Epstein-Barr virus lymphoproliferative disease after solid organ transplantation

EBV T-cell immunotherapy generated by peptide selection has enhanced effector functionality compared to LCL stimulation

Adoptive immunotherapy with Epstein-Barr virus (EBV)-specific T cells is an effective treatment for relapsed or refractory EBV-induced post-transplant lymphoproliferative disorders (PTLD) with overall survival rates of up to 69%. EBV-specific T cells have been conventionally made by repeated stimulation with EBV-transformed lymphoblastoid cell lines (LCL), which act as antigen-presenting cells. However, this process is expensive, takes many months, and has practical risks associated with live virus. We have developed a peptide-based, virus-free, serum-free closed system to manufacture a bank of virus-specific T cells (VST) for clinical use. We compared these with standard LCL-derived VST using comprehensive characterization and potency assays to determine differences that might influence clinical benefits. Multi-parameter flow cytometry revealed that peptide-derived VST had an expanded central memory population and less exhaustion marker expression than LCL-derived VST. A quantitative HLA-matched allogeneic cytotoxicity assay demonstrated similar specific killing of EBV-infected targets, though peptide-derived EBV T cells had a significantly higher expression of antiviral cytokines and degranulation markers after antigen recall. High-throughput T cell receptor-beta (TCRβ) sequencing demonstrated oligoclonal repertoires, with more matches to known EBV-binding complementary determining region 3 (CDR3) sequences in peptide-derived EBV T cells. Peptide-derived products showed broader and enhanced specificities to EBV nuclear antigens (EBNAs) in both CD8 and CD4 compartments, which may improve the targeting of highly expressed latency antigens in PTLD. Importantly, peptide-based isolation and expansion allows rapid manufacture and significantly increased product yield over conventional LCL-based approaches.

EBV Reactivation and Lymphomagenesis: More Questions than Answers

PURPOSE OF REVIEW

Epstein-Barr Virus (EBV) is a ubiquitous herpesvirus that affects almost all humans and establishes lifelong infections by infecting B-lymphocytes leading to their immortalization. EBV has a discrete life cycle with latency and lytic reactivation phases. EBV can reactivate and cause lymphoproliferation in both immunocompetent and immunocompromised individuals. There is sparse literature on monitoring protocols for EBV reactivation and no standardized treatment protocols to treat EBV-driven lymphoproliferation.

RECENT FINDINGS

While there are no FDA-approved therapies to treat EBV, there are several strategies to inhibit EBV replication. These include immunosuppression reduction, nucleoside analogs, HDAC inhibitors, EBV-specific cytotoxic T-lymphocytes (CTLs), and monoclonal antibodies, such as rituximab. There is currently an open clinic trial combining the use of a HDAC inhibitor, nanatinostat, and ganciclovir to treat refractory/relapsed EBV lymphomas. Another novel therapy includes tabelecleucel, which is an allogenic EBV-directed T-cell immunotherapy that was approved by the European Medicines Agency, but is currently only available in the US for limited use in relapsed or refractory EBV-positive PTLD. Further research is needed to establish EBV monitoring protocols in high-risk populations, such as those with autoimmune disease, cancer, HIV, or receiving immunosuppressive therapy. Additionally, standardized treatments for both the prevention of EBV reactivation in high-risk populations and treatment of EBV reactivation and lymphoproliferation need to be established.

The case for the therapeutic use of mechanistic/mammalian target of rapamycin (mTOR) inhibitors in xenotransplantation

The mechanistic/mammalian target of rapamycin (mTOR) is one of the systems that are necessary to maintain cell homeostasis, such as survival, proliferation, and differentiation. mTOR inhibitors (mTOR-Is) are utilized as immunosuppressants and anti-cancer drugs. In organ allotransplantation, current regimens infrequently include an mTOR-I, which are positioned more commonly as alternative immunosuppressants. In clinical allotransplantation, long-term efficacy has been established, but there is a significant incidence of adverse events, for example, inhibition of wound healing, buccal ulceration, anemia, hyperglycemia, dyslipidemia, and thrombocytopenia, some of which are dose-dependent. mTOR-Is have properties that may be especially beneficial in xenotransplantation. These include suppression of T cell proliferation, increases in the number of T regulatory cells, inhibition of pig graft growth, and anti-inflammatory, anti-viral, and anti-cancer effects. We here review the potential benefits and risks of mTOR-Is in xenotransplantation and suggest that the benefits exceed the adverse effects.

