Posttransplant lymphoproliferative disease after pediatric solid organ transplantation. Clin Dev Immunol. 2013;2013:814973. [PMID: 24174972 PMCID: PMC3794558 DOI: 10.1155/2013/814973]

Post-transplant lymphoproliferative disorder in pediatric liver transplant recipients: Experience from a South African transplant center

INTRODUCTION

Post-transplant lymphoproliferative disorder (PTLD) is a clinically heterogeneous potentially fatal complication of pediatric liver transplantation (PLT). We determined the prevalence, complications, and associated factors for PTLD in PLT recipients from Wits Donald Gordon Medical Centre, South Africa from January 2012 to August 2019.

METHODS

We performed a retrospective record review of 150 PLT recipients.

RESULTS

Histologically proven PTLD occurred in 17/150 PLT recipients (11.3%). Children with PTLD were significantly younger at transplant (17.9 vs. 32.7 months, p = 0.001) with a significantly higher prevalence of obstructive etiology (17/17 vs. 81/133, p = 0.001). Fifteen (88.2%) children with PTLD were Epstein-Barr virus (EBV) seronegative at transplant. High post-transplant EBV viral load at a threshold value of 4.8 log10 DNA copies/mL (sensitivity: 80.0% [95% confidence interval {CI}, 46.7%-100.0%]; specificity: 73.1% [95% CI 42.3%-93.3%; area under the curve {AUC} 75.8%]) and low post-transplant albumin levels at a threshold value of 21.5 g/L (sensitivity: 70.6% [95% CI, 41.2%-94.1%]; specificity: 85.7% [95% CI, 60.4%-94.5%; {AUC} 74.8%]) were associated with PTLD. The prevalence of cytomegalovirus (CMV) disease was significantly higher in children who developed PTLD versus non-PTLD (12/17 vs. 18/133; p < 0.001). CMV disease and the combination of post-transplant high EBV viral load and low albumin were independently associated with an increased risk of developing PTLD. Four (23.5%) children with PTLD died, however, survival was equivalent to non-PTLD PLT (p = 0.580).

CONCLUSION

The prevalence of PTLD in our cohort mirrors international cohorts, with mortality similar to non-PTLD PLT recipients.

Treatment of Monomorphic Posttransplant Lymphoproliferative Disorder in Pediatric Solid Organ Transplant: A Multicenter Review

Posttransplant lymphoproliferative disorder (PTLD) is the most common posttransplant malignancy in children. We reviewed data from 3 Canadian pediatric centers to determine patient characteristics, treatment approaches, and outcomes for children with monomorphic PTLD. There were 55 eligible children diagnosed between January 2001 to December 2021. Forty-eight patients (87.2%) had B-cell PTLD: Burkitt lymphoma (n = 25; 45.4%) and diffuse large B-cell lymphoma (n = 23; 41.2%), the remainder had natural killer (NK)/T-cell lymphoma (n = 5; 9.1%), Hodgkin lymphoma (n = 1;1.8%), or other (n = 1;1.8%). Thirty-nine (82.1%) patients with B-cell PTLD were treated with rituximab and chemotherapy with or without a reduction in immunosuppression (reduced immune suppression). The chemotherapy used was primarily one of 2 regimens: Mature Lymphoma B-96 protocol in 22 patients (56.4%) and low-dose cyclophosphamide with prednisone in 14 patients (35%). Most patients with T/NK-cell lymphoma were treated with reduced immune suppression + chemotherapy (n = 4; 80%). For all patients with monomorphic PTLD, the projected 3-year event-free survival/3-year overall survival was 62% and 77%, respectively. Of the patients, 100% with T/NK-cell PTLD 100% progressed or relapsed and, subsequently, died of disease. For patients with B-cell PTLD, there was no significant difference in outcome between the two main chemotherapy regimens employed.

Changes in the gut microbiome can predict and decrease Epstein-Barr virus infection risk in children after liver transplantation

OBJECTIVE

Primary Epstein-Barr virus (EBV) infection is observed in 60% of children during the first year after liver transplantation as usage of imm-unosuppressant. Finding predictive indicators of EBV infection is important to reduce the morbidity and mortality of EBV infection-related diseases by suggesting a dose reduction of immunosuppressant.

METHODS

We compared and analysed the gut microbiome of EBV-infected children with an asymptomatic virus-carrying status and EBV-uninfected children after liver transplantation using high-throughput sequencing.

RESULTS

Significant differences in gut microbiome composition in two groups were detected. In detail, Firmicutes and Lactobacillus were increased in EBV-infected group, while Clostridium was increased in EBV-uninfected group. Furthermore, CD4 percentage in T cells of blood showed a significant positive correlation with the content of Clostridium sp. CAG: 127 in EBV-uninfected group.

CONCLUSION

Changes in the gut microbiome could predict and decrease the EBV infection risk of children after liver transplantation.

Immunology of THymectomy And childhood CArdiac transplant (ITHACA): protocol for a UK-wide prospective observational cohort study to identify immunological risk factors of post-transplant lymphoproliferative disease (PTLD) in thymectomised children

INTRODUCTION

Paediatric heart transplant patients are disproportionately affected by Epstein-Barr virus (EBV)-related post-transplant lymphoproliferative disease (PTLD) compared with other childhood solid organ recipients. The drivers for this disparity remain poorly understood. A potential risk factor within this cohort is the routine surgical removal of the thymus-a gland critical for the normal development of T-lymphocyte-mediated antiviral immunity-in early life, which does not occur in other solid organ transplant recipients. Our study aims to describe the key immunological differences associated with early thymectomy, its impact on the temporal immune response to EBV infection and subsequent risk of PTLD.

METHODS AND ANALYSIS

Prospective and sequential immune monitoring will be performed for 34 heart transplant recipients and 6 renal transplant patients (aged 0-18 years), stratified into early (<1 year), late (>1 year) and non-thymectomy groups. Peripheral blood samples and clinical data will be taken before transplant and at 3, 6, 12 and 24 months post-transplant. Single cell analysis of circulating immune cells and enumeration of EBV-specific T-lymphocytes will be performed using high-dimensional spectral flow cytometry with peptide-Major Histocompatibilty Complex (pMHC) I/II tetramer assay, respectively. The functional status of EBV-specific T-lymphocytes, along with EBV antibodies and viral load will be monitored at each of the predefined study time points.

ETHICS AND DISSEMINATION

Ethical approval for this study has been obtained from the North of Scotland Research Ethics Committee. The results will be disseminated through publications in peer-reviewed journals, presentations at scientific conferences and patient-centred forums, including social media.

TRIAL REGISTRATION NUMBER

ISRCTN10096625.

Rare Case of Pediatric Post-transplant Lymphoproliferative Disorder Presenting With Pleural Masses Complicated by Pleural Effusions

Post-transplant lymphoproliferative disorder is a complication in organ transplant recipients characterized by uncontrolled proliferation of B-lymphocytes, occurring in 6% of pediatric patients, with risk factors including primary Epstein-Barr virus infection, intensity of immunosuppression, and cytomegalovirus infection. The clinical symptoms are often nonspecific, and it is associated with a high mortality rate if left untreated. We describe a rare case of post-transplant lymphoproliferative disorder who presented with pleural-based masses resulting in pleural effusions.

Decoding the molecular heterogeneity of pediatric monomorphic post-solid organ transplant lymphoproliferative disorders

Posttransplant lymphoproliferative disorders (PTLDs) represent a broad spectrum of lymphoid proliferations, frequently associated with Epstein-Barr virus (EBV) infection. The molecular profile of pediatric monomorphic PTLDs (mPTLDs) has not been elucidated, and it is unknown whether they display similar genetic features as their counterpart in adult and immunocompetent (IMC) pediatric patients. In this study, we investigated 31 cases of pediatric mPTLD after solid organ transplantation, including 24 diffuse large B-cell lymphomas (DLBCLs), mostly classified as activated B cell, and 7 cases of Burkitt lymphoma (BL), 93% of which were EBV positive. We performed an integrated molecular approach, including fluorescence in situ hybridization, targeted gene sequencing, and copy number (CN) arrays. Overall, PTLD-BL carried mutations in MYC, ID3, DDX3X, ARID1A, or CCND3 resembling IMC-BL, higher mutational burden than PTLD-DLBCL, and lesser CN alterations than IMC-BL. PTLD-DLBCL showed a very heterogeneous genomic profile with fewer mutations and CN alterations than IMC-DLBCL. Epigenetic modifiers and genes of the Notch pathway were the most recurrently mutated in PTLD-DLBCL (both 28%). Mutations in cell cycle and Notch pathways correlated with a worse outcome. All 7 patients with PTLD-BL were alive after treatment with pediatric B-cell non-Hodgkin lymphoma protocols, whereas 54% of patients with DLBCL were cured with immunosuppression reduction, rituximab, and/or low-dose chemotherapy. These findings highlight the low complexity of pediatric PTLD-DLBCL, their good response to low-intensity treatment, and the shared pathogenesis between PTLD-BL and EBV-positive IMC-BL. We also suggest new potential parameters that could help in the diagnosis and the design of better therapeutic strategies for these patients.

