Managing post-transplant lymphoproliferative disorders in solid-organ transplant recipients: a review of immunosuppressant regimens

The 'Oma's of the Gammas-Cancerogenesis by γ-Herpesviruses

Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV), which are the only members of the gamma(γ) herpesviruses, are oncogenic viruses that significantly contribute to the development of various human cancers, such as Burkitt's lymphoma, nasopharyngeal carcinoma, Hodgkin's lymphoma, Kaposi's sarcoma, and primary effusion lymphoma. Oncogenesis triggered by γ-herpesviruses involves complex interactions between viral genetics, host cellular mechanisms, and immune evasion strategies. At the genetic level, crucial viral oncogenes participate in the disruption of cell signaling, leading to uncontrolled proliferation and inhibition of apoptosis. These viral proteins can modulate several cellular pathways, including the NF-κB and JAK/STAT pathways, which play essential roles in cell survival and inflammation. Epigenetic modifications further contribute to EBV- and KSHV-mediated cancerogenesis. Both EBV and KSHV manipulate host cell DNA methylation, histone modification, and chromatin remodeling, the interplay of which contribute to the elevation of oncogene expression and the silencing of the tumor suppressor genes. Immune factors also play a pivotal role in the development of cancer. The γ-herpesviruses have evolved intricate immune evasion strategies, including the manipulation of the major histocompatibility complex (MHC) and the release of cytokines, allowing infected cells to evade immune detection and destruction. In addition, a compromised immune system, such as in HIV/AIDS patients, significantly increases the risk of cancers associated with EBV and KSHV. This review aims to provide a comprehensive overview of the genetic, epigenetic, and immune mechanisms by which γ-herpesviruses drive cancerogenesis, highlighting key molecular pathways and potential therapeutic targets.

Expert Consensus on the Characteristics of Patients with Epstein-Barr Virus-Positive Post-Transplant Lymphoproliferative Disease (EBV+ PTLD) for Whom Standard-Dose Chemotherapy May be Inappropriate: A Modified Delphi Study

INTRODUCTION

Following hematopoietic stem cell transplantation or solid organ transplantation, patients are at risk of developing Epstein-Barr virus-positive post-transplant lymphoproliferative disease (EBV⁺ PTLD), which is an ultra-rare and potentially lethal hematologic malignancy. Common treatments for EBV⁺ PTLD include rituximab alone or combined with chemotherapy. Given specific considerations for this population, including severity of the underlying condition requiring transplant, the rigors of the transplant procedure, as well as risks to the transplanted organ, there is a group of patients with EBV⁺ PTLD for whom chemotherapy may be inappropriate; however, there is limited information characterizing these patients. This study aimed to reach expert consensus on the key characteristics of patients for whom chemotherapy may be inappropriate in a real-world setting.

METHODS

A two-round modified Delphi study was conducted to reach consensus among clinicians with expertise treating EBV⁺ PTLD. Articles identified in a targeted literature review guided the development of round 1 and 2 topics and related statements. The consensus threshold for round 1 statements was 75.0%. If consensus was achieved in round 1, the statement was not discussed further in round 2. The consensus thresholds for round 2 were moderate (62.5-75.0%), strong (87.5%), or complete (100.0%).

RESULTS

The panel was composed of a total of eight clinicians (seven hematologists/hemato-oncologists) from six European countries. The panel generated a final list of 43 consensus recommendations on the following topics: terminology used to describe patients for whom chemotherapy may be inappropriate; demographic characteristics; organ transplant characteristics; comorbidities that preclude the use of chemotherapy; EBV⁺ PTLD characteristics; and factors related to treatment-related mortality and morbidity.

CONCLUSIONS

This modified Delphi panel successfully achieved consensus on key topics and statements that characterized patients with EBV⁺ PTLD for whom chemotherapy may be inappropriate. These recommendations will inform clinicians and aid in the treatment of EBV⁺ PTLD.

Successful treatment of central nervous system lymphoproliferative disorder in a kidney-pancreas and stem cell transplanted patient using intrathecal rituximab

Central nervous system lymphoproliferative disorder (CNS-PTLD) after organ transplant is a unique clinicopathological entity and is associated with poor survival rates. When the CNS is involved, intravenous rituximab might not be the treatment of choice, due to its poor CNS penetration. However, intrathecal (IT) administration of rituximab has shown to be safe and efficient in small studies and in case series. We report here the case of a patient with late development of CNS-PTLD after kidney-pancreas transplantation who achieved complete remission after surgical resection and four cycles of IT rituximab and we provide a review of the literature for this treatment option.

