Post-transplant lymphoproliferative disorder in children: recent outcomes and response to dual rituximab/low-dose chemotherapy combination

Late effects in survivors of post-transplant lymphoproliferative disease

BACKGROUND

Treatment of post-transplant lymphoproliferative disease (PTLD) varies, with only some patients receiving chemotherapy. Concern for chemotherapy toxicities may influence treatment decisions as little is known regarding the late effects (LE) in PTLD survivors. This report characterizes LE in PTLD survivors at our institution.

PROCEDURE

Pediatric patients (0-18 years old) diagnosed with PTLD from 1990 to 2020 were examined. All patients included survived 6 months after completing chemotherapy or were 6 months from diagnosis if received no chemotherapy. Treatment with anti-CD20 antibody (rituximab) alone was not considered chemotherapy. Toxicities were classified per Common Terminology Criteria for Adverse Events Version 5.0. Chi-square tests assessed differences between categorical groups, or Fischer's exact test or the Fischer-Freeman-Halton exact test for limited sample sizes.

RESULTS

Of the 44 patients included, 24 (55%) were treated with chemotherapy. Twenty-four (55%) were alive at last follow-up. Chemotherapy was not associated with differences in survival (odds ratio [OR] 1.40, confidence interval [CI]: 0.42-4.63; p = .31). All patients experienced LE. Grade 3 toxicity or higher was experienced by 82% of patients with no difference in incidence (OR 1.20, CI: 0.27-5.80; p > .99) or median toxicity grade (3.00 vs. 4.00, p = .21) between treatment groups. Patients who received chemotherapy were more likely to experience blood and lymphatic toxicity (58% vs. 25%, p = .03) and cardiac toxicity (46% vs. 15%, p = .03), but less likely to have infections (54% vs. 85%, p = .03).

CONCLUSIONS

Survivors of PTLD experience LE including late mortality regardless of chemotherapy exposure. Further investigation to better understand LE could optimize upfront therapy for children with PTLD and improve outcomes.

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.

Non-Hodgkin lymphoma after pediatric kidney transplantation

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

Ultra-low-dose (boom-boom) radiotherapy for management of recurrent ocular post-transplant lymphoproliferative disorder

Purpose

To report a case of recurrent iris post-transplant lymphoproliferative disorder (PTLD) treated with ultra-low-dose (boom-boom) radiotherapy (RT).

Observations

A 12-year-old Caucasian male with a history of bilateral, recurrent iris PTLD of the extranodal marginal zone lymphoma (MALT) type presented with persistent bilateral anterior chamber cellular infiltration, which was incompletely controlled on topical corticosteroids, and with elevated intraocular pressure (IOP) in the right eye secondary to steroid response. The patient was diagnosed with PTLD recurrence and was successfully treated with ultra-low-dose RT to both eyes in 2 fractions of 2 Gy. At 15 month follow-up the patient maintained complete disease control with normal IOP off all topical ophthalmic medications.

Conclusions and Importance

Ultra-low-dose RT for ocular PTLD of the MALT subtype represents a novel therapeutic approach that may provide a durable treatment response and could be considered as either primary or adjuvant therapy for this rare condition.

De novo and recurrent malignancy

Cancer is an important cause of morbidity and mortality after liver transplantation and can occur through three mechanisms: recurrence of a recipient's pre-transplant malignancy, donor-related transmission and de novo development. Currently, the decision to list a patient with a history of malignancy is an individual one. Screening guidelines for potential donors and for recipients after transplant are still widely based on general population guidelines, while the role of chronic immunosuppression remains controversial. These shortcomings mean that patients present at diagnosis with advanced stages of the disease, often precluding curative treatments. The present review summarizes current recommendations for the screening of recipients and donors for pre- and post-transplant malignancies, and current management of recipients who develop cancer after a liver transplant.

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.

Cancer morbidity and mortality after pediatric solid organ transplantation-a nationwide register study

BACKGROUND

The prevalence of malignancies after pediatric solid organ transplantation was evaluated in a nationwide study.