Post-transplant Lymphoproliferative Disorder (PTLD) in the US Population: Demographics, Treatment Characteristics, and Survival Analysis

BACKGROUND

Post-transplant lymphoproliferative disorder (PTLD) is a lymphoplasmacytic proliferative disorder in the setting of hematopoietic stem cells and solid organ transplants. PTLD is divided into nondestructive, polymorphic, monomorphic, and classical Hodgkin lymphoma subtypes. Most cases of PTLDs are Epstein-Barr virus (EBV) related (two third of the cases), and most are of B cell (80-85%) origin. The polymorphic PTLD subtype can be locally destructive and show malignant features. Treatment for PTLD includes a reduction in immunosuppression, surgery, cytotoxic chemotherapy and/or immunotherapy, anti-viral agents, and/or radiation. The aim of this study was to examine the demographic factors and treatment modalities that influence survival in patients with polymorphic PTLD.

METHODS

About 332 cases of polymorphic PTLD were identified from 2000 to 2018 using the Surveillance, Epidemiology, and End Results (SEER) database.

RESULTS

The median age of the patients was found to be 44 years. The most common age groups were between the ages of 1-19 years (n=100. 30.1%) and 60-69 years (n=70. 21.1%). The majority of cases in this cohort underwent systemic (cytotoxic chemo and/or immuno) therapy only (n=137, 41.3%), while 129 (38.9%) cases did not undergo any treatment. The overall five-year observed survival was 54.6% (95% confidence interval (CI), 51.1 - 58.1). One-year and five-year survival with systemic therapy was 63.8% (95% CI, 59.6 - 68.0) and 52.5% (95% CI, 47.7 - 57.3), respectively. The one-year and five-year survival with surgery was 87.3% (95% CI, 81.2-93.4) and 60.8% (95% CI., 42.2 - 79.4), respectively. The one-year and five-year without therapy were 67.6% (95% CI, 63.2-72.0) and 49.6% (95% CI, 43.5-55.7), respectively. Univariate analysis revealed that surgery alone (hazard ratio (HR) 0.386 (0.170-0.879), p = 0.023) was a positive predictor of survival. Race and sex were not predictors of survival, although age >55 years was a negative predictor for survival (HR 1.128 (1.139-1.346), p <0.001).

CONCLUSION

Polymorphic PTLD is a destructive complication of organ transplantation that is usually associated with EBV positivity. We found that it most often presents in the pediatric age group, and its occurrence in those older than 55 years was associated with a worse prognosis. Treatment with surgery alone is associated with improved outcomes and should be considered in addition to a reduction in immunosuppression in cases of polymorphic PTLD.

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.

Multicenter study of pediatric Epstein-Barr virus-negative monomorphic post solid organ transplant lymphoproliferative disorders

BACKGROUND

Pediatric Epstein-Barr virus-negative monomorphic post solid organ transplant lymphoproliferative disorder [EBV(-)M-PTLD] comprises approximately 10% of M-PTLD. No large multi-institutional pediatric-specific reports on treatment and outcome are available.

METHODS

A multi-institutional retrospective review of solid organ recipients diagnosed with EBV(-)M-PTLD aged ≤21 years between 2001 and 2020 in 12 centers in the United States and United Kingdom was performed, including demographics, staging, treatment, and outcomes data.

RESULTS

Thirty-six patients were identified with EBV(-)M-PTLD. Twenty-three (63.9%) were male. Median age (range) at transplantation, diagnosis of EBV(-)M-PTLD, and interval from transplant to PTLD were 2.2 years (0.1-17), 14 years (3.0-20), and 8.5 years (0.6-18.3), respectively. Kidney (n = 17 [47.2%]) and heart (n = 13 [36.1%]) were the most commonly transplanted organs. Most were Murphy stage III (n = 25 [69.4%]). Lactate dehydrogenase was elevated in 22/34 (64.7%) and ≥2 times upper limit of normal in 11/34 (32.4%). Pathological diagnoses included diffuse large B-cell lymphoma (n = 31 [86.1%]) and B-non-Hodgkin lymphoma (B-NHL) not otherwise specified (NOS) (n = 5 [13.9%]). Of nine different regimens used, the most common were: pediatric mature B-NHL-specific regimen (n = 13 [36.1%]) and low-dose cyclophosphamide, prednisone, and rituximab (n = 9 [25%]). Median follow-up from diagnosis was 3.0 years (0.3-11.0 years). Three-year event-free survival (EFS) and overall survival (OS) were 64.8% and 79.9%, respectively. Of the seven deaths, six were from progressive disease.

CONCLUSIONS

EFS and OS were comparable to pediatric EBV(+) PTLD, but inferior to mature B-NHL in immunocompetent pediatric patients. The wide range of therapeutic regimens used directs our work toward developing an active multi-institutional registry to design prospective studies.

PLAIN LANGUAGE SUMMARY

Pediatric Epstein-Barr virus-negative monomorphic post solid organ transplant lymphoproliferative disorders (EBV(-)M-PTLD) have comparable outcomes to EBV(+) PTLD, but are inferior to diffuse large B-cell lymphoma in immunocompetent pediatric patients. The variety of treatment regimens used highlights the need to develop a pediatric PTLD registry to prospectively evaluate outcomes. The impact of treatment regimen on relapse risk could not be assessed because of small numbers. In the intensive pediatric B-non-Hodgkin lymphoma chemoimmunotherapy group, 11 of 13 patients remain alive in complete remission after 0.6 to 11 years.

Presentation and outcomes of post-transplant lymphoproliferative disorder at a single institution pediatric transplant center

BACKGROUND

This study aimed to characterize features present at the time of diagnosis and describe outcomes in patients with post-transplant lymphoproliferative disorder (PTLD) following pediatric solid organ transplantation.

METHODS

We performed a retrospective review of solid organ transplant patients who developed pathologically confirmed PTLD at our center from 2006 to 2016.

RESULTS

Of 594 patients included in this study, 41(6.9%) were diagnosed with PTLD. Median age at transplant was 5.6(IQR 1.7-16.1) years. Proportion of PTLD cases by organ transplanted and median time (IQR) to disease onset were: heart 11/144(7.6%) at 13.6(8.5-55.6) months, lung 7/52(13.5%) at 9.1(4.9-35) months, kidney 8/255(3.1%) at 39.5(13.9-57.1) months, liver 12/125(9.6%) at 7.7(5.5-22) months, intestine 0/4(0%), and multi-visceral 3/14(21.4%) at 5.4(5.4-5.6) months. No significant correlation was seen between recipient EBV status at transplant and timing of development of PTLD. There were six early lesions, 15 polymorphic, 19 monomorphic, and one uncharacterizable PTLD. Following immunosuppression reduction, 30 patients received rituximab, and 14 required chemotherapy. At median 25(IQR 12-53) months follow-up from the onset of PTLD, eight patients died secondary to transplant related complications, three are alive with active disease, and 30 have no evidence of disease.

CONCLUSION

PTLD is a significant complication following pediatric solid organ transplantation. EBV levels in conjunction with symptomatic presentation following transplant may assist in detection of PTLD. Most patients can achieve long-term disease-free survival through immunosuppression reduction, anti-CD20 treatment, and chemotherapy in refractory cases.

Comparison of Post-Transplantation Lymphoproliferative Disorder Risk and Prognostic Factors between Kidney and Liver Transplant Recipients

Post-transplantation lymphoproliferative disorder (PTLD) is a life-threatening complication of solid organ transplantation (SOT). Its development risk varies among organ graft recipients. In this study, retrospective data were analyzed to compare PTLD’s risk and prognostic factors between adult kidney and liver transplant recipients (KTRs and LTRs, respectively). Over 15 years, 2598 KTRs and 1378 LTRs were under observation at our center. Sixteen KTRs (0.62%) and twenty-three LTRs (1.67%) were diagnosed with PTLD. PTLD developed earlier in LTRs (p < 0.001), SOT patients > 45 years old (p = 0.002), and patients receiving tacrolimus (p < 0.001) or not receiving cyclosporin (p = 0.03) at diagnosis. Tacrolimus use, male sex, and age > 45 years old significantly affected the time of PTLD onset in KTRs (hazard ratio (HR) = 18.6, 7.9 and 5.2, respectively). Survival was longer in LTRs < 45 years old (p < 0.009). LTRs were more likely than KTRs to achieve complete remission (p = 0.039). Factors affecting PTLD development and outcome differ between KTRs and LTRs; thus, these populations should be separately evaluated in future studies.