Curcumin as a Natural Modulator of B Lymphocytes: Evidence from In Vitro and In Vivo Studies

Abstract:

B cells are the only player of humoral immune responses by the production of various types of antibodies. However, B cells are also involved in the pathogenesis of several immune-mediated diseases. Moreover, different types of B cell lymphoma have also been characterized. Selective depletion of B cells by anti-CD20 and other B cell-depleting agents in the clinic can improve a wide range of immune-mediated diseases. B cells' capacity to act as cytokine-producing cells explains how they can control immune cells' activity and contribute to disease pathogenesis. Thus, researchers investigated a safe, low-cost, and effective treatment modality for targeting B cells. In this respect, curcumin, the biologically active ingredient of turmeric, has a wide range of pharmacological activities. Evidence showed that curcumin could affect various immune cells, such as monocytes and macrophages, dendritic cells, and T lymphocytes. However, there are few pieces of evidence about the effects of curcumin on B cells. This study aims to review the available evidence about curcumin's modulatory effects on B cells' proliferation, differentiation, and function in different states. Apart from normal B cells, the modulatory effects of curcumin on B cell lymphoma will also discuss.

Epstein-Barr virus-associated post-transplant lymphoproliferative disorders: beyond chemotherapy treatment

Post-transplant lymphoproliferative disorder (PTLD) is a rare but life-threatening complication of both allogeneic solid organ (SOT) and hematopoietic cell transplantation (HCT). The histology of PTLD ranges from benign polyclonal lymphoproliferation to a lesion indistinguishable from classic monoclonal lymphoma. Most commonly, PTLDs are Epstein-Barr virus (EBV) positive and result from loss of immune surveillance over EBV. Treatment for PTLD differs from the treatment for typical non-Hodgkin lymphoma because prognostic factors are different, resistance to treatment is unique, and there are specific concerns for organ toxicity. While recipients of HCT have a limited time during which they are at risk for this complication, recipients of SOT have a lifelong requirement for immunosuppression, so approaches that limit compromising or help restore immune surveillance are of high interest. Furthermore, while EBV-positive and EBV-negative PTLDs are not intrinsically resistant to chemotherapy, the poor tolerance of chemotherapy in the post-transplant setting makes it essential to minimize potential treatment-related toxicities and explore alternative treatment algorithms. Therefore, reduced-toxicity approaches such as single-agent CD20 monoclonal antibodies or bortezomib, reduced dosing of standard chemotherapeutic agents, and non-chemotherapy-based approaches such as cytotoxic T cells have all been explored. Here, we review the chemotherapy and non-chemotherapy treatment landscape for PTLD.

Pathogen-Specific T Cells Beyond CMV, EBV and Adenovirus

PURPOSE OF REVIEW

Infectious diseases contribute significantly to morbidity and mortality in recipients of allogeneic haematopoietic stem cell transplantation (aHSCT), particularly in the era of highly immunosuppressive transplant regimens and alternate donor transplants. Delayed cellular immune recovery is a major mechanism for the increased risk in these patients. Adoptive cell therapy with ex vivo manipulated pathogen-specific T cells (PSTs) is increasingly taking its place as a treatment strategy using donor-derived or third party-banked cells.

RECENT FINDINGS

The majority of clinical trial data in the form of early-phase studies has been in the prophylaxis or treatment of cytomegalovirus (CMV), Epstein-Barr virus (EBV) and adenovirus (AdV). Advancements in methods to select and enrich PSTs offer the opportunity to target the less common viral pathogens as well as fungi with this technology. Early clinical studies of PSTs targeting polyomaviruses (BK virus and JC virus), human herpesvirus 6 (HHV6), varicella zoster virus (VZV) and Aspergillus spp. have shown promising results in small numbers of patients. Other potential targets include herpes simplex virus (HSV), respiratory viruses and other invasive fungal species. In this review, we describe the burden of disease of this wider spectrum of pathogens, the progress in the development of manufacturing capability, early clinical results and the opportunities and challenges for implementation in the clinic.

Infection prophylaxis and management of viral infection

Viral infections are associated with significant morbidity and mortality in lung transplant recipients. Importantly, several viral infections have been associated with the development of chronic lung allograft dysfunction (CLAD). Community-acquired respiratory viruses (CARV) such as influenza and respiratory syncytial virus (RSV), are frequently associated with acute and chronic rejection. Cytomegalovirus (CMV) remains a significant burden in regards to morbidity and mortality in lung transplant recipients. Epstein-Barr virus (EBV) is mostly involved with the development of post-transplant lymphoproliferative disorder (PTLD), a lymphoid proliferation that occurs in the setting of immunosuppression. On the other hand, the development of direct acting antivirals for hepatitis C virus (HCV) is changing the use of HCV-positive organs in transplantation. In this article we will focus on reviewing common viral infections that have a significant impact on lung transplant recipients looking at epidemiology, prevention and potential treatment.

