant patient

Abstract:  PTLD is an important post-transplant complication. Although PTLD affects kidney allografts after renal transplantation, it has not been reported in native kidneys of other solid organ recipients. Herein, we report a child who underwent an orthotropic liver transplant for cryptogenic cholestatic hepatitis and developed fever, generalized lymphadenopathy, chronic EBV viremia, and lymphatic PTLD. Subsequently, she also developed gross hematuria and nephrotic range proteinuria. Kidney histology revealed EBV-positive mononuclear infiltrates within the renal parenchyma consistent with PTLD. Electron microscopy examination demonstrated subepithelial electron-dense deposits consistent with a membranous glomerulopathy pattern. The PTLD was successfully treated with reduced immunosuppression and cyclic cyclophosphamide, rituximab, and prednisone, but the renal disease progressed to end-stage renal failure within two yr. Repeat kidney histology showed chronic nephropathy and membranous glomerulopathy without PTLD infiltrates or detectable EBV staining, although chronic viremia persisted. To our knowledge, this is the first such child to be reported and highlights the importance of remaining vigilant for renal PTLD even in non-kidney organ recipients.     

Emerging therapeutic strategies for Epstein-Barr virus+ post-transplant lymphoproliferative disorder

De novo malignancies represent an increasing concern in the transplant population, particularly as long-term graft and patient survival improves. EBV-associated B-cell lymphoma in the setting of PTLD is the leading malignancy in children following solid organ transplantation. Therapeutic strategies can be categorized as pharmacologic, biologic, and cell-based but the variable efficacy of these approaches and the complexity of PTLD suggest that new treatment options are warranted. Here, we review current therapeutic strategies for treatment of PTLD. We also describe the life cycle of EBV, addressing the viral mechanisms that contribute to the genesis and persistence of EBV+ B-cell lymphomas. Specifically, we focus on the oncogenic signaling pathways activated by the EBV LMP1 and LMP2a to understand the underlying mechanisms and mediators of lymphomagenesis with the goal of identifying novel, rational therapeutic targets for the treatment of EBV-associated malignancies.     

Limitations of EBV-PCR monitoring to detect EBV associated post-transplant lymphoproliferative disorder

Post-transplant lymphoproliferative disorder (PTLD) represents a significant threat to the survival of pediatric transplant recipients. Epstein-Barr (EBV) viral load monitoring using polymerase chain reaction (PCR) has been reported to have a variable sensitively with relatively higher specificity as in an indicator of the development of PTLD. We report two cases of pathologically confirmed PTLD in children who failed to develop sustained increases in their EBV-PCR determined viral loads. We suggest that clinicians should be aware of the potential for false-negative results of EBV-PCR in pediatric transplant recipients.