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

Pediatric Kidney Transplantation: Cancer and Cancer Risk

Children with end-stage kidney disease (ESKD) face a lifetime of complex medical care, alternating between maintenance chronic dialysis and kidney transplantation. Kidney transplantation has emerged as the optimal treatment of ESKD for children and provides important quality of life and survival advantages. Although transplantation is the preferred therapy, lifetime exposure to immunosuppression among children with ESKD is associated with increased morbidity, including an increased risk of cancer. Following pediatric kidney transplantation, cancer events occurring during childhood or young adulthood can be divided into two broad categories: post-transplant lymphoproliferative disorders and non-lymphoproliferative solid tumors. This review provides an overview of cancer incidence, types, outcomes, and preventive strategies in this population.

Seropositivity for cytomegalovirus and PCR-EBV monitoring: Protective factors for posttransplant lymphoproliferative disorder in pediatric liver transplant

BACKGROUND

PTLD is a clinical condition with high mortality. Monitoring EBV replication can be a useful tool to avoid the development of PTLD.

MATERIALS AND METHODS

This was a retrospective analysis of 428 pediatric patients who underwent liver transplantation between 1989 and 2016. The patients were divided into 2 groups (transplanted before 2006, when PCR-EBV was not monitored, and after 2006, when PCR-EBV monitoring was started). Patients with continuous PCR measurements for EBV were evaluated for the impact of a reduction in immunosuppression or a change in immunosuppressants on the number of viral copies. A logistic regression model was applied to evaluate factors related to PTLD.

RESULTS

The prevalence of PTLD was 4.2%. After monitoring patients with PCR for EBV levels, a predominance of the most severe, monomorphic form of lymphoproliferative disorder was observed (p = .009). The PTLD mortality was 5%. There was a change in the PCR level after tacrolimus reduction (p = .002) and after tacrolimus exchange for mTOR (p = .008). The number of EBV copies was significantly higher (p = .029) in patients who developed PTLD. In the multiple regression model, seropositivity for CMV was an independent protective factor for lymphoproliferative disorder (OR=0.09; 95% CI 0.02-0.42), reducing the chance of having PTLD adjusted by serology for EBV by 91%.

CONCLUSIONS

Monitoring the EBV viral load by PCR seems to prevent the emergence of milder forms of lymphoproliferative disorder. Pretransplant seropositivity for CMV is a protective factor for PTLD.

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.

Joining Efforts for PTLD: Lessons Learned from Comparing the Approach and Treatment Strategies Across the Pediatric and Adult Age Spectra

PURPOSE OF REVIEW

Post-transplant lymphoproliferative disorders are a rare and heterogeneous group of diseases, where large prospective studies have been difficult to perform and treatment paradigms are often based on retrospective studies. Here, we critically analyze and present the clinical algorithms commonly used for this disease, with a special focus on the challenges and differences of the approaches in the adult and pediatric populations.

RECENT FINDINGS

Clinical trials exploring combinations of immunochemotherapies with a sequential and risk-stratified strategy have demonstrated exciting results, but are hampered from specialty and age-determined silos. Approaches introducing novel-targeted therapies and cellular therapies are currently being explored with a goal of joining efforts across the pediatric and adult age spectra. We propose that future therapeutic approaches would benefit from combining pediatric and adult PTLD efforts, gaining from the experience garnered from the age- and subtype-specific tailored strategies, with the aim of limiting treatment-related toxicities while maximizing the efficacy. Joining of efforts holds enormous potential for accelerating access to novel therapeutic strategies for PTLD in the near future.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Post-transplantation lymphoproliferative disease in pediatric liver recipients in Taiwan

BACKGROUND

Post-transplantation lymphoproliferative disorder (PTLD) is a heterogeneous, potentially life-threatening complication after liver transplantation in children. In this study, the disease characteristics, outcomes, and prognostic factors of PTLD were investigated.

METHODS

A retrospective, observational study was conducted on 16 pediatric liver transplant (LT) recipients who developed PTLD between February 2001 and December 2013 at a tertiary referral center in Taiwan. The disease characteristics and treatment outcomes of the patients were analyzed.

RESULTS

The median time from liver transplantation to the development of PTLD was 8 months. Early onset (<1 year post-transplantation) PTLD constituted 62.5% of the cases. PTLD location was frequently extranodal (81.3%) and mostly involved the gastrointestinal tract (68.8%). Histopathologic findings showed polymorphic PTLD in six cases (37.5%), diffuse large B-cell lymphoma in five cases (31.3%), and Burkitt's PTLD in two cases (12.5%). Early lesions in PTLD, T-cell lymphoma, and Hodgkin's lymphoma were observed in one case each (6.3%). Overall survival at 1- and 5-years post-PTLD diagnosis was 87.5% and 79.5%, respectively. St Jude's classification stage IV disease was associated with poor survival (hazard ratio [HR] = 13.37, P = 0.037). Two patients (12.5%) had chronic rejection after the treatment for PTLD and one patient (6.3%) developed graft failure.