Update on posttransplant lymphoproliferative disease

PURPOSE OF REVIEW

Posttransplant lymphoproliferative disorder (PTLD), frequently associated with Epstein-Barr virus (EBV), is one of the most serious complications leading to worse patient and graft outcomes. Hence, we summarize in this review relevant studies published about PTLD in the last 18 months.

RECENT FINDINGS

Recent studies have improved the knowledge about epidemiology, prophylaxis, diagnosis and PTLD treatment. Special interest has developed in improving the last PTLD classification of the World Health Organization, increasing the accuracy of diagnostic tests for EBV viral load quantification and discriminating the genetic differences between PTLD types. There seems to be no real advantage in the use of antiviral drugs for prophylaxis, but better results in therapeutic approaches are being obtained mainly with the use of rituximab with or without chemotherapy, but also with the possibility of using adoptive T-cell therapy or new drugs.

SUMMARY

PTLD continues being a complication that requires continued effort of the scientific community to reduce its incidence and to develop better diagnostic tests and new strategies that improve results in prophylaxis and treatment.

Two-year-old female with EBV-positive diffuse large B-cell lymphoma and subsequent CNS involvement with neurolymphomatosis

We describe a case of Epstein-Barr virus (EBV) positive, diffuse large B-cell lymphoma in a 2-year-old female who went on to develop relapsed/refractory central nervous system (CNS) disease, manifesting as cranial nerve neurolymphomatosis. Although her atypical presentation was thought to be associated with an immune deficiency, extensive work-up was negative. Despite subsequent treatment with third-party EBV-specific cytotoxic T-lymphocytes, she died of progressive disease. This case report raises questions as to whether tailored treatment approaches should be considered for atypical presentations of pediatric lymphoma (e.g., CNS and virus-associated).

Dynamics of virus-specific T cell immunity in pediatric liver transplant recipients

Immunosuppression following solid organ transplantation (SOT) has a deleterious effect on cellular immunity leading to frequent and prolonged viral infections. To better understand the relationship between posttransplant immunosuppression and circulating virus-specific T cells, we prospectively monitored the frequency and function of T cells directed to a range of latent (CMV, EBV, HHV6, BK) and lytic (AdV) viruses in 16 children undergoing liver transplantation for up to 1 year posttransplant. Following transplant, there was an immediate decline in circulating virus-specific T cells, which recovered posttransplant, coincident with the introduction and subsequent routine tapering of immunosuppression. Furthermore, 12 of 14 infections/reactivations that occurred posttransplant were successfully controlled with immunosuppression reduction (and/or antiviral use) and in all cases we detected a temporal increase in the circulating frequency of virus-specific T cells directed against the infecting virus, which was absent in 2 cases where infections remained uncontrolled by the end of follow-up. Our study illustrates the dynamic changes in virus-specific T cells that occur in children following liver transplantation, driven both by active viral replication and modulation of immunosuppression.

DDX5 RNA Helicases: Emerging Roles in Viral Infection

Asp-Glu-Ala-Asp (DEAD)-box polypeptide 5 (DDX5), also called p68, is a prototypical member of the large ATP-dependent RNA helicases family and is known to participate in all aspects of RNA metabolism ranging from transcription to translation, RNA decay, and miRNA processing. The roles of DDX5 in cell cycle regulation, tumorigenesis, apoptosis, cancer development, adipogenesis, Wnt-β-catenin signaling, and viral infection have been established. Several RNA viruses have been reported to hijack DDX5 to facilitate various steps of their replication cycles. Furthermore, DDX5 can be bounded by the viral proteins of some viruses with unknown functions. Interestingly, an antiviral function of DDX5 has been reported during hepatitis B virus and myxoma virus infection. Thus, the precise roles of this apparently multifaceted protein remain largely obscure. Here, we provide a rapid and critical overview of the structure and functions of DDX5 with a particular emphasis on its role during virus infection.

Perspectives of Phage-Eukaryotic Cell Interactions to Control Epstein-Barr Virus Infections

Recently, leading medical journals emphasized the importance of further studies on the potential application of bacterial viruses (phages) for the treatment of antibiotics-resistant infections outlining the present status of the therapy and perspectives for the future. Furthermore, a leading scientific journal pointed to the recent progress in research on phage interactions with eukaryotic cells (especially cells of the immune system) and potential implications of their results for our broader understanding of the role of phages – not only as “bacteria eaters” – but also as an important part of our body defense protecting against external and internal pathogenic invaders (as suggested previously). This illustrates how our understanding of the actual role and potential of phages is expanding and how worldwide interest in their use in medicine is growing. In this article we envision how this advancement of our knowledge about phages could be translated into the progress in combating herpesvirus infections especially those caused by Epstein–Barr virus (EBV).