Preemptive diagnosis and treatment of Epstein-Barr virus-associated post transplant lymphoproliferative disorder after hematopoietic stem cell transplant: an approach in development

αβ and γδ T-cell responses to Epstein-Barr Virus: insights in immunocompetence, immune failure and therapeutic augmentation in transplant patients

Epstein-Barr Virus (EBV) is a human gamma herpes virus, which causes several diseases in immunocompetent (mononucleosis, chronic fatigue syndrome, gastric cancer, endemic Burkitt's lymphoma, head and neck cancer) and immunosuppressed (post-transplant lymphoproliferative disease, EBV-associated soft tissue tumors) patients. It elicits a complex humoral and cellular immune response with both innate and adaptive immune components. Substantial progress has been made in understanding the interplay of immune cells in EBV-associated diseases in recent years, and several therapeutic approaches have been developed to augment cellular immunity toward EBV for control of EBV-associated malignancy. This review will focus on recent developments in immunosuppressed transplant recipients.

Case Report: Successful Chimeric Antigen Receptor T Cell Therapy in Haploidentical-Allogeneic Stem Cell Transplant Patients With Post-Transplant Lymphoproliferative Disorder

Background

Epstein–Barr virus-associated post-transplant lymphoproliferative disorder (EBV-PTLD) is a potentially fatal complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Rituximab has been proven to dramatically improve the prognosis of patients with EBV reactivation and PTLD. However, reports on the curative management of refractory PTLD are scarce.

Case Presentation

In this report, we describe the successful management of two patients with EBV-PTLD with chimeric antigen receptor T-cell (CAR-T) therapy.

Conclusion

The present results demonstrated that patients with EBV-PTLD may benefit from CAR-T therapy and that the toxicity is manageable. Further studies are needed to verify these findings.

Infection-Related Mortality in Adults and Children Undergoing Allogeneic Hematopoietic Cell Transplantation: An Australian Registry Report

Infection-related mortality (IRM) is the most common non-relapse-related cause of death reported after allogeneic hematopoietic cell transplantation (HCT). Information on the incidence and timing of specific infective organisms and the risk factors for IRM is essential to developing prevention strategies. This report provides the first account of IRM in adults and children undergoing HCT in Australia. Between 2013 and 2018, 2705 adult and 689 pediatric first HCTs were identified from the Australasian Bone Marrow Transplant Recipient Registry database, associated with 1075 (39.7%) total overall deaths in adults and 134 (19.4%) in children. Demographics and causes of death, including infectious etiology and causative organisms, were extracted from the database for adults and children for analysis. At day +100 and 1 year post-HCT, IRM was the leading cause of early post-HCT mortality in adults, accounting for 6.2% and 9.8%, respectively; in children, IRM was the leading cause of post-HCT mortality at day +100 at 2.5% and the second highest cause of post-HCT mortality at 1 year post-HCT at 4.9%, following relapse at 5.8%. In adults, older age, transplantation not in a first complete remission (non-CR1), the use of antithymocyte globulin (ATG) or alemtuzumab, donor-positive/recipient-negative cytomegalovirus (CMV) serostatus, and acute graft-versus-host disease were significant risk factors for IRM. However, in children, age >5 years, acute lymphocytic leukemia as the primary disease, and mismatched unrelated or haploidentical donor source were predictive of IRM. Of the deaths in which an infectious etiology was reported in adults (52.4%), 49.3% were attributed to bacteria, 25.3% to fungus, 21.7% to viruses, and 3.6% to post-transplantation lymphoproliferative disorder (PTLD). The most common organisms were Pseudomonas spp, Enterococcus spp, Candida spp, Aspergillus spp, and CMV. In children where an infectious etiology was reported (64%), 13% were attributed to bacteria, 26% to fungus, 45% to viruses, and 16% to PTLD. This report highlights that IRM was the leading cause of death early post-HCT in Australia. Strategies to reduce IRM, such as individualized pre-transplantation infection risk assessment, rapid diagnostics, and prevention management strategies should be explored to determine whether these outcomes can be improved. In addition, improving the completeness and accuracy of reported data, particularly for infectious pathogens, could assist in directing management strategies to reduce IRM in HCT.

Immunosuppression for inflammatory bowel disease does not influence Epstein-Barr viral load in the short-term

INTRODUCTION

Immunomodulators and biologics are two of the main drugs used for the treatment of inflammatory bowel disease (IBD). Some of these agents have been associated with certain infections and lymphoproliferative disorders, including Epstein-Barr virus (EBV) infection. Our aim was to determine the influence of immunosuppression in the EBV viral load in patients with IBD.

MATERIALS AND METHODS

We prospectively included naïve patients with IBD who were starting immunosuppressive therapy in four IBD Units. All patients were assessed at baseline and four months after starting immunosuppression for clinical disease activity, biomarkers, EBV serology (IgM VCA, IgG VCA and IgG EBNA) and viral load.

RESULTS

Thirty-two patients were included. At baseline, all patients showed positive results for IgG VCA or IgG EBNA with undetectable EBV viral load. No patient showed detectable EBV viral load after starting the immunosuppressive therapy.

CONCLUSION

Immunosuppression did not influence on EBV viral load in the short-term in naïve IBD patients.