Role of Radiotherapy in Post-transplant Lymphoproliferative Disorders: Three Case Reports and Review of the Literature

Post-transplant lymphoproliferative disorder (PTLD) is an aggressive malignancy that occurs in patients who have undergone solid organ transplantation or hematopoietic stem cell transplantation. It develops as the result of uncontrolled cell proliferations owing to reduced immunological surveillance. PTLD may occur with a various spectrum of clinical presentations, including both localized and extensive disease. Management can be significantly variable according both to the clinical presentation and to the histologic features. The most important systemic treatment strategies are reduction of immunosuppressive therapy, chemotherapy, anti B-cell antibodies, especially rituximab and cytokine-based therapies. The localized form of PTLD could be efficiently treated, and potentially cured, with surgery or radiotherapy (RT). Involved site RT may be a feasible effective option for the treatment of patients with PTLD, given the excellent radio-sensitivity of lymphoid disorders. In this report, we describe 3 adult patients with PTLD treated with moderate-dose RT (24-36 Gy) having a good local control with negligible toxicity. We also review the literature data on the role of radiation therapy in this particular setting.

De novo and recurrent malignancy

Cancer is an important cause of morbidity and mortality after liver transplantation and can occur through three mechanisms: recurrence of a recipient's pre-transplant malignancy, donor-related transmission and de novo development. Currently, the decision to list a patient with a history of malignancy is an individual one. Screening guidelines for potential donors and for recipients after transplant are still widely based on general population guidelines, while the role of chronic immunosuppression remains controversial. These shortcomings mean that patients present at diagnosis with advanced stages of the disease, often precluding curative treatments. The present review summarizes current recommendations for the screening of recipients and donors for pre- and post-transplant malignancies, and current management of recipients who develop cancer after a liver transplant.

Clinical and Radiographic Characteristics of Sinonasal Posttransplant Lymphoproliferative Disorder and Invasive Fungal Sinusitis

BACKGROUND

Sinonasal posttransplant lymphoproliferative disorder (PTLD) is a serious but uncommon complication of solid organ and hematopoietic stem cell transplantation that can overlap in many features with invasive fungal sinusitis (IFS).

OBJECTIVE

To identify clinical, laboratory, and radiographic features that may help to differentiate sinonasal IFS and PTLD in the posttransplant population.

METHODS

We performed a retrospective chart review of patients with posttransplant sinonasal PTLD and IFS to evaluate for clinical, laboratory, and imaging characteristics.

RESULTS

A total of 4 patients with sinonasal PTLD and 10 posttransplant IFS patients were evaluated. A total of 2 of 4 PTLD patients presented with a symptom duration of greater than 3 months compared to none in the IFS group (p = 0.07). Mean absolute neutrophil count (ANC) was 2,976 per mm3 (range 2,488-3,462) in the PTLD group compared to 773 per mm3 (range 0.0-2,744) in the IFS group (p = 0.01). Both PTLD lesions with available diffusion-weighted imaging demonstrated diffusion restriction on magnetic resonance im-aging (MRI) compared to zero of the IFS lesions (p = 0.10). No PTLD lesions demonstrated mucosal infarcts compared to three of seven IFS lesions (p = 0.23).

CONCLUSION

IFS was associated with a significantly lower ANC at the time of diagnosis compared to PTLD. Additionally, three other measures trend towards association with their respective pathology. PTLD typically has a more chronic time course than IFS, diffusion restriction on MRI is predominantly associated with PTLD patients, and mucosal infarct on MRI is more suggestive of IFS. Additionally, all cases of sinonasal PTLD arose following solid organ transplantation. These factors may assist clinicians during diagnosis.

Stoma formation after lymphoproliferative disorders and immunosuppression therapy

Post-transplant lymphoproliferative disorders (PTLD) are lymphomas that may arise in organ, bone marrow or stem cell transplant recipients who are taking immunosuppressive drugs to prevent rejection of the transplant. The likelihood of developing PTLD depends on the type of transplant. PTLD is a potentially severe complication of post-transplant treatment, with an uncertain prognosis. Lymphoproliferative disorders can also occur in people taking immunosuppressants for inflammatory bowel disease. This article will explore PTLD and discuss the experience of caring for patients who developed lymphoproliferative conditions and required emergency stoma formation. The emotional and physical impact of surgery upon these patients, who have already experienced a protracted treatment journey, will be explored. Implications for practice for the lymphoma team and stoma nurse specialists involved with the care of these patients will also be considered.

