Clinical and pathological prognostic markers for survival in adult patients with post-transplant lymphoproliferative disorders in solid transplant

The pathobiology of select adolescent young adult lymphomas

Lymphoid cancers are among the most frequent cancers diagnosed in adolescents and young adults (AYA), ranging from approximately 30%-35% of cancer diagnoses in adolescent patients (age 10-19) to approximately 10% in patients aged 30-39 years. Moreover, the specific distribution of lymphoid cancer types varies by age with substantial shifts in the subtype distributions between pediatric, AYA, adult, and older adult patients. Currently, biology studies specific to AYA lymphomas are rare and therefore insight into age-related pathogenesis is incomplete. This review focuses on the paradigmatic epidemiology and pathogenesis of select lymphomas, occurring in the AYA patient population. With the example of posttransplant lymphoproliferative disorders, nodular lymphocyte-predominant Hodgkin lymphoma, follicular lymphoma (incl. pediatric-type follicular lymphoma), and mediastinal lymphomas (incl. classic Hodgkin lymphoma, primary mediastinal large B cell lymphoma and mediastinal gray zone lymphoma), we here illustrate the current state-of-the-art in lymphoma classification, recent molecular insights including genomics, and translational opportunities. To improve outcome and quality of life, international collaboration in consortia dedicated to AYA lymphoma is needed to overcome challenges related to siloed biospecimens and data collections as well as to develop studies designed specifically for this unique population.

Post-transplant lymphoproliferative disorders (PTLD) in adolescents and young adults: A category in need of definition

Post-transplant lymphoproliferative disorders are a well-recognized complication of solid organ and stem cell transplantation. Much data has accumulated with respect to the pathobiology and clinical behavior of these lesions in the general post-transplant population as well as in the pediatric and adult age groups. However, information as to these lesions in the adolescent and young adult populations, which bridge the pediatric and adult groups, is limited. In this review, the focus is on this unique population of PTLD patients and their proliferations.

How I treat posttransplant lymphoproliferative disorder

Posttransplant lymphoproliferative disorder (PTLD) is an important and potentially life-threatening complication of solid organ transplant and hematopoietic stem cell transplant (HSCT). Given the heterogeneity of PTLD and the risk of infectious complications in patients with immunosuppression, the treatment of this disease remains challenging. Monomorphic PTLD and lymphoma of B-cell origin account for the majority of cases. Treatment strategies for PTLD consist of response-adapted, risk-stratified methods using immunosuppression reduction, immunotherapy, and/or chemotherapy. With this approach, ∼25% of the patients do not need chemotherapy. Outcomes for patients with high risk or those who do not respond to frontline therapies remain dismal, and novel treatments are needed in this setting. PTLD is associated with Epstein-Barr virus (EBV) infection in 60% to 80% of cases, making EBV-directed therapy an attractive treatment modality. Recently, the introduction of adoptive immunotherapies has become a promising option for refractory cases; hopefully, these treatment strategies can be used as earlier lines of therapy in the future.

Tumor Infiltrating Lymphocytes Predict Survival in Solid Organ Transplant Recipients With Monomorphic Post-transplant Lymphoproliferative Disorders

INTRODUCTION

The tumor microenvironment (TME) in post-transplant lymphoproliferative disorders (PTLDs) remains unexplored. Tumor infiltrating lymphocytes (TILs) are prognostic in other lymphomas. We assessed the prognostic impact of TILs in monomorphic B-cell PTLD.

METHODS

TIL density (CD3+ cells/mm²) was determined by CD3 immunohistochemistry in archived diagnostic biopsies from patients diagnosed with monomorphic B-cell PTLD.