Screening, prophylaxis and counselling before the start of biological therapies: A practical approach focused on IBD patients

The standard of care in the management of immune-mediated inflammatory conditions relies on immunomodulators, glucocorticoids, and biologicals (including anti-tumour necrosis factor -α and other monoclonal antibodies). These agents have an overall favourable benefit/risk ratio; however, they modulate the immune response as part of their mechanisms of action, and therefore they may increase the risk of developing infections, particularly in older patients or in patients with concomitant corticosteroids. Some of these infections may be preventable by immunization, chemoprophylaxis or counselling.

AIM

screening for and monitoring infections throughout these therapies is so mandatory to ensure patients' safety. Still, standardized guidelines focused on these procedures have yet to be established. This review aims to fill such a gap. The authors searched for articles published in English from 2009 until 2017 using PUBMED, with the terms "immunomodulators", "biological drugs", "anti-TNF α", "inflammatory bowel diseases", "immunomediated inflammatory diseases", "risk of infection", "infection prevention", "screening", "immunization", "tuberculosis", "latent tuberculosis", "listeriosis", "endemic mycosis", "Pneumocystis jiroveci pneumonia", "granulomatous infection", "varicella", "herpes virus", "hepatitis B", "hepatitis A", "hepatitis C" and identified the journal articles. Based on the literature and in their own experience the authors established recommendations and a practical guide for infections' screening, monitoring and prevention before and during immunomodulatory and biological therapies.

Investigation on the association between thyroid tumorigeneses and herpesviruses

Herpesviruses have been associated with various human malignancies and with thyroid autoimmunity. Aiming to investigate the presence of these viruses in thyroid nodules, we analyzed serum and thyroid tissue from 183 patients (83 benign and 100 malignant thyroid nodules). We also obtained 104 normal thyroid tissues extracted from the contralateral lobe of these patients. We used ELISA to screen the serology of all patients and a real-time quantitative PCR to analyze thyroid tissue viral load in antibody-positive patients. In addition, the presence of herpesviruses was tested by histological analysis in 20 EBV-positive tissues using the expression of LMP-1 by immunohistochemistry (IHC) and EBER by in situ hybridization (ISH). There was no evidence of HSV-2 or CMV DNA, but we found EBV DNA sequences in 29 (16%) thyroid tissue samples. We also found 7 positive EBV cases out of 104 normal tissues. Viral load was higher in tumors than in their respective normal tissues (p = 0.0002). ISH analysis revealed EBER expression in 11 out of 20 (52%) EBV-positive tissues, mostly in malignant cases (8/11, 73%). The presence of high EBV copy numbers in thyroid tumors and the expression of EBER only in malignant cases suggest an association between EBV and thyroid malignancies. However, we did not find any association between the presence of EBV and/or its viral load and any clinical or pathological tumor feature. Further studies aiming to clarify the mechanisms of EBV infection in thyroid cells are necessary to support a possible role in the development of thyroid cancer.

Post-transplant lymphoproliferative disorder after solid-organ transplant in children

The post-transplant lymphoproliferative disorders (PTLD) are a diverse group of potentially life-threatening conditions affecting organ transplant recipients. PTLD arises in the setting of an attenuated host immunologic system that is manipulated to allow a foreign graft but then fails to provide adequate immune surveillance of transformed malignant or premalignant lymphocytes. The diversity of biological behavior and clinical presentation makes for a challenging clinical situation for those involved in the care of children with PTLD occurring after solid-organ transplantation. This review details a large transplant center's multidisciplinary approach to monitoring for PTLD and systematic approach to intervention, which has been essential for early recognition and successful treatment.

Management of Epstein-Barr Virus infections and post-transplant lymphoproliferative disorders in patients after allogeneic hematopoietic stem cell transplantation: Sixth European Conference on Infections in Leukemia (ECIL-6) guidelines

Epstein-Barr virus-related post-transplant lymphoproliferative disorders are recognized as a significant cause of morbidity and mortality in patients undergoing hematopoietic stem cell transplantation. To better define current understanding of post-transplant lymphoproliferative disorders in stem cell transplant patients, and to improve its diagnosis and management, a working group of the Sixth European Conference on Infections in Leukemia 2015 reviewed the literature, graded the available quality of evidence, and developed evidence-based recommendations for diagnosis, prevention, prophylaxis and therapy of post-transplant lymphoproliferative disorders exclusively in the stem cell transplant setting. The key elements in diagnosis include non-invasive and invasive methods. The former are based on quantitative viral load measurement and imaging with positron emission tomography; the latter with tissue biopsy for histopathology and detection of Epstein-Barr virus. The diagnosis of post-transplant lymphoproliferative disorder can be established on a proven or probable level. Therapeutic strategies include prophylaxis, preemptive therapy and targeted therapy. Rituximab, reduction of immunosuppression and Epstein-Barr virus-specific cytotoxic T-cell therapy are recommended as first-line therapy, whilst unselected donor lymphocyte infusions or chemotherapy are options as second-line therapy; other methods including antiviral drugs are discouraged.

Epstein-Barr virus-associated post-transplantation lymphoproliferative disorder: potential treatments and implications for nursing practice

BACKGROUND

Considered to be a secondary malignancy, Epstein-Barr virus (EBV)-associated post-transplantation lymphoproliferative disorder (PTLD) is a potentially fatal complication of hematopoietic cell transplantation (HCT). With 50%-70% of all reported cases of PTLD being associated with EBV, the incidence in HCT is relatively low. However, mortality rates in this population of patients are 70%-90%.

OBJECTIVES

The focus of this article is to discuss published literature regarding the risk factors, clinical manifestations, diagnosis, prevention, and potential treatment options for EBV-PTLD, as well as nursing implications and the importance of patient education in high-risk HCT recipients.

