Response to Rituximab Induction Is a Predictive Marker in B-Cell Post-Transplant Lymphoproliferative Disorder and Allows Successful Stratification Into Rituximab or R-CHOP Consolidation in an International, Prospective, Multicenter Phase II Trial

Post Transplant Lymphoproliferative Disorder risk factors in children: Analysis of a 23-year single-institutional experience

INTRODUCTION

PTLD is the most frequent malignancy following SOT in children and the second most common SOT complication in adults. However, factors determining outcomes in children are poorly understood due to its relative rarity.

METHODS

This study was performed at the University of Florida. Univariate and multivariate analyses were used to identify prognostic factors in pediatric patients diagnosed with PTLD.

RESULTS

We reviewed records of 54 pediatric (younger than 18 years old at diagnosis) patients diagnosed with PTLD from 1994 to 2017. The median follow-up was 28.8 months. The estimated 5-year survival rate was 87.6% (95% CI 74.3-94.2%). Univariate analysis showed that organ transplanted (specifically heart transplant), poor response to initial treatment, allograft rejection, and low Karnofsky score were statistically significant for negative prognostic factors in determining survival. Multivariate analysis determined progression in response to initial treatment and presence of allograft rejection as statistically significant prognostic factors affecting overall survival. We found no statistically significant impact of EBV serological status on PTLD prognosis.

CONCLUSIONS

Disease progression and allograft rejection were strong negative prognostic indicators in our study cohort. Close attention to graft status and development of therapies that protect the graft from rejection while bolstering anti-EBV immunity will be essential to further improving PTLD outcomes in children.

Roles of F-18-Fluoro-2-Deoxy-Glucose PET/Computed Tomography Scans in the Management of Post-Transplant Lymphoproliferative Disease in Pediatric Patient

Post-transplant lymphoproliferative disease is a well-known complication in transplant recipients. Evaluating the extent and stage of disease is important for management and follow-up. As a combination of anatomic and functional imaging, PET/CT is a sensitive and specific tool to stage and detect occult disease compared with conventional imaging. PET/CT also has a role in monitoring treatment response. Although PET/CT has been shown to be potentially useful in adults, evidence in children is insufficient. This review provides an overview of the use of PET/CT in post-transplant lymphoproliferative disease, especially in pediatric patients.

The FcγRIIIA-158 VV genotype increased the risk of post-transplant lymphoproliferative disorder in T-cell-depleted kidney transplant recipients - a retrospective study

Post-transplantation lymphoproliferative disorder (PTLD) is a severe complication in organ transplant recipients. The use of T lymphocyte-depleting antibodies (TLDAb), especially rabbit TLDAb, contributes to PTLD, and the V158F polymorphism of Fc gamma receptor IIIA (FcγRIIIA) also named CD16A could affect the concentration-effect relationship of TLDAb. We therefore investigated the association of this polymorphism with PTLD in kidney transplant recipients. We characterized the V158F polymorphism in two case-control cohorts (discovery, n = 196; validation, n = 222). Then, we evaluated the binding of rabbit IgG to human FcγRIIIA-158V and FcγRIIIA-158F. The V158F polymorphism was not linked to PTLD in the overall cohorts, but risk of PTLD was increased in VV homozygous recipients receiving TLDAb compared with F carriers in both cohorts, especially in recipients receiving TLDAb without muromonab (discovery: HR = 2.22 [1.03-4.76], P = 0.043, validation: HR = 1.75 [1.01-3.13], P = 0.049). In vitro, we found that the binding of rabbit IgG to human NK-cell FcγRIIIA was increased when cells expressed the 158-V versus the 158-F allotype. While the 158-V allotype of human FcγRIIIA binds rabbit immunoglobulin-G with higher affinity, the risk of PTLD was increased in homozygous VV kidney transplant recipients receiving polyclonal TLDAb.