CONCLUSION

PTLD is a major complication in pediatric LT recipients, but long-term survival is possible in most cases with an adequate treatment strategy. Stage IV disease is a major risk factor for poor survival in pediatric PTLD patients. During the management of PTLD, the possibility of chronic rejection and even graft failure should be considered.

Systematic review and meta-analysis of post-transplant lymphoproliferative disorder in lung transplant recipients

A systematic review of papers in English on post-transplant lymphoproliferative disorder (PTLD) in lung transplant recipients (LTR) using MEDLINE, EMBASE, SCOPUS, and Cochrane databases was performed. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations were strictly adhered to. Pooled odds ratios (pOR) were calculated from a random-effects model, and heterogeneity among studies was quantitated using I² values. Fourteen studies published from 2005 to 2015 were included in the meta-analysis. One hundred and sixty-four lung transplant recipients were included. LTRs who received single vs bilateral were associated with a 7.67-fold risk of death after PTLD (6 studies with 64 LTRs; pOR 7.67 95% CI 1.98-29.70; P = .003). pOR of death for early onset PTLD (<1 year post-LT) vs late onset (>1 year post-LT) was not different (3 studies with 72 LTRS; pOR 0.62, 95% CI 0.20-1.86, P = .39). Standardized mean difference (SMD) in time from transplant to PTLD onset between LTRs who died vs alive was not different (9 studies with 109 LTRs; SMD 0.03, 95% CI -0.48-0.53, P = .92). Survival in polymorphic vs monomorphic PTLD and extranodal vs nodal disease was similar (4 studies with 31 LTRs; pOR 0.44, 95% CI 0.08-2.51; P = .36. 6 studies with 81 LTRs; pOR 1.05 95% CI 0.31-3.52, P = .94). This meta-analysis demonstrates that single LTRs are at a higher risk of death vs bilateral LTRs after the development of PTLD.

Malignancies after pediatric kidney transplantation: more than PTLD?

Post-transplant lymphoproliferative disease (PTLD) is the most frequent malignant complication of transplantation in childhood. Even with modern post-transplant immunosuppressive strategies, 1-2% of all kidney transplant recipients will develop PTLD within the first 5 years after transplantation, and the risk remains high even thereafter as long as immunosuppression is required. In addition to PTLD, adult kidney transplant recipients have an increased incidence of other immunosuppression-related malignancies, such as non-melanoma skin cancer or Kaposi's sarcoma. It is foreseeable that pediatric transplant recipients will face similar complications during their adult life. Not only immunosuppression but also other risk factors have been identified for some of these malignancies. Strategies addressing these risk factors during childhood may contribute to life-long cancer prevention. Furthermore, early recognition and regular screening may facilitate early diagnosis and treatment, thereby reducing transplant-related morbidity. In this review we focus on malignant complications after renal transplantation and discuss known risk factors. We also review current screening strategies for malignancies during post-transplant follow-up.

Posttransplant lymphoproliferative disease after pediatric solid organ transplantation

Patients after solid organ transplantation (SOT) carry a substantially increased risk to develop malignant lymphomas. This is in part due to the immunosuppression required to maintain the function of the organ graft. Depending on the transplanted organ, up to 15% of pediatric transplant recipients acquire posttransplant lymphoproliferative disease (PTLD), and eventually 20% of those succumb to the disease. Early diagnosis of PTLD is often hampered by the unspecific symptoms and the difficult differential diagnosis, which includes atypical infections as well as graft rejection. Treatment of PTLD is limited by the high vulnerability towards antineoplastic chemotherapy in transplanted children. However, new treatment strategies and especially the introduction of the monoclonal anti-CD20 antibody rituximab have dramatically improved outcomes of PTLD. This review discusses risk factors for the development of PTLD in children, summarizes current approaches to therapy, and gives an outlook on developing new treatment modalities like targeted therapy with virus-specific T cells. Finally, monitoring strategies are evaluated.

Low-dose chemotherapy and rituximab for posttransplant lymphoproliferative disease (PTLD): a Children's Oncology Group Report

Optimal therapy for posttransplant lymphoproliferative disease (PTLD) remains problematic. A phase II trial adding rituximab to a low-dose cyclophosphamide and prednisone regimen was conducted for pediatric patients with Epstein-Barr virus (EBV) (+), CD20 (+) PTLD. Fifty-five patients were enrolled. Toxicity was similar for cycles of therapy containing rituximab versus those without. The complete remission (CR) rate was 69% (95% confidence interval (CI); 57%-84%). Of 12 patients with radiographic evidence of persistent disease at the end of therapy, eight were in CR 28 weeks later without further PTLD therapy. There were 10 deaths, 3 due to infections while receiving therapy and 7 from PTLD. The 2-year event-free survival (alive with functioning original allograft and no PTLD) was 71% (95% CI: 57%-82%) and overall survival was 83% (95% CI: 69%-91%) with median follow-up of 4.8 years. Due to small numbers, we were unable to determine significance of tumor histology, stage of disease, allograft type or early response to treatment on outcome. These data suggest rituximab combined with low-dose chemotherapy is safe and effective in treating pediatric with EBV (+) PTLD following solid-organ transplantation.