METHODS

This review of literature focused on locating, summarizing, and synthesizing data from published clinical studies that focused on treatment options, guidelines, and recommendations for EBV-PTLD. CINAHL® and PubMed databases were used to search for articles published within the past 10 years that included the following key words: post-transplantation lymphoproliferative disorder, Epstein-Barr virus, and hematopoietic cell transplantation.

FINDINGS

Prevention and preemptive therapy are paramount when caring for patients undergoing HCT. Early determination of risk, close observation of EBV DNA levels in the blood, and prompt initiation of therapy are essential to improving patients' overall prognosis. Reduction in immunosuppression is considered first-line therapy for those diagnosed with EBV-PTLD. The literature also supports rituximab-based therapies, administration of EBV-specific cytotoxic T cells, and donor lymphocyte infusion as treatment strategies.

The Epstein-Barr virus DNA load in the peripheral blood of transplant recipients does not accurately reflect the burden of infected cells

Transplant recipients frequently exhibit an increased Epstein-Barr virus (EBV) load in the peripheral blood. Here, we quantitated the EBV-infected cells in the peripheral blood of these patients and defined the mode of viral infection, latent or lytic. These data indicated that there is no strong correlation between the number of infected cells and the EBV load (EBVL). This can be explained by a highly variable number of EBV copies per infected cell and by lytic replication in some cells. The plasma of these patients did not contain any free infectious viruses, but contained nevertheless EBV DNA, sometimes in large amounts, that probably originates from cell debris and contributed to the total EBVL. Some of the investigated samples carried a highly variable number of infected cells in active latency, characterized by an expression of the Epstein-Barr nuclear antigens (EBNA2) protein. However, a third of the samples expressed neither EBNA2 nor lytic proteins. Patients with an increased EBVL represent a heterogeneous group of patients whose infection cannot be characterized by this method alone. Precise characterization of the origin of an increased EBVL, in particular, in terms of the number of EBV-infected cells, requires additional investigations including the number of EBV-encoded small RNA-positive cells.

What is the best way to manage screening for infections and vaccination of inflammatory bowel disease patients?

The use of biological agents and immunomodulators for inflammatory bowel disease (IBD) is associated with an increased risk of opportunistic infections, in particular of viral or bacterial etiology. Despite the existence of international guidelines, many gastroenterologists have not adopted routine screening and vaccination in those patients with IBD, which are candidate for biologic therapy. Available strategies to screen, diagnose and prevent bacterial and viral infections in patients with IBD prior to start biological therapy are discussed in this review.

Epstein-Barr Virus-related Posttransplant Lymphoproliferative Disorder in Children: A Single-institution Experience

We report 4 pediatric cases of biopsy-proven posttransplant lymphoproliferative disorder (PTLD) in the context of allogeneic hematopoietic stem cell transplantation (HSCT). All cases showed diffuse staining with latent membrane protein-1 in immunohistochemistry. The median age at transplant of 4 patients with PTLD was 10.1 years (range, 2.2 to 13.2 y). The median interval between HSCT and the diagnosis of PTLD was 5.5 months (range, 4 to 8 mo). All patients were treated with rituximab at dosage of 375 mg/m at weekly intervals. Reduction of immunosuppression was warranted in all cases. All patients survived with median follow-up duration of 27 months. Although PTLD has been rare following allogeneic HSCT, reduction of immunosuppression combined with rituximab yielded significant response rates in patients with this infrequent but potentially lethal complication. The preliminary finding of this study demonstrated that severe aplastic anemia is closely associated with the development of PTLD in children.

Epstein-Barr virus-associated posttransplant lymphoproliferative disorder after allogeneic stem cell transplantation

PURPOSE OF REVIEW

Epstein-Barr virus (EBV)-associated posttransplant lymphoproliferative disorder is an increasingly life-threatening complication after allogeneic stem cell transplantation with the use of more complex transplant procedures.

RECENT FINDINGS

Reduced intensity conditioning regimens in combination with in-vivo or ex-vivo T-cell depletion are particularly important risk factors. Prospective monitoring of EBV viremia by real-time quantitative polymerase-chain reaction (PCR) should be performed after high-risk allogeneic stem cell transplantation. However, lack of standardization and concerns about sensitivity and low positive-predictive value challenge the interpretation of PCR monitoring. Preemptive treatment is feasible and can reduce EBV-related mortality but may lead to overtreatment in some patients. Readily available rituximab and methods of adoptive transfer of T-cells are valuable tools. Rituximab is probably the most attractive agent showing the most robust data in this setting. Rituximab seems to offer a good balance between efficacy and toxicity for the treatment of established EBV-associated posttransplant lymphoproliferative disorder. But most often there is a need to combine with adoptive immunotherapy with T-cells to maintain long-term disease control, with either simple unmanipulated donor lymphocyte infusion or more specific and complex adoptive EBV-specific cytotoxic T-cells.

SUMMARY

EBV-associated posttransplant lymphoproliferative disorder can often be prevented or treated, especially in earlier stages. The specific role and timing of the different treatment strategies need to be defined.

