Epstein-Barr virus posttransplant lymphoproliferative disorder: update on management and outcomes

Epstein-Barr virus gp42 antibodies reveal sites of vulnerability for receptor binding and fusion to B cells

Epstein-Barr virus (EBV) causes infectious mononucleosis and is associated with B cell lymphomas. EBV glycoprotein 42 (gp42) binds HLA class II and activates membrane fusion with B cells. We isolated gp42-specific monoclonal antibodies (mAbs), A10 and 4C12, which use distinct mechanisms to neutralize virus infection. mAb A10 was more potent than the only known neutralizing gp42 mAb, F-2-1, in neutralizing EBV infection and blocking binding to HLA class II. mAb 4C12 was similar to mAb A10 in inhibiting glycoprotein-mediated B cell fusion but did not block receptor binding, and it was less effective in neutralizing infection. Crystallographic structures of gH/gL/gp42/A10 and gp42/4C12 complexes revealed two distinct sites of vulnerability on gp42 for receptor binding and B cell fusion. Passive transfer of mAb A10 into humanized mice conferred nearly 100% protection from viremia and EBV lymphomas after EBV challenge. These findings identify vulnerable sites on EBV that may facilitate therapeutics and vaccines.

Immune deficiency/dysregulation -associated lymphoproliferative disorders. Revised classification and management

Significant advances in the field of lymphoma have resulted in two recent classification proposals, the International Consensus Classification (ICC) and the 5th edition WHO. A few entities are categorized differently in the ICC compared to the WHO. Nowhere is this more apparent than the immunodeficiency lymphoproliferative disorders. The three previous versions of the WHO classification (3rd, 4th and revised 4th editions) and the ICC focused on four clinical settings in which these lesions arise for primary categorization. In contrast the 2023 WHO 5th edition includes pathologic characteristics including morphology and viral status, in addition to clinical setting, as important information for lesion classification. In addition, the 2023 WHO recognizes a broader number of clinical scenarios in which these lesions arise, including not only traditional types of immune deficiency but also immune dysregulation. With this classification it is hoped that new treatment strategies will be developed leading to better patient outcomes.

The role of 18F-FDG PET/CT metabolic parameters in the differential diagnosis of post-transplant lymphoproliferative disorder after pediatric liver transplantation

Background

Post-transplant lymphoproliferative disorder (PTLD) is a significant complication after liver transplantation. Research on the diagnostic value of the Fluorine-18 fluorodeoxyglucose positron emission tomography/computerized tomography (18F-FDG PET/CT) metabolic parameters of PTLD in pediatric liver transplantation (pLT) recipients is limited. This study sought to evaluate the diagnostic efficacy of 18F-FDG PET/CT in differentiating between PTLD and non-PTLD lymphadenopathy in pLT recipients.

Methods

This retrospective study collected the 18F-FDG PET/CT scans with clinical and pathological information of all consecutive children who were clinically suspected of PTLD from November 2016 to September 2022 at the Beijing Friendship Hospital. The 18F-FDG PET/CT metabolic parameters of the two groups were analyzed. We then established a diagnostic model composed of the clinical characteristics and metabolic parameters.

Results

In total, 57 eligible patients were enrolled in this study, of whom 40 had PTLD and 17 had non-PTLD lymphadenopathy. Of the metabolic parameters examined in this study, total lesion glycolysis (TLG) had the highest area under the curve (AUC) value [0.757, 95% confidence interval (CI): 0.632-0.883, P=0.002]. The AUCs of the other metabolic parameters were all less than the AUC of TLG, including the maximum standardized uptake value (SUVmax) (AUC: 0.725, 95% CI: 0.597-0.853, P=0.008), mean standardized uptake value (SUVmean) (AUC: 0.701, 95% CI: 0.568-0.834, P=0.017), metabolic tumor volume total (MTVtotal) (AUC: 0.688, 95% CI: 0.549-0.827, P=0.040), TLG total (AUC: 0.674, 95% CI: 0.536-0.812, P=0.026). The diagnostic model, which was composed of clinical characteristics (digestive symptoms), the SUVmax, TLG, and the MTVtotal, showed excellent performance in the differential diagnosis (sensitivity: 0.675, 95% CI: 0.508-0.809; specificity: 0.941, 95% CI: 0.692-0.997; positive predictive value: 0.964, 95% CI: 0.798-0.998; and negative predictive value: 0.552, 95% CI: 0.360-0.730).