Intensive Safety Monitoring of Rituximab (Biosimilar Novex® and the Innovator) in Pediatric Patients With Complex Diseases

Although rituximab is widely used off-label for complex pediatric diseases, safety reports are limited. We aimed to report evidence of its use in clinical practice, to describe the incidence of adverse drug reactions (ADR) to rituximab biosimilar Novex^® and innovator, and to identify risk factors for the development of ADR in a real-life follow-up cohort of pediatric patients with complex diseases. We conducted a prospective, longitudinal, observational, single-centre study in patients that received rituximab for any complex disease, and as part of an intensive pharmacovigilance program. Demographic, pharmacological, clinical, and drug-related data were collected for all patients. ADR-free survival, including infusion-related reactions (IRR) and delayed ADR (dADR), was estimated using Kaplan-Meier curves. Risk factors were evaluated by multivariable Cox regression models. In total, 77 patients (<19 y.o.) received 187 infusions of rituximab Novex^® (n = 155) or innovator rituximab (n = 32) for neurologic (Neu), immune-hematologic-rheumatic (IHR), oncologic (O) diseases, and hematopoietic stem-cell transplantation (HSCT) or solid-organ transplantation (SOT). We recorded 29 IRR and 58 dADR that occurred in 27 (35.1%) and 29 (37.7%) patients, respectively. The respiratory tract was the most affected during IRR (29.6%) and hypogammaglobulinemia (37.9 %) was the most frequent dADR. First versus subsequent infusions (HR 5.4, CI95% 2.4-12.1, p<0.05), sex (boys vs. girls, HR 0.3, CI95% 0.1-0.8, and p<0.05), and diagnosis (Neu-IHR diseases vs. O-HSCT-SOT, HR 2.3, CI95% 1.02-5.4, and p < 0.05) were significantly associated with the development of IRR. For dADR, risk factors were diagnosis (Neu-IHR diseases vs. O-HSCT-SOT, HR 0.4, CI95% 0.2-0.9, and p < 0.05) and cumulative body surface area-normalized dosage (HR 1.0003, CI95% 1.0001-1.0006, and p < 0.05). The present is the largest real-world safety assessment of rituximab in Latin-American children with complex diseases supporting its use based on the overall acceptable safety. Identification of risk factors may contribute to optimization of off-label rituximab treatment in pediatrics.

Post-transplant lymphoproliferative disease after pediatric kidney transplant

Post-transplant lymphoproliferative disease (PTLD) is the most common malignancy complicating solid organ transplantation (SOT) in adults and children. PTLD encompasses a spectrum of histopathologic features and organ involvement, ranging from benign lymphoproliferation and infectious-mononucleosis like presentation to invasive neoplastic processes such as classical Hodgkin lymphoma. The predominant risk factors for PTLD are Epstein-Barr virus (EBV) serostatus at the time of transplant and the intensity of immunosuppression following transplantation; with EBV-negative recipients of EBV-positive donor organs at the highest risk. In children, PTLD commonly presents in the first two years after transplant, with 80% of cases in the first year, and over 90% of cases associated with EBV-positive B-cell proliferation. Though pediatric kidney transplant recipients are at lower risk (1-3%) for PTLD compared to their other SOT counterparts, there is still a significant risk of morbidity, allograft failure, and an estimated 5-year mortality rate of up to 50%. In spite of this, there is no consensus for monitoring of at-risk patients or optimal management strategies for pediatric patients with PTLD. Here we review pathogenesis and risk factors for the development of PTLD, with current practices for prevention, diagnosis, and management of PTLD in pediatric kidney transplant recipients. We also highlight emerging concepts, current research gaps and potential future developments to improve clinical outcomes and longevity in these patients.

Incidence and mortality of post-transplant lymphoproliferative disorders after kidney transplantation: A real-world retrospective analysis in Japan

OBJECTIVES

Post-transplant lymphoproliferative disorder is a potentially life-threatening complication that has a greater risk of occurrence in the setting of immunosuppression and oncogenic viral infections after transplant surgery. Few studies have reported the cumulative incidence, histological subtypes and clinical outcomes of this disorder in kidney transplant recipients.

METHODS

We retrospectively investigated 34 post-transplant lymphoproliferative disorder patients diagnosed out of the 1210 kidney transplant recipients who had undergone the surgery at the two largest centers in Japan between January 1983 and December 2017.

RESULTS

A total of 32 patients (94.1%) developed late-onset post-transplant lymphoproliferative disorder (diagnosed 1 year after transplantation). The cumulative incidence rates were 0.76% and 1.59% at 5 and 10 years post-transplantation, respectively. The central nervous system was the most common site (35.3%, 12/34). Overall survival was similar between patients with and without central nervous system lesions (P = 0.676). Of all of the cases, 23.5% (8/34) were detected through cancer screening. Importantly, patients with screening-detected post-transplant lymphoproliferative disorder had better overall survival than those with the disorder who had been symptom detected (P = 0.0215). Overall survival was significantly reduced in patients who developed the disorder compared with those who did not (P = 0.0001).

CONCLUSIONS

Post-transplant lymphoproliferative disorder was more likely to occur in the late post-transplantation period, which showed that long-term medical examination for transplant recipients is required. Based on our findings, we propose vigilant, long-term, cancer screening in kidney transplant recipients.

Evolution of pediatric gastrointestinal ulcer disease: Is acute surgical intervention relevant?

BACKGROUND

There is a lack of contemporary data about pediatric gastrointestinal ulcer disease. We hypothesized that ulcers found in immunosuppressed children were more likely to require surgical intervention.

METHODS

All children <21 years (n = 129) diagnosed with ulcers at a quaternary hospital from 1990 to 2019 were retrospectively reviewed. Clinical findings and pertinent information were collected.

RESULTS

Of 129 cases, 19 (14.7%) were immunosuppressed. Eight were post-transplant; four were diagnosed with post-transplant lymphoproliferative disease (PTLD).  Eight were associated with cancer. Three were both.  Three of 19 immunosuppressed and 28/110 immunocompetent patients were taking acid suppression therapy. Nine immunosuppressed patients required surgical intervention, including all PTLD cases, compared to 14 immunocompetent (47.3% vs 16.4%, p < 0.01). Five patients had duodenal perforation, two had multiple small bowel perforations, and two had uncontrolled bleeding. Of 9/19 immunosuppressed patients, surgical complications included bleeding (n = 7), sepsis (n = 2), ostomy reoperation/readmissions (n = 2), and death within 30 days (n = 2). Two/eighteen immunocompetent patients had bleeding complications.

CONCLUSION

Surgical treatment for ulcers remains relevant for pediatric patients. Immunosuppressed patients have more complications, longer hospital stays, and are more likely to need surgical intervention. Efforts should be made for ulcer prophylaxis with a low threshold to investigate epigastric pain in these complex patients.

LEVEL OF EVIDENCE

Prognosis Study Level III Evidence.

Clinicopathologic Characteristics, Treatment, and Outcomes of Post-transplant Lymphoproliferative Disorders: A Single-institution Experience Using 2017 WHO Diagnostic Criteria

The World Health Organization Classification of Tumours of Haematopoietic and Lymphoid Tissues (WHO 2017) included updated criteria for diagnosis and classification of post-transplant lymphoproliferative disorders (PTLDs). This study evaluated the clinicopathologic spectrum using WHO 2017 criteria and adult PTLD patients' outcomes over 30 years between 1987 and 2017 at Mayo Clinic (Rochester, MN). Patients were retrospectively reviewed for clinical features, outcomes, and diagnostic pathology material and classified based on WHO 2017 criteria. A total of 227 patients were diagnosed with PTLD, with a median time from transplant to PTLD of 45 months. PTLD occurred >1 year after transplant in 149 (66%) patients. Monomorphic PTLD was the most common subtype (173, 76%), with diffuse large B cell lymphoma as the commonest morphology (n = 137). Epstein-Barr virus was positive in 61% of total cases and 90% of PTLD that developed within 1 year from transplant. The median event-free survival (EFS) and overall survival for the entire cohort were 21 months (95% confidence interval [CI]: 9-35) and 82 months (95% CI: 39-115), respectively. The EFS or overall survival was not impacted by Epstein-Barr virus status but differed based on WHO subtypes and year of diagnosis. Management changed over time with increased use of rituximab or chemotherapy + immunosuppression reduction as initial therapy. When compared to the matched general population and de novo diffuse large B cell lymphoma, patients not achieving EFS 24 status (no progression/treatment or death within 24 mo of diagnosis) had a worse standardized mortality ratio 16.75 (95% CI: 13.91-20) versus SMR 1.72 (95% CI: 1.26-2.28) in those who achieved EFS24. Cause of death was mostly attributed to non-lymphoma-related causes in those achieving EFS 24.