Post-transplant lymphoproliferative disorders

Post-transplant lymphoproliferative disorders (PTLD) are a serious complication after solid organ or allogeneic hematopoietic stem cell transplantation and include a range of diseases from benign proliferations to malignant lymphomas. Risk factors for developing PTLD include Epstein-Barr virus (EBV) infection, recipient age, transplanted organ, type of immunosuppression, and genetics. Uncontrolled proliferation of EBV-infected B cells is implicated in EBV-positive PTLD, whereas the pathogenesis of EBV-negative PTLD may be similar to non-Hodgkin's lymphoma in the general population. The World Health Organization (WHO) classifies PTLD into four categories: early lesions, polymorphic PTLD, monomorphic PTLD, and classical Hodgkin's lymphoma (cHL). Treatment is aimed at cure of PTLD, while maintaining transplanted organ function. However, there are no established guidelines for the treatment of PTLD. Immune suppression reduction (ISR) is the first line of treatment in most cases, with more recent data suggesting early use of rituximab. In more aggressive forms of PTLD, upfront chemotherapy may offer a better and more durable response. Sequential therapy using rituximab followed by chemotherapy has demonstrated promising results and may establish a standard of care. Novel therapies including anti-viral agents, adoptive immunotherapy, and monoclonal antibodies targeting cytokines require further study in the prevention and treatment of PTLD.

Infectious Complications

Infections remain a cause of significant morbidity and mortality following hematopoietic stem cell transplantation (HSCT). The conditioning regimen (chemotherapy, radiation therapy), mucosal damage, type of transplant, immune suppressive therapy, and graft-versus-host disease (GVHD) all predispose the HSCT recipient to infection. Abnormal B- and T-lymphocyte function results in impaired humoral and cellular immunity, respectively. Neutrophil function is impaired by the use of corticosteroids and other medications. Hypogammaglobulinemia and functional asplenia are common. The occurrence of infections in an individual patient varies according to the phase of the transplant process and reflects the type(s) of immune defect(s), underlying disease, endogenous host flora, exposure history, and pre-treatment infections.

Epstein-Barr virus serology and PCR: conflicting results in an immunocompetent host. A case report and review of literature

We present the case of a 27-year-old immunocompetent man who progressively developed a generalized lymphadenopathy and B symptoms. Results of Epstein-Barr virus (EBV) serology were suggestive for a past infection, but the EBV viral load in whole blood was high. Also, core needle biopsy of the largest lymph node showed an image which could fit an EBV-driven reactive lymphoproliferation. Despite the absence of an immune disorder, all medical evidence points to an EBV-driven lymphoproliferative proces. In immunocompetent patients, it seems extremely uncommon to detect a high EBV viral load in the absence of serological evidence of an acute EBV infection or reactivation. We reviewed literature on this topic and on the selection of the appropriate sample type for EBV PCR, as this is known to be a critical point. Serological testing for the diagnosis of EBV infection is the gold standard in immunocompetent patients. Measuring EBV viral load is only recommended when dealing with immunocompromised patients. Although extremely rare, this case report shows that there is a place for EBV PCR in certain situations in immunocompetent patients. Besides, there is still no consensus regarding the specimen of choice for the determination of the EBV viral load. The preferred specimen type seems to depend on the patient's underlying condition.

Opportunistic infections due to inflammatory bowel disease therapy

The use of biological agents and immunomodulators for inflammatory bowel disease (IBD) has remarkably improved disease management in the current era but at the same time has increased the risk of infectious complications. Patients with IBD on corticosteroids, immunomodulators, and biological agents are considered immunocompromised and are at risk for opportunistic infections. These are infections caused by organisms that take advantage of a weakened immune system, and cause disease, when they ordinarily would cause mild illness or no disease in an immunocompetent host. Risk factors for opportunistic infections include malnutrition, older age, congenital immunodeficiency, HIV infection, chronic diseases, and use of corticosteroids, immunomodulators, and anti-tumor necrosis factor alpha therapy. Apart from immunosuppressive medications and older age, there is only indirect evidence for above risk factors contributing directly to opportunistic infection risk in patients with IBD. Opportunistic infections in patients with IBD include viral infections (herpes viruses, human papillomavirus, influenza virus, and JC virus), bacterial infections (tuberculosis, nocardiosis, Clostridium difficile infection, pneumococcal infection, legionellosis, and listeriosis), fungal infections (histoplasmosis, cryptococcosis, Pneumocystis jirovecii infection, aspergillosis, and candidiasis), and parasite infections (Strongyloides stercoralis). Although these infections lead to high morbidity and mortality, only a minority of patients with IBD develop opportunistic infections. Currently, we lack a test to accurately predict patients at risk of opportunistic infection, and future research needs to focus on biomarkers or predictive models for risk stratification. Until such a test is developed, we need to screen, prevent, diagnose, and treat opportunistic infections in all patients with IBD in a timely manner.

EBV-induced post transplant lymphoproliferative disorders: a persisting challenge in allogeneic hematopoetic SCT

EBV-induced post transplantation lymphoproliferative disorder (EBV-PTLD) is a life-threatening complication after allogeneic hematopoietic cell transplantation. Profound T-cell depletion of the allograft represents a major risk factor for EBV-PTLD. With regard to the increasing use of alternative stem cell sources such as cord blood or purified haploidentical stem cell grafts both associated with impaired immune reconstitution, the frequent occurrence of EBV-PTLD demands particular vigilance on laboratory changes and early symptoms. Here we have summarized today's knowledge about EBV-PTLD in a comprehensive review explaining the underlying mechanisms of EBV-based transformation, EBV-PTLD development, clinical presentation, incidence, diagnosis, screening, therapy and prognosis. In this context, we emphasize on the necessity of regularly applied screening tools and pre-emptive treatment strategies including anti-CD20 Abs particularly in high-risk patients to avoid disease progression to malignant lymphoma. Although EBV-PTLD has always been associated with a high mortality rate, novel immunotherapeutic approaches such as the transfer of EBV-specific T cells nowadays offer improved chances of disease control even at late stages.