RESULTS

Amongst monomorphic PTLDs (N = 107), low TIL-count was associated with inferior 2-year progression-free survival (PFS) (41% versus 86%, P = .003) and 2-year overall survival (OS) (52% versus 93%, P = .003) by Kaplan-Meier analysis. Low TIL-count was significant on Cox univariate regression for inferior PFS (HR 4.5, 95% CI 2.0-9.9, P < .001) and OS (HR 4.6, 95% CI 1.8-11.8, P < .001). Multivariate analysis with clinical variables (age ≥60 years, high LDH, stage III/IV, CNS involvement) and TIL-count showed significance for PFS (HR 3.3, 95% CI 1.3-8.3, P = .010) and a non-significant trend for OS (HR 2.6, 95% CI 0.9-7.3, P = .064). A composite score including TILs and clinical variables (age ≥60 years, high LDH, stage III/IV, CNS involvement) effectively stratified monomorphic PTLD patients by PFS and OS (2-year OS: low-risk 93%, intermediate-risk 61%, high-risk 23%, P < .001).

CONCLUSIONS

The TME and TILs are prognostically relevant in monomorphic PTLD. Prognostic models including measures of the TME may improve risk stratification for patients with monomorphic PTLDs.

Non-Hodgkin lymphoma after pediatric kidney transplantation

Non-Hodgkin lymphoma (NHL) that develops after kidney transplantation belongs to post-transplant lymphoproliferative disorders (PTLD) occurring with an incidence of 2-3%. Most pediatric cases are related to primary infection with Epstein-Barr virus (EBV), able to transform and immortalize B cells and widely proliferate due to the lack of relevant control of cytotoxic T cells in patients receiving post-transplant immunosuppression. NHL may develop as a systemic disease or as a localized lesion. The clinical pattern is variable, from non-symptomatic to fulminating disease. Young age of transplant recipient, seronegative EBV status at transplantation, and EBV mismatch between donor and recipient (D+/R-) are regarded as risk factors. Immunosuppression impacts the development of both early and late NHLs. Specific surveillance protocols, including monitoring of EBV viral load, are used in patients at risk; however, detailed histopathology diagnosis and evaluation of malignancy staging is crucial for therapeutic decisions. Minimizing of immunosuppression is a primary management, followed by the use of rituximab in B-cell NHLs. Specific chemotherapeutic protocols, adjusted to lymphoma classification and staging, are used in advanced NHLs. Radiotherapy and/or surgical removal of malignant lesions is limited to the most severe cases. Outcome is variable, depending on risk factors and timing of diagnosis, however is positive in pediatric patients in terms of graft function and patient survival. Kidney re-transplantation is possible in survivors who lost the primary graft due to chronic rejection, however may be performed after at least 2-3 years of waiting time, careful verification of malignancy-free status, and gaining immunity against EBV.

Characteristics, management, and outcome of pediatric patients with post-transplant lymphoproliferative disease-A 20 years' experience from Austria

BACKGROUND

Management of pediatric post-transplantation lymphoproliferative disorder (PTLD) after hematopoietic stem cell (HSCT) and solid organ transplantation (SOT) is challenging.

AIM

This study of 34 PTLD patients up to 19-years old diagnosed in Austria from 2000 to 2018 aimed at assessing initial characteristics, therapy, response, and outcome as well as prognostic markers of this rare pediatric disease.

METHODS AND RESULTS

A retrospective data analysis was performed. Types of allografts were kidney (n = 12), liver (n = 7), heart (n = 5), hematopoietic stem cells (n = 4), lungs (n = 2), multi-visceral (n = 2), small intestine (n = 1), and vessels (n = 1). Eighteen/34 were classified as monomorphic PTLD, with DLBCL accounting for 15 cases. Polymorphic disease occurred in nine, and non-destructive lesions in six cases. One patient had a non-classifiable PTLD. Thirteen/34 patients are surviving event-free in first remission (non-destructive, n = 4/6; polymorphic, n = 4/9; monomorphic, n = 6/18). Fourteen/34 patients lacked complete response to first-line therapy, of whom seven died. Four/34 patients relapsed, of whom two died. In 3/34 patients, death occurred as a first event. The 5-year overall and event-free survival rates were 64% ± 9% and 35% ± 9% for the whole cohort. Among all parameters analyzed, only malignant disease as the indication for transplantation had a significantly poor influence on survival.