EBV Predicts Post-Pediatric Heart Transplant Malignancy; Induction Therapy and Tacrolimus Don't

BACKGROUND

Patients after heart transplantation are at increased risk for malignancy secondary to immunosuppression and oncogenic viral infections. Most common amongst children is post-transplant lymphoproliferative disorder (PTLD), occurring in 5-10% of patients. We utilized a national database to examine incidence and risk factors for post-transplant malignancy.

METHODS

The United Network for Organ Sharing (UNOS) database was queried for pediatric (<18 years) heart transplant recipients from 10/1987-10/2019. Kaplan-Meier analysis was performed to assess freedom from malignancy post-transplant. Cox regression was performed to generate hazard ratios (HR [95% CI]) for risk of malignancy development.

RESULTS

Of 8,581 pediatric heart transplant recipients, 8.1% developed malignancy over median follow-up time of 6.3 years, with PTLD compromising the majority (86.4%) of diagnosed cancers. The incidence of PTLD development was 1.3% and 4.5% at one and five years. Older age at the time of transplant was protective against the development of malignancy (HR 0.98 [0.96-0.99], p<0.001), whereas a history of previous malignancy (HR 1.9 [1.2-3.0], p=0.007) and Ebstein-Barr virus (EBV) recipient-donor mismatch (HR 1.7 [1.3-2.2], p<0.001) increased the risk. Use of induction therapy (utilized in 78.9% of the cohort) did not increase malignancy risk (p=0.355); nor did use of maintenance tacrolimus (p=0.912).

CONCLUSIONS

PTLD occurred after 7% of pediatric heart transplants, with risk increased by younger age and EBV mismatch, highlighting the importance of PTLD monitoring in EBV seronegative recipients. Induction therapy, utilized in the majority of pediatric heart transplants, does not seem to increase post-transplant malignancy, nor does the most commonly used calcineurin inhibitor tacrolimus.

Cancer After Pediatric Kidney Transplantation: A Long-term Single-center Experience in Japan

Background

The cancer incidence, types, and risk factors after pediatric kidney transplantation (KT) have been reported in the United States, Canada, Europe, Australia, and New Zealand. However, no information is available about cancer in pediatric KT recipients in Asian countries.

Methods

Children aged <20 y who underwent initial KT from 1983 to 2016 were analyzed. We compared the cancer incidence with that in the general Japanese population using standardized incidence ratio and examined posttransplant cancer risk using Cox proportional hazards models.

Results

A total of 356 children (median age, 11.7 y; interquartile range, 5.0-17.6) received KT with a follow-up period of 4466 person-years. The median age of cancer onset was 18.5 y (interquartile range, 8.0-32.3), and 13 cancers occurred in 12 patients (3.4%). Two patients died from cancer. The most common cancers were posttransplant lymphoproliferative disorders (PTLDs) (38.5%). The median time to PTLD and non-PTLD diagnosis after KT was 0.6 and 16.4 y, respectively. There was no occurrence of skin cancer. The posttransplant cancer incidence was 9.9 times higher than that in the general age-matched population (standardized incidence ratio = 9.9; 95% confidence interval, 4.80-18.39). The cumulative cancer incidence was 5.3% in 20 y after KT, which is lower than that reported in previous studies. We could not identify any risk factors for all cancer after KT in all patients, whereas subgroup analysis in 264 patients with available data of recipient Epstein-Barr virus serological status showed that recipient Epstein-Barr virus-negative serology was an independent risk factor for cancer development.

Conclusions

The incidence of cancer is higher in Japanese pediatric KT recipients than in the general population. The cumulative incidence of cancer after KT was lower in our population than that previously reported. This may be because there was no skin cancer observed in the Japanese pediatric KT recipients in our study.

The impact of chronic Epstein-Barr virus infection on the liver graft of pediatric liver transplant recipients: A retrospective observational study

BACKGROUND

Chronic high Epstein-Barr virus loads (CHEBV) are commonly observed in pediatric liver transplant patients. However, it is unclear how CHEBV impacts the liver graft. The aim of this study was to clarify the clinical and pathological impacts of CHEBV on the liver graft.

METHODS

From 2012 to 2020, we retrospectively investigated 46 pediatric liver transplant patients (under 16 years) who survived ≥6 months. The patients were divided into two groups: CHEBV group (EBV DNA >10 000 IU/ml of whole blood for ≥6 months) and nonchronic high EBV (NCHEBV) group (patients who did not meet CHEBV criteria). Tacrolimus was reduced to <3.0 ng/ml in patients with EBV DNA >5000 IU/ml. Blood biochemistry data and pathological findings, obtained at the time of protocol and episodic biopsies, were compared between the two groups.

RESULTS

Out of 46 patients, 28 CHEBV and 18 NCHEBV patients were enrolled. The blood biochemical examination did not show a significant difference between the two groups. In addition, no significant differences between the two groups were found in the pathological findings, including frequency of late acute rejection and the progression of fibrosis at the time of both protocol and episodic biopsies. Appropriate adjustment of immunosuppression for CHEBV management may have contributed to the prevention of the progression of fibrosis.

CONCLUSION

CHEBV had little adverse effect on the liver graft. Graft fibrosis might have been avoided through optimal dose modification of tacrolimus. Further long-term monitoring is necessary because CHEBV may affect the pediatric liver graft in the long term.

Course of renal allograft function after diagnosis and treatment of post-transplant lymphoproliferative disorders in pediatric kidney transplant recipients

BACKGROUND

Post-transplant lymphoproliferative disease (PTLD) is a life-threatening complication in renal transplant recipients. Immunomodulatory and chemotherapeutic treatment potentially affect allograft function. The aim of this study was to evaluate graft function of pediatric kidney transplant recipients following diagnosis and standardized treatment of PTLD.

METHODS

Patients were identified from the German Ped-PTLD registry, and data on renal function were retrospectively retrieved from patient charts. For PTLD treatment, immunosuppressive therapy was reduced and all children received rituximab (375 mg/m² ) for up to six doses. Two patients required additional low-dose chemotherapy. Renal allograft function was monitored by consecutive measurements of estimated glomerular filtration rate (eGFR) at defined time points. Follow-up was up to 60 months after PTLD.

RESULTS

Twenty patients were included in this cohort analysis. Median time from transplantation to PTLD was 2.4 years. Histopathology showed monomorphic lesions in 16 and polymorphic in 4 patients. Two patients experienced PTLD relapse after 2 and 14 months. Range-based analysis of variance showed stable allograft function in 17 of 20 patients (85%). Mean eGFR increased during early treatment phase. One patient experienced graft rejection 5.3 years after diagnosis of PTLD. Another patient developed recurrence of primary renal disease (focal-segmental glomerulosclerosis) and lost his renal allograft 3.8 years post-transplant (2.0 years after PTLD diagnosis).

CONCLUSION

Treatment of PTLD with rituximab with or without low-dose chemotherapy in combination with reduced immunosuppression, mostly comprising of an mTOR inhibitor-based, calcineurin inhibitor-free regimen, is associated with stable graft function and favorable graft survival in pediatric renal transplant patients.

Complete remission from post-heart transplant lymphoproliferative disorder: A case report

We report a case of Burkitt's lymphoma, post-transplant lymphoproliferative disorder (BL-PTLD) that was treated with intensive chemotherapy. The patient was a 4-year-old boy who underwent heart transplantation at 7 months of age for refractory heart failure due to dilated cardiomyopathy. He was admitted to our hospital with a chief complaint of abdominal pain associated with an abdominal mass. Computed tomography was notable for a bulky mass arising from the terminal ileum. Fluorodeoxyglucose-positron emission tomography revealed multiple lesions in brain, bone, and lymph nodes. He was diagnosed with BL-PTLD stage III by pathological and clinical scoring. He was Epstein-Barr virus (EBV)-seronegative with a low EBV viral DNA load. No EBV-encoded small RNAs were in his intra-abdominal lymph nodes by in situ hybridization. On cytogenetic examination, the intra-abdominal lymph nodes revealed both a MYC rearrangement and a t(8;14)(q24;32), t(16;19)(q24;q13.1) translocation. Administration of tacrolimus and mycophenolate mofetil was discontinued; immunosuppression was maintained with everolimus. Intensive chemotherapy based on the modified LMB 96 protocol for BL was initiated, resulting in complete remission achieved. During the intensive chemotherapy and immunosuppressive switching period, cardiac dysfunction and allograft rejection had not been shown. The patient has remained well for two years after the treatment with no evidence of relapse. <Learning objective: Post-transplant lymphoproliferative disorder (PTLD) is a life-threatening complication that can develop after heart transplantation and result in significant morbidity and mortality. In the case presented here, intensive chemotherapy and modified immunosuppressive therapy are among the most effective treatments for PTLD patients with an otherwise poor prognosis. Maintaining a fine balance between management of the PTLD and preventing allograft rejection is critically important.>.