Epstein-Barr virus reactivation in allogeneic stem cell transplantation is highly related to cytomegalovirus reactivation

Monitoring of Epstein-Barr virus (EBV) load and pre-emptive rituximab is an appropriate approach to prevent post-transplant lymphoproliferative disease (PTLD) occurring after hematopoietic stem cell transplantation (HSCT). This pre-emptive approach, based on EBV-DNA monitoring through a quantitative polymerase chain reaction, was applied to 101 consecutive patients who underwent allo HSCT at our Institute (median age 50). A single infusion of rituximab was administered to 11 of 16 patients who were at high risk for progression to PTLD, defined as a DNA value >10 000 copies/mL. All patients cleared EBV DNAemia, without any recurrences. Main factors significantly associated with high risk for PTLD were as follows: (i) unrelated vs. sibling (26% vs. 7%; p = 0.011); (ii) T-cell depletion (29% vs. 6%; p = 0.001); (iii) graft versus host disease (GVHD; 30% vs. 7%; p = 0.002); and (iv) cytomegalovirus (CMV) reactivation (29% vs. 4%; p = 0.001). Multivariate analysis showed that CMV reactivation was the only independent variable associated with EBV reactivation. We conclude that: (i) a single infusion of rituximab is able to prevent the risk of progression into EBV-related PTLD; and (ii) CMV reactivation is strongly associated with EBV reactivation; therefore, an intensive EBV monitoring strategy could be advisable only in case of CMV reactivation.

Reduced PTLD-related mortality in patients experiencing EBV infection following allo-SCT after the introduction of a protocol incorporating pre-emptive rituximab

The mortality associated with post-transplant lymphoproliferative disorder (PTLD) induced by EBV infection can be reduced by monitoring EBV by polymerase-chain-reaction and rituximab given pre-emptively. We performed a retrospective analysis of the risk factors for the occurrence of EBV infection/disease and EBV-related mortality among 273 consecutive recipients of a T-cell-depleted allo-SCT during two periods: (a) before the implementation of a comprehensive protocol (2006-2008) and (b) afterwards (2009-2011). EBV infection was detected in 61 (22%) cases, and 28 cases were considered to have had EBV disease. Treatment with antithymocyte globulin was the most important risk factor (odds ratio (OR) 2.4; 95% confidence interval (CI) 1.3-4.2, P=0.001). After implementation of the protocol, in patients experiencing EBV infection, pre-emptive therapy was started more often and sooner (median 3 vs 6 days, P=0.002). Moreover, there were fewer cases of monomorphic PTLD (4/33 (12%) vs 11/28 (39%), P=0.01), and the EBV-related mortality was lower for patients experiencing EBV infection (2/33 (6%) vs 8/28 (29%), OR 0.2; 95% CI 0.05-0.9, P=0.03). The EBV protocol proved feasible and resulted in faster initiation of pre-emptive therapy, the diagnosis in an earlier stage of EBV disease, and decreased EBV-related mortality.

Prognostic factors and outcome of Epstein-Barr virus DNAemia in high-risk recipients of allogeneic stem cell transplantation treated with preemptive rituximab

AIMS AND METHODS

This study assessed incidence, predictive factors, and outcome of Epstein-Barr virus (EBV) DNAemia in 100 recipients of allogeneic hematopoietic stem cell transplant. A total of 68 patients received anti-thymocyte globulin before unrelated grafts.

RESULTS

Cumulative incidence of high-load EBV DNAemia defined by levels >10,000 copies/mL was 14% at 12 months. In multivariate analysis, a CD4+ T-lymphocyte count >50 μL at day +30 was the only factor significantly associated with a reduced risk of high-load EBV DNAemia. Thirteen of 16 patients with high viral loads were preemptively treated with rituximab and achieved EBV DNA negativity. Three patients had already developed post-transplant lymphoproliferative disorder (PTLD) at the time of detection of high EBV DNA loads, and they obtained complete response after rituximab infusions and chemotherapy. Patients with high EBV DNA load had a significantly higher transplant-related mortality (TRM) compared with patients with negative or low viral load (54% vs. 16%, P = 0.009) and a trend to lower overall survival (55% vs. 29%, P = 0.060).

CONCLUSION

We conclude that CD4+ cell count at day +30 is a predictive factor for EBV DNAemia and may help identify patients requiring closer monitoring. Although only 3% of patients progressed to PTLD and were all successfully managed, EBV reactivation was associated with higher TRM, mainly because of infections.

Case 2-2012: a 57-year-old woman with post-transplant lymphoproliferative disorder after allogeneic stem cell transplantation for primary myelofibrosis

Article without abstract

Epstein-Barr virus: general factors, virus-related diseases and measurement of viral load after transplant

The Epstein-Barr virus is responsible for infectious mononucleosis syndrome and is also closely associated to several types of cancer. The main complication involving Epstein-Barr virus infection, both in recipients of hematopoietic stem cells and solid organs, is post-transplant lymphoproliferative disease. The importance of this disease has increased interest in the development of laboratory tools to improve post-transplant monitoring and to detect the disease before clinical evolution. Viral load analysis for Epstein-Barr virus through real-time polymerase chain reaction is, at present, the best tool to measure viral load. However, there is not a consensus on which sample type is the best for the test and what is its predictive value for therapeutic interventions.