METHODS

All patients who had undergone kidney, liver, or heart transplantation during childhood between the years 1982 and 2015 in Finland were identified. The inclusion criteria were age under 16 years at transplantation and age over 18 years at the last follow-up day. A total of 233 (137 kidney, 53 liver, and 43 heart) transplant recipients were enrolled. Controls (n = 1157) matched by the year of birth, gender, and hometown were identified using the Population Register Center registry. The cancer diagnoses were searched using the Finnish Cancer Registry.

RESULTS

Altogether 26 individuals diagnosed with cancer were found, including 18 transplant recipients. Cancer was diagnosed at a median of 12.0 (IQR 7.8-17.8) years after the transplantation. The transplant recipients' risk for cancer was significantly higher when compared with the controls (HR 14.7; 95% CI 6.4-33.9). There was no difference for different graft types. Sixty-one percent of cancers among the transplant recipients were diagnosed at age older than 18 years.

CONCLUSION

The risk for cancer is significantly higher among young adults having undergone solid organ transplantation during childhood in comparison with population controls. Careful follow-up and attention to prevent cancers throughout adulthood are warranted.

Pediatric Lung Transplantation

Lung transplantation is considered the last therapeutic resource for children with life threatening end-stage lung disease, but it is also a lifelong commitment to a complex clinical follow-up. The main indications in childhood are pulmonary hypertension in infancy and cystic fibrosis in children and adolescents. Contraindications are absolute and relative and often vary from one to another transplant program. Multi-organ disorders, active malignancy, and specific active infection are general agreed upon contraindications. Only 21% of organ donors had suitable lungs for transplant. Although immunosuppressive regimens vary, most lung transplant centers use induction to avoid early acute rejection. The postoperative period is not only crucial for early detection of complications, such as infections and rejection, but also in the long term when gastrointestinal and neurological complications may compromise up to 50% of the patients. One year survival rate is around 85%, and 3 year survival is around 65%. Long-term survival is determined primarily by the development of bronchiolitis obliterans syndrome (BOS), so it is important to plan better therapeutic regimes to preserve graft function.

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

Background

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

Material/Methods

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

Results

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

Conclusions

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

Hemophagocytic lymphohistiocytosis is a sign of poor outcome in pediatric Epstein-Barr virus-associated post-transplant lymphoproliferative disease after allogeneic hematopoietic stem cell transplantation

EBV-related PTLD developing after HSCT is a potentially life-threatening disease. HLH is uncommon after allogeneic HSCT. Data on outcome of patients with PTLD and concomitant HLH after allogeneic HSCT are limited. In this retrospective study, we collected demographic, clinical, laboratory, and outcome data for 408 patients who underwent allogeneic HSCT from 2006 to 2015. Graft source included CB (n = 135; 33.1%), PBSCs (n = 34; 8.3%), and BM (n = 239; 58.6%). Eight out of 408 patients (2%) developed EBV-PTLD with a median age at HSCT of 5.9 years (range: 2.3-17.3). All eight patients received ATG as part of the conditioning regimen. Graft source was PBSC in three patients (37.5%), BM in four patients (50%), and CB in one patient (12.5%). Donors were matched unrelated in five patients (62.5%) and matched sibling in three patients (37.5%). Seven out of eight patients developed EBV-PTLD within the first 100-day post-HSCT. Lymph node biopsy revealed early lesions in three patients, polymorphic in three patients, and monomorphic PTLD in two patients. Three patients (37.5%) died within 1 month of EBV-PTLD diagnosis. All deceased patients developed HLH manifestations with two of them meeting HLH diagnostic criteria and one having an incomplete workup. PTLD after allogeneic HSCT with manifestations of HLH is associated with high mortality. Early identification and treatment of EBV-PTLD seems imperative to control the disease, especially if signs of HLH are evolving.

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.

Combined intraocular and systemic rituximab for ocular lymphoproliferative disorder with extranodal marginal zone lymphoma-type morphology after heart transplant

Post-transplant lymphoproliferative disorder (PTLD) has rarely been associated with ocular manifestations. We report a case of bilateral ocular involvement by PTLD with histopathologic features of extranodal marginal zone (MALT) lymphoma in an 8-year-old boy following orthotopic heart transplantation. The anterior segment disease was treated successfully using a combination of intraocular and systemic injections of humanized anti-CD20 antibody (rituximab).