Emergence of CD4+ and CD8+ Polyfunctional T Cell Responses Against Immunodominant Lytic and Latent EBV Antigens in Children With Primary EBV Infection

Long term carriers were shown to generate robust polyfunctional T cell (PFC) responses against lytic and latent antigens of Epstein-Barr virus (EBV). However, the time of emergence of PFC responses against EBV antigens, pattern of immunodominance and difference between CD4+ and CD8+ T cell responses during various stages of EBV infection are not clearly understood. A longitudinal study was performed to assess the development of antigen-specific PFC responses in children diagnosed to have primary symptomatic (infectious mononucleosis [IM]) and asymptomatic (AS) EBV infection. Evaluation of IFN-γ secreting CD8+ T cell responses upon stimulation by HLA class I-specific peptides of EBV lytic and latent proteins by ELISPOT assay followed by assessment of CD4+ and CD8+ PFC responses upon stimulation by a panel of overlapping EBV peptides for co-expression of IFN-γ, TNF-α, IL-2, perforin and CD107a by flow cytometry were performed. Cytotoxicity of T cells against autologous lymphoblastoid cell lines (LCLs) as well as EBV loads in PBMC and plasma were also determined. Both IM and AS patients had elevated PBMC and plasma viral loads which declined steadily during a 12-month period from the time of diagnosis whilst decrease in the magnitude of CD8+ T cell responses toward EBV lytic peptides in contrast to increase toward latent peptides was shown with no significant difference between those of IM and AS patients. Both lytic and latent antigen-specific CD4+ and CD8+ T cells demonstrated polyfunctionality (defined as greater or equal to three functions) concurrent with enhanced cytotoxicity against autologous LCLs and steady decrease in plasma and PBMC viral loads over time. Immunodominant peptides derived from BZLF1, BRLF1, BMLF1 and EBNA3A-C proteins induced the highest proportion of CD8+ as well as CD4+ PFC responses. Diverse functional subtypes of both CD4+ and CD8+ PFCs were shown to emerge at 6–12 months. In conclusion, EBV antigen-specific CD4+ and CD8+ PFC responses emerge during the first year of primary EBV infection, with greatest responses toward immunodominant epitopes in both lytic and latent proteins, correlating to steady decline in PBMC and plasma viral loads.

Management of post-transplant lymphoproliferative disorders

PURPOSE OF REVIEW

Post-transplant lymphoproliferative disease (PTLD) is a major complication of hematopoietic stem cell and solid organ transplantation. The incidence of transplantation in childhood has been steadily rising, making PTLD the most common form of lymphoproliferation in childhood. The purpose of this review is to summarize the role of the Epstein-Barr virus (EBV) in the pathophysiology and discuss the management of PTLD.

RECENT FINDINGS

More than 90% of pediatric PTLD is EBV-positive. In immunocompetent hosts, the virus is controlled by cytotoxic T-cells, the cells targeted by immunosuppression to avoid graft-versus-host disease and/or organ rejection in transplant patients. The majority of pediatric transplant candidates are EBV-negative prior to transplant increasing the risk of EBV-induced lymphoproliferation upon seroconversion after transplant. Treatment options include reduction of immunosuppression, anti-CD20 monoclonal antibodies, and/or chemotherapy. Advanced understanding of the importance of cellular immunity in controlling lymphoproliferation has led to the development of cellular therapies targeting virus-specific antigens.

SUMMARY

PTLD is the most common form of lymphoproliferation in childhood due to the rising incidence of transplantation. EBV plays a pivotal role in the pathophysiology. Cellular therapies targeting viral antigens may replace chemotherapy in the treatment of PTLD in the near future.

Matched-pair analysis: identification of factors with independent influence on the development of PTLD after kidney or liver transplantation

BACKGROUND

Post-transplant lymphoproliferative disorder (PTLD) adversely affects patients' long-term outcome.

METHODS

The paired t test and McNemar's test were applied in a retrospective 1:1 matched-pair analysis including 36 patients with PTLD and 36 patients without PTLD after kidney or liver transplantation. Matching criteria were age, gender, indication, type of transplantation, and duration of follow-up. All investigated PTLD specimen were histologically positive for EBV. Risk-adjusted multivariable regression analysis was used to identify independence of risk factors for PTLD detected in matched-pair analysis. The resultant prognostic model was assessed with ROC-curve analysis.

RESULTS

Patients suffering with PTLD had shorter mean survival (p = 0.004), more episodes of CMV infections or reactivations (p = 0.042), and fewer recipient HLA A2 haplotypes (p = 0.007), a tacrolimus-based immunosuppressive regimen (p = 0.052) and higher dosages of tacrolimus at hospital discharge (Tac dosage) (p = 0.052). Significant independent risk factors for PTLD were recipient HLA A2 (OR = 0.07, 95 % CI = 0.01-0.55, p = 0.011), higher Tac dosages (OR = 1.29, 95 % CI = 1.01-1.64, p = 0.040), and higher numbers of graft rejection episodes (OR = 0.38, 95 % CI = 0.17-0.87, p = 0.023). The following prognostic model for the prediction of PTLD demonstrated good model fit and a large area under the ROC curve (0.823): PTLD probability in % = Exp(y)/(1 + Exp(y)) with y = 0.671 - 1.096 × HLA A2-positive recipient + 0.151 × Tac dosage - 0.805 × number of graft rejection episodes.

CONCLUSIONS

This study suggests prognostic relevance for recipient HLA A2, CMV, and EBV infections or reactivations and strong initial tacrolimus-based immunosuppression. Patients with risk factors may benefit from intensified screening for PTLD.

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.

Lymphoma in Danon disease with chronic rhabdomyolysis treated with EPOCH-R: A case report

Rare disorders often represent a challenge for clinicians and require close collaboration of an interdisciplinary team.We present the complex case of a 22-year-old male with Danon disease and late-onset of posttransplant lymphoproliferative disorder after heart transplantation. The critical aspects of his condition were: pre-existing rhabdomyolysis; infiltration of muscle and gut with lymphoma; advanced clinical stage with bulky disease; nonresponsiveness to the reduction of immunosuppression and rituximab monotherapy; expected cardiotoxicity of anthracyclines. Therefore, the patient was treated with the EPOCH-R protocol, which includes continuous administration of doxorubicin over 4 days, instead of R-CHOP, in which the anthracycline is given in a short single infusion. Complete remission was achieved after the third cycle; rhabdomyolysis did not increase and heart function was not affected. The patient received a total of 6 cycles and is still in metabolic complete remission.We conclude that patients with Danon disease can be treated with anthracycline-containing chemotherapy and that continuous infusion of EPOCH-R does not exacerbate pre-existing rhabdomyolysis.

Rituximab, Dexamethasone, Cytarabine, and Cisplatin as Effective Platinum-Based Salvage Chemotherapy for Periportal Posttransplant Lymphoproliferative Disorder After an Orthotopic Liver Transplant

Posttransplant lymphoproliferative disorder is a group of heterogenous disorders that occur after solid-organ transplant. The overall incidence is between 1% and 20%. In orthotopic liver transplant recipients, the reported incidence ranges from 2% to 10%, while the incidence is greater in children (9.7%-11%) and lesser in adults (1.7%-3%). The following treatment options are considered for patients with posttransplant lymphoproliferative disorder: reduction of immunosuppression, single-agent rituximab, rituximab and chemotherapy, surgery and radiation, antivirals targeted at the Epstein-Barr virus, and cytotoxic T-lymphocytes targeting the Epstein-Barr virus. This report describes a 61-year-old man who presented after an orthotopic liver transplant with a large periportal soft tissue mass that was shown on biopsy to be a monomorphic, CD20+, diffuse, large B-cell lymphoma, nongerminal center type. He was treated with reduced immunosuppression, followed by single-agent rituximab, then with an anthracycline-based chemotherapy regimen: rituximab, etoposide, prednisone, vincristine, doxorubicin, and then a platinum-based salvage chemotherapy with rituximab, dexamethasone, cytarabine, and cisplatin with a good response.

The impact of abdominal complications on the outcome after thoracic transplantation--a single center experience

BACKGROUND

Abdominal complications after thoracic transplantation (Tx) are potentially associated with an increased risk of mortality. We recently reported about the severe outcome after bowel perforation in patients following lung transplantation (LuTx). The aim of the present study was to likewise identify the risk factors with an impact on patient survival following heart transplantation (HTx).

METHODS

A retrospective analysis for the frequency and outcome of abdominal interventions following HTx was performed in 342 patients, and these data thereafter compared to a re-evaluated pool of 1,074 patients following LuTx. All patients were transplanted at Hanover Medical School, Germany, between January 2000 and October 2011.