Long-term follow-up of a prospective phase 2 clinical trial of extended treatment with rituximab in patients with B cell post-transplant lymphoproliferative disease and validation in real world patients

The purpose of this report is to provide long-term follow-up of 38 patients diagnosed of post-transplant lymphoproliferative disease (PTLD) included in a phase 2 clinical trial of first line therapy with rituximab and to evaluate the same therapy in a real world cohort of 21 consecutive patients treated once the trial was closed. Eligible patients were ≥ 18 years of age with a biopsy-proven CD20 positive B cell PTLD and treatment naive except for reduction of immunosuppression. Treatment consisted in four weekly infusions of rituximab at the standard dose of 375 mg/m². Patients in complete remission (CR) were followed without further treatment, and those in partial remission (PR) were treated with another four cycles of weekly rituximab. Median follow-up in the clinical trial was 13.0 years. Disease-specific survival (DSS) at 10 years was 64.7% [95% confidence interval (CI) 48.2-81.2%]. For those patients who achieved CR (61%), DSS at 5 and 10 years was 94.4% (95% CI 83.8-100%) and 88.1% (95% CI 72.6-100%), respectively, and only 1 patient progressed beyond 5 years. The median follow-up of the real world patients was 6.5 years. DSS at 5 years was 75.2% (95% CI 56.4-94.0%). DSS at 5 years of patients who achieved CR (38%) was 87.5% (95% CI 64.6-100%). In conclusion, PTLD patients in CR after rituximab have an excellent long-term outcome. These results not only apply in the clinical trial setting but are also reproducible in the real world. However, those patients who do not respond represent an unmet clinical need and should be included in prospective clinical trials.

Prevention and therapy of viral infections in patients with solid organ transplantation

Solid organ transplantation (SOT) is the best treatment option for end-stage organ disease. The number of SOT procedures has been steadily increasing worldwide during the past decades. This trend has been accompanied by the continuous incorporation of new antimicrobial drugs and by the refinement of strategies aimed at minimizing the risk of opportunistic infection. Nonetheless, viral infections, which can occur at any stage of the post-transplant period, remain a clinical challenge that negatively impacts both patient and graft outcomes. This review offers an overview of the most relevant viral infections in the SOT population, with a focus on herpesviruses (cytomegalovirus, Epstein-Barr virus, varicella-zoster virus, and herpes simplex virus 1 and 2) and polyomaviruses (human BK polyomavirus). In addition, the currently recommended prophylactic and treatment approaches are summarized, as well as the new antiviral agents in different phases of clinical development.

Post-transplantation lymphoproliferative disorders: Current concepts and future therapeutic approaches

Transplant recipients are vulnerable to a higher risk of malignancy after solid organ transplantation and allogeneic hematopoietic stem-cell transplant. Post-transplant lymphoproliferative disorders (PTLD) include a wide spectrum of diseases ranging from benign proliferation of lymphoid tissues to frank malignancy with aggressive behavior. Two main risk factors of PTLD are: Firstly, the cumulative immunosuppressive burden, and secondly, the oncogenic impact of the Epstein-Barr virus. The latter is a key pathognomonic driver of PTLD evolution. Over the last two decades, a considerable progress has been made in diagnosis and therapy of PTLD. The treatment of PTLD includes reduction of immunosuppression, rituximab therapy, either isolated or in combination with other chemotherapeutic agents, adoptive therapy, surgical intervention, antiviral therapy and radiotherapy. In this review we shall discuss the prevalence, clinical clues, prophylactic measures as well as the current and future therapeutic strategies of this devastating disorder.

Isolated peritoneal lymphomatosis defined as post-transplant lymphoproliferative disorder after a liver transplant: A case report

BACKGROUND

Post-transplant lymphoproliferative disorder (PTLD) is a fatal complication of solid organ transplantation or allogenic hematopoietic stem cell transplantation that is associated with immunosuppressive therapy. Potential manifestations are diverse, ranging from reactive lymphoid hyperplasia to high-grade lymphoma. PTLD is usually of B-cell origin and associated with Epstein-Barr virus (EBV) infection. Herein, we describe a case of PTLD involving the peritoneal omentum. There has been only case of PTLD as a diffuse large B-cell lymphoma (DLBCL) in the peritoneum.