Molecular diagnosis and management of viral infections in hematopoietic stem cell transplant recipients

Viral infections after allogeneic hematopoietic stem cell transplantation (HSCT) are important complications associated with high morbidity and mortality. In this setting, reactivations of persisting latent viral pathogens from donor and/or recipient cells play a central role whereas the sterile environment of transplant units renders new infections less likely. The viruses currently regarded as most relevant in the HSCT setting include particularly the herpes virus family--specifically cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpesvirus 6 (HHV-6)--as well as human adenoviruses (AdVs) and the polyoma virus BK (BKV). Timely detection and monitoring of virus copy numbers are prerequisites for successful preemptive treatment approaches. Pre- and post-transplant surveillance by sensitive and quantitative molecular methods has therefore become an essential part of the diagnostic routine. In this review, we discuss diagnostic aspects and the clinical management of the most important viral infections in HSCT recipients, with a focus on pediatric patients.

Quantitative Epstein-Barr virus shedding and its correlation with the risk of post-transplant lymphoproliferative disorder

We postulated that quantitative monitoring of Epstein-Barr virus (EBV) shedding after transplantation could distinguish EBV-associated illnesses and predict clinical outcome. EBV DNA was measured in solid organ (SOT) and hematopoietic cell transplants (HCT) using our own real-time TaqMan EBV PCR. The proportion of patients who had EBV DNAemia post-transplant was significantly lower in HCT vs. SOT (p < 0.001). Over a 7.5-yr period, post-transplant lymphoproliferative disorder (PTLD) occurred in 66 (5.8%) of 1131 patients who met adequate monitoring criteria. SOT recipients developed PTLD significantly later than HCT recipients (median, 2.8 yr vs. 121 d; p < 0.001). PTLD was documented in 53 (14%) of 376 patients who had EBV in ≥1 whole blood sample vs. 13 (2%) of 755 patients who had at least three EBV-negative blood samples and were never positive. PTLD risk in viremic patients increased with the peak quantity of EBV DNAemia (p < 0.001). PTLD occurred in 37/333 (11%) of patients with peak blood levels 10(3) -10(5) copies/mL vs. 16/43 (37%) of patients with levels >10(5) (p < 0.001). EBV PCR was predictive in 29 (78%) of 37 patients tested within three wk prior to tissue diagnosis of PTLD, and thus, we conclude that EBV PCR with careful attention paid to changes in EBV DNAemia could lead to earlier diagnosis and treatment of PTLD.

Infections in Leukemia and Hematopoietic Stem Cell Transplantation

Infections are one of the most common complications in patients diagnosed with leukemia and serve as a major obstacle to treatment. Through the early 1970s, infections were the most common cause of death in patients diagnosed with acute leukemia, but improvement in treatment and supportive care over the past few decades, coupled with expanded prophylaxis and prevention regimens, have led to reduction in both the frequency and severity of infections. Regardless, due in part to an aging cancer population and the diversity of cancer treatments and procedures, infectious diseases remain a major cause of morbidity and mortality in patients with leukemia.

Graft-vs-Host Disease following Allogeneic Hematopoietic Cell Transplantation

Background

Allogeneic hematopoietic cell transplantation (HCT) is a potentially curative therapy with proven efficacy in the management of hematologic malignancies. However, it is complicated by the syndromes of acute and chronic graft-vs-host disease (GVHD).

Methods

A narrative review is provided to summarize major biologic insights into the pathogenesis of these immune-mediated disorders, as well as advances in diagnosis, classification, prevention, management, and allied supportive care with the aim of providing essential understanding for clinicians with or without subspecialty experience in the field of blood and marrow transplantation.

Results

Major scientific advances have contributed to enhanced understanding of the pathogenesis of these disorders, and clinical investigation has provided more effective preventive and therapeutic strategies for GVHD. However, since acute GVHD and chronic GVHD remain leading sources of transplantation-related morbidity and mortality, ongoing investigation is needed to develop new approaches to addressing these syndromes.

Conclusions

The major challenge for future investigation will be to capitalize on biologic insights in order to develop novel strategies for the prevention and therapy of acute and chronic GVHD that will address the current shortcomings in existing therapeutic approaches.

Immunoselection and clinical use of T regulatory cells in HLA-haploidentical stem cell transplantation

INTRODUCTION

Haploidentical transplantation, with extensive T cell depletion to prevent GvHD, is associated with a high incidence of infection-related deaths. The key challenge is to improve immune recovery with allogeneic donor T cells without triggering GvHD. As T regulatory cells (Tregs) controlled GvHD in pre-clinical studies, the present study evaluated the impact of an infusion of donor CD4/CD25 + Tregs, followed by an inoculum of donor mature T cells (Tcons) and positively immunoselected CD34 + cells in the setting of haploidentical stem cell transplantation.

PATIENTS AND METHODS

Twenty-eight patients were enrolled in this study (22 AML; 5 ALL; 1 NHL). All received immunoselected Tregs (CliniMACS, Miltenyi Biotec) followed by positively immunoselected CD34 + cells together with Tcons 4 days later. No GvHD prophylaxis was administered.

RESULTS

26/28 patients engrafted. No acute GvHD developed in 24/26 patients; 2 developed ≥ grade II acute GvHD. No patient has developed chronic GvHD. CD4 and CD8 counts rapidly increased after transplant. Episodes of CMV reactivation were significantly fewer than in controls.

