Epstein-Barr virus related post-transplant lymphoproliferative disorder prevention strategies in allogeneic hematopoietic stem cell transplantation

EBV Reactivation and Disease in Allogeneic Hematopoietic Stem Cell Transplant (HSCT) Recipients and Its Impact on HSCT Outcomes

The acquisition or reactivation of Epstein-Barr virus (EBV) after allogeneic Hematopoietic Stem Cell Transplant (HSCT) can be associated with complications including the development of post-transplant lymphoproliferative disorder (PTLD), which is associated with significant morbidity and mortality. A number of risk factors for PTLD have been defined, including T-cell depletion, and approaches to monitoring EBV, especially in high-risk patients, with the use of preemptive therapy upon viral activation have been described. Newer therapies for the preemption or treatment of PTLD, such as EBV-specific cytotoxic T-cells, hold promise. Further studies to help define risks, diagnosis, and treatment of EBV-related complications are needed in this at-risk population.

Letermovir prophylaxis reduced cytomegalovirus reactivation and resistance post umbilical cord blood transplantation

To explore the impact of letermovir (LET) prophylaxis on cytomegalovirus (CMV) reactivation and resistance in both adult and paediatric umbilical cord blood transplantation (UCBT) patients, we retrospectively compared 43 UCBT patients who received LET as CMV prophylaxis with a historical cohort of 207 UCBT patients without LET usage. LET was administered from Day +1 to Day +100. The 180-day cumulative incidence of CMV reactivation (47.3% vs. 74.4%, p < 0.001) and the proportion of refractory CMV reactivation (15.0% vs. 42.9%, p = 0.016) were significantly lower than those in the control group. However, more frequent late CMV infection (31.0% vs. 4.3%, p = 0.002) and the 180-day cumulative incidence of Epstein-Barr virus (EBV) reactivation (9.3% vs. 3.4%, p = 0.087) were observed in UCBT patients with LET prophylaxis. Meanwhile, older age (>15 years old) and the occurrence of pre-engraftment syndrome were identified as the significant risk factors for CMV reactivation, and in patients at high risk, the incidence of CMV reactivation in the LET group was lower than that in the control group (46.7% vs. 86.5%, p < 0.001), while this decline was less pronounced among patients at low risk (47.8% vs. 62.1%, p = 0.120).

Epstein-Barr Virus Monitoring after an Allogeneic Hematopoietic Stem Cell Transplant: Review of the Recent Data and Current Practices in Canada

Epstein-Barr virus-related post-transplantation lymphoproliferative disorder (EBV-PTLD) is a serious complication following hematopoietic stem cell transplantation (HSCT). A pre-emptive strategy using rituximab, which aims to manage patients early at the time of EBV reactivation to avoid PTLD, has been recommended by the most recent ECIL-6 guidelines in 2016. However, there is still a great heterogeneity of viral-load monitoring protocols, targeted patient populations, and pre-emptive treatment characteristics between centers, making precise EBV monitoring recommendations difficult. We conducted a literature review from the most recent publications between 1 January 2015 and 1 August 2023, to summarize the emerging data on EBV-PTLD prevention strategies in HSCT recipients, including the EBV-DNA threshold and use of rituximab. We also present the results of a survey of current practices carried out in 12 of the main HSCT centers across Canada. We confirm that pre-emptive rituximab remains an efficient strategy for EBV-PTLD prevention. However, there is an urgent need to perform prospective, randomized, multicentric trials with larger numbers of patients reflecting current practices to determine the best clinical conduct with regards to rituximab dosing, timing of treatment, and criteria to initiate treatments. Longer follow-ups will also be necessary to assess patients' long-term outcomes.