CASE SUMMARY

The patient was a 62-year-old man who had been receiving immunosuppressive therapy with tacrolimus since undergoing a liver transplant 15 years prior. He reported that he had experienced abdominal discomfort and anorexia 1 month prior to the current admission. Abdominal pelvic computed tomography (CT) revealed peritoneal and omental mass-like lesions without bowel obstruction. Ultrasonography-guided biopsy was performed, and he was histologically diagnosed with EBV-negative DLBCL. Positron emission tomography (PET)-CT depicted peritoneum and omentum involvement only, without any lymphadenopathy or organ masses, including in the gastrointestinal tract. Six cycles of chemotherapy with a “R-CHOP“ regimen (rituximab-cyclophosphamide, doxorubicin, vincristine, prednisolone) were administered, and PET-CT performed thereafter indicated complete remission.

CONCLUSION

This is the first report of isolated peritoneal lymphomatosis defined as PTLD in a liver transplant recipient.

Iatrogenic immunodeficiency-associated lymphoproliferative disorder in a child with B-cell acute lymphoblastic leukemia

Iatrogenic immunodeficiency-associated lymphoproliferative disorders (LPDs) are a group of lymphoid proliferations or lymphomas that are well known to be associated with an immunosuppressed state. These disorders most commonly occur following hematopoietic or solid organ transplantation (called post-transplant lymphoproliferative disorders or PTLD), but cases have also been described during the treatment of autoimmune and rheumatologic disorders by immunosuppressive and immunomodulatory medications. These disorders are strongly associated with infection by the Epstein-Barr virus (EBV) as a result of impaired immune function in the immunosuppressed state. While this phenomenon has been well documented in autoimmune conditions, cases affecting pediatric patients while on anti-leukemia chemotherapy are lacking. In this report, we describe a case of a pediatric immunosuppressed patient with recurrent sinusitis found to have a nasopharyngeal mass consistent with EBV-positive B-cell lymphoproliferative disorder resembling a polymorphic PTLD during the maintenance phase of B-cell Acute Lymphoblastic Leukemia (ALL) therapy. The patient was successfully treated with rituximab without any cytotoxic chemotherapy, highlighting the importance of recognizing this clinical entity in non-transplant patients with hematologic malignancies.

Post-transplant lymphoproliferative disorders, Epstein-Barr virus infection, and disease in solid organ transplantation: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

PTLD with the response-dependent sequential use of RIS, rituximab, and cytotoxic chemotherapy is recommended. Evidence gaps requiring future research and alternate treatment strategies including immunotherapy are highlighted.

Role of interim and end of treatment positron emission tomography for response assessment and prediction of relapse in posttransplant lymphoproliferative disorder

Background: Fluorine-18-fluorodeoxyglucose positron emission tomography (PET) has an established and central role in diagnosis, staging and response evaluation of lymphoproliferative diseases. It has shown a high sensitivity and specificity at diagnosis in posttransplant lymphoproliferative disorders (PTLDs). However, little is known about the performance of interim and end of treatment (EOT) PET in PTLD patients with regards to response assessment, relapse prediction and outcome. Methods: We performed a single-center retrospective study in which we analyzed consecutive patients diagnosed with CD20-positive PTLD after solid organ transplantation between 2008 and 2017, who all received risk-stratified sequential treatment according to the PTLD-1 phase II trial. Interim and EOT PET studies were scored according to the Deauville criteria. Results: Forty-one patients were included with median follow-up of 41.5 months (range 1-108). Positive and negative predictive values for disease recurrence were 13% and 85% for interim and 33% and 87% for EOT PET, respectively. There was no significant difference in overall survival, progression-free survival nor time to progression between negative versus positive patients on interim and EOT scans. Conclusions: Negative interim and/or negative end of treatment PET identify PTLD patients with low risk of disease recurrence.

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.

Immunosuppression Is Associated With Clinical Features and Relapse Risk of B Cell Posttransplant Lymphoproliferative Disorder: A Retrospective Analysis Based on the Prospective, International, Multicenter PTLD-1 Trials

BACKGROUND

Current guideline recommendations for immunosuppression reduction after diagnosis of posttransplant lymphoproliferative disorder (PTLD) include stopping antimetabolites, reducing calcineurin inhibitors, and maintaining corticosteroids. However, the effect of immunosuppression on PTLD relapse risk after up-to-date therapy is unclear.