CONCLUSIONS

In the setting of haploidentical transplantation infusion of Tregs makes administration of a high dose of T cells feasible. This strategy provides a long-term protection from GvHD and robust immune reconstitution.

Secondary cancers following allogeneic haematopoietic cell transplantation in adults

Secondary cancers that arise in allogeneic haematopoietic-cell transplant recipients, possibly as a result of treatment exposures, are a relatively rare complication of transplantation. However, they can be associated with significant morbidity and mortality. Secondary cancers include post-transplant lymphoproliferative disorders, new solid cancers and donor-derived haematological malignancies. This review describes the epidemiology, risk factors and screening recommendations for secondary cancers among adult allogeneic haematopoietic-cell transplant recipients. Constructing a patient-specific risk profile based on known exposures and risk-factors is the key to developing appropriate screening and preventative strategies for secondary cancers after allogeneic transplantation.

Herpes viruses in transplant recipients: HSV, VZV, human herpes viruses, and EBV

The herpes viruses are responsible for a wide range of diseases in patients following transplant, resulting from direct viral effects and indirect effects, including tumor promotion. Effective treatments and prophylaxis exist for the neurotropic herpes viruses HSV-1, HSV-2, varicella zoster virus, and possibly HHV-6. Antivirals seem to be less effective at prevention of the tumor-promoting effects of Epstein-Barr virus and HHV-8. Reduction in immunosuppression is the cornerstone to treatment of many diseases associated with herpes virus infections.

ATG prevents severe acute graft-versus-host disease in mismatched unrelated donor hematopoietic cell transplantation

Severe acute graft-versus-host disease (aGVHD) remains a major source of morbidity and mortality following mismatched unrelated donor hematopoietic cell transplantation (HCT). Through a retrospective analysis, we investigated the efficacy of GVHD prophylaxis with rabbit anti-thymocyte globulin (ATG) 7.5 mg/kg (1 mg/kg given on day -3, then 3.25 mg/kg/day on days -2 and -1 before stem cell infusion) followed by standard tacrolimus plus methotrexate in a consecutive series of 45 HLA partially matched unrelated donor HCT recipients. The cumulative incidence of grade III-IV aGVHD was 11% by 100 days (95% confidence interval [CI] 5%-25%). Moderate to severe chronic GVHD (per NIH consensus criteria) was 19% (95% CI 10%-36%) at 1 year, and 28% (95% CI 16%-48%) at 2 years. With a median follow-up time for surviving patients of 12 months (range: 5-39 months), overall survival was 55% (95% CI 39%-71%) at 1 year, and 45% (95% CI 27%-63%) at 2 years. Nonrelapse mortality was 11% (95% CI 5%-25%) by 100 days post-HCT, 26% (95% CI 16%-44%) by 1 year, and 30% (95% CI 18%-50%) by 2 years. The cumulative incidence of primary disease relapse was 23% (95% CI 13%-41%) at 1 year, and 33% (95% CI 20%-56%) by 2 years after HCT. Cytomegalovirus (CMV) infection or reactivation varied according to recipient and donor CMV serostatus. Epstein-Barr Virus (EBV) reactivation occurred in 54% (95% CI 40%-71%) of patients. Preemptive rituximab therapy was administered for EBV reactivation, however, posttransplant lymphoproliferative disorder was diagnosed in 5 (11%) cases, and was fatal in 1. A regimen of ATG 7.5 mg/kg total ending on day -1 effectively decreased the occurrence of grade III-IV aGVHD and severe chronic GVHD.

Epstein-Barr virus replication linked to B cell proliferation in inflamed areas of colonic mucosa of patients with inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the gastrointestinal tract. Epstein-Barr virus (EBV) infection is associated with increased disease severity in therapeutically immunosuppressed IBD patients. The role of EBV infection in patients with IBD who are unresponsive to medical therapy is unclear. Anti-viral strategies may be a viable treatment option if severity of EBV infection, reflected in peripheral blood, contributes to IBD progression.

OBJECTIVES

We investigated the role of EBV in IBD patients unresponsive to medical therapy by examining EBV reactivation and B-cell proliferation in colonic mucosa.

STUDY DESIGN

EBV DNA copy numbers were measured by real-time PCR in peripheral blood mononuclear cells (PBMC) of 84 patients with IBD and 115 non-IBD controls in a retrospective cross-sectional study. EBV-infected cells in colonic mucosa were identified by immunohistochemistry.

RESULTS

EBV load in PBMC was higher in patients with IBD than in non-IBD controls, especially in patients not responding to medication. Inflamed colonic mucosa of these patients had high levels of expression of lytic and latent EBV genes that localized to proliferating B-lymphocytes, which was not seen in patients responding to therapy.

CONCLUSIONS

EBV replication was associated with severe IBD and mucosal inflammation. Increased proliferation and EBV infection of B-lymphocytes in inflamed colonic mucosa highlight the potential role of EBV in mucosal inflammation. The immunomodulatory effects of EBV could delay the resolution of the IBD associated inflammation, thus contributing to disease progression. These results indicate that anti-viral therapeutic strategies for the resolution of IBD may be useful.