CONCLUSIONS

This study shows PTLD still to be a major cause of mortality following SOT or HSCT in children. A continued understanding of the molecular biology of the disease shall allow to decrease treatment intensity for lower risk patients and to identify patients who may benefit from newer therapy approaches to improve outcome and decrease morbidity.

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.

Reappraisal of the prognostic value of Epstein-Barr virus status in monomorphic post-transplantation lymphoproliferative disorders-diffuse large B-cell lymphoma

The role of the Epstein-Barr virus (EBV) status in the blood for predicting survival in post-transplantation lymphoproliferative disorders-diffuse large B-cell lymphoma (PTLD-DLBCL) is unknown. We evaluated the prognostic values of pre-treatment EBV-encoded small RNA (EBER) detected with in situ hybridization in tissues and EBV DNA in the whole blood (WB) and plasma in 58 patients with monomorphic PTLD-DLBCL after solid organ transplantation. There were no significant differences in the rates of overall response, complete response, and survival according to EBER EBV and WB EBV status. In contrast, patients with positive plasma EBV DNA had significantly lower rates of overall response (60.0% vs. 94.4%, P = 0.043) and complete response (40.0% vs. 88.9%, P = 0.019) as well as worse progression-free survival (PFS) (P = 0.035) and overall survival (OS) (P = 0.039) compared with patients with negative plasma EBV DNA. In multivariate analysis, plasma EBV DNA positivity was a significantly unfavorable prognostic factor for PFS [hazard ratio (HR) 4.92, 95% confidence interval (CI) 1.22-19.86, P = 0.025] and OS (HR 4.48, 95% CI 1.14-17.63, P = 0.032). Despite small number of 6 patients with plasma EBV positivity, plasma EBV DNA positivity might be more prognostic for survival than EBER or WB EBV DNA positivity in patients with monomorphic PTLD-DLBCL.

Pathobiology and treatment of lymphomatoid granulomatosis, a rare EBV-driven disorder

Lymphomatoid granulomatosis (LYG) is a rare Epstein-Barr virus (EBV)-driven B-cell lymphoproliferative disease (LPD). This disease is hypothesized to result from defective immune surveillance of EBV, with most patients showing evidence of immune dysfunction, despite no known primary immunodeficiency. Pathologically, LYG is graded by the number and density of EBV+ atypical B cells, and other characteristic findings include an angioinvasive/angiodestructive reactive T-cell infiltrate and various degrees of necrosis. Clinically, LYG universally involves the lungs with other common extranodal sites, including skin, central nervous system, liver, and kidneys. Nodal and/or bone marrow involvement is extremely rare and, if present, suggests an alternative diagnosis. Treatment selection is based on histologic grade and underlying pathobiology with low-grade disease hypothesized to be immune-dependent and typically polyclonal and high-grade disease to be immune-independent and typically oligoclonal or monoclonal. Methods of augmenting the immune response to EBV in low-grade LYG include treatment with interferon-α2b, whereas high-grade disease requires immunochemotherapy. Given the underlying defective immune surveillance of EBV, patients with high-grade disease may have a recurrence in the form of low-grade disease after immunochemotherapy, and those with low-grade disease may progress to high-grade disease after immune modulation, which can be effectively managed with crossover treatment. In patients with primary refractory disease or in those with multiple relapses, hematopoietic stem cell transplantation may be considered, but its efficacy is not well established. This review discusses the pathogenesis of LYG and highlights distinct histopathologic and clinical features that distinguish this disorder from other EBV+ B-cell LPDs and lymphomas. Treatment options, including immune modulation and combination immunochemotherapy, are discussed.