Treatment of post-transplant lymphoproliferative disorder (PTLD) in a heart transplant recipient with chimeric antigen receptor T-cell therapy

Post-transplant lymphoproliferative disorders (PTLD) are a group of lesions that can complicate solid organ or hematopoietic stem cell transplantation and are often associated with Epstein-Barr virus (EBV). The treatment of PTLD is dependent on the type of lesion and includes a wide range of therapies, but chimeric antigen receptor (CAR) T-cell therapy has not previously been reported as a treatment option for PTLD. We present a patient who developed refractory PTLD in her right retroperitoneum, right inguinal and iliac chains, and right axillary region shortly after heart transplantation and was treated with CAR T-cell therapy. She could not tolerate complete discontinuation of immunosuppression due to the risk of rejection of a life-supporting graft. The patient's PTLD responded to CAR T-cell therapy, and her heart was monitored throughout the treatment course without any signs of rejection or ventricular dysfunction. CAR T-cell therapy may be a viable treatment option in patients who develop PTLD after a solid organ transplant.

Distinctive Clinicopathologic Features of Monomorphic B-cell Post-transplant Lymphoproliferative Disorders in Children

INTRODUCTION

Post-transplant lymphoproliferative disorders (PTLDs) comprise a heterogeneous group of Epstein-Barr virus (EBV)-positive or negative lymphoid or plasmacytic lesions in solid organ or hematopoietic stem cell (HSC) transplant recipients. Although PTLDs in adults have been extensively studied, the clinicopathologic features of monomorphic B-cell PTLD in children, particularly EBV-negative forms, are still poorly understood.

METHODS

We retrospectively reviewed all our pediatric cases of monomorphic B-cell PTLDs diagnosed in the past 10 years. Clinical data were reviewed. Pathologic data including histologic types and EBV status were analyzed. Additional immunohistochemical stains, FISH studies, and TP53 gene mutational status were performed.

RESULTS

4 of 18 cases were EBV-negative. All 4 EBV-negative cases were strikingly confined to the gastrointestinal (GI) tract or abdominal lymph nodes, while tumors in EBV-positive cases were found at various anatomic sites; 2 of 4 EBV-negative cases carried mutations in TP53 gene. Our cohort also included 2 rare types of PTLD, one plasmablastic lymphoma and one high-grade B-cell lymphoma, not otherwise specified (HGBL, NOS).

CONCLUSION

We report that monomorphic B-cell PTLDs in children have distinctive clinical and pathological features. More studies are needed to clarify whether and how much these pediatric PTLDs differ from their adult counterparts.

Recurrent Intestinal Perforation After Cessation of Immunosuppression in Posttransplant Lymphoproliferative Disease in Pediatric Liver Transplant Recipient

Posttransplant lymphoproliferative disease (PTLD) is the most common malignant complication after solid organ transplantation. Gastrointestinal involvement as the presentation in early PTLD can occur in 25-30% of pediatric liver transplant recipients and can be the only system involved in 20%. Recurrent gastrointestinal perforation due to resolution of PTLD is an extremely rare complication. We report a 13-month-old male child diagnosed with PTLD, treatment of which lead to recurrent intestinal perforations. The child presented with gastrointestinal bleed 5 months after living donor liver transplantation for biliary atresia. Evaluation was suggestive of PTLD and biopsy confirmed diffuse large B-cell lymphoma. Positron emission tomography scan showed diffuse involvement of small intestine and ileum. Tacrolimus was withdrawn abruptly following diagnosis of PTLD as there was associated renal impairment. Child developed six episodes of small intestinal perforations over 3 weeks which required multiple laparotomies with closure of perforation and/or small bowel resection. Complete remission was achieved six months after diagnosis with cessation of immunosuppression alone and child is alive at 48 months follow-up without any recurrence. To avoid bowel perforation and complications related to tumor necrosis, immunosuppression reduction in PTLD should be gradual while carefully monitoring Epstein-Barr virus levels, tumor response, graft function, and general health status of the patient.

Analysis of Post-Transplant Lymphoproliferative Disorder (PTLD) Outcomes with Epstein-Barr Virus (EBV) Assessments-A Single Tertiary Referral Center Experience and Review of Literature

Post-transplant lymphoproliferative disorders (PTLDs) are lymphoid or plasmacytic proliferations ranging from polyclonal reactive proliferations to overt lymphomas that develop as consequence of immunosuppression in recipients of solid organ transplantation (SOT) or allogeneic bone marrow/hematopoietic stem cell transplantation. Immunosuppression and Epstein-Barr virus (EBV) infection are known risk factors for PTLD. Patients with documented histopathologic diagnosis of primary PTLD at our institution between January 2000 and October 2019 were studied. Sixty-six patients with PTLD following SOT were followed for a median of 9.0 years. The overall median time from transplant to PTLD diagnosis was 5.5 years, with infant transplants showing the longest time to diagnosis at 12.0 years, compared to pediatric and adolescent transplants at 4.0 years and adult transplants at 4.5 years. The median overall survival (OS) was 19.0 years. In the monomorphic diffuse large B-cell (M-DLBCL-PTLD) subtype, median OS was 10.7 years, while median OS for polymorphic subtype was not yet reached. There was no significant difference in OS in patients with M-DLBCL-PTLD stratified by quantitative EBV viral load over and under 100,000 copies/mL at time of diagnosis, although there was a trend towards worse prognosis in those with higher copies.

18F-FDG PET/CT for Evaluation of Post-Transplant Lymphoproliferative Disorder (PTLD)

Post-transplant lymphoproliferative disorders (PTLD) are a spectrum of heterogeneous lymphoproliferative conditions that are serious and possibly fatal complications after solid organ or allogenic hematopoietic stem cell transplantation. Most PTLD are attributed to Epstein-Barr virus reactivation in B-cells in the setting of immunosuppression after transplantation. Early diagnosis, accurate staging, and timely treatment are of vital importance to reduce morbidity and mortality. Given the often nonspecific clinical presentation and disease heterogeneity of PTLD, tissue biopsy and histopathological analysis are essential to establish diagnosis and most importantly, determine the subtype of PTLD, which guides treatment options. Advanced imaging modalities such as ¹⁸F-FDG PET/CT have played an increasingly important role and have shown high sensitivity and specificity in detection, staging, and assessing treatment response in multiple clinical studies over the last two decades. However, larger multicenter prospective validation is still needed to further establish the clinical utility of PET imaging in the management of PTLD. Significantly, new hybrid imaging modalities such as PET/MR may help reduce radiation exposure, which is especially important in pediatric transplant patients.

Thiopurines in Pediatric Inflammatory Bowel Disease: Current and Future Place

Thiopurines have been widely used to maintain steroid-free remission in children with inflammatory bowel disease (IBD). However, within the expanding treatment armamentarium, the role of these non-selective immunomodulators has been questioned, especially in pediatric patients, who often present with a more aggressive disease course, which can impact growth and development. The less favorable safety but also inferior efficacy profile associated with thiopurines, in contrast to the newer biological therapies, has interfered with their use. The future place of thiopurines in the management of childhood IBD, therefore, needs revisiting. This review provides a practical overview on the historical and current use of thiopurines in pediatric IBD with specific attention for thiopurine S-methyltransferase testing and monitoring of thiopurine metabolite levels as an approach to improve outcomes. We also give a personal expert opinion on the future role of these drugs in childhood IBD.

Ex-vivo delivery of monoclonal antibody (Rituximab) to treat human donor lungs prior to transplantation

Background

Ex-vivo lung perfusion (EVLP) is an innovative platform for assessing donor lungs in the pre-transplant window. In this study, we demonstrate an extension of its utility by administering the anti-CD20 monoclonal antibody, Rituximab, during EVLP. We hypothesized that this would lead to targeted depletion of allograft B-cells which may provide significant clinical benefit, including the potential to reduce latent Epstein-Barr virus (EBV) and decrease the incidence of post-transplant lymphoproliferative malignancies.

Methods

Twenty human donor lungs rejected for transplantation were placed on EVLP with (n = 10) or without (n = 10) 500 mg of Rituximab. Safety parameters such as lung physiology and inflammatory cytokines were evaluated. We measured the delivery efficacy through flow cytometry, immunohistochemistry and ELISA. An in-vitro culture assay, in the presence of complement, was further conducted to monitor whether B-cell depletion would occur in Rituximab-perfused samples.

Findings

Rituximab was successfully delivered to human lungs during EVLP as evidenced by flow cytometric binding assays where lung tissue and lymph node biopsies demonstrated occupied CD20 epitopes after perfusion with the antibody. Lymph nodes from Rituximab perfusions demonstrated a 10.9 fold-reduction in CD20+ staining compared to controls (p = 0.0003). In lung tissue, Rituximab resulted in an 8.75 fold-reduction in CD20+ staining relative to controls (p = 0.0002). This decrease in CD20+ binding illustrates the successful delivery and occupation of epitopes after perfusion with the Rituximab. No apparent safety concerns were seen as exhibited by markers associated with acute cell injury (e.g., proinflammatory cytokines), cell death (e.g., TUNEL staining), or pulmonary physiology. In a post-perfusion tissue culture model, the addition of complement (human serum) resulted in evidence of B-cell depletion consistent with what would be expected with posttransplant activation of bound Rituximab.

Interpretation

Our experiments illustrate the potential of EVLP as a platform to deliver monoclonal antibody therapies to treat donor lungs pretransplant with the goal of eliminating a latent virus responsible for considerable morbidity after lung transplantation.

Funding

Supported by the University Health Network Transplant Center.

Transient-mixed Chimerism With Nonmyeloablative Conditioning Does Not Induce Liver Allograft Tolerance in Nonhuman Primates

BACKGROUND

Although short-term outcomes for liver transplantation have improved, patient and graft survival are limited by infection, cancer, and other complications of immunosuppression. Rapid induction of tolerance after liver transplantation would decrease these complications, improving survival and quality of life. Tolerance to kidneys, but not thoracic organs or islets, has been achieved in nonhuman primates and humans through the induction of transient donor chimerism. Since the liver is considered to be tolerogenic, we tested the hypothesis that the renal transplant transient chimerism protocol would induce liver tolerance.

METHODS

Seven cynomolgus macaques received immune conditioning followed by simultaneous donor bone marrow and liver transplantation. The more extensive liver surgery required minor adaptations of the kidney protocol to decrease complications. All immunosuppression was discontinued on postoperative day (POD) 28. Peripheral blood chimerism, recipient immune reconstitution, liver function tests, and graft survival were determined.

RESULTS

The level and duration of chimerism in liver recipients were comparable to those previously reported in renal transplant recipients. However, unlike in the kidney model, the liver was rejected soon after immunosuppression withdrawal. Rejection was associated with proliferation of recipient CD8 T effector cells in the periphery and liver, increased serum interleukin (IL)-6 and IL-2, but peripheral regulatory T cell (Treg) numbers did not increase. Antidonor antibody was also detected.

CONCLUSIONS

These data show the transient chimerism protocol does not induce tolerance to livers, likely due to greater CD8 T cell responses than in the kidney model. Successful tolerance induction may depend on greater control or deletion of CD8 T cells in this model.

Epstein-Barr viral load monitoring for diagnosing post-transplant lymphoproliferative disorder in pediatric liver transplant recipients

This study aimed to investigate the incidence of PTLD in pediatric liver transplant recipients and the risk factors for the development of PTLD. We also determined clinically useful quantitative EBV PCR parameters for aiding in the diagnosis of EBV-associated PTLD in the pediatric liver transplant recipients at our institute. We reviewed children < 18 years old who had undergone liver transplantations and quantitative analysis of whole blood EBV load at our institute from January 2006 to March 2015. A total of 142 liver transplant recipients were included, and their median age was 1.5 years. Clinically significant high-level EBV DNAemia ≥ 10 000 copies/mL at least twice was observed in 53.5% and PTLD occurred in 9.9%. Among PTLD group, graft failure and mortality rate were as high as 21.4% and 14.3%, respectively. Deceased donor, presence of high-level EBV DNAemia, and primary CMV infection following transplant were associated with an increased risk for PTLD in the multivariate analysis. The peak titer at 10 875 copies/mL could be used as a cutoff value with a sensitivity of 92.9% and a specificity of 37.9%; the rate of increase in EBV load suggested a sensitivity of 64.3% and a specificity of 70.9% at the cutoff value of 44 000 copies/mL/week. In conclusion, the incidence of PTLD following liver transplant in children was as high as 10%. PTLD is associated with significant morbidity and mortality. Close monitoring of EBV DNAemia is crucial for the early diagnosis and proper treatment of PTLD in pediatric liver transplant recipients.

Spectrum of Posttransplant Lymphoproliferations in NSG Mice and Their Association With EBV Infection After Engraftment of Pediatric Solid Tumors

Pediatric patients receiving solid organ transplants may develop lymphoproliferative diseases, including graft-versus-host disease (GvHD) and posttransplant lymphoproliferative diseases (PTLDs). We characterized lesions in 11 clinically ill NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice that received pediatric-patient-derived solid tumors (PDXs) and developed immunodeficiency-associated lymphoproliferations comparable to GvHD and PTLDs over a period of 46 to 283 days after implantation. Lymphoproliferations were diffusely positive for human-specific biomarkers, including NUMA1, CD45, and CD43, but lacked immunoreactivity for murine CD45. Human immune cells were CD3-positive, with subsets having immunoreactivity for CD4 and CD8 as well as PAX5, CD79a, and IRF4, resulting from populations of human T and B cells present within the xenotransplants. Tissues and organs infiltrated included mucocutaneous zones (oral cavity and perigenital and perianal regions), haired skin, tongue, esophagus, forestomach, thyroid, salivary glands, lungs, liver, kidneys, spleen, lymph nodes, bone marrow, and brain. In 4 of 5 mice with PTLD, Epstein-Barr virus (EBV)-encoded small RNAs (EBERs) were detected by in situ hybridization in PAX5+ human B cells associated with the PDX (n = 1/4) or with engrafted human immune cells at other anatomic locations (n = 4/11). One of the 4 mice had an EBV-associated human large B-cell lymphoma. NSG mice receiving xenotransplants can develop combinations of GvHD, EBV-driven PTLD, and B-cell lymphoma similar to those occurring in human pediatric patients. Therefore, pediatric xenotransplants should undergo histopathologic and immunohistochemical assessment upon collection to ensure that the specimen is not a lymphoma and does not contain lymphoma cells because these neoplasms can morphologically mimic small round blue cell pediatric solid tumors.

Atypical malignancies after intestinal transplantation in children: A European single-centre experience

BACKGROUND

Post-transplant malignancies, that is, lymphomas, are a recognized complication in intestinal transplant recipients but are mostly secondary to EBV infection. There is an increased risk for malignancies in unusual sites in intestinal transplant recipients as compared to other solid organ transplants and the general population.

OBJECTIVE

To evaluate the incidence, course, and outcome of unusual malignancies in children after ITx.

METHODS

Retrospective analysis of children who underwent ITx for primary digestive disorders at Birmingham Children's Hospital between January 1989 and December 2017.

RESULTS

Ninety-eight intestinal transplants were performed in 90 children (49 males and 41 females) with an underlying primary digestive disorder. Median age was 2.7 years (0.6-16.2), and median weight was 14.5 kg (5.7-53.2) at the time of transplant. Within this cohort, we identified four cases of unusual malignancies at rare sites of presentation. One patient developed cerebral PTLD, two patients were diagnosed with SMT, located at the stomal orifice and in cervicothoracic paravertebral area, respectively, and the last patient developed a retroperitoneal angiosarcoma. Unfortunately, the overall patient outcome was poor in all but one child with SMT, who currently survives with cytotoxic T-cell therapy.

CONCLUSION

Unusual malignancies can occur in approximately 5% of children following ITx. A high index of suspicion is required for a timely diagnosis and adequate treatment.

De novo malignancies after liver transplantation: The effect of immunosuppression-personal data and review of literature

BACKGROUND

Immunosuppression has undoubtedly raised the overall positive outcomes in the post-operative management of solid organ transplantation. However, long-term exposure to immunosuppression is associated with critical systemic morbidities. De novo malignancies following orthotopic liver transplants (OLTs) are a serious threat in pediatric and adult transplant individuals. Data from different experiences were reported and compared to assess the connection between immunosuppression and de novo malignancies in liver transplant patients.

AIM

To study the role of immunosuppression on the incidence of de novo malignancies in liver transplant recipients.

METHODS

A systematic literature examination about de novo malignancies and immunosuppression weaning in adult and pediatric OLT recipients was described in the present review. Worldwide data were collected from highly qualified institutions performing OLTs. Patient follow-up, immunosuppression discontinuation and incidence of de novo malignancies were reported. Likewise, the review assesses the differences in adult and pediatric recipients by describing the adopted immunosuppression regimens and the different type of diagnosed solid and blood malignancy.

RESULTS

Emerging evidence suggests that the liver is an immunologically privileged organ able to support immunosuppression discontinuation in carefully selected recipients. Malignancies are often detected in liver transplant patients undergoing daily immunosuppression regimens. Post-transplant lymphoproliferative diseases and skin tumors are the most detected de novo malignancies in the pediatric and adult OLT population, respectively. To date, immunosuppression withdrawal has been achieved in up to 40% and 60% of well-selected adult and pediatric recipients, respectively. In both populations, a clear benefit of immunosuppression weaning protocols on de novo malignancies is difficult to ascertain because data have not been specified in most of the clinical experiences.