Conclusions

The 18F-FDG PET/CT metabolic parameters can be used to distinguishing between PTLD and non-PTLD lymphadenopathy in pLT recipients.

T-Cell Posttransplant Lymphoproliferative Disorders After Allogeneic Hematopoietic Stem Cell Transplantation: Case Series and Systemic Review

Posttransplant lymphoproliferative disorder (PTLD) is a rare lymphoid and/or plasmocytic proliferation that occurs after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We aimed to identify the pathologic features and clinical outcomes of T-cell PTLD, an extremely rare subtype of PTLD, after allo-HSCT. In this study, six allo-HSCT recipients with T-cell PTLD from five transplant centers in China were enrolled. All the T-cell PTLD were donor-derived, and three patients were with monomorphic and three with polymorphic types, respectively. All patients received cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP)-based chemotherapy. Five patients achieved complete response (CR), and one experienced progressive disease (PD). The median time from HSCT to onset was 4 (range: 0.6-72) months, analyzed in combination with the other 16 patients with T-cell PTLD identified from previous reports. About 56.3% of the T-cell samples (9/16) were positive for in situ hybridization with an Epstein-Barr virus (EBV)-encoded small nuclear early region (EBER ISH). CHOP-based chemotherapy might be the optimal strategy for patients who showed no response to empiric therapy with a CR rate of 87.5%. In conclusion, our study observed that T-cell PTLD has distinct clinical manifestations and morphological features, which characterized by less relation to EBV, later occurrence, and poorer prognosis when compared with B-cell PTLD.

Rituximab for posttransplant lymphoproliferative disorder - therapeutic, preemptive, or prophylactic?

To minimize mortality due to posttransplant lymphoproliferative disorder (PTLD), the following strategies have been used: (1) Therapy without EBV Monitoring, i.e., administration of rituximab after PTLD diagnosis, usually by biopsy, in the absence of routine Epstein-Barr virus (EBV) DNAemia monitoring, (2) Prompt Therapy, i.e., monitoring EBV DNAemia, searching for PTLD by imaging when the DNAemia has exceeded a pre-specified threshold, and administration of rituximab if the imaging is consistent with PTLD, (3) Preemptive Therapy, i.e., monitoring EBV DNAemia and administration of rituximab when the DNAemia has exceeded a pre-specified threshold, and (4) Prophylaxis, i.e., administration of rituximab to all transplant recipients. The superiority of one of these strategies over the other strategies has not been established. Here we review the pros and cons of each strategy. Preemptive therapy or prophylaxis may currently be preferred for patients who are at a high risk of dying due to PTLD. However, Therapy without EBV Monitoring may be used for both high- and low-risk patients in the future, if effective and relatively non-toxic therapies for rituximab-refractory PTLD (e.g., EBV-specific T cells) have become easily available.

Malignant lymphoma after liver transplantation for liver cirrhosis caused by human immunodeficiency virus and hepatitis C virus co-infection

Here, we describe a rare case of malignant lymphoma after liver transplantation for liver cirrhosis caused by human immunodeficiency virus (HIV) and hepatitis C virus (HCV) co-infection. A male patient was diagnosed with hemophilia A at 8 months of age. Since then, he had been receiving blood products, which led to HIV and HCV co-infection. His HIV viral load was suppressed with antiretroviral therapy, and a sustained virologic response was achieved for HCV using direct-acting antivirals. However, his decompensated liver cirrhosis progressed, and deceased donor liver transplantation was performed. A post-transplant lymphoproliferative disorder (PTLD) developed 105 days after liver transplantation, with enlarged para-aortic and hilar lymph nodes, a right renal mass, and masses in the small and large intestines. Histopathological examination confirmed monomorphic PTLD (diffuse large B-cell lymphoma). Against the treatment (reduction of immunosuppression, rituximab, and chemotherapy), the response was poor, and the patient died 94 days after the outbreak of PTLD. Both transplantation and HIV infection are risk factors for lymphoproliferative diseases. To the best of our knowledge, this is one of the very few reports of PTLD in a patient with HIV/HCV co-infection.

18F-FDG PET/CT findings in a patient with blastic plasmacytoid dendritic cell neoplasm and post-transplant lymphoproliferative disorder after hematopoietic stem cell transplantation: a case report

Background

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an extremely rare hematopoietic malignancy, which originating from precursors of plasmacytoid dendritic cells. Allogeneic hematopoietic stem cell transplantation (HSCT) is normally considered in the treatment of BPDCN patients to acquire sustained remission. Post-transplant lymphoproliferative disorder (PTLD) is a group of conditions involving abnormal lymphoid cells proliferation in the context of extrinsic immunosuppression after solid organ transplantation (SOT) or HSCT. Herein, we report a patient with BPDCN, who suffered from PTLD after allogeneic HSCT.

Case presentation

A 66-year-old man was diagnosed with BPDCN, confirmed by pathologic examination after splenectomy. The post-surgery 18F-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (18F-FDG PET/CT) showed multifocal 18F-FDG avidity in the left cheek, lymph nodes and bone marrow. The patient started chemotherapy, followed by allogeneic HSCT and immunosuppressive therapy. Four months after the HSCT, the patient developed intermittent fever and recurrent lymphadenopathy, accompanied with progressively elevated Epstein-Barr virus (EBV)-DNA both in serum and lymphocytes. 18F-FDG PET/CT was performed again and found multiple new enlarged 18F-FDG-avid lymph nodes, while the previous hypermetabolic lesions all disappeared. The pathology of mesenteric lymph node indicated a monomorphic PTLD (diffuse large B-cell lymphoma). Then the immunosuppressive medications were stopped and two cycles of Rituximab were given, and the follow-up CT scan indicated a complete response.

Conclusion

When patients with BPDCN recurred new enlarged lymph nodes after allogeneic HSCT and immunosuppressive therapy, PTLD should be taken into consideration. 18F-FDG PET/CT may provide additional evidence for supporting or refuting the suspicion of PTLD, and suggest lesions accessible for biopsy.

Important Considerations in the Diagnosis and Management of Post-transplant Lymphoproliferative Disorder

PURPOSE OF REVIEW

A relative lack of molecular and clinical studies compared to other lymphoid cancers has historically made it difficult to determine optimal management approaches in post-transplant lymphoproliferative disorder (PTLD). We sought to better define the "state of the science" in PTLD by examining recent advances in risk assessment, genomic profiling, and trials of PTLD-directed therapy.

RECENT FINDINGS

Several major clinical trials highlight risk-stratified sequential therapy incorporating rituximab with or without chemotherapy as a rational treatment strategy in patients with CD20+ PTLD who do not respond to reduction of immunosuppression alone. Epstein Barr virus (EBV)-targeted cytotoxic lymphocytes are a promising approach in patients with relapsed/refractory EBV+ PTLD, but dedicated clinical trials should determine how autologous chimeric antigen receptor T cell therapy (CAR-T) may be safely administered to PTLD patients. Sequencing studies underscore the important effect of EBV infection on PTLD pathogenesis, but comprehensive genomic and tumor microenvironment profiling are needed to identify biomarkers that predict response to treatment in this clinically heterogeneous disease.

EBV-encoded miRNAs BHRF1-1 and BART2-5p aggravate post- transplant lymphoproliferative disorder via LZTS2-PI3K-AKT axis

Post-transplant lymphoproliferative disorder (PTLD) is one of the most serious complications after transplantation. Epstein-Barr virus (EBV) is a key pathogenic driver of PTLD. About 80% of PTLD patients are EBV positive. However, the accuracy of preventing and diagnosing EBV-PTLD by monitoring EBV DNA load is limited. Therefore, new diagnostic molecular markers are urgently needed. EBV-encoded miRNAs can regulate a variety of EBV-associated tumors and are expected to be potential diagnostic markers and therapeutic targets. We found BHRF1-1 and BART2-5p were significantly elevated in EBV-PTLD patients, functionally promoting proliferation and inhibiting apoptosis in EBV-PTLD. Mechanistically, we first found that LZTS2 acts as a tumor suppressor gene in EBV-PTLD, and BHRF1-1 and BART2-5p can simultaneously inhibit LZTS2 and activate PI3K-AKT pathway. This study shows that BHRF1-1 and BART2-5p can simultaneously inhibit the expression of tumor suppressor LZTS2, and activate the PI3K-AKT pathway, leading to the occurrence and development of EBV-PTLD. Therefore, BHRF1-1 and BART2-5p are expected to be potential diagnostic markers and therapeutic targets for EBV-PTLD patients.

Who is the patient at risk for EBV reactivation and disease: expert opinion focused on post-transplant lymphoproliferative disorders following hematopoietic stem cell transplantation

INTRODUCTION

Post-transplant lymphoproliferative disorders (PTLD) represent a diverse group of diseases. They develop as a consequence of uncontrolled proliferation of lymphoid or plasmacytic cells resulting from T-cell immunosuppression after transplantation of either hematopoietic cells (HCT) or solid organs (SOT), caused mainly by latent Epstein-Barr virus (EBV). The risk for EBV recurrence is dependent on the level of incompetency of the immune system, presented as an impairment of T-cell immunity.

AREAS COVERED

This review summarizes the data on incidence and risk factors of EBV infection in patients after HCT. The median rate of EBV infection in HCT recipients was estimated at 30% after allogeneic and<1% after autologous transplant; 5% in non-transplant hematological malignancies; 30% in SOT recipients. The median rate of PTLD after HCT is estimated at 3%. The most frequently reported risk factors for EBV infection and disease include: donor EBV-seropositivity, use of T-cell depletion, especially with ATG; reduced-intensity conditioning; mismatched family or unrelated donor transplants; and acute or chronic graft-versus-host-disease.

EXPERT OPINION

The major risk factors for EBV infection and EBV-PTLD can be easily identified: EBV-seropositive donor, depletion of T-cells, and the use of immunosuppressive therapy. Strategies for avoiding risk factors include elimination EBV from the graft and improving T-cell function.

Post-Transplant Lymphoproliferative Disease (PTLD) after Allogeneic Hematopoietic Stem Cell Transplantation: Biology and Treatment Options

Post-transplant lymphoproliferative disease (PTLD) is a serious complication occurring as a consequence of immunosuppression in the setting of allogeneic hematopoietic stem cell transplantation (alloHSCT) or solid organ transplantation (SOT). The majority of PTLD arises from B-cells, and Epstein-Barr virus (EBV) infection is present in 60-80% of the cases, revealing the central role played by the latent infection in the pathogenesis of the disease. Therefore, EBV serological status is considered the most important risk factor associated with PTLDs, together with the depth of T-cell immunosuppression pre- and post-transplant. However, despite the advances in pathogenesis understanding and the introduction of novel treatment options, PTLD arising after alloHSCT remains a particularly challenging disease, and there is a need for consensus on how to treat rituximab-refractory cases. This review aims to explore the pathogenesis, risk factors, and treatment options of PTLD in the alloHSCT setting, finally focusing on adoptive immunotherapy options, namely EBV-specific cytotoxic T-lymphocytes (EBV-CTL) and chimeric antigen receptor T-cells (CAR T).

MicroRNA-mediated control of Epstein-Barr virus infection and potential diagnostic and therapeutic implications

Herpesviruses, such as Epstein-Barr virus (EBV), encode multiple viral microRNAs that are expressed throughout various infection stages. While much progress has been made in evaluating both the viral and host microRNAs (miRNAs) that are detected during infection as well as elucidating their molecular targets in vitro, our understanding of their contributions to pathogenesis in vivo, viral oncogenesis, and clinical implications for these small molecules remains limited. miRNAs are widely recognized as key regulators of global cellular processes, including apoptosis, cell differentiation, and development of immune responses. This review discusses the roles of miRNAs in EBV infection and current advances in miRNA-based diagnostic and therapeutic strategies potentially applicable toward EBV-associated diseases.

The Potential for EBV Vaccines to Prevent Multiple Sclerosis

There is increasing evidence suggesting that Epstein-Barr virus infection is a causative factor of multiple sclerosis (MS). Epstein-Barr virus (EBV) is a human herpesvirus, Human Gammaherpesvirus 4. EBV infection shows two peaks: firstly, during early childhood and, secondly during the teenage years. Approximately, 90-95% of adults have been infected with EBV and for many this will have been a subclinical event. EBV infection can be associated with significant morbidity and mortality; for example, primary infection in older children or adults is the leading cause of infectious mononucleosis (IM). A disrupted immune response either iatrogenically induced or through genetic defects can result in lymphoproliferative disease. Finally, EBV is oncogenic and is associated with several malignancies. For these reasons, vaccination to prevent the damaging aspects of EBV infection is an attractive intervention. No EBV vaccines have been licensed and the prophylactic vaccine furthest along in clinical trials contains the major virus glycoprotein gp350. In a phase 2 study, the vaccine reduced the rate of IM by 78% but did not prevent EBV infection. An EBV vaccine to prevent IM in adolescence or young adulthood is the most likely population-based vaccine strategy to be tested and adopted. National registry studies will need to be done to track the incidence of MS in EBV-vaccinated and unvaccinated people to see an effect of the vaccine on MS. Assessment of vaccine efficacy with MS being a delayed consequence of EBV infection with the average age of onset being approximately 30 years of age represents multiple challenges.

Pediatric intestinal transplantation

Advancements in donor management, organ preservation and operative techniques, as well as immunosuppressive therapies, have provided children with intestinal failure and its complications a chance not only for enteral autonomy but also long-term survival through intestinal transplantation (ITx). First described in the 1960's, experience has grown in managing these complex patients both pre- and post-transplant. The goals of this review are to provide a brief history of intestinal transplantation and intestinal rehabilitation in pediatric patients, followed by focused discussions of the indications for ITx, induction and maintenance immunosuppression therapies, common post-operative complications, and outcomes/quality of life post-transplant.

Epstein-Barr Virus Reactivation After Paediatric Haematopoietic Stem Cell Transplantation: Risk Factors and Sensitivity Analysis of Mathematical Model

Epstein-Barr virus (EBV) establishes a lifelong latent infection in healthy humans, kept under immune control by cytotoxic T cells (CTLs). Following paediatric haematopoetic stem cell transplantation (HSCT), a loss of immune surveillance leads to opportunistic outgrowth of EBV-infected cells, resulting in EBV reactivation, which can ultimately progress to post-transplant lymphoproliferative disorder (PTLD). The aims of this study were to identify risk factors for EBV reactivation in children in the first 100 days post-HSCT and to assess the suitability of a previously reported mathematical model to mechanistically model EBV reactivation kinetics in this cohort. Retrospective electronic data were collected from 56 children who underwent HSCT at Great Ormond Street Hospital (GOSH) between 2005 and 2016. Using EBV viral load (VL) measurements from weekly quantitative PCR (qPCR) monitoring post-HSCT, a multivariable Cox proportional hazards (Cox-PH) model was developed to assess time to first EBV reactivation event in the first 100 days post-HSCT. Sensitivity analysis of a previously reported mathematical model was performed to identify key parameters affecting EBV VL. Cox-PH modelling revealed EBV seropositivity of the HSCT recipient and administration of anti-thymocyte globulin (ATG) pre-HSCT to be significantly associated with an increased risk of EBV reactivation in the first 100 days post-HSCT (adjusted hazard ratio (AHR) = 2.32, P = 0.02; AHR = 2.55, P = 0.04). Five parameters were found to affect EBV VL in sensitivity analysis of the previously reported mathematical model. In conclusion, we have assessed the effect of multiple covariates on EBV reactivation in the first 100 days post-HSCT in children and have identified key parameters in a previously reported mechanistic mathematical model that affect EBV VL. Future work will aim to fit this model to patient EBV VLs, develop the model to account for interindividual variability and model the effect of clinically relevant covariates such as rituximab therapy and ATG on EBV VL.

EBV-Driven Lymphoproliferative Disorders and Lymphomas of the Gastrointestinal Tract: A Spectrum of Entities with a Common Denominator (Part 3)

EBV is the first known oncogenic virus involved in the development of several tumors. The majority of the global population are infected with the virus early in life and the virus persists throughout life, in a latent stage, and usually within B lymphocytes. Despite the worldwide diffusion of EBV infection, EBV-associated diseases develop in only in a small subset of individuals often when conditions of immunosuppression disrupt the balance between the infection and host immune system. EBV-driven lymphoid proliferations are either of B-cell or T/NK-cell origin, and range from disorders with an indolent behavior to aggressive lymphomas. In this review, which is divided in three parts, we provide an update of EBV-associated lymphoid disorders developing in the gastrointestinal tract, often representing a challenging diagnostic and therapeutic issue. Our aim is to provide a practical diagnostic approach to clinicians and pathologists who face this complex spectrum of disorders in their daily practice. In this part of the review, the chronic active EBV infection of T-cell and NK-cell type, its systemic form; extranodal NK/T-cell lymphoma, nasal type and post-transplant lymphoproliferative disorders are discussed.