Post Transplant Lymphoproliferative Disorder

Posttransplant lymphoproliferative disorder is an extremely fatal complication arising in transplant recipients as a side effect of immunosuppression. PTLDs are seen after both solid organ and hematopoietic stem cell transplants though the incidence is much higher in the former. Primary Epstein-Barr virus (EBV) infection or reactivation due to a state of immune dysregulation along with intensity of immunosuppression used are of paramount importance in pathogenesis of PTLD. EBV associated PTLDs occur early in the post transplant period whereas late onset lymphomas are usually EBV negative. The uncontrolled B cell proliferation can create a spectrum of histological patterns from nondestructive lesions to destructive polymorphic or more aggressive monomorphic PTLDs. Early detection of seropositivity by serial monitoring in the recipient can prevent PTLD development by starting pre-emptive therapy. The mainstay treatment in established cases remains reduction of immunosuppression. Chemotherapeutic and immunomodulatory agents are added sequentially based on the type of PTLD and based on its response to initial therapy. Despite various treatment options available, the morbidity remains high and achieving state of disease remission without causing graft rejection can be quite challenging. Hence, a better understanding in pathobiology of EBV+ versus EBV- PTLDS may help prevent lymphomagenesis in transplant recipients.

Sterile necrotizing and non-necrotizing granulomas in a heart transplant patient with history of PTLD: A unique finding

INTRODUCTION

Posttransplant lymphoproliferative disease (PTLD) is a known complication in patients with solid organ transplant. It can present as localized or disseminated tumor. The cornerstone of management consists of reduced immunosuppression (RI). In select cases, localized disease can potentially be curative with surgical excision.

PRESENTATION OF CASE

Here we present a case of a 19-year-old female with orthotopic heart transplant with two episodes of recurrent PTLD. After the second episode she was found to have asymptomatic splenic lesions which were refractory to RI and chemotherapy. She subsequently underwent splenectomy that showed sterile necrotizing and non-necrotizing granulomas with no evidence of PTLD.

DISCUSSION

Based on our literature search this is the first ever reported case of sterile granulomas in a patient with recurrent PTLD which could potentially be diagnosed with minimally invasive biopsy rather than diagnostic splenectomy.

CONCLUSION

This report is an attempt to create awareness regarding potential for presence of sterile granulomas in patients with recurrent PTLD and discuss the use of percutaneous biopsy before splenectomy.

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.

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.

Blastic Epstein-Barr virus associated post-transplant lymphoproliferative disorder after allogeneic stem cell transplantation for severe aplastic anemia

Post-transplant lymphoproliferative disorder (PTLD) is a well-recognized complication of organ transplantation. Progress has recently been made in the pathological classification of PTLD. However, the clinical course has not been clarified because of the rarity of this disease. We experienced a case of PTLD with a fulminant clinical course. The patient had been under longterm immunosuppressive treatment for aplastic anemia. He received related allogeneic hematopoietic stem cell transplantation. Soon after transplantation, he developed PTLD. According to the guidelines, we reduced immunosuppression. However, the disease course was so fulminant that there was no time for the patient to respond, and he died of multi-organ failure. There may be various clinical types of PTLD, which may include some fulminant cases. In such a case, it is not sufficient to reduce immunosuppression. The patient should be carefully observed and an appropriate individual treatment should be chosen.

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.

EBV-negative monomorphic B-cell post-transplant lymphoproliferative disorders are pathologically distinct from EBV-positive cases and frequently contain TP53 mutations