METHODS

This is a retrospective analysis of immunosuppression, patient baseline characteristics, and relapse risk measured as landmark time to progression (TTP) starting 1 year after start of therapy in 159 patients with B cell PTLD after solid organ transplantation treated in the prospective, international, multicenter PTLD-1 trials with either sequential treatment (rituximab followed by cyclophosphamide (CHOP-21 chemotherapy) 750 mg/m intravenously [IV] day (d) 1, doxorubicin 50 mg/m IV d1, vincristine 1.4 mg/m (maximum, 2 mg) IV d1, and prednisone 50 mg/m PO d1-5, every 21 days) or risk-stratified sequential treatment (rituximab followed by rituximab or rituximab (R-CHOP-21 immunochemotherapy) 375 mg/m IV day (d) 1, cyclophosphamide 750 mg/m IV d1, doxorubicin 50 mg/m IV d1, vincristine 1.4 mg/m (max. 2 mg) IV d1, and prednisone 50 mg/m PO d1-5, every 21 days).

RESULTS

Patient baseline characteristics at diagnosis of PTLD differed significantly depending on immunosuppression before diagnosis. Compared with immunosuppression before diagnosis, significantly fewer patients received an antimetabolite or a calcineurin inhibitor (CNI) after diagnosis of PTLD. Relapse risk measured as landmark TTP was significantly higher for patients on corticosteroids compared to all others (P = 0.010) as well as for patients on ciclosporin compared with those on tacrolimus (P = 0.002), but similar for those on antimetabolites compared with all others (P = 0.912). In a Cox regression analysis of landmark TTP, corticosteroid-containing immunosuppression after diagnosis of PTLD (P = 0.002; hazard ratio, 11.195) and age (P = 0.001; hazard ratio, 1.076/year) were identified as independent, significant risk factors for PTLD relapse.

CONCLUSIONS

In the prospective PTLD-1 trials, corticosteroid use after diagnosis of PTLD is associated with an increased risk of relapse, whereas the use of antimetabolites is not. These findings require prospective validation.

Outcome of Rituximab-Based Treatment for Post-Transplant Lymphoproliferative Disorder After Allogeneic Hematopoietic Stem Cell Transplantation: A Single-Center Experience

Background

Post-transplant lymphoproliferative disorder (PTLD) is a rare complication following solid organ transplantation and allogeneic hematopoietic stem cell transplantation (Allo-HSCT), which gives rise to high mortality rates.

Material/Methods

This was a single-center retrospective analysis based on 27 patients who were diagnosed with PTLD following Allo-HSCT between January 1, 2007 and June 2018 at the Chinese PLA General Hospital. The purpose of this analysis was to investigate responses and prognostic factors of rituximab-based treatment.

Results

Twenty-seven patients were treated with rituximab. Among them, 20 of 27 patients (74.07%) had a complete response, 2 of 27 patients (7.41%) had a partial response, 5 of 27 patients (18.52%) had no response, and 22 of 27 patients (81.48%) cleared Epstein-Barr virus (EBV) copies. There were no obvious side effects. The 1-year overall survival (OS) estimate was 46.8% (95% CI, 23.1–65.5%). Univariate analysis revealed that lower OS was correlated with Eastern Cooperative Oncology Group (ECOG) score standard (3–4), Epstein-Barr virus (EBV) viral load (≥10⁶ copies/mL), bacteria or fungal infection, and EBV reactivation were positive after treatment with 1 or 2 doses of rituximab (P<0.05). Multivariate analysis showed that each of the following were independently associated with lower OS (P<0.05): female, ECOG score standard (3–4), and EBV reactivation were positive after treatment with 1 or 2 doses of rituximab.

Conclusions

Our results demonstrated that rituximab-based treatment was a safe and effective strategy for patients who were diagnosed with PTLD following Allo-HSCT. The identified prognostic factors may help to detect which PTLD patients are at a higher risk of mortality.