CONCLUSION

The selected populations of tolerant pediatric and adult liver transplant recipients greatly benefit from immunosuppression weaning. There is still no strong clinical evidence on the usefulness of immunosuppression withdrawal in OLT recipients on malignancies. An interesting focus is represented by the complete reconstitution of the immunological pathways that could help in decreasing the incidence of de novo malignancies and may also help in treating liver transplant patients suffering from cancer.

Hypogammaglobulinemia and bacterial infections following pediatric post-transplant lymphoproliferative disorder in the rituximab era

INTRODUCTION

Treatment of PTLD using immune-depleting agents such as RTX may be associated with increased risk of infections. The aim of this report was to describe the incidence of hypogammaglobulinemia and bacterial infections in children with PTLD after SOT at a single center since the introduction of RTX.

METHODS

A retrospective review was conducted over a study period of 2000-2016 in pediatric patients diagnosed with biopsy-proven PTLD based on the WHO histologic criteria. Hypogammaglobulinemia was defined by serum IgG <4 g/L; CPBI was defined by clinically significant infection by an identified pathogenic bacteria isolated from a normally sterile body site.

RESULTS

Twenty-eight patients were included, comprising 16 LTx and 12 ITx patients, and 17 patients received RTX therapy. Total of 31 episodes of CPBI occurred in 16 patients. Incidence of CPBI was 31.4 infections per 100 patient-years in RTX-treated patients, as compared to 8.4 infections per 100 patient-years in non-RTX-treated patients (P < 0.001). Hypogammaglobulinemia was significantly more prevalent after 6 months (P = 0.001) and 2 years (P = 0.005) in RTX-treated patients, as compared to none in the group that did not receive RTX. Hypogammaglobulinemia (P = 0.047), ITx (P = 0.027), and monomorphic PTLD (P = 0.024) were significantly associated with recurrent (≥2) CPBI and/or CPBI-related deaths within the first year post-PTLD.

CONCLUSION

While RTX is an effective treatment for PTLD, hypogammaglobulinemia can persist for up to 2 years following RTX therapy, which may be associated with the higher cumulative rates of CPBI observed in RTX-treated patients.

Risk factors and incidence of malignant neoplasms after kidney transplantation at a single institution in Japan

BACKGROUND

The risk of malignant neoplasms increases in kidney transplantation (KT) recipients (KTRs). However, Japanese registry studies have not been reported since 2000.

METHODS

We retrospectively reviewed the medical records of 346 patients who underwent KT at Gifu University Hospital, Japan since 2000. Patients were divided into two groups based on whether they developed malignancy after KT or not. The incidence, type of malignancy, risk factors, and prognosis for malignancy were examined.

RESULTS

In this study, 22 de novo malignant neoplasms were identified in 20 KTRs (7.3%), with a median follow-up period of 8.2 years. Cumulative incidence of any malignant neoplasms was 1.1% within 1 year and 4.4% within 5 years. The 5-year overall survival (OS) rates were 71.8% in KTRs with malignant neoplasms and 98.6% in KTRs without malignant neoplasms. Uni- and multivariate analysis revealed that age at KT and acute rejection (AR) episode were significant predictors for incidence of malignancy.

CONCLUSIONS

The development of malignant neoplasms was associated with poor OS and graft survival. We consider that appropriate screening and investigation of symptoms are important for KTRs, particularly for older KTRs at transplantation and those with AR episode.

Various initial presentations of Epstein-Barr virus infection-associated post-transplant lymphoproliferative disorder in pediatric liver transplantation recipients: Case series and literature review

PTLD is a rare but potentially life-threatening condition, which shows a higher prevalence in children than in adults. From 129 children who underwent LT, we reported 5 cases with biopsy-proven PTLD at a single teaching hospital. Four patients had shared clinical presentations including fever, lymphadenopathy, and splenomegaly. They were noted to be given a prolonged course of IS due to the management of comorbid complications such as acute cellular rejection or severe food allergy or eosinophilic gastrointestinal disease. The other one patient presented with upper gastrointestinal bleeding from gastric mass during an early post-transplantation period. Notably, hypoalbuminemia was noted in all reported patients. Similar to previous studies, both EBV serology mismatch between the donor and recipient with high EBV viral load were noted in all except one case, whose EBV serology was unknown before LT. At least one episode of CMV reactivation was also observed in 3 of 5 patients prior to the PTLD diagnosis. The histopathology revealed 1 of 5 early PTLD, 1 of 5 polymorphic PTLD, and 3 of 5 monomorphic PTLD. The treatment included IS withdrawal, chemotherapy, and/or rituximab. One patient died of multiorgan dysfunction, one remains in complete remission, and three patients are either still on treatment or await response evaluation. Even though most of our reported PTLD cases had shared manifestations with fever, lymphadenopathy, splenomegaly, EBV serology mismatch, and high EBV viral load, various initial presentations such as respiratory symptoms, hypoalbuminemia, and prolonged use of IS from other causes such as significant food allergy were noted.

Targeted Therapy for EBV-Associated B-cell Neoplasms

Epstein-Barr virus (EBV) is directly implicated in several B-cell lymphoid malignancies. EBV-associated lymphomas are characterized by prominent activation of the NF-κB pathway and targeting this pathway establishes a rationale for a therapeutic approach. The ubiquitin/proteasome signaling plays an essential role in the regulation of the NF-κB pathway. Ixazomib is an FDA-approved, orally bioavailable proteasome inhibitor. Here we report the first preclinical evaluation of ixazomib-mediated growth-inhibitory effects on EBV-infected B-lymphoblastoid cell lines Raji and Daudi. Ixazomib induced apoptosis in these cell lines in a dose-dependent manner. Cell-cycle analysis demonstrated ixazomib treatment induced cell-cycle arrest at the G₂-M phase with a concomitant decrease in G₀-G₁ and S phases. The results further revealed an increase in p53, p21, and p27 levels and a decrease in survivin and c-Myc protein levels. Mechanistically, ixazomib treatment resulted in the accumulation of polyubiquitinated proteins, including phosphorylated IκBα with a significant reduction of p65 subunit nuclear translocation. Altogether, our preclinical data support the rationale for in vivo testing of ixazomib in EBV-associated B-cell neoplasms. IMPLICATIONS: This preclinical study supports the use of oral proteasome inhibitor ixazomib for targeting NF-κB signaling in the treatment of EBV-associated B-cell neoplasms.Visual Overview: http://mcr.aacrjournals.org/content/molcanres/17/4/839/F1.large.jpg.

Posttransplant Lymphoproliferative Disorder: Experience from a Pediatric Nephrology Unit in North India

Posttransplant lymphoproliferative disorder (PTLD) is reported in 1%–3% among pediatric renal allograft recipients. We report the experience of PTLD among pediatric renal allograft recipients at a pediatric nephrology center in North India. Four cases of PTLD were identified from among records of 95 pediatric renal allograft recipients over a period of 21 years. Constitutional and localizing symptoms were present in three patients each. The diagnosis was suggested on positron emission tomography in three patients and confirmed by histopathology in all. Sites affected included tonsils, cervical lymph nodes, duodenum, and para-aortic lymph nodes in one patient each. The lymphocytic infiltrate was polymorphic in three patients and monomorphic in one. Immunostaining suggested B-cell origin in all patients. There was evidence of Epstein–Barr virus infection in only one patient. The patients were successfully managed with reduction of immunosuppression (in all), rituximab (in 3), and excision of affected tissue (in 1). Over a follow-up period of 30–88 months, there were no episodes of disease recurrence or allograft rejection, and renal function was preserved.

Improvements in intestine transplantation

Transplantation of the intestine in children has presented significant challenges even as it has become a standard to treat nutritional failure due to short gut syndrome. These challenges have been addressed in part by significant improvements in short and long-term care. Noteworthy enhancements include reduced need for intestine transplantation, drug-sparing immunosuppressive regimens, immune monitoring, and improved surveillance and management of PTLD and non-adherence.

Post-transplant lymphoproliferative disorder in pediatric intestinal transplant recipients: A literature review

Intestinal transplantation is a successful treatment for children with intestinal failure, but has many potential complications. PTLD, a clinically and histologically diverse malignancy, occurs frequently after intestinal transplantation and can be fatal. The management of this disease is particularly challenging. The rejection-prone intestinal allograft requires high levels of immunosuppression, a precondition for PTLD. While EBV infection clearly plays a role in disease pathogenesis, the relatively naïve immune system of children is another likely contributor. As a result, pediatric intestine recipients have a higher risk of developing PTLD than other solid organ recipients. Other risk factors for disease development such as molecular and genomic changes that precipitate malignant transformation are not fully understood, especially among children. Studies on adults have started to describe the molecular pathogenesis of PTLD, but the genomic landscape of the malignancy remains largely undefined in pediatric intestinal transplant patients. In this review, we describe what is known about PTLD in pediatric patients after intestinal transplant and highlight current knowledge gaps to better direct future investigations in the pediatric population.