Monomorphic post-transplant lymphoproliferative disorder commonly resembles diffuse large B-cell lymphoma or Burkitt lymphoma, and most are Epstein-Barr virus (EBV) positive. We retrospectively identified 32 cases of monomorphic post-transplant lymphoproliferative disorder from two institutions and evaluated EBV in situ hybridization; TP53 mutation status; p53, CD30, myc, and BCL2 expression by immunohistochemistry; proliferation index by Ki67; and germinal center vs non-germinal center immunophenotype by Hans criteria. Post-transplant lymphoproliferative disorder arose after hematopoietic stem cell transplant in five and solid organ transplant in 27 patients, a median of 4 and 96 months after transplant, respectively (overall median latency 71 months, range 2-295). The most common morphology was diffuse large B-cell lymphoma (28 cases), with three cases of Burkitt lymphoma, and one case of plasmablastic lymphoma. Ten cases (31%) were EBV negative. Of those with the morphology of diffuse large B-cell lymphoma, the EBV-negative cases were more frequently TP53-mutated (P<0.001), p53 positive by immunohistochemistry (P<0.001), CD30 negative (P<0.01), and of germinal center immunophenotype (P=0.01) compared with EBV-positive cases. No statistically significant difference in overall survival was identified based on EBV, TP53 mutation status, germinal center vs non-germinal center immunophenotype, or other immunohistochemical parameters evaluated. Patients who died of post-transplant lymphoproliferative disorder were older with a longer latency from time of transplant to diagnosis (P<0.05). Our study demonstrates that diffuse large B-cell lymphoma-related immunohistochemical prognostic markers have limited relevance in the post-transplant setting and underscores differences between EBV-positive and EBV-negative post-transplant lymphoproliferative disorder in terms of immunophenotype and TP53 mutation frequency, supporting an alternative pathogenesis for EBV-negative post-transplant lymphoproliferative disorder.

Matched-pair analysis: identification of factors with independent influence on the development of PTLD after kidney or liver transplantation

BACKGROUND

Post-transplant lymphoproliferative disorder (PTLD) adversely affects patients' long-term outcome.

METHODS

The paired t test and McNemar's test were applied in a retrospective 1:1 matched-pair analysis including 36 patients with PTLD and 36 patients without PTLD after kidney or liver transplantation. Matching criteria were age, gender, indication, type of transplantation, and duration of follow-up. All investigated PTLD specimen were histologically positive for EBV. Risk-adjusted multivariable regression analysis was used to identify independence of risk factors for PTLD detected in matched-pair analysis. The resultant prognostic model was assessed with ROC-curve analysis.

RESULTS

Patients suffering with PTLD had shorter mean survival (p = 0.004), more episodes of CMV infections or reactivations (p = 0.042), and fewer recipient HLA A2 haplotypes (p = 0.007), a tacrolimus-based immunosuppressive regimen (p = 0.052) and higher dosages of tacrolimus at hospital discharge (Tac dosage) (p = 0.052). Significant independent risk factors for PTLD were recipient HLA A2 (OR = 0.07, 95 % CI = 0.01-0.55, p = 0.011), higher Tac dosages (OR = 1.29, 95 % CI = 1.01-1.64, p = 0.040), and higher numbers of graft rejection episodes (OR = 0.38, 95 % CI = 0.17-0.87, p = 0.023). The following prognostic model for the prediction of PTLD demonstrated good model fit and a large area under the ROC curve (0.823): PTLD probability in % = Exp(y)/(1 + Exp(y)) with y = 0.671 - 1.096 × HLA A2-positive recipient + 0.151 × Tac dosage - 0.805 × number of graft rejection episodes.

CONCLUSIONS

This study suggests prognostic relevance for recipient HLA A2, CMV, and EBV infections or reactivations and strong initial tacrolimus-based immunosuppression. Patients with risk factors may benefit from intensified screening for PTLD.

Secondary Malignant Neoplasms Following Haematopoietic Stem Cell Transplantation in Childhood

Improving survival rates in children with malignancy have been achieved at the cost of a high frequency of late adverse effects of treatment, especially in intensively treated patients such as those undergoing haematopoietic stem cell transplantation (HSCT), many of whom suffer the high burden of chronic toxicity. Secondary malignant neoplasms (SMNs) are one of the most devastating late effects, cause much morbidity and are the most frequent cause of late (yet still premature) treatment-related mortality. They occur in up to 7% of HSCT recipients by 20 years post-HSCT, and with no evidence yet of a plateau in incidence with longer follow-up. This review describes the epidemiology, pathogenesis, clinical features and risk factors of the three main categories of post-HSCT SMNs. A wide range of solid SMNs has been described, usually occurring 10 years or more post-HSCT, related most often to previous or conditioning radiotherapy. Therapy-related acute myeloid leukaemia/myelodysplasia occurs earlier, typically three to seven years post-HSCT, mainly in recipients of autologous transplant and is related to previous alkylating agent or topoisomerase II inhibitor chemotherapy. Post-transplant lymphoproliferative disorders occur early (usually within two years) post-HSCT, usually presenting as Epstein-Barr virus-related B cell non-Hodgkin lymphoma.