Epstein Barr Virus Associated B-Cell Lymphomas and Iatrogenic Lymphoproliferative Disorders

Epstein-Barr virus (EBV) is a ubiquitous herpesvirus, affecting up to 90% of the population. EBV was first identified as an oncogenic virus in a Burkitt lymphoma cell line, though subsequently has been found to drive a variety of malignancies, including diffuse large B-cell lymphoma (DLBCL) and other lymphoma subtypes. EBV has a tropism for B-lymphocytes and has the unique ability to exist in a latent state, evading the host immune response. In cases of impaired cell mediated immunity, as in patients with advanced age or iatrogenic immune suppression, the virus is able to proliferate in an unregulated fashion, expressing viral antigens that predispose to transformation. EBV-positive DLBCL not otherwise specified, which has been included as a revised provisional entity in the 2016 WHO classification of lymphoid malignancies, is thought to commonly occur in older patients with immunosenescence. Similarly, it is well-established that iatrogenic immune suppression, occurring in both transplant and non-transplant settings, can predispose to EBV-driven lymphoproliferative disorders. EBV-positive lymphoproliferative disorders are heterogeneous, with variable clinical features and prognoses depending on the context in which they arise. While DLBCL is the most common subtype, other histologic variants, including Burkitt lymphoma, NK/T-cell lymphoma, and Hodgkin lymphoma can occur. Research aimed at understanding the underlying biology and disease prevention strategies in EBV-associated lymphoproliferative diseases are ongoing. Additionally, personalized treatment approaches, such as immunotherapy and adoptive T-cell therapies, have yielded encouraging results, though randomized trials are needed to further define optimal management.

Posttransplant Malignancy

Posttransplant malignancy is a leading cause of death after solid organ transplantation (SOT). Recipients of SOT are at significantly higher risk of multiple cancers compared with the general population, most notably nonmelanoma skin cancer and posttransplant lymphoproliferative disorders. Risk factors for posttransplant malignancy include history of malignancy, immunosuppression, oncogenic viral infections, sun exposure, and disease-specific associations. Early detection and treatment of malignancies can improve survival.

Post-transplant lymphoproliferative disorders after solid organ and hematopoietic stem cell transplantation

Post-transplant lymphoproliferative disorders (PTLD) are a rare complication after both solid organ (SOT) and allogeneic hematopoietic stem cell transplantation (allo-HSCT). In this single center retrospective study, we compared clinical, biological, and histological features, and outcomes of PTLD after both types of transplant. We identified 82 PTLD (61 after SOT and 21 after allo-HSCT). The presence of B symptoms, Waldeyer ring, spleen, central nervous system, and liver involvement, and advanced Ann-Arbor stage were more frequent in allo-HSCT recipients. PTLD had an earlier onset in allo-HSCT than in SOT cohort (4 vs. 64 months, p < .0001). PTLD was EBV-positive in 100% of allo-HSCT, in contrast to 47% of SOT (p = .0002). Four years after PTLD diagnosis, median overall survival was 32% (95% CI, 22-48) and 10% (95% CI, 2-49) in SOT and allo-HSCT recipients, respectively (p = .002). In conclusion, the clinical presentation and the outcome of PTLD varies greatly depending on the type of transplant.

Construction and Characterization of a Humanized Anti-Epstein-Barr Virus gp350 Antibody with Neutralizing Activity in Cell Culture

Acute Epstein-Barr virus (EBV) infection in immunosuppressed transplant patients can give rise to a malignant B-cell proliferation known as post-transplant lymphoproliferative disease (PTLD). The EBV major virion surface glycoprotein (gp)350 is a principal target of naturally occurring neutralizing antibodies and is viewed as the best target to prevent acute infection and PTLD in at-risk transplant recipients. We have constructed a humanized (hu) version of the murine anti-gp350 neutralizing monoclonal antibody 72a1. The hu72a1 IgG1 antibody displayed no significant anti-mouse activity, recognized both gp350 and its splice variant gp220 as well as a gp350 peptide that was shown to constitute the principal EBV gp350 neutralizing epitope when tested in immunoassays. Hu72a1 antibody blocked in vitro EBV infection of B cells at a level which equaled that of a mouse-human chimeric 72a1 antibody construct. This work provides a further structural and immunological understanding of the 72a1 antibody interaction with EBV gp350, and constitutes a launch point for future anti-EBV therapeutic antibodies designed to block EBV infection and prevent PTLD while eliminating the deleterious antigenic murine features of the original 72a1 antibody.