Autoimmune Lymphoproliferative Syndrome Masquerading as Posttransplant Lymphoproliferative Disorder

We present a case of a 2-year-old female presenting with diffuse lymphadenopathy 2 years following orthotopic heart transplant. Initially, she was diagnosed with posttransplant lymphoproliferative disease based on clinical presentation and pathology and she was treated accordingly. Because of persistent lymphadenopathy following the completion of chemotherapy and new onset of autoimmune cytopenias, repeat flow of the lymph node showed an elevated double negative T-cell population prompting evaluation for autoimmune lymphoproliferative syndrome (ALPS). A complete workup was confirmative of a germline Fas mutation consistent with ALPS-FAS. This case emphasizes the importance of considering ALPS-FAS in a patient with lymphadenopathy of unknown cause.

Dissecting Epstein-Barr Virus-Specific T-Cell Responses After Allogeneic EBV-Specific T-Cell Transfer for Central Nervous System Posttransplant Lymphoproliferative Disease

Epstein-Barr virus (EBV)-associated posttransplant lymphoproliferative disease (PTLD) with central nervous system (CNS) involvement is a severe complication after solid organ transplantation. Standard treatment with reduction of immunosuppression and anti-CD20 antibody application often fails leading to poor outcome. Here, we report the case of an 11-year-old boy with multilocular EBV-positive CNS PTLD 10 years after liver transplantation. Complete remission was achieved by repeated intravenous and intrathecal anti-CD20 antibody rituximab administration combined with intrathecal chemotherapy (methotrexate, cytarabine, prednisone) over a time period of 3 months. Due to the poor prognosis of CNS PTLD and lack of EBV-specific T-cells (EBV-CTLs) in patient's blood, we decided to perform EBV-directed T-cell immunotherapy as a consolidating treatment. The patient received five infusions of allogeneic EBV-CTLs from a 5/10 HLA-matched unrelated third-party donor. No relevant acute toxicity was observed. EBV-CTLs became detectable after first injection and increased during the treatment course. Next-generation sequencing (NGS) TCR-profiling verified the persistence and expansion of donor-derived EBV-specific clones. After two transfers, epitope spreading to unrelated EBV antigens occurred suggesting onset of endogenous T-cell production, which was supported by detection of recipient-derived clones in NGS TCR-profiling. Continuous complete remission was confirmed 27 months after initial diagnosis.

Cytotoxic T-lymphocyte therapy for post-transplant lymphoproliferative disorder after solid organ transplantation in children

EBV-CTL immunotherapy targets EBV antigens expressed by tumor cells in PTLD. Data on outcome of EBV-CTL in pSOT patients are limited. The aim of the study is to describe our experience with allogeneic, third-party EBV-CTL for the treatment of PTLD in pSOT patients in a single tertiary center. Retrospective review was performed of all pSOT patients who received EBV-CTL for PTLD. PTLD was diagnosed using World Health Organization histologic criteria. EBV-CTLs were derived from human leukocyte antigen-typed, EBV-seropositive third-party donors, and cryopreserved and maintained by an accredited national blood transfusion service. Ten patients received EBV-CTL for histologically proven PTLD from 1999 to 2016 following liver (n=5), combined intestinal/liver (n=4), and liver/kidney (n=1) transplantation. PTLD occurred at median age of 40 months (range: 12-144) and median post-transplant interval of 8 months (range: 2-107). Seven had monomorphic, two had polymorphic, and one had Hodgkin-type PTLD. All were of B-cell origin and EBV-positive on histology. EBV-CTL achieved an overall remission rate of 80% (8 of 10). Transient adverse effects included fever, tachycardia, and vomiting. None developed graft-versus-host disease or opportunistic infections. EBV-CTL is an effective treatment for PTLD in pSOT patients, with good remission rate and minimal toxicity.

Personalized adoptive immunotherapy for patients with EBV-associated tumors and complications: Evaluation of novel naturally processed and presented EBV-derived T-cell epitopes

Morbidity and mortality of immunocompromised patients are increased by primary infection with or reactivation of Epstein-Barr virus (EBV), possibly triggering EBV⁺ post-transplant lymphoproliferative disease (PTLD). Adoptive transfer of EBV-specific cytotoxic T cells (EBV-CTLs) promises a non-toxic immunotherapy to effectively prevent or treat these complications. To improve immunotherapy and immunomonitoring this study aimed at identifying and evaluating naturally processed and presented HLA-A*03:01-restricted EBV-CTL epitopes as immunodominant targets. More than 15000 peptides were sequenced from EBV-immortalized B cells transduced with soluble HLA-A*03:01, sorted using different epitope prediction tools and eleven candidates were preselected. T2 and Flex-T peptide-binding and dissociation assays confirmed the stability of peptide-MHC complexes. Their immunogenicity and clinical relevance were evaluated by assessing the frequencies and functionality of EBV-CTLs in healthy donors (n > 10) and EBV⁺ PTLD-patients (n = 5) by multimer staining, Eli- and FluoroSpot assays. All eleven peptides elicited EBV-CTL responses in the donors. Their clinical applicability was determined by small-scale T-cell enrichment using Cytokine Secretion Assay and immunophenotyping. Mixtures of these peptides when added to the EBV Consensus pool revealed enhanced stimulation and enrichment efficacy. These EBV-specific epitopes broadening the repertoire of known targets will improve manufacturing of clinically applicable EBV-CTLs and monitoring of EBV-specific T-cell responses in patients.

Diagnosis and treatment of neoplastic post-transplant lymphoproliferative disorder following hematopoietic stem cell transplant in β-thalassemia: A pediatric case report

INTRODUCTION

Post-transplant lymphoproliferative disorder (PTLD) is the most common form of lymphoproliferation in childhood and is associated with significant morbidity and mortality. In this report we reviewed the case of a pediatric patient who experienced PTLD after allogeneic hematopoietic stem cell transplantation (HSCT) from a human leukocyte antigen (HLA)-identical sibling.

METHODS

The clinical characteristics, diagnosis, and treatment of PTLD after sibling HSCT in a 4-year-old boy with severe β-thalassemia was retrospectively reviewed.

RESULTS

Medical records revealed the patient developed a fever and superficial lymphadenopathy and soft palate enlargement 8 months post-HSCT. Pathologic diagnosis indicated non-Hodgkin lymphoma (B-cell type), which resulted in a reduced dose of immunosuppressant and the initiation of chemotherapy (administered according to the BFM95 protocol for 2 courses; 4 courses of rituximab therapy was also administered). Currently, the patient has been disease-free for over 3 years. There are no specific guidelines for the treatment of PTLD. The status of stem cell implantation after transplantation, and graft versus host disease should be evaluated jointly, and rituximab therapy and chemotherapy with BFM-95 may be used for treatment of pediatric PTLD after HSCT.

CONCLUSION

The current case represents a unique opportunity to review a pediatric patient with β-thalassemia. The successful treatment of post-transplant non-Hodgkin B lymphoma may help other physicians in the management of similar pediatric cases.

Special Considerations in Pediatric Kidney Transplantation

Universally accepted as the treatment of choice for children needing renal replacement therapy, kidney transplantation affords children the opportunity for an improved quality of life over dialysis therapy. Immunologic and surgical advances over the last 15 years have improved the pediatric patient and kidney graft survival. Unique to pediatrics, congenital genitourinary anomalies are the most common primary diseases leading to kidney failure, many with urological issues. Early urological evaluation for post-transplant bladder dysfunction and emphasis on immunization adherence are the mainstays of pediatric pretransplant and post-transplant evaluations. A child's height can be challenging, sometimes requiring an intra-abdominally placed graft, particularly if the patient is <20 kg. Maintenance immunosuppression regimens are similar to adult kidney graft recipients, although distinctive pharmacokinetics may change dosing intervals in children from twice a day to thrice a day. Viral infections and secondary malignancies are problematic for children relative to adults. Current trends to reduce/remove corticosteroid therapy from post-transplant protocols have produced improved linear growth with less steroid toxicity; although these studies are still ongoing, graft function and survival are considered acceptable. Finally, all children with a kidney transplant need a smooth transition to adult clinics. Future research in pertinent psychosocial aspects and continued technological advances will only serve to optimize the transition process. Although some aspects of kidney transplantation are similar in children and adults, for instance immunosuppression and immunosuppressive regimens, and rejection mechanisms and their diagnosis using the Banff criteria, there are important differences this review will focus on and which continue to drive innovation.