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.

Post-transplant lymphoproliferative disease (PTLD): risk factors, diagnosis, and current treatment strategies

Post-transplant lymphoproliferative diseases (PTLD) are heterogeneous lymphoid disorders ranging from indolent polyclonal proliferations to aggressive lymphomas that complicate solid organ or hematopoietic transplantation. Risk factors for PTLD include viral infections, degree of immunosuppression, recipient age and race, allograft type, and host genetic variations. Clinically, extra-nodal disease is common including 10-15 % presenting with central nervous system (CNS) disease. Most PTLD cases are B cell (5-10 % T/NK cell or Hodgkin lymphoma), while over one-third are EBV-negative. World Health Organization (WHO) diagnostic categories are: early lesions, polymorphic, and monomorphic PTLD; although in practice, a clear separation is not always possible. Therapeutically, reduction in immunosuppression remains a mainstay, and recent data has documented the importance of rituximab +/- combination chemotherapy. Therapy for primary CNS PTLD should be managed according to immunocompetent CNS paradigms. Finally, novel treatment strategies for PTLD have emerged, including adoptive immunotherapy and rational targeted therapeutics (e.g., anti-CD30 based therapy and downstream signaling pathways of latent membrane protein-2A).

Primary CNS posttransplant lymphoproliferative disease (PTLD): an international report of 84 cases in the modern era

We performed a multicenter, International analysis of solid organ transplant (SOT)-related primary central nervous system (PCNS) posttransplant lymphoproliferative disease (PTLD). Among 84 PCNS PTLD patients, median time of SOT-to-PTLD was 54 months, 79% had kidney SOT, histology was monomorphic in 83% and tumor was EBV+ in 94%. Further, 33% had deep brain involvement, 10% had CSF involvement, while none had ocular disease. Immunosuppression was reduced in 93%; additional first-line therapy included high-dose methotrexate (48%), high-dose cytarabine (33%), brain radiation (24%) and/or rituximab (44%). The overall response rate was 60%, while treatment-related mortality was 13%. With 42-month median follow-up, three-year progression-free survival (PFS) and overall survival (OS) were 32% and 43%, respectively. There was a trend on univariable analysis for improved PFS for patients who received rituximab and/or high-dose cytarabine. On multivariable Cox regression, poor performance status predicted inferior PFS (HR 2.61, 95% CI 1.32-5.17, p = 0.006), while increased LDH portended inferior OS (HR 4.16, 95% CI 1.29-13.46, p = 0.02). Moreover, lack of response to first-line therapy was the most dominant prognostic factor on multivariable analysis (HR 8.70, 95% CI 2.56-29.57, p = 0.0005). Altogether, PCNS PTLD appears to represent a distinct clinicopathologic entity within the PTLD spectrum that is associated with renal SOT, occurs late, is monomorphic and retains EBV positivity.

Molecular pathogenesis of B-cell posttransplant lymphoproliferative disorder: what do we know so far?

Posttransplant lymphoproliferative disorder (PTLD) is a potentially fatal disease that arises in 2%-10% of solid organ and hematopoietic stem cell transplants and is most frequently of B-cell origin. This very heterogeneous disorder ranges from benign lymphoproliferations to malignant lymphomas, and despite the clear association with Epstein-Barr Virus (EBV) infection, its etiology is still obscure. Although a number of risk factors have been identified (EBV serostatus, graft type, and immunosuppressive regimen), it is currently not possible to predict which transplant patient will eventually develop PTLD. Genetic studies have linked translocations (involving C-MYC, IGH, BCL-2), various copy number variations, DNA mutations (PIM1, PAX5, C-MYC, RhoH/TTF), and polymorphisms in both the host (IFN-gamma, IL-10, TGF-beta, HLA) and the EBV genome to B-cell PTLD development. Furthermore, the tumor microenvironment seems to play an important role in the course of disease representing a local niche that can allow antitumor immune responses even in an immunocompromised host. Taken together, B-cell PTLD pathogenesis is very complex due to the interplay of many different (patient-dependent) factors and requires thorough molecular analysis for the development of novel tailored therapies. This review aims at giving a global overview of the currently known parameters that contribute to the development of B-cell PTLD.