Risk-adapted Treatment for Severe B-Lineage Posttransplant Lymphoproliferative Disease After Solid Organ Transplantation in Children

BACKGROUND

Optimal management of posttransplant lymphoproliferative disease (PTLD) remains to be defined due to heterogeneity of this condition and lack of predictors of the outcome. Here we report our experience with pediatric PTLD nonresponsive to immunosuppression (IS) withdrawal, managed after stratification into high and low risk according to the presenting features.

METHODS

This is a single-center retrospective review of prospectively enrolled patients. From 2001 to 2011, 17 children were diagnosed with severe B-lineage, CD20+, PTLD after a median of 37 months (range, 5-93) from liver (12), heart (4), or multiorgan (1) transplantation. Treatment was tailored on 2 risk groups: (1) standard-risk (SR) patients received IS reduction and rituximab; (2) high-risk (HR) patients received IS discontinuation, rituximab and polychemotherapy.

RESULTS

The cumulative incidence of rejection at 1 and 5 years after the diagnosis of PTLD was 35% (95% confidence interval [95% CI], 18-69%) and 53% (33-85%), respectively, whereas the disease-free survival at 1 and 5 years was 94% (95% CI, 65-99%) and 75% (45-90%), respectively. Three children died, PTLD-free, from different transplant-related complications: primary nonfunction after retransplantation (liver), cytomegalovirus disease 21 months after PTLD treatment (liver), graft dysfunction 25 months after PTLD (heart).

CONCLUSIONS

Severe B-lineage PTLD after solid organ transplantation may be classified as SR or HR and treated accordingly with a tailored protocol obtaining a satisfactory long-term outcome. This approach accomplishes the control of lymphoproliferation in severe forms as well as the minimization of toxicity in milder PTLDs.

Remission of late-onset post-heart transplantation lymphoproliferative disorder following treatment with rituximab and modified mini-CHOP chemotherapy: A case report

Post-transplant lymphoproliferative disorder (PTLD) is one of the most frequent secondary malignancies that can follow immunosuppressive therapy for solid organ transplantation, and may result in severe morbidities and even mortality. A middle-aged Han Chinese patient, prescribed with immunosuppressive cyclosporine and prednisone, developed PTLD that manifested as a painless cervical lymph node enlargement, 12 years following heart transplantation. Histology revealed monomorphic B-cell PTLD (diffuse large-cell lymphoma); as a result the immunosuppressive regimen of the patient was changed to tacrolimus and mycophenolate mofetil. In addition, the patient was changed to 6-cycle rituximab with a modified mini-CHOP (R-mini-CHOP) regimen for induction, and 8-cycle quarterly rituximab treatment and maintenance therapy. R-mini-CHOP therapy was well tolerated, and no allograft rejection occurred. The patient exhibited clinical remission as demonstrated by the results of the positron emission tomography-computed tomography at the 5-year follow-up visit following R-mini-CHOP therapy. In conclusion, R-mini-CHOP therapy following reduced immunosuppression is effective and safe for the treatment of late-onset PTLD following heart transplantation.

Rituximab-based treatments followed by adoptive cellular immunotherapy for biopsy-proven EBV-associated post-transplant lymphoproliferative disease in recipients of allogeneic hematopoietic stem cell transplantation

To improve prognosis of post-transplant lymphoproliferative disease (PTLD), a sequential therapeutic strategy that rituximab-based treatments followed by donor lymphocyte infusion (DLI) or autologous EBV-specific cytotoxic T lymphocytes (EBV-CTL) for biopsy-proven EBV-associated PTLD in recipients of allogeneic hematopoietic stem cell transplantation was designed. 84 patients with EBV-PTLD were enrolled in this prospective study. After two cycles of the rituximab-based treatments, 68 of 84 patients (81% [95% CI 71-88]) responded and 52 (62% [51-72]) had CRs. This increased to 73 of 77 patients (95% [87-98]) with completion of sequential cell infusions, and 70 of 77 (91% [82-96]) achieved CRs after DLI or autologous EBV-CTL infusion. 22 patients experienced acute GVHD (aGVHD) (grade I in 5 and grade II in 13, grade III in 4) and 13 chronic GVHD (limited cGVHD in 7 and extensive cGVHD in 6) in 62 patients undergoing a median of three doses of DLI. The incidences of GVHD were similar between DLI and EBV-CTL group (aGVHD 35% vs. 33%, p = 0.876; cGVHD 21% vs. 13%; p = 0.503). EBV-CTL activity after the rituximab-based treatments did not change, while increased after cell infusions and reached its maximum in the 3rd or 6th month after EBV-CTL or DLI treatment, respectively. The 5-y cumulative incidence of PTLD relapse was 4.5% ± 3.3%. The 5-y overall survival (OS) and progression-free survival (PFS) after PTLD were 70.7% ± 5.2% and 68.9% ± 5.3%, respectively. Rituximab-based treatments combined with adoptive cellular immunotherapy might elevate CR rates and reduce relapse of PTLD after allo-HSCT.

Post-transplant lymphoproliferative disorders: from epidemiology to pathogenesis-driven treatment

Post-transplant lymphoproliferative disorders (PTLDs) represent the most severe complication of both solid organ and hematopoietic stem cell transplantation. The Epstein-Barr Virus (EBV) is the main driver of PTLD, particularly those occurring early after transplantation. EBV-driven malignancies are associated with selective expression of latent viral proteins, but uncontrolled lytic replication may favor early phases of cell transformation. Besides immunodepression, persistent immune activation and chronic inflammation play an important role in both virus reactivation and expansion of EBV-infected B cells. EBV-induced immortalization requires the expression of telomerase. TERT, the rate-limiting component of the telomerase complex, is central in the switch from the lytic to the latent viral program, and TERT inhibition induces the EBV lytic cycle and cell death. Immunotherapy and combination of EBV lytic cycle inducers with antiviral drugs are promising strategies to improve the treatment of PTLD patients. This review is aimed at providing an update on the intriguing association between EBV and PTLD, mainly focusing on cases arising after kidney and liver transplantation, which account for the vast majority of transplants.

Neoplastic disease after liver transplantation: Focus on de novo neoplasms

De novo neoplasms account for almost 30% of deaths 10 years after liver transplantation and are the most common cause of mortality in patients surviving at least 1 year after transplant. The risk of malignancy is two to four times higher in transplant recipients than in an age- and sex-matched population, and cancer is expected to surpass cardiovascular complications as the primary cause of death in transplanted patients within the next 2 decades. Since exposure to immunosuppression is associated with an increased frequency of developing neoplasm, long-term immunosuppression should be therefore minimized. Promising results in the prevention of hepatocellular carcinoma (HCC) recurrence have been reported with the use of mTOR inhibitors including everolimus and sirolimus and the ongoing open-label prospective randomized controlled SILVER. Study will provide more information on whether sirolimus-containing vs mTOR-inhibitor-free immunosuppression is more efficacious in reducing HCC recurrence.

Increased incidence of adenoidectomy and tonsillectomy in children with renal transplantation

BACKGROUND

Previous studies have found that pediatric solid organ transplant recipients suffer from adenotonsillar hyperplasia. However, as this condition is also common in normal children, it remains unclear whether the incidence is truly increased. The aim of this study was to compare the incidences of surgery on the adenoids and tonsils of normal children with those receiving renal transplants and to define risk factors in the transplant population.

METHODS

Data on 49 consecutive children from a single renal transplant unit were compared to data from a large governmental survey of healthy German children (KiGGS). For analysis of 'survival without operation', controls were matched for gender, region and immigration status (n = 8,650), as well as for age to compare incidence rates (n = 637).

RESULTS

The age-matched solid organ transplant recipients had a higher incidence of adenoidectomies [2.3-fold, [95 % confidence interval (CI) for relative risk 1.6-3.3) and a higher incidence of tonsillectomies/tonsillotomies (3.5-fold, 95 % CI 2.1-5.7). The normal peak of adenoidectomies was delayed by 2 years in the pre-school group, and transplanted teenagers showed an extra peak for both operations. Boys and those transplanted at a younger age were significantly more likely to need adenoidectomies. Ciclosporin levels, Epstein-Barr virus and cytomegalovirus infections did not influence the incidence of operations.

CONCLUSION

Children receiving renal transplants are at markedly increased risk of adenotonsillar hyperplasia requiring surgery, especially males and young recipients.

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.

Antibody therapy of pediatric B-cell lymphoma

B-cell lymphoma in children accounts for about 10% of all pediatric malignancies. Chemotherapy has been very successful leading to an over-all 5-year survival between 80 and 90% depending on lymphoma type and extent of disease. Therapeutic toxicity remains high calling for better targeted and thus less toxic therapies. Therapeutic antibodies have become a standard element of B-cell lymphoma therapy in adults. Clinical experience in pediatric lymphoma patients is still very limited. This review outlines the rationale for antibody treatment of B-cell lymphomas in children and describes potential target structures on B-cell lymphoma cells. It summarizes the clinical experience of antibody therapy of B-cell lymphoma in children and gives an outlook on new developments and challenges for antibody therapy of pediatric B-cell lymphoma.

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.

Post-transplantation lymphoproliferative disorder in pediatric kidney-transplant recipients - a national study

PTLD is the most common malignancy in pediatric kidney-transplant recipients. We examined the prevalence, clinical features, and outcome of PTLD in Israel. Twelve (4.4%) of 272 pediatric (<19 yr) kidney-transplant recipients retrieved from a search of the NIKTR for 1991-2008 had acquired PTLD at a median of 3.2 yr post-transplantation. PTLD-affected patients were younger at transplantation (4.2 vs. 12.5 yr, p = 0.02), had a higher rate of OKT3 therapy for acute rejection (25% vs. 4%, p = 0.015), and 5/12 were EBV-seropositive at transplantation. Graft dysfunction was the presenting sign in six (50%). PTLD was predominantly abdominal (83%) and B-cell type (67%); T-cell PTLD occurred exclusively in EBV-seropositive patients. Treatment consisted of immunosuppression cessation (6/12, 50%), antiviral agents (7/12, 58%), anti-CD20 monoclonal antibodies (4/12, 33%), and chemotherapy (6/12, 50%). Survival was 100% in the EBV-naïve patients and 40% in the EBV-seropositive patients. Graft loss occurred in three of eight survivors (37.5%). PTLD-associated mortality risk was older age: 11.2 vs. 3.4 yr, longer dialysis: 15 vs. 6.5 months, T-cell type disease (75%), later PTLD onset: 6.35 vs. 1.9 yr post-transplantation and era of transplantation (43% mortality before vs. 20% after 2001). Pretransplantation EBV-seronegative status might confer a survival benefit with early detected PTLD. EBV-seropositive patients are at risk for aggressive late-onset lethal PTLD.

Emerging therapeutic strategies for Epstein-Barr virus+ post-transplant lymphoproliferative disorder

De novo malignancies represent an increasing concern in the transplant population, particularly as long-term graft and patient survival improves. EBV-associated B-cell lymphoma in the setting of PTLD is the leading malignancy in children following solid organ transplantation. Therapeutic strategies can be categorized as pharmacologic, biologic, and cell-based but the variable efficacy of these approaches and the complexity of PTLD suggest that new treatment options are warranted. Here, we review current therapeutic strategies for treatment of PTLD. We also describe the life cycle of EBV, addressing the viral mechanisms that contribute to the genesis and persistence of EBV+ B-cell lymphomas. Specifically, we focus on the oncogenic signaling pathways activated by the EBV LMP1 and LMP2a to understand the underlying mechanisms and mediators of lymphomagenesis with the goal of identifying novel, rational therapeutic targets for the treatment of EBV-associated malignancies.

Rituximab and cyclosporine therapy for accelerated phase Chediak-Higashi syndrome

A 19-month-old male with Chediak-Higashi syndrome developed Epstein-Barr virus (EBV)-associated accelerated phase. Real-time polymerase chain reaction showed high EBV-DNA levels in plasma and peripheral blood mononuclear cells. His condition was refractory to conventional treatments for hemophagocytic lymphohistiocytosis, including corticosteroids, cyclosporine, and etoposide. In situ hybridization revealed higher proportion of EBER-1-positive cells in CD19+ cell fraction than in CD8+ cell fraction. Complete remission was achieved by combination therapy with rituximab and cyclosporine; subsequent bone marrow transplantation was successful. Combination therapy with rituximab and cyclosporine could be effective in patients with EBV-infected T and B cells.