A Multiplex Fluorescence of Loop Primer Upon Self-Dequenching Loop-Mediated Isothermal Amplification Assay for the Detection of Epstein-Barr Virus and Human Parvovirus B19 in Clinical Transplant Samples

Viral infections are major causes of mortality in solid-organ and hematopoietic stem cell transplant recipients. Epstein-Barr virus (EBV) and Parvovirus B19 (B19V) are among the common viral infections after transplantation and were recommended for increased screening in relevant guidelines. Therefore, the development of rapid, specific, and cost-effective diagnostic methods for EBV and B19V is of paramount importance. We applied Fluorescence of Loop Primer Upon Self-Dequenching Loop-mediated Isothermal Amplification (FLOS-LAMP) for the first time to develop a novel multiplex assay for the detection of EBV and B19V; the fluorophore attached to the probe are self-quenched in unbound state. After binding to the dumbbell-shaped DNA target, the fluorophore is dequenched, resulting in fluorescence development. The novel multiplex FLOS-LAMP assay was optimized by testing various ratios of primer sets. This novel assay, with great specificity, did not cross-react with the common virus. For the detection of EBV and B19V, the limits of detection could reach 969 and 798 copies/μL, respectively, and the assay could be completed within 25 min. Applying this novel assay to detect 200 clinical transplant individuals indicated that the novel assay had high specificity and good sensitivity. We developed multiplex FLOS-LAMP assay for the detection of EBV and B19V, which has the potential to become an important tool for clinical transplant patient screening.

Clinical characteristics and outcomes of Epstein-Barr virus viral load after allogeneic hematopoietic stem cell transplantation

Epstein-Barr virus (EBV) reactivation can occur following allogenic hematopoietic stem cell transplantation (allo-HSCT). However, the clinical characteristics and outcomes of EBV-viral load are not well known. Thus, we retrospectively analyzed the clinical features and prognostic impact of the EBV viral load in 121 allo-HSCT recipients from our hospital. EBV DNA quantification was performed in whole blood after transplantation. Patients were grouped based on whether EBV DNA quantification reached > 1000 copies/mL during follow-up (N = 50) or not (N = 71). Patients with EBV > 1000 EBV copies/mL were relatively more common in the groups with graft versus host disease (GVHD) prophylaxis including ATG, haploidentical donor type, peripheral blood as a donor source, and acute GVHD II-IV. The 20-month OS and DFS were not significantly different between patients with < 1000 EBV copies/mL and patients with > 1000 EBV copies/mL (20-month OS, 56.0% vs. 60.6%; p = 0.503, 20-month DFS, 50.0% vs. 57.7%; p = 0.179). Immunosuppressant (ISS) dose reduction was achieved after the maximum increase in EBV in 41/50 (82%) patients. Additionally, 30/50 (60%) patients achieved a 50% dose reduction or no restarting of ISS within 3 months of the maximum EBV increase. Among cases wherein EBV DNA quantification reached > 1000 copies/mL, those that achieved rapid dose reduction of ISS tended to have longer overall survival ("not reached" vs 5.4 months, p < 0.001) and disease-free survival (88.4 months vs 5.3 months, p < 0.001) than those in patients who did not. Our data highlight the importance of rapid ISS reduction in post-transplant EBV reactivation.

Herpes Virus Infection in Lung Transplantation: Diagnosis, Treatment and Prevention Strategies

Lung transplantation is an ultimate treatment option for some end-stage lung diseases; due to the intense immunosuppression needed to reduce the risk of developing acute and chronic allograft failure, infectious complications are highly incident. Viral infections represent nearly 30% of all infectious complications, with herpes viruses playing an important role in the development of acute and chronic diseases. Among them, cytomegalovirus (CMV) is a major cause of morbidity and mortality, being associated with an increased risk of chronic lung allograft failure. Epstein-Barr virus (EBV) is associated with transformation of infected B cells with the development of post-transplantation lymphoproliferative disorders (PTLDs). Similarly, herpes simplex virus (HSV), varicella zoster virus and human herpesviruses 6 and 7 can also be responsible for acute manifestations in lung transplant patients. During these last years, new, highly sensitive and specific diagnostic tests have been developed, and preventive and prophylactic strategies have been studied aiming to reduce and prevent the incidence of these viral infections. In this narrative review, we explore epidemiology, diagnosis and treatment options for more frequent herpes virus infections in lung transplant patients.

Expanding the scope of the infectious diseases pharmacist in HCT: Beyond antimicrobial stewardship

BACKGROUND

Infectious disease (ID) pharmacists and antimicrobial stewardship (AMS) programs are integral to the infection management of hematopoietic cell transplant (HCT) recipients demonstrating effective implementation of clinical pathways, de-escalation of empirical antibiotics for febrile neutropenia (FN), allergy assessments, and use of rapid diagnostic testing. The HCT procedure is complex, dynamic, and a high risk for infectious complications. Therefore, there is an important role for an ID and AMS pharmacist to collaborate with the primary treating team, with ongoing care, involving the optimal individual patient prophylactic, pre-emptive and treatment management of infections in this high-risk population.

CONCLUSION

This review highlights key factors for consideration of ID/AMS Pharmacists in relation to HCT, including important aspects in the evaluation of infection risk prior to transplant, risk from donor sources, length of, and changes in immunosuppression, and potential drug-drug interactions from other essential supportive care therapies.

Applying Rituximab During the Conditioning Regimen Prevents Epstein-Barr Virus Infection Following Allogeneic Hematopoietic Stem Cell Transplant in a Children's Cohort: A Retrospective Case-Control Study

INTRODUCTION

Since hematopoietic stem cell transplant (HSCT) is an important therapy for malignant and non-malignant pediatric diseases, improving transplant-related mortality remains a challenge. Currently, rituximab, a monoclonal antibody of anti-CD20, is widely used for several post-HSCT complications. However, few studies have focused on the application of rituximab before HSCT.

METHODS

We conducted a retrospective case-control study from January 2019 to July 2021 to determine this effect in a single center. Forty-eight patients were included in the rituximab group, with a one-to-one ratio matched to the control group.

RESULTS

Both the occurrence rate and cumulative incidence rate of Epstein-Barr virus (EBV) infection were significantly lower in the rituximab group than in the without-rituximab group (10.4% vs. 33.3%, p = 0.014 and 12.2% vs. 39.3% p = 0.0026, respectively). Furthermore, without the application of rituximab was identified as a risk factor for post-HSCT EBV infection via both univariate [hazard ratio (HR) = 4.17, 95%CI (1.52-11.43), p = 0.005] and multivariate analyses [HR = 4.65, 95%CI (1.66-13.0), p = 0.003]. Although the overall survival (OS) probability of the rituximab group was comparable to the without-rituximab group, a markedly improved OS of the rituximab group was found in the malignant disease subgroup (78.9% vs. 42.1%, p = 0.032). The outcomes of graft-versus-host disease, neutrophil and platelet engraftment, other viral infections, and the reconstitution of lymphocytes showed no significant differences between the two groups.

CONCLUSIONS

The administration of rituximab before HSCT may prevent EBV infection following HSCT.

Advancing therapeutic strategies for Epstein-Barr virus-associated malignancies through lytic reactivation

Epstein-Barr virus (EBV) is a widespread human herpes virus associated with lymphomas and epithelial cell cancers. It establishes two separate infection phases, latent and lytic, in the host. Upon infection of a new host cell, the virus activates several pathways, to induce the expression of lytic EBV antigens and the production of infectious virus particles. Although the carcinogenic role of latent EBV infection has been established, recent research suggests that lytic reactivation also plays a significant role in carcinogenesis. In this review, we summarize the mechanism of EBV reactivation and recent findings about the role of viral lytic antigens in tumor formation. In addition, we discuss the treatment of EBV-associated tumors with lytic activators and the targets that may be therapeutically effective in the future.

Virological Markers in Epstein–Barr Virus-Associated Diseases

Epstein–Barr virus (EBV) is an oncogenic virus infecting more than 95% of the world’s population. After primary infection—responsible for infectious mononucleosis in young adults—the virus persists lifelong in the infected host, especially in memory B cells. Viral persistence is usually without clinical consequences, although it can lead to EBV-associated cancers such as lymphoma or carcinoma. Recent reports also suggest a link between EBV infection and multiple sclerosis. In the absence of vaccines, research efforts have focused on virological markers applicable in clinical practice for the management of patients with EBV-associated diseases. Nasopharyngeal carcinoma is an EBV-associated malignancy for which serological and molecular markers are widely used in clinical practice. Measuring blood EBV DNA load is additionally, useful for preventing lymphoproliferative disorders in transplant patients, with this marker also being explored in various other EBV-associated lymphomas. New technologies based on next-generation sequencing offer the opportunity to explore other biomarkers such as the EBV DNA methylome, strain diversity, or viral miRNA. Here, we review the clinical utility of different virological markers in EBV-associated diseases. Indeed, evaluating existing or new markers in EBV-associated malignancies or immune-mediated inflammatory diseases triggered by EBV infection continues to be a challenge.

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

PURPOSE OF REVIEW

Management of Epstein-Barr virus posttransplant lymphoproliferative disorder (EBV PTLD) is complex, involving risk stratification, prevention and/or preemptive measures involving monitoring EBV DNAemia and balancing treatment options, using a combination of reduction of immune suppression, anti-B cell therapy, and cytotoxic T lymphocytes (CTLs).

RECENT FINDINGS

The highest risk factor for the development of EBV PTLD in hematopoietic cell transplant (HCT) remains T cell depletion, with increasing use of antithymocyte globulin (ATG) or alemtuzumab in conditioning. In solid organ transplantation (SOT), the incidence of PTLD is highest among EBV seronegative recipients who are at risk for primary EBV infection following transplant in the first 12 months. Prevention is a critical component of the management of EBV PTLD. Although preemptive therapy remains standard of care, there continues to be heterogenicity and debate over the optimal choice of EBV DNA quantification and the threshold to use. Novel therapies such as donor-derived multipathogen and EBV specific CTLs for the prevention and third party CTLs for the treatment of EBV PTLD are promising, with rapidly expanding evidence, including large scale Phase III trials currently underway.

SUMMARY

With an increasing number of risk groups for developing EBV PTLD in HCT and SOT, management strategies using prophylaxis or preemptive therapy remain standard of care, however the use of prophylactic or preemptive EBV specific or multipathogen CTLs show promising results and safety profiles.

Dynamics of Epstein-Barr virus on post-transplant lymphoproliferative disorders after antithymocyte globulin-conditioned allogeneic hematopoietic cell transplant

BACKGROUND

The use of antithymocyte globulin (ATG) in allogeneic hematopoietic cell transplant (HCT) is associated with an increased risk of Epstein-Barr virus (EBV) reactivation and post-transplant lymphoproliferative disorders (PTLD). The dynamics and outcomes of EBV-DNAemia are not well described in this population.

METHODS

We retrospectively assessed the kinetics of EBV-DNAemia after ATG conditioning of HCT recipients. Receiver operating characteristic (ROC) curves were used to assess EBV-DNAemia to predict EBV-PTLD in this group.

RESULTS

A total of 174/405 (43%) consecutive HCT recipients from two centers met inclusion criteria of ATG conditioned, non-B-cell lymphoma patients. Of these with EBV-DNA measured using standardized IU/ml, 78.6% (92/117) developed EBV-DNAemia: 62% spontaneously resolved; 19% cleared after preemptive rituximab, and 13% developed EBV-PTLD. ROC curve analysis using maximum pre-EBV-PTLD EBV-DNAemia, demonstrated an AUC of 0.912 with EBV-DNAemia of 9782 IU/ml, associated with 82.6% sensitivity and 94.4% specificity for development of EBV-PTLD. Median time for EBV-DNAemia to increase from initial detection to >1000 IU/ml was 7 days; to >10 000 IU/ml, 12 days; and to >100 000 IU/ml, 18 days. Median EBV-DNAemia level prior to administration of rituximab was significantly lower in patients with successful preemptive treatment, compared with those who developed EBV-PTLD (3.41 log₁₀  IU/ml [3.30-3.67] vs. 4.34 log₁₀  IU/ml [3.85-5.13], p = .002; i.e., 2628 IU/ml vs. 21 965 IU/ml, respectively).

CONCLUSIONS

EBV-DNAemia >10 000 IU/ml was the strongest predictor of the development of EBV-PTLD, and progression to this level was rapid in ATG-conditioned HCT recipients. This information may guide EBV-PTLD management strategies in these high-risk patients.

Local FK506 implants in non-human primates to prevent early acute rejection in vascularized composite allografts

Background

Previous vascularized composite allograft (VCA) studies from our laboratory have shown that topical FK506 delivery in non-human primates (NHPs) was limited by inadequate dermal penetration and rejection persisted. Herein, we report the first utilization of FK506 via subcutaneously implanted discs to mitigate VCA rejection in NHPs.

Methods

Full major histocompatibility complex (MHC)-mismatched NHP pairs underwent partial-face VCA and FK506 disc implantation along the suture line. All allotransplants were maintained post-operatively for two months on the FK506 discs, methylprednisolone, mycophenolate mofetil, and supplemented with intramuscular FK506 if necessary. Group 1 (n=4) was used for optimization of the implant, while Group 2 (n=3) underwent delayed bone marrow transplantation (DBMT) after two months. VCA skin biopsies and peripheral blood samples were obtained for serial assessment of rejection and mixed chimerism by histopathology and flow cytometry respectively.

Results

In Group 1, two technical failures occurred. Of the remaining two NHPs, one developed supratherapeutic levels of FK506 (50–120 ng/mL) and had to be euthanized on postoperative day (POD) 12. Reformulation of the implant resulted in stable FK506 levels (20–30 ng/mL) up to POD12 when further intramuscular (IM) FK506 injections were necessitated. In Group 2, two NHPs survived to undergo conditioning and one successfully developed chimerism at 2–3 weeks post-DBMT (96–97% granulocytes and 7–11% lymphocytes of recipient-origin). However, all three NHPs had to be terminated from study at POD64, 77 and 86 due to underlying post-transplant lymphoproliferative disorder. All VCAs remained rejection-free up to study endpoint otherwise.

Conclusions

This study shows preliminary results of local FK506 implants in potentially mitigating VCA acute rejection for tolerance protocols based on mixed chimerism approach.

Adverse Reactions to Drugs of Special Interest in a Pediatric Oncohematology Service

Introduction: Drugs used in oncological diseases are frequently related to adverse drug reactions (ADR). Few studies have analyzed the toxicity of cancer treatments in children in real practice.

Methods: An observational, longitudinal and prospective study has been carried out in an Oncohematology Service of a tertiary hospital. During 2017, patients exposed to one or more drugs of a previously agreed list were identified and followed-up for at least 6 months each. Characteristics of ADR, incidence, causality and possible preventability, have been evaluated.

Results: 72 patients have been treated with at least one study drug, and 159 ADR episodes involving at least one of these drugs have been identified, with a total of 293 ADR. Most episodes required hospital admission (35.2%) or happened during the hospital stay (33%), and 91.2% were severe. Blood disorders were the most frequent ADR (96; 32.8%), related to thioguanine (42) and pegaspargase (39) mainly, followed by infections (86; 29.4%) related to thioguanine (32), pegaspargase (27), Erwinia asparaginase (14) and rituximab (13). Two ADR were unknown. Most ADR were dose-dependent or expectable (>90%). The global incidence of ADR was 3.1/100 days at risk (95% CI 2.7–3.5), with 3.5 ADR/100 days at risk with pegaspargase (95% CI 2.9–4.2), 1.2/100 days at risk with rituximab (95% CI 0.8–1.8) and 11.6/100 days at risk with thioguanine (95% CI 9.4–14.2). Controversial additional measures of prevention, other than those already used, were identified.

Conclusion: ADR are frequent in pediatric oncohematological patients, mainly blood disorders and infectious diseases. Findings regarding incidence and preventability may be useful to compare data between different centers and to evaluate new possibilities for action or prevention.