Comprehensive review of post-organ transplant hematologic cancers

A higher risk for a variety of cancers is among the major complications of posttransplantation immunosuppression. In this part of a continuing series on cancers posttransplantation, this review focuses on the hematologic cancers after solid organ transplantation. Posttransplantation lymphoproliferative disorders (PTLDs), which comprise the great majority of hematologic cancers, represent a spectrum of conditions that include, but are not limited to, the Hodgkin and non-Hodgkin lymphomas. The oncogenic Epstein-Barr virus is a key pathogenic driver in many PTLD cases, through known and unknown mechanisms. The other hematologic cancers include leukemias and plasma cell neoplasms (multiple myeloma and plasmacytoma). Clinical features vary across malignancies and location. Preventive screening strategies have been attempted mainly for PTLDs. Treatments include the chemotherapy regimens for the specific cancers, but also include reduction of immunosuppression, rituximab, and other therapies.

Post-transplantation lymphoproliferative disorder with gastrointestinal involvement

Post-transplantation lymphoproliferative disorders (PTLDs) are lymphoid proliferations or lymphomas that are the second most common tumors in adult transplant recipients. Most cases of PTLD are attributed to Epstein-Barr virus, which induces B-cell proliferation and occurs in the setting of severe immunosuppression after solid organ or bone marrow transplantation. The disorder is seen in 1-3% of liver transplant recipients and has a variable presentation chronology. Herein, we chronicle a case of aggressive B-cell lymphoma (PTLD WHO class-3) presenting with isolated gastrointestinal involvement in an Epstein-Barr virus-negative patient with living-donor liver transplantation, 4 years after receiving the transplant. While typical symptoms may be elusive in the immunocompromised setting, clinicians should be vigilant for underlying PTLD with isolated gastrointestinal involvement. Prompt detection and characterization by endoscopic evaluation with biopsy should be particularly stressed in such patients.

Posttransplant Lymphoproliferative Disorder Isolated to the Adrenal Gland in a Liver Transplant Patient

Posttransplant lymphoproliferative disorder (PTLD) is a serious complication that accounts for up to 20% of malignancies after solid organ transplantation. We describe a rare case of isolated PTLD in the adrenal gland occurring 7 months after liver transplant in a patient who developed a primary Epstein-Barr virus infection. He was treated with rituximab and his immunosuppression regimen was minimized. We review the incidence, pathogenesis, presentation, and management of PTLD in the liver-transplant population. Our case highlights the variation in the presentation of PTLD and the importance of a high index of suspicion among the at-risk group.

Decreased survival in hepatitis C patients with monomorphic post-transplant lymphoproliferative disorder after liver transplantation treated with frontline immunochemotherapy

Post-transplant lymphoproliferative disorder (PTLD) develops in 1-3% of liver transplant recipients and no consensus exists about therapeutic management. From 2006 to 2016, 1489 liver transplants were performed at our institution with 20 patients (incidence 1.3%) developing PTLD. Hepatitis C virus (HCV) was the leading cause (n = 10) of liver transplant in PTLD patients. Diffuse large B-cell lymphoma was the most frequent histologic subtype (n = 17), and we report our experience in the management of these patients. Patients were treated with frontline immunochemotherapy without immunosuppression reduction. All evaluable patients achieved a complete remission. Statistically significant decreased survival was identified in HCV-positive patients. Six patients (60%) exhibited increases in HCV RNA levels during therapy. Four patients (40%) developed graft failure and three of them (30%) died from liver dysfunction. This is the first study providing evidence of decreased survival in HCV-positive PTLD patients after liver transplant receiving immunochemotherapy.

Posttransplant Lymphoproliferative Disease Presenting as an Extracranial Mass

Posttransplant lymphoproliferative disease is a serious complication following stem cell and solid organ transplantation. Early recognition of the disease is important in facilitating timely therapy and improving long-term outcomes. We report a renal transplant recipient presenting with an extracranial frontoparietal soft tissue mass that was subsequently diagnosed as a B-cell lymphoma. The patient was treated successfully with immunosuppression reduction, anti-CD20 monoclonal antibody therapy, and cytotoxic chemotherapy. Our case highlights the importance of recognizing soft tissue masses in the head and neck as a potential clinical manifestation of PTLD in solid organ transplant recipients.