Plasmablastic lymphoma following transplantation

Posttransplant lymphoproliferative disorder is a serious complication following solid organ as well as hematopoietic stem cell transplantation due to prolonged immunosuppressive therapy. Plasmablastic lymphoma, although classically associated with HIV infection, has since been described in transplant patients as a variant of posttransplant lymphoproliferative disorder with varying clinical presentations. Here we add two additional cases to the literature: one following lung transplantation and one following pancreatic transplantation. In addition, the demographic, therapeutic, and immunophenotypic characteristics from prior reported cases are summarized.

Post transplant lymphoproliferative disorders: risk, classification, and therapeutic recommendations

OPINION STATEMENT

Post transplant lymphoproliferative disorder (PTLD) is a heterogeneous disease that may occur in recipients of solid organ transplants (SOT) and hematopoietic stem cell transplant. The risk of lymphoma is increased 20-120% compared with the general population with risk dependent in part on level of immune suppression. In addition, recent data have emerged, including HLA and cytokine gene polymorphisms, regarding genetic susceptibility to PTLD. Based on morphologic, immunophenotypic, and molecular criteria, PLTD are classified into 4 pathologic categories: early lesions, polymorphic, monomorphic, and classical Hodgkin lymphoma. Evaluation by expert hematopathology is critical in establishing the diagnosis. The aim of therapy for most patients is cure with the concurrent goal of preservation of allograft function. Given the pathologic and clinical heterogeneity of PTLD, treatment is often individualized. A mainstay of therapy remains reduction of immune suppression (RI) with the level of reduction being dependent on several factors (e.g., history of rejection, current dosing, and type of allograft). Outside of early lesions and/or low tumor burden, however, RI alone is associated with cure in a minority of subjects. We approach most newly-diagnosed polymorphic and monomorphic PTLDs similarly using frontline single-agent rituximab (4 weeks followed by abbreviated maintenance) in conjunction with RI. Frontline combination chemotherapy may be warranted for patients with high tumor burden in need of prompt response or following failure of RI and/or rituximab. Due to chemotherapy-related complications in PTLD, especially infectious, we advocate comprehensive supportive care measures. Surgery or radiation may be considered for select patients with early-stage disease. For PTLD subjects with primary CNS lymphoma, we utilize therapeutic paradigms similar to immunocompetent CNS lymphoma using high-dose methotrexate-based therapy with concurrent rituximab therapy and sequential high-dose cytarabine. Finally, novel therapeutic strategies, especially adoptive immunotherapy, should continued to be explored.

Post-transplantation lymphoproliferative disorders: diagnosis, prognosis, and current approaches to therapy

Post-transplantation lymphoproliferative disorders (PTLD) are a heterogenous group of abnormal lymphoid proliferations that occur after solid organ transplant (SOT) or hematopoietic transplantation. PTLDs consist of a disease spectrum ranging from hyperplasia to aggressive lymphomas with 60-70% being Epstein-Barr virus positive. The majority of cases are B-cell, although 10-15% are of T-cell origin or rarely Hodgkin lymphoma. Recent SOT series suggest PTLD occurs at a median of 36-40 months after transplant. Clinically, extra-nodal disease is common (up to 75-85%) including CNS involvement, which is seen in 10-15% of all cases. Since the first report over 40 years ago, PTLD has remained one of the most morbid complications associated with SOT. However, recent data suggests improved survival in the modern era, especially with the integration of early rituximab-based therapy. These studies utilized first line rituximab (+/- chemotherapy) together with reduced immune suppression (RI) for monomorphic and polymorphic PTLD. It will be critical in future studies to determine which PTLDs are most amenable to initial therapy with RI alone, versus RI/rituximab, versus RI/rituximab/chemotherapy. Additionally, novel therapeutics, such as adoptive immunotherapy, should continue to be explored.

CD20 expression predicts survival in paediatric post-transplant lymphoproliferative disease (PTLD) following solid organ transplantation

The prognostic role of CD20 expression and Epstein-Barr virus (EBV) positivity in post-transplant lymphoproliferative disease (PTLD) after solid organ transplantation (SOT) in paediatric patients is poorly understood. We retrospectively examined the relationship of CD20 and EBV with the time interval from SOT to PTLD diagnosis, and PTLD-related event-free (EFS) and overall survival (OS) in 45 consecutive PTLD patients (≤25 years) following SOT. These 45 paediatric SOT patients (28 heart, 11 liver, six kidney) were diagnosed with PTLD 45 months (mean; SD 43; range 4-153; median 24·5) after SOT, with PTLD diagnosis at 118 months (mean) (SD 77; range 14-287) of age. Of 40 evaluable tumours (11 monomorphic, 19 polymorphic, five early lesions, five rare subtypes), 32 (80%) had detectable EBV and 28 (70%) were classified as CD20(+) . Patients whose PTLD expressed CD20 or EBV had shorter intervals between SOT and PTLD onset (28 vs. 64 or 77 months for CD20 and EBV respectively) (P < 0·02), even after adjusting for age at SOT. Patients with CD20(+) tumours had higher 5-year PTLD-related EFS (83·7% vs. 28·6%, P < 0·001) and OS (95·8% vs. 56·3%, P = 0·01). EBV expression was unrelated to PTLD-related EFS or OS. CD20 expression is associated with timing of development of PTLD and predicts survival in PTLD diagnosed following paediatric SOT.

Multicenter analysis of 80 solid organ transplantation recipients with post-transplantation lymphoproliferative disease: outcomes and prognostic factors in the modern era

PURPOSE Adult post-transplantation lymphoproliferative disease (PTLD) has a reported 3-year overall survival (OS) of 35% to 40%. The impact of rituximab on the outcome of PTLD is not well defined. METHODS We examined the clinical features and outcomes among a large cohort of solid organ transplantation (SOT) -related patients with PTLD who were recently treated at four Chicago institutions (from January 1998 to January 2008). Results Eighty patients with PTLD were identified who had a median SOT-to-PTLD time of 48 months (range, 1 to 216 months). All patients had reduction of immunosuppression as part of initial therapy, whereas 59 (74%) of 80 patients received concurrent first-line rituximab with or without chemotherapy. During 40-month median follow-up, 3-year progression-free survival (PFS) for all patients was 57%, and the 3-year overall survival (OS) rate was 62%. Patients who received rituximab-based therapy as part of initial treatment had 3-year PFS of 70% and OS 73% compared with 21% (P < .0001) and 33% (P = .0001), respectively, without rituximab. Notably, of all relapses, only 9% (4 of 34 patients) occurred beyond 12 months from PTLD diagnosis. On multivariate regression analysis, three factors were associated with progression and survival: CNS involvement (PFS, 4.70; P = .01; OS, 3.61; P = .04), bone marrow involvement (PFS, 2.95; P = .03; OS, 3.14; P = .03), and hypoalbuminemia (PFS, 2.96; P = .05; OS, 3.64; P = .04). Furthermore, a survival model by multivariate CART analysis that was based on number of adverse factors present (ie, 0, 1, > or = 2) was formed: 3-year PFS rates were 84%, 66%, 7%, respectively, and 3-year OS rates were 93%, 68%, 11%, respectively (P < .0001). CONCLUSION This large, multicenter, retrospective analysis suggests significantly improved PFS and OS associated with early rituximab-based treatment in PTLD. In addition, clinical factors at diagnosis identified patients with markedly divergent outcomes.