Circulating cell-free and Epstein-Barr virus DNA in pediatric B-non-Hodgkin lymphomas

Tumor-derived DNA is elevated in the plasma of patients with cancer. The analysis of circulating DNA may be useful for diagnosis, prognosis evaluation, and early detection of disease recurrence. In order to investigate cf-DNA as a marker during treatment, we serially quantified total cell-free (cf) and EBV plasma DNA in 30 cases of pediatric B-non-Hodgkin lymphoma by real-time PCR. The cf-DNA levels were significantly increased in patient samples at diagnosis as compared with the healthy controls (p < 0.001). At the end of treatment, a significant decrease in plasma DNA concentration was observed as compared with values observed at diagnosis (median: 94.0 copies/mL, p = 0.001). EBV was detected by ISH in 7/30 patients. Plasma EBV DNA levels were obtained from seven EBV-positive patients (median: 1278 copies/mL), while EBV DNA was not detected in 23 EBV-negative patients and 10 healthy controls. The association between the two methods of detection was statistically significant, with 100% correlation (Kappa coefficient, p = 1). In addition, the decrease of EBV viral load was associated with therapy response. Quantification of plasma EBV DNA may become a valuable source for disease detection of pediatric EBV-associated lymphomas and for monitoring treatment response.

Successful treatment of EBV-associated posttransplantation lymphoma after cord blood transplantation using third-party EBV-specific cytotoxic T lymphocytes

Cellular therapy of Epstein-Barr virus (EBV)(+) posttransplantation lymphoproliferative diseases (PTLD) in cord blood transplant (CBT) recipients is limited by lack of donor access and the donor's naive neonatal immune system. We therefore used partially human leukocyte antigen-matched third-party in vitro expanded EBV-specific cytotoxic T lymphocytes (CTLs) to treat 2 CBT recipients with life-threatening, donor-derived monoclonal EBV(+) diffuse large B-cell lymphomas with extranodal involvement developing in the context of graft-versus-host disease. Both patients had failed immunosuppression taper and Rituximab. After 5 and 9 infusions of 10(6) EBV-CTL/kg, respectively, each patient achieved a sustained complete remission without toxicity or graft-versus-host disease. Each is alive without recurrence at 20 and 15 months, respectively, post-EBV-PTLD diagnosis. This approach demonstrates the efficacy of using "off-the-shelf," virus-specific third-party CTLs restricted by human leukocyte antigens expressed by the tumor to treat otherwise lethal EBV-PTLD. Such therapy may also be applicable to the treatment of other infections and residual or recurrent malignancy after CBT.

Immunotherapeutic options for Epstein-Barr virus-associated lymphoproliferative disease following transplantation

Epstein-Barr virus-associated lymphoproliferative diseases (EBV-LPD) after hematopoietic stem cell transplantation or solid-organ transplantation remain a serious and potentially life-threatening complication. In the last decade, outcomes for EBV-LPD have significantly improved. Key to this success was the development of early detection methods, such as serial measurements of EBV-DNA load in the peripheral blood of transplant recipients. Immunotherapeutic interventions for EBV-LPD include reduction of immunosuppression, CD20 monoclonal antibodies (rituximab) as monotherapy or in conjunction with chemotherapy, and adoptive immunotherapy with EBV-specific T cells. Pre-emptive immunotherapeutic interventions can prevent the development of EBV-LPD. As monotherapy, immunotherapy is effective in inducing remissions of EBV-LPD with low-risk features. For high-risk disease, combining immunotherapy with conventional therapies has led to superior outcomes. Current challenges consist of risk stratifying patients so that patients receive the most efficacious therapy without suffering from unwanted side effects.

Epstein-Barr virus-related lymphoproliferative disorder induced by equine anti-thymocyte globulin therapy

Post-transplant lymphoproliferative disorder (PTLD) is generally caused by an uncontrolled B-cell proliferation induced by Epstein-Barr virus (EBV) in the setting of impaired EBV-specific T-cell immunity. PTLD has been described in allogeneic hematopoietic stem cell transplant (HSCT) and rarely in autologous HSCT. Anti-thymocyte globulin (ATG) is being increasingly utilized for acute rejection in organ transplantation, severe autoimmune diseases and aplastic anemia. Mainly, the use of rabbit ATG has been associated with PTLD, which is considered to be more immunosuppressive than equine ATG. The sole administration of equine ATG has rarely been associated with PTLD. Due to the increased use of these potent and novel immunosuppressive agents, it is paramount to be aware of these complications. We present a 55-year-old man with an autologous HSCT who presented with an unusual case of monoclonal plasmacytic PTLD. His lymphoproliferative disorder occurred 3 years after his HSCT and 1 month after the use of equine ATG administered for severe aplastic anemia. We review current concepts of EBV-PTLD, including risk factors, the potential for preemptive therapy and various management strategies.

The role of rituximab in autologous and allogeneic hematopoietic stem cell transplantation for non-Hodgkin's lymphoma

The addition of rituximab to chemotherapy has substantially changed the treatment strategies for patients with B-cell lymphomas. Rituximab, combined with standard chemotherapy regimens, shows consistently improved results compared with chemotherapy alone and has been extensively employed in both newly diagnosed and relapsed patients with B-cell lymphoma. Because of its low toxicity profile and its potent antilymphoma activity mediated through direct apoptotic and indirect effector mechanisms, rituximab also has been actively incorporated into stem cell transplantation (SCT) protocols to attain a state of minimal disease, provide a safe and effective method for in vivo purging prior to autologous SCT, and promote graft-versus-lymphoma effects in allogeneic SCT. This review compiles the still immature but rapidly growing data on this combined modality.