A retrospective analysis of post-transplant lymphoproliferative disorder following liver transplantation

OBJECTIVE

To evaluate response rates and survival in adults developing post-transplant lymphoproliferative disorder (PTLD) following liver transplantation.

METHODS

Patients were identified retrospectively and data collected through local liver and haematology electronic databases and pharmacy records.

RESULTS

Forty-five patients were identified. The median age at first transplant and at development of PTLD was 48 and 54 years, respectively, with the median time from transplant to PTLD diagnosis of 56 months. The majority of cases (76%) were monomorphic B-cell lymphomas, and 36% of tumours were EBV positive. Treatment involved reduction in immune-suppression (RIS) in 30 (67%) with RIS the only treatment in 3. Ten (22%) patients were treated with rituximab alone, 13 (29%) with chemotherapy alone and 14 (31%) patients were treated with rituximab and chemotherapy. Twenty-six (58%) patients achieved a complete response (CR). At a median follow-up of 27 months, the median overall survival (OS) was 50 months. Response and OS were not associated with clinical factors or the use of rituximab.

CONCLUSION

Outcomes reported in this study are favourable and comparable to those reported previously. The addition of rituximab did not appear to have improved outcomes in this series, although a significant proportion of patients were able to avoid chemotherapy.

Rituximab in B-Cell Hematologic Malignancies: A Review of 20 Years of Clinical Experience

Rituximab is a human/murine, chimeric anti-CD20 monoclonal antibody with established efficacy, and a favorable and well-defined safety profile in patients with various CD20-expressing lymphoid malignancies, including indolent and aggressive forms of B-cell non-Hodgkin lymphoma. Since its first approval 20 years ago, intravenously administered rituximab has revolutionized the treatment of B-cell malignancies and has become a standard component of care for follicular lymphoma, diffuse large B-cell lymphoma, chronic lymphocytic leukemia, and mantle cell lymphoma. For all of these diseases, clinical trials have demonstrated that rituximab not only prolongs the time to disease progression but also extends overall survival. Efficacy benefits have also been shown in patients with marginal zone lymphoma and in more aggressive diseases such as Burkitt lymphoma. Although the proven clinical efficacy and success of rituximab has led to the development of other anti-CD20 monoclonal antibodies in recent years (e.g., obinutuzumab, ofatumumab, veltuzumab, and ocrelizumab), rituximab is likely to maintain a position within the therapeutic armamentarium because it is well established with a long history of successful clinical use. Furthermore, a subcutaneous formulation of the drug has been approved both in the EU and in the USA for the treatment of B-cell malignancies. Using the wealth of data published on rituximab during the last two decades, we review the preclinical development of rituximab and the clinical experience gained in the treatment of hematologic B-cell malignancies, with a focus on the well-established intravenous route of administration. This article is a companion paper to A. Davies, et al., which is also published in this issue.

FUNDING

F. Hoffmann-La Roche Ltd., Basel, Switzerland.

Post-transplant lymphoproliferative disorder (PTLD): single institutional experience of 141 patients

Background

Post-transplant lymphoproliferative disorder is a well-recognized but rare complication of hematopoietic stem cell and solid organ transplant. Due to rarity of this disease, retrospective studies from major transplant centers has been the main source to provide treatment guidelines, which are still in evolution. The sample size of this study is among one of the largest study on PTLD till date reported throughout the world.

Methods

This study was performed at University of Florida which is one of the largest transplant center in South East United States. We performed treatment and survival analysis along with univariate and multivariate analysis to identify prognostic factors.

Results

We reviewed 141 patients diagnosed with PTLD over last 22 years with median follow-up of 2.4 years. The estimated median overall survival of the entire group was 15.0 years. Sub group analysis showed that 5-year overall survival rates of pediatric population were 88% (median not reached). For adults, median OS was 5.35 years while for elderly patients it was 1.32 years. The estimated median OS of patients with monomorphic PTLD was 9.0 years while in polymorphic PTLD was 19.3 years. Univariate analysis identified gender, age at transplant and PTLD diagnosis, performance status, IPI score, allograft type, recipient EBV status, multiple acute rejections prior to PTLD diagnosis, PTLD sub-type, extra-nodal site involvement, immunosuppressive drug regimen at diagnosis, initial treatment best response were statistically significant prognostic factors (p < 0.05). On multivariate analysis, age at PTLD diagnosis, recipient EBV status, bone marrow involvement, and initial best response were statistically significant prognostic factors (p < 0.05). Surprisingly, use of Rituximab alone as upfront therapy had poor hazard ratio in the cumulative group as well less aggressive PTLD subgroup comprising of early lesions and polymorphic PTLD.

Conclusions

Our experience with treatment and analysis of outcomes does challenge current role of Rituximab use in treatment of PTLD. Currently as we define role of immunotherapy in cancer treatment, the role of acute rejections and immunosuppressant in PTLD becomes more relevant as noticed in our study. This study was also able to find new prognostic factors and also verified other known prognostic factors.

Posttransplant Lymphoproliferative Disorder After Clinical Islet Transplantation: Report of the First Two Cases

We report the first two cases of posttransplant lymphoproliferative disorder (PTLD) in recipients of islet transplants worldwide. First, a 44-year-old recipient of three islet infusions developed PTLD 80 months after his initial transplantation, presenting with abdominal pain and diffuse terminal ileum thickening on imaging. He was treated with surgical excision, reduction of immunosuppression, and rituximab. Seven months later, he developed central nervous system PTLD, presenting with vertigo and diplopia; immunosuppression was discontinued, resulting in graft loss, and he was given high-dose methotrexate and underwent consolidative autologous stem cell transplantation. He remains in remission 37 months after the initial diagnosis. Second, a 58-year-old female recipient of two islet infusions developed PTLD 24 months after initial islet infusion, presenting with pancytopenia secondary to extensive bone marrow involvement. Immunosuppression was discontinued, resulting in graft loss, and she received rituximab and chemotherapy, achieving complete remission. Both patients were monomorphic B cell PTLD subtype by histology and negative for Epstein-Barr virus in tissue or blood. These cases document the first occurrences of this rare complication in islet transplantation, likely secondary to prolonged, intensive immunosuppression, and highlight the varying clinical manifestations of PTLD. Further studies are needed to determine incidence rate and risk factors in islet transplantation.

Drug Modulators of B Cell Signaling Pathways and Epstein-Barr Virus Lytic Activation

Epstein-Barr virus (EBV) is a ubiquitous human gammaherpesvirus that establishes a latency reservoir in B cells. In this work, we show that ibrutinib, idelalisib, and dasatinib, drugs that block B cell receptor (BCR) signaling and are used in the treatment of hematologic malignancies, block BCR-mediated lytic induction at clinically relevant doses. We confirm that the immunosuppressive drugs cyclosporine and tacrolimus also inhibit BCR-mediated lytic induction but find that rapamycin does not inhibit BCR-mediated lytic induction. Further investigation shows that mammalian target of rapamycin complex 2 (mTORC2) contributes to BCR-mediated lytic induction and that FK506-binding protein 12 (FKBP12) binding alone is not adequate to block activation. Finally, we show that BCR signaling can activate EBV lytic induction in freshly isolated B cells from peripheral blood mononuclear cells (PBMCs) and that activation can be inhibited by ibrutinib or idelalisib.IMPORTANCE EBV establishes viral latency in B cells. Activation of the B cell receptor pathway activates lytic viral expression in cell lines. Here we show that drugs that inhibit important kinases in the BCR signaling pathway inhibit activation of lytic viral expression but do not inhibit several other lytic activation pathways. Immunosuppressant drugs such as cyclosporine and tacrolimus but not rapamycin also inhibit BCR-mediated EBV activation. Finally, we show that BCR activation of lytic infection occurs not only in tumor cell lines but also in freshly isolated B cells from patients and that this activation can be blocked by BCR inhibitors.