RESULTS

The incidence for abdominal surgery was comparable between patients following HTx (n = 33; 9.6 %) and LuTx (n = 90; 8.4 %). Elective operations were more frequently performed in patients after HTx (8.5 vs. 5.1 %). In contrast, the incidence of emergency interventions was higher after LuTx (5.3 %) than that following HTx (2.3 %). Herewith associated was the mortality observed in these transplant recipients (15.3 and 9.9 % for LuTx and HTx, respectively). Leading diagnosis for emergency surgery was bowel perforation (n = 18, regarding all cases). In 11 of these patients, perforation occurred within the first 6 months after Tx and eight of them died in the course of this complication (one patient after HTx and seven patients after LuTx).

CONCLUSIONS

Abdominal complications after HTx are less frequently than after LuTx but equally correlate with a high mortality rate. In finding or even reasonable suspicion of an acute abdomen after thoracic Tx, a broad practice for extended diagnostics and a low barrier for an early explorative laparotomy thus are recommended.

Blood disorders after kidney transplantation

Post transplant anemia (PTA) is a common issue in kidney transplant recipients. Most importantly it is associated with an impaired allograft function. Other important factors associated with PTA are immunosuppressive drugs (MPA, AZA and SRL), iron deficiency, infections (Parvo B19), older donor age, rejection episodes, an increased inflammatory state, and erythropoietin hyporesponsiveness. As there are no adequately powered RCTs in the kidney transplant population on anemia treatment with ESA, we have to rely on what we know from the large RCTs in the CKD population. The recently published KDIGO guidelines do not recommend treatment with ESA if Hb is >10 g/dl. Repletion of iron stores is emphasized. Post transplant leukopenia (PTL) and thrombocytopenia (PTT) are frequent complications especially in the first six months after kidney transplantation. Myelosuppression caused by immunosuppressive agents (MPA, AZA, SRL, rATG), antimicrobial drugs (VGCV), and CMV infection is the predominant cause. There are no widely accepted guidelines on treatment strategies, but most often dose reduction or discontinuation of causative medication is done. Most clinicians tend to decrease MPA dose, but this is eventually associated with an increase in acute rejection episodes. VGCV dose reduction (preemptive treatment instead of CMV prophylaxis) may be a successful strategy. In severe cases G-CSF treatment is an important management option and seems to be safe.

Post-transplant lymphoproliferative disease in pediatric solid organ transplant recipients

Post-transplant lymphoproliferative disease (PTLD) in solid organ transplant (SOT) recipients has become one of the most common forms of lymphoproliferation in childhood and is a serious complication of SOT. More than 90% of cases are of B-cell origin, Epstein Barr virus (EBV) positive and are mostly occurring in the early post-transplant period. Pathologically and clinically it is a heterogenous disease ranging from being responsive to reduced immunosuppression without further intervention to rapidly progressive fulminant PTLD requiring prompt initiation of therapy. Prognosis overall is favorable. Current treatment strategies as well new promising targeted immune-based therapies such as rituximab and EBV-specific cytotoxic T-lymphocytes are being discussed.

Molecular pathogenesis of B-cell posttransplant lymphoproliferative disorder: what do we know so far?

Posttransplant lymphoproliferative disorder (PTLD) is a potentially fatal disease that arises in 2%-10% of solid organ and hematopoietic stem cell transplants and is most frequently of B-cell origin. This very heterogeneous disorder ranges from benign lymphoproliferations to malignant lymphomas, and despite the clear association with Epstein-Barr Virus (EBV) infection, its etiology is still obscure. Although a number of risk factors have been identified (EBV serostatus, graft type, and immunosuppressive regimen), it is currently not possible to predict which transplant patient will eventually develop PTLD. Genetic studies have linked translocations (involving C-MYC, IGH, BCL-2), various copy number variations, DNA mutations (PIM1, PAX5, C-MYC, RhoH/TTF), and polymorphisms in both the host (IFN-gamma, IL-10, TGF-beta, HLA) and the EBV genome to B-cell PTLD development. Furthermore, the tumor microenvironment seems to play an important role in the course of disease representing a local niche that can allow antitumor immune responses even in an immunocompromised host. Taken together, B-cell PTLD pathogenesis is very complex due to the interplay of many different (patient-dependent) factors and requires thorough molecular analysis for the development of novel tailored therapies. This review aims at giving a global overview of the currently known parameters that contribute to the development of B-cell PTLD.