Incidence and predictors of post-transplant lymphoproliferative disease after kidney transplantation during adulthood and childhood: a registry study

Prevention of post-transplant lymphoproliferative disorder in pediatric kidney transplant recipients

BACKGROUND

Post-transplant lymphoproliferative disorder (PTLD) is a devastating complication of immunosuppressive treatment in both solid organ transplantations (SOT) and hematopoietic stem cell transplantations (HSCT). Epstein-Barr virus (EBV) infection precedes PTLD in 90% of patients. Rituximab, a monoclonal anti-CD20 antibody, depletes B-lymphocytes, which are the ultimate reservoir for EBV. Although rituximab therapy is commonly used as a preventive measure for PTLD in high-risk HSCT, it is not established in SOT.

METHODS

Pediatric kidney transplant recipients (PKTR) underwent routine EBV-PCR surveillance. Patients with increasing viral loads, despite immunosuppressive dose reduction, were managed with preventive rituximab therapy.

RESULTS

Between 2012 and 2023, we identified eight episodes of asymptomatic EBV-PCR-positive blood tests in seven out of 65 PKTR (11%) under our care. EBV DNAemia emerged 120-720 days post-transplantation. Five of seven patients with EBV DNAemia (71%) were EBV-seronegative prior to transplantation. All five patients did not respond to MMF dose reduction and were therefore treated with preventive rituximab therapy. Following this treatment, EBV PCR clearance was observed in all patients with only minimal complications.

CONCLUSIONS

PKTR who are EBV-naïve prior to transplantation are expected to have a higher prevalence of EBV DNAemia. We found that PKTR who were EBV seronegative prior to transplantation were less likely to achieve EBV clearance in response to immunosuppression dose reduction. We suggest that rituximab therapy in PKTR may be safe and effective in EBV clearance and PTLD prevention.

Donor-derived posttransplant lymphoproliferative disease detection by donor-derived cell-free DNA

Posttransplant lymphoproliferative disorder (PTLD) is a life-threatening complication of organ transplantation, commonly diagnosed after patients present with nonspecific constitutional symptoms and/or transplant organ dysfunction. In this article, we report a case of a kidney transplant recipient who was found to have highly elevated circulating donor-derived cell-free DNA (dd-cfDNA) levels on routine serum surveillance for allograft rejection, initially without organ dysfunction or evidence of allograft rejection on biopsy. Later, for cause imaging revealed retroperitoneal lymphadenopathy and an allograft hilar mass, which was biopsied to show PTLD/diffuse large B cell lymphoma. The elevated circulating dd-cfDNA levels in this patient prompted targeted next-generation sequencing of the same 266 single-nucleotide polymorphisms used to detect dd-cfDNA on the diffuse large B cell lymphoma, which identified it as derived from the donor. The patient achieved complete remission with retained allograft kidney function after reduced immunosuppression and 6 cycles of immunochemotherapy. This case suggests that dd-cfDNA may be an early detection tool in rare but potentially life-threatening cases of donor-derived malignancy, such as donor-derived PTLD.

Risk and prognosis of posttransplant lymphoproliferative disease in Epstein-Barr virus-seronegative kidney transplant recipients - an observational cohort study from Norway and western Denmark

Posttransplant lymphoproliferative disorder (PTLD) poses a serious challenge in kidney transplant recipients. Epstein-Barr virus (EBV)-seronegative recipients have a significantly increased risk of PTLD, but few studies have investigated risk factors for PTLD in EBV-seronegative recipients in the current era of immunosuppression. This cohort study from Norway and western Denmark included first-time kidney transplant recipients between 2007 and 2021 and estimated the cumulative incidence, risk, and prognosis of PTLD. In total, 80 of 5084 recipients developed biopsy-proven PTLD (median follow-up of 6.8 years). Two-year cumulative incidence of PTLD was 7.3% in EBV-seronegative adults and 14.1% in EBV-seronegative children. The age-adjusted hazard ratio (HR) for PTLD was 30.7 (95% CI, 13.9-67.9) in EBV-seronegative vs EBV-seropositive adults and 5.4 (95% CI, 1.1-26.9) in children. Recipients receiving induction therapy with antithymocyte globulin had an increased risk of PTLD (HR, 4.4; 95% CI, 1.8-10.6), while rituximab induction was associated with a lower risk of PTLD (HR, 0.20; 95% CI, 0.03-1.49). The age-adjusted mortality rate was higher in EBV-seronegative recipients with vs without PTLD (HR, 3.3; 95% CI, 1.3-8.3). In conclusion, the risk of PTLD in EBV-seronegative kidney transplant recipients is high in the contemporary era of immunosuppression. Induction therapy should be carefully considered in this high-risk population.

KAP1/TRIM28 - antiviral and proviral protagonist of herpesvirus biology

Dysregulation of the constitutive heterochromatin machinery (HCM) that silences pericentromeric regions and endogenous retroviral elements in the human genome has consequences for aging and cancer. By recruiting epigenetic regulators, Krüppel-associated box (KRAB)-associated protein 1 (KAP1/TRIM28/TIF1β) is integral to the function of the HCM. Epigenetically silencing DNA genomes of incoming herpesviruses to enforce latency, KAP1 and HCM also serve in an antiviral capacity. In addition to gene silencing, newer reports highlight KAP1's ability to directly activate cellular gene transcription. Here, we discuss the many facets of KAP1, including recent findings that unexpectedly connect KAP1 to the inflammasome, reveal KAP1 cleavage as a novel mode of regulation, and argue for a pro-herpesviral KAP1 function that ensures transition from transcription to replication of the herpesvirus genome.

De novo malignancies after kidney transplantation

Cancer is the second cause of death in kidney transplant patients in most Western countries. The excess risk of cancer after kidney transplantation is two to three times higher than in the age and sex matched general population. Once cancer develops, the outcome is generally poor, particularly for melanoma, renal cell carcinoma and post-transplant lymphoproliferative disorder.A multidisciplinary approach for screening, prevention, diagnosis and treatment of neoplastic disease after kidney transplantation is necessary.

Cancer Screening and Cancer Treatment in Kidney Transplant Recipients

As the population ages and post-transplant survival improves, pretransplant and post-transplant malignancy are becoming increasingly common. In addition, rapid advances in cancer therapies and improving outcomes prompt us to rethink pretransplant cancer-free wait time and screening strategies. Although kidney transplant recipients (KTRs) are at higher risk of developing cancer, epidemiological data on how to best screen and treat cancers in KTRs are incomplete. Thus, current recommendations are still largely on the basis of studies in the general population, and their validity in KTRs is uncertain. Kidney transplant candidates without prior cancer should be evaluated for latent malignancies even in the absence of symptoms. Conversely, individuals with a history of malignancy require thorough monitoring to detect potential recurrences or de novo malignancies. When treating KTRs with cancer, reducing immunosuppression can enhance antitumor immunity, yet this also increases the risk of graft rejection. Optimal treatment and immunosuppression management remains undefined. As the emergence of novel cancer therapies adds complexity to this challenge, individualized risk-benefit assessment is crucial. In this review, we discuss up-to-date data on pretransplant screening and cancer-free wait time, as well as post-transplant cancer screening, prevention strategies, and treatment, including novel therapies such as immune checkpoint inhibitors and chimeric antigen receptor T-cell therapies.

The impact of induction therapy on the risk of posttransplant lymphoproliferative disorder in adult kidney transplant recipients with donor-recipient serological Epstein-Barr virus mismatch

Posttransplant lymphoproliferative disorder (PTLD) poses a significant concern in Epstein-Barr virus (EBV)-negative patients transplanted from EBV-positive donors (EBV R-/D+). Previous studies investigating the association between different induction agents and PTLD in these patients have yielded conflicting results. Using the Organ Procurement and Transplant Network database, we identified EBV R-/D+ patients >18 years of age who underwent kidney-alone transplants between 2016 and 2022 and compared the risk of PTLD with rabbit antithymocyte globulin (ATG), basiliximab, and alemtuzumab inductions. Among the 6620 patients included, 64.0% received ATG, 23.4% received basiliximab, and 12.6% received alemtuzumab. The overall incidence of PTLD was 2.5% over a median follow-up period of 2.9 years. Multivariable analysis demonstrated that the risk of PTLD was significantly higher with ATG and alemtuzumab compared with basiliximab (adjusted subdistribution hazard ratio [aSHR] = 1.98, 95% confidence interval [CI] 1.29-3.04, P = .002 for ATG and aSHR = 1.80, 95% CI 1.04-3.11, P = .04 for alemtuzumab). However, PTLD risk was comparable between ATG and alemtuzumab inductions (aSHR = 1.13, 95% CI 0.72-1.77, P = .61). Therefore, the risk of PTLD must be taken into consideration when selecting the most appropriate induction therapy for this patient population.

First-in-Human Whole-Eye Transplantation: Ensuring an Ethical Approach to Surgical Innovation

As innovations in the field of vascular composite allotransplantation (VCA) progress, whole-eye transplantation (WET) is poised to transition from non-human mammalian models to living human recipients. Present treatment options for vision loss are generally considered suboptimal, and attendant concerns ranging from aesthetics and prosthesis maintenance to social stigma may be mitigated by WET. Potential benefits to WET recipients may also include partial vision restoration, psychosocial benefits related to identity and social integration, improvements in physical comfort and function, and reduced surgical risk associated with a biologic eye compared to a prosthesis. Perioperative and postoperative risks of WET are expected to be comparable to those of facial transplantation (FT), and may be similarly mitigated by immunosuppressive protocols, adequate psychosocial support, and a thorough selection process for both the recipient and donor. To minimize the risks associated with immunosuppressive medications, the first attempts in human recipients will likely be performed in conjunction with a FT. If first-in-human attempts at combined FT-WET prove successful and the biologic eye survives, this opens the door for further advancement in the field of vision restoration by means of a viable surgical option. This analysis integrates recent innovations in WET research with the existing discourse on the ethics of surgical innovation and offers preliminary guidance to VCA programs considering undertaking WET in human recipients.

Post-transplant lymphoproliferative disorders following kidney transplantation: A literature review with updates on risk factors, prognostic indices, screening strategies, treatment and analysis of donor type

Post-transplant lymphoproliferative disorders (PTLD) is a devastating complication of kidney transplantation with an insidious presentation and potential to disseminate aggressively. This review delineates the risk factors, prognostic indexes, screening, current management algorithm and promising treatment strategies for PTLD. Kidneys from both extended criteria donors (ECD) and living donors (LD) are being increasingly used to expand the donor pool. This review also delineates whether PTLD outcomes vary based on these donor sources. While Epstein-Barr virus (EBV) is a well-known risk factor for PTLD development, the use of T-cell depleting induction agents has been increasingly implicated in aggressive, monomorphic forms of PTLD. Research regarding maintenance therapy is sparse. The international prognostic index seems to be the most validate prognostic tool. Screening for PTLD is controversial, as annual PET-CT is most sensitive but costly, while targeted monitoring of EBV-seronegative patients was more economically feasible, is recommended by the American Society of Transplantation, but is limited to a subset of the population. Other screening strategies such as using Immunoglobulin/T-cell receptor require further validation. A risk-stratified approach is taken in the treatment of PTLD. The first step is the reduction of immunosuppressants, after which rituximab and chemotherapy may be introduced if unsuccessful. Some novel treatments have also shown potential benefit in studies: brentuximab vedotin, chimeric antigen receptor T-cell therapy and EBV-specific cytotoxic T lymphocytes. Analysis of LD v DD recipients show no significant difference in incidence and mortality of PTLD but did reveal a shortened time to development of PTLD from transplant. Analysis of SCD vs ECD recipients show a higher incidence of PTLD in the ECD group, which might be attributed to longer time on dialysis for these patients, age, and the pro-inflammatory nature of these organs. However, incidence of PTLD overall is still extremely low. Efforts should be focused on optimising recipients instead. Minimising the use of T-cell depleting therapy while encouraging research on the effect of new immunosuppressants on PTLD, screening for EBV status are essential, while enabling shared decision-making during counselling when choosing kidney donor types and individualised risk tailoring are strongly advocated.

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.

Incidence and Features of Lymphoid Proliferation and Lymphomas after Solid Organ or Hematopoietic Stem Cell Transplantation in a National Database Cohort

PURPOSE

Post-transplantation lymphoproliferative disorders (PTLDs) after hematopoietic stem transplantation (HCT) or solid organ transplantation (SOT) result in poorer outcomes, including death. There are limited large cohort data on the incidence and natural course of PTLD in Asians.

MATERIALS AND METHODS

We investigated PTLD using Korean national health insurance claims data of 47,518 patients who underwent HCT or SOT in 2008-2020. Patient demographics, time and type of PTLD diagnosis, type of PTLD treatment, and death data were collected. We used Fine and Gray subdistribution hazard models to calculate the cumulative incidence and risk factors for PTLD.

RESULTS

During median follow-up of 5.32 years, PTLD occurred in 294 of 36,945 SOT patients (0.79%) and 235 of 10,573 HCT patients (2.22%). Cumulative incidence of PTLD were 0.49% at 1 year, 1.02% at 5 years, and 1.50% at 10 years post-transplantation. Age < 20 years (subdistribution hazard ratio [SHR] of 1.67 in age 10-19, SHR 1.51 in age 0-9), HCT (SHR 3.02), heart transplantation (SHR 2.27), and liver transplantation (SHR 1.47) were significant risk factors for PTLD. The presence of PTLD was associated with an increased risk of death (hazard ratio of 2.84). Overall, 5-year survival of PTLD patients was 68.9% (95% confidence interval, 64.9 to 73.2).

CONCLUSION

We observed a steady increase in PTLD over 10 years after HCT or SOT in this large cohort study. Pediatric age group, HCT, liver transplantation, and heart transplantation were suggested to be risk factors for PTLD, and PTLD was associated with a higher risk of death.

Post-Transplant Lymphoproliferative Disorders

Post-transplant lymphoproliferative disorders (PTLDs) are a heterogenous set of unregulated lymphoid cell proliferations after organ or tissue transplant. A majority of cases are associated with the Epstein-Barr virus and higher intensity of pharmacologic immunosuppression. The clinical presentations are numerous. The diagnosis is ideally by histology, except in cases where the tumor is inaccessible to biopsy. While some pre-emptive therapies and treatment strategies are available have reasonable success are available, they do not eliminate the high morbidity and significant mortality after PTLD.

T cell posttransplant lymphoproliferative disorder after kidney transplantation progressing to acute liver failure: a case report

Posttransplant lymphoproliferative disorder (PTLD) is a rare and serious complication of kidney transplantation (KT), with 85% of cases being of B cell lineage. We present a case of T cell PTLD (T-PTLD) that rapidly progressed to liver failure, septic shock, and death despite various therapeutic interventions. A 50-year-old woman underwent ABO- and human leukocyte antigen-compatible preemptive living donor KT for diabetic endstage kidney disease under basiliximab induction therapy. During routine monitoring, 2 months after KT, her Epstein-Barr (EB) viral load was found to be elevated to 318,443 copies/mL. Despite a reduction in maintenance immunosuppressants and preemptive rituximab treatment, the EB viremia continued to increase. Eight months after KT, abdominopelvic computed tomography revealed multifocal splenic lesions and nonspecific lymph node enlargement. Concurrently, the patient's liver function tests began to deteriorate without evidence of viral hepatitis infection. A liver biopsy confirmed the diagnosis of EB virus-associated T-PTLD with CD3 and CD56 expression. Only 2 months after the PTLD diagnosis, the patient developed acute and severe liver failure. She died 12 days after being hospitalized, despite the administration of rescue cytotoxic chemotherapy. This case exemplifies the challenges of managing refractory EB virus-associated T-PTLD after KT, for which no specific treatment options are currently available. Further research into preventative and therapeutic methods for T-PTLD is warranted.

Programmed cell death ligand 1 expression associated with subtypes of post-transplant lymphoproliferative disorder among pediatric kidney transplant recipients

BACKGROUND

Programmed cell death ligand 1 (PD-L1) expression on tumor cells engages the PD-1 receptor on T cells, inhibiting anti-tumor responses. PD-L1 has been detected in cases of post-transplant lymphoproliferative disorder (PTLD) but reports are limited. Here we examine PD-L1 expression and evaluate for clinical correlations.

METHODS

Twenty-one cases of PTLD were identified among pediatric kidney transplant recipients at our institution from February 1996 to April 2017. Using paraffin-embedded tissue biopsies, we examined 21 primary tumors for expression using PD-L1 monoclonal antibody performed with PAX5 as a double stain. We scored expression of PD-L1 on lesional B-cells as a percentage of positive cells. Clinical course and outcome were obtained from retrospective chart review.

RESULTS

Applying revised 2017 WHO PTLD classification showed five non-destructive, nine polymorphic, and seven monomorphic cases. Average PD-L1 expression based upon PTLD subtype was: non-destructive 11%, polymorphic 43%, and monomorphic 73% (p = .01). Two patients transferred shortly after diagnosis, five received chemotherapy, and three died from PTLD. Among the fatalities, all showed monomorphic PTLD and 90% of lesional B-cells expressed PD-L1.

CONCLUSION

In this case series, significant differences in PD-L1 expression were seen among different subtypes, and monomorphic PTLD demonstrated the highest expression. Study of a larger cohort is needed, and if the correlation of PD-L1 expression and PTLD subtype is confirmed, this may highlight the potential utility of checkpoint inhibitor therapy in cases of severe or refractory disease among kidney transplant recipient in whom the risk of allograft loss is acceptable given the option of chronic dialysis.

NLRP3 and cancer: Pathogenesis and therapeutic opportunities

More than a decade ago IL-1 blockade was suggested as an add-on therapy for the treatment of cancer. This proposal was based on the overall safety record of anti-IL-1 biologics and the anti-tumor properties of IL-1 blockade in animal models of cancer. Today, a new frontier in IL-1 activity regulation has developed with several orally active NLRP3 inhibitors currently in clinical trials, including cancer. Despite an increasing body of evidence suggesting a role of NLRP3 and IL-1-mediated inflammation driving cancer initiation, immunosuppression, growth, and metastasis, NLRP3 activation in cancer remains controversial. In this review, we discuss the recent advances in the understanding of NLRP3 activation in cancer. Further, we discuss the current opportunities for NLRP3 inhibition in cancer intervention with novel small molecules.

Graft lymphoma in a kidney transplant recipient: a case report

Posttransplant lymphoproliferative disorders (PTLDs) are severe complications with heterogeneous clinical pictures involving abnormal lymphoproliferation in solid organ transplants and are known to be closely associated with Epstein-Barr virus (EBV) infection. Herein, we present a case of graft lymphoma in a febrile kidney transplant recipient. A 37-year-old woman was admitted with an abrupt 39 °C fever, mild graft discomfort, and gross hematuria. She had received deceased donor kidney transplantation 8 years earlier, but developed graft failure due to a recurrence of immunoglobulin A nephropathy. Laboratory tests revealed anemia and elevated levels of inflammatory markers. Enhanced abdominopelvic computed tomography showed graft swelling with perirenal fat stranding. Thus, we administered antibiotics for a urinary tract infection and increased the doses of steroids due to suspicion of graft intolerance syndrome. However, the patient's symptoms gradually worsened. Eventually, we performed graft nephrectomy and histologically confirmed EBV-positive diffuse large B cell lymphoma. We report a case in which a PTLD was considered in the differential diagnosis of a kidney transplant recipient with symptoms similar to those of a urinary tract infection or graft intolerance syndrome.

Genomic profiling of post-transplant lymphoproliferative disorders using cell-free DNA

Diagnosing post-transplant lymphoproliferative disorder (PTLD) is challenging and often requires invasive procedures. Analyses of cell-free DNA (cfDNA) isolated from plasma is minimally invasive and highly effective for genomic profiling of tumors. We studied the feasibility of using cfDNA to profile PTLD and explore its potential to serve as a screening tool. We included seventeen patients with monomorphic PTLD after solid organ transplantation in this multi-center observational cohort study. We used low-coverage whole genome sequencing (lcWGS) to detect copy number variations (CNVs) and targeted next-generation sequencing (NGS) to identify Epstein-Barr virus (EBV) DNA load and somatic single nucleotide variants (SNVs) in cfDNA from plasma. Seven out of seventeen (41%) patients had EBV-positive tumors, and 13/17 (76%) had stage IV disease. Nine out of seventeen (56%) patients showed CNVs in cfDNA, with more CNVs in EBV-negative cases. Recurrent gains were detected for 3q, 11q, and 18q. Recurrent losses were observed at 6q. The fraction of EBV reads in cfDNA from EBV-positive patients was 3-log higher compared to controls and EBV-negative patients. 289 SNVs were identified, with a median of 19 per sample. SNV burden correlated significantly with lactate dehydrogenase levels. Similar SNV burdens were observed in EBV-negative and EBV-positive PTLD. The most commonly mutated genes were TP53 and KMT2D (41%), followed by SPEN, TET2 (35%), and ARID1A, IGLL5, and PIM1 (29%), indicating DNA damage response, epigenetic regulation, and B-cell signaling/NFkB pathways as drivers of PTLD. Overall, CNVs were more prevalent in EBV-negative lymphoma, while no difference was observed in the number of SNVs. Our data indicated the potential of analyzing cfDNA as a tool for PTLD screening and response monitoring.

Important Considerations in the Diagnosis and Management of Post-transplant Lymphoproliferative Disorder

PURPOSE OF REVIEW

A relative lack of molecular and clinical studies compared to other lymphoid cancers has historically made it difficult to determine optimal management approaches in post-transplant lymphoproliferative disorder (PTLD). We sought to better define the "state of the science" in PTLD by examining recent advances in risk assessment, genomic profiling, and trials of PTLD-directed therapy.

RECENT FINDINGS

Several major clinical trials highlight risk-stratified sequential therapy incorporating rituximab with or without chemotherapy as a rational treatment strategy in patients with CD20+ PTLD who do not respond to reduction of immunosuppression alone. Epstein Barr virus (EBV)-targeted cytotoxic lymphocytes are a promising approach in patients with relapsed/refractory EBV+ PTLD, but dedicated clinical trials should determine how autologous chimeric antigen receptor T cell therapy (CAR-T) may be safely administered to PTLD patients. Sequencing studies underscore the important effect of EBV infection on PTLD pathogenesis, but comprehensive genomic and tumor microenvironment profiling are needed to identify biomarkers that predict response to treatment in this clinically heterogeneous disease.

Pathological Approach to Kidney Allograft Infection

Infectious agents can pose a significant challenge in kidney transplantation, as they have the potential to cause direct infections in the transplanted kidney. These infections can lead to a decline in kidney function and reduce the longevity of the transplanted kidney. Common post-transplant allograft infections include bacterial pyelonephritis and the BK virus infection, while adenovirus, JC virus, and cytomegalovirus are less frequent but can also lead to significant allograft dysfunctions. The histopathological features of these infections are characterized by the infiltration of inflammatory cells in the kidney interstitial area and the presence of viral nuclear inclusions or cytopathic changes in the renal tubular epithelial cells. The confirmation of causative organisms can be achieved by immunohistochemical staining or the visualization of viral particles using electron microscopic examination. However, these methods typically require a longer turnaround time and are not readily available in developing countries, unlike standard hematoxylin-eosin staining. Notably, the differential diagnosis of interstitial inflammation in kidney allografts almost always includes T cell-mediated rejection, which has a different treatment approach than allograft infections. The aim of this review was to prompt clinicians to identify diverse pathological alterations as observed in kidney allograft biopsies, thereby facilitating further investigations and the management of suspected kidney allograft infections.

Single-center "Argentine" analysis of post-transplant lymphoproliferative disorders: incidence, histopathological characteristics and EBV status

INTRODUCTION

Post-transplant lymphoproliferative disorders (PTLDs) are a heterogeneous group of lymphoid proliferations occurring after solid organ or bone marrow transplantation. The primary aims of our study were to characterize cumulative incidence of PTLDs, clinical and pathological features according to the Epstein-Barr virus (EBV) status and survival.

METHODS

This was a retrospective cohort study on adult and pediatric patients, from January 2001 to December 2017. The cumulative incidence of PTLD was calculated by analyzing all the patients transplanted at our hospital, based on the database of the Organ Donation and Ablation Authority of Argentina (INCUCAI). The Kaplan-Meier method was used to plot the survival.

RESULTS

Fifty-eight cases of biopsy-confirmed PTLD were identified and 12 cases of clinical data were incomplete and these patients were excluded. The median age at the time of the PTLD diagnosis was 17.5 years (interquartile range [IQR] 9 - 57). The median interval between transplant and PTLD diagnosis was 39 months (IQR 9 - 113). The most commonly transplanted organ was the liver (24 cases, 52.2%), followed by kidney (20 cases, 43.5%). The Epstein-Barr encoding region in situ hybridization (EBER ISH) was positive in 29 (69.8%) of the 43 evaluable biopsies. The PTLD cumulative incidence was 1.84% (95%CI 1.77 - 1.91) for solid organ and 0.84% (95%CI 0.48 - 1.2) for bone marrow transplant patients. The overall survival rate at 5 years was 0.77 (95%CI 0.61 - 0.87). Subgroups by the EBV EBER status, transplant type, PTLD subtype and age group (adult vs. pediatric) showed no statistically significant association with the overall survival.

CONCLUSION

The PTLD incidence was similar to that of previous series and the EBER did not appear as a relevant factor in our patient survival.

Children Are Not Small Adults: Similarities and Differences in Renal Transplantation Between Adults and Pediatrics

Kidney transplantation is the treatment of choice for all patients with end-stage kidney disease, including pediatric patients. Graft survival in pediatrics was lagging behind adults, but now is comparable with the adult cohort. Although many of the protocols have been adopted from adults, there are issues unique to pediatrics that one should be aware of to take care of this population. These issues include recipient size consideration, increased incidence of viral infections, problems related to growth, common occurrence of underlying urological issues, and psychosocial issues. This article addresses the similarities and differences in renal transplantation, from preparing a patient for transplant, the transplant process, to post-transplant complications.

18F-FDG PET/CT imaging of posttransplant lymphoproliferative disorder following renal transplantation: Three clinical cases

Posttransplant lymphoproliferative disorder (PTLD) is a serious complication of kidney transplantation, and whole-body ¹⁸F- FDG PET/CT imaging plays a key role in patients with PTLD. This article reports three cases of ¹⁸F-FDG PET/CT manifestations of gastric, prostate, and pulmonary lymphomas after kidney transplantation, all of which showed local lesions without involvement of adjacent or distant lymph nodes and lymphoid node organs. All patients were treated with a reduced dose of R-CHOP and were generally in a good condition after discharge. Early diagnosis and reasonable treatment are key factors in achieving a better prognosis in patients with PTLD, and whole-body ¹⁸F-FDG PET/CT imaging plays an important role in the diagnosis and monitoring of PTLD.

[From the first kidney transplants to the current pediatric kidney transplant]

Kidney transplantation is the preferred treatment for end-stage renal failure in children but remains a rare procedure with only 100 to 120 pediatric kidney transplants per year in France. Although the main principles of kidney transplantation are the same in children and adults, some specificities regarding underlying kidney diseases, surgical technique, immunosuppressive drugs metabolism and the risk of infectious complications require a specific expertise to care for these patients. Similarly, the major morbidity of dialysis in children and the need for repeated transplants during the patient's life justify pediatric specificities in the choice of donors and the allocation of grafts in most kidney allocation systems worldwide. The objectives of this review are to present the history and specificities of pediatric kidney transplantation, to describe the current activity in France and to discuss future developments while emphasizing the need for basic and clinical research focused on the pediatric population.

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.

Short-term decreased post transplant lymphoproliferative disorder risk after kidney transplantation using two novel regimens

BACKGROUND

Belatacept is employed alongside calcineurin inhibitor (CNI) therapy to prevent graft rejection in kidney transplant patients who are Epstein-Barr virus (EBV) seropositive. Preliminary data suggested that rates of post-transplant lymphoproliferative disorder (PTLD) were higher in individuals treated with belatacept compared to CNI therapy alone.

METHODS

The records of 354 adults who underwent kidney only transplantation from January 2015 through September 2021 at one medical center were evaluated. Patients underwent treatment with either low-doses of mycophenolate, tacrolimus and sirolimus (B⁰, n = 235) or low-doses of mycophenolate, tacrolimus and belatacept (B¹, n = 119). All recipients underwent induction with antithymocyte globulin and a rapid glucocorticosteroid taper. Relevant donor and recipient information were analyzed and endpoints of PTLD were assessed.

RESULTS

There were no cases of PTLD in either cohort within the study period. Recipients in the belatacept cohort experienced lower estimated glomerular filtration rates at 12 months (B⁰: 67.48 vs. B¹: 59.10, p = 0.0014). Graft failure at 12 (B⁰: 1.28% vs. B¹: 0.84%, p = 1.0) and 24 months (B⁰:2.55% vs. B¹: 0.84%, p = 0.431) were similar. There was no difference in rejection rates at 12 (B⁰: 1.27% vs. B¹: 2.52%, p = 0.408) or 24 months (B⁰: 2.12% vs. B¹: 2.52%, p = 1.000). Both groups had similar rates of malignancy, mortality and CMV/BK viremia.

CONCLUSION

Non-belatacept (MMF, tacrolimus and sirolimus) and belatacept-based (MMF, tacrolimus and belatacept) regimens do not appear to pose any increased risk of early onset PTLD. Both cohorts benefited from low rates of rejection, malignancy, mortality and graft failure. Recipients will continue to be monitored as PTLD can manifest as a long-term complication.

Defining new reference intervals for serum free light chains in individuals with chronic kidney disease: Results of the iStopMM study

Serum free light chain (FLC) concentration is greatly affected by kidney function. Using a large prospective population-based cohort, we aimed to establish a reference interval for FLCs in persons with chronic kidney disease (CKD). A total of 75422 participants of the iStopMM study were screened with serum FLC, serum protein electrophoresis and immunofixation. Estimated glomerular filtration rate (eGFR) was calculated from serum creatinine. Central 99% reference intervals were determined, and 95% confidence intervals calculated. Included were 6461 (12%) participants with measured FLCs, eGFR < 60 mL/min/1.73 m², not receiving renal replacement therapy, and without evidence of monoclonality. Using current reference intervals, 60% and 21% had kappa and lambda FLC values outside the normal range. The FLC ratio was outside standard reference interval (0.26-1.65) in 9% of participants and outside current kidney reference interval (0.37-3.10) in 0.7%. New reference intervals for FLC and FLC ratio were established. New reference intervals for the FLC ratio were 0.46-2.62, 0.48-3.38, and 0.54-3.30 for eGFR 45-59, 30-44, and < 30 mL/min/1.73 m² groups, respectively. The crude prevalence of LC-MGUS in CKD patients was 0.5%. We conclude that current reference intervals for FLC and FLC ratio are inaccurate in CKD patients and propose new eGFR based reference intervals to be implemented.

Early- and late onset post-transplant lymphoproliferative disorders (PTLD) among adult kidney and liver transplant recipients

OBJECTIVES

Post-transplant lymphoproliferative disorder (PTLD) in solid organ transplant recipients has a high mortality and may present early (<2 years) or late (≥ 2 years) post-transplantation. We investigated the clinical characteristics of early and late PTLD among kidney and liver transplant recipients.

METHODS

Recipients, transplanted at Rigshospitalet, with PTLD development as adults from January 2010 to August 2020, were included. Clinical characteristics, laboratory parameters, and pathology of early and late PTLD were compared.

RESULTS

Thirty-one PTLD cases were detected where 10 (32%) were early and 21 (68%) were late PTLD. EBV DNA in plasma was detected in 78% vs 28% in early and late PTLD (p = 0.037). None of the recipients with early PTLD and 9 recipients with late PTLD (47%) had Ann Arbor stage IV at the time of their diagnosis (p = 0.006). Cyclophosphamid-Hydroxyrubicin-Oncovin-Prednisolon (CHOP) was used for treatment in 10 (48%) recipients with late PTLD (p = 0.032) only. There was no difference in mortality between the two groups.

CONCLUSIONS

Recipients with late PTLD had a lower prevalence of detectable EBV DNA in plasma, were diagnosed with more advanced disease, and were more frequently treated with chemotherapy compared to recipients with early PTLD. This article is protected by copyright. All rights reserved.

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.

Incidence and outcomes of post-transplant lymphoproliferative disease after 5365 solid-organ transplants over a 20-year period at two UK transplant centres

Post-transplant lymphoproliferative disease (PTLD) is a life-threatening complication of solid-organ transplantation (SOT). We present the incidence and outcomes of PTLD in a cohort of 5365 SOT recipients over a 20-year period at two UK transplant centres. With a median follow-up of 7.7 years, 142 of 5365 patients have developed PTLD. Cumulative incidence was 18% at five years after multivisceral transplant and 1%-3% at five years following the other SOT types. Twenty-year cumulative incidence was 2%-3% following liver and heart transplantation and 10% following kidney transplantation. Median overall survival (OS) following SOT was 16 years, which is significantly reduced compared with the age-adjusted UK population. There is relatively high early mortality following diagnosis of PTLD and only patients surviving two years regained a longer-term survival approaching the non-PTLD SOT cohort. Of 90 patients with monomorphic PTLD, diffuse large B-cell lymphoma, 66 were treated with first-line rituximab monotherapy and 24 received first-line rituximab plus chemotherapy. Up-front rituximab monotherapy does not appear to compromise OS, but the number of patients dying from non-lymphoma causes before and after treatment remains high with both treatment approaches. Multivariate analysis of all 90 monomorphic PTLD patients identified an International Prognostic Index (IPI) of 3+ as the strongest pretreatment variable associating with inferior one-year OS.

De Novo Malignancies after Kidney Transplantation

Cancer is an important outcome after kidney transplantation because it is the second leading cause of death in most Western countries. The excess risk of cancer after transplantation is approximately two to three times higher than the age- and sex-matched general population, driven largely by viral- and immune-related cancers. Once cancer develops, outcomes are generally poor, particularly for those with melanoma, renal cell carcinoma, and post-transplant lymphoproliferative disease. More importantly, effective screening and treatment strategies are limited in this high-risk population. In this review, we begin with a patient's journey that maps the experience of living with a kidney transplant and understand the patient's knowledge, education, and experience of cancer in the context of transplantation. The epidemiology and burden of cancer in recipients of kidney transplants, along with the up-to-date screening and treatment strategies, are discussed. We also focus on the current understanding of optimal care for recipients of kidney transplants who are living with cancer from the patients' perspectives.

Antiviral T-Cell Frequencies in a Healthy Population: Reference Values for Evaluating Antiviral Immune Cell Profiles in Immunocompromised Patients

Viral infections and reactivations are major causes of morbidity and mortality after hematopoietic stem cell (HSCT) and solid organ transplantation (SOT) as well as in patients with immunodeficiencies. Latent herpesviruses (e.g., cytomegalovirus, Epstein-Barr virus, and human herpesvirus 6), lytic viruses (e.g., adenovirus), and polyomaviruses (e.g., BK virus, JC virus) can cause severe complications. Antiviral drugs form the mainstay of treatment for viral infections and reactivations after transplantation, but they have side effects and cannot achieve complete viral clearance without prior reconstitution of functional antiviral T-cell immunity. The aim of this study was to establish normal ranges for virus-specific T-cell (VST) frequencies in healthy donors. Such data are needed for better interpretation of VST frequencies observed in immunocompromised patients. Therefore, we measured the frequencies of VSTs against 23 viral protein-derived peptide pools from 11 clinically relevant human viruses in blood from healthy donors (n = 151). Specifically, we determined the VST frequencies by interferon-gamma enzyme-linked immunospot assay and classified their distribution according to age and gender to allow for a more specific evaluation and prediction of antiviral immune responses. The reference values established here provide an invaluable tool for immune response evaluation, intensity of therapeutic drugs and treatment decision-making in immunosuppressed patients. This data should make an important contribution to improving the assessment of immune responses in immunocompromised patients.

Case report: Genetic defects in laminin α5 cause infantile steroid-resistant nephrotic syndrome

Single gene pathogenic mutations have been implicated in up to 30% of pediatric steroid-resistant nephrotic syndrome (SRNS) cases, mostly in infantile patients. Among them is LAMA5, which has been recently discovered and encodes the laminin α5 chain. The laminin α5β2γ1 heterotrimer is an essential component of the glomerular basement membrane and is necessary for embryogenesis and immune modulation. Biallelic LAMA5 variants have been identified in one adult and ten pediatric nephrotic syndromes (NS) patients with variable phenotypes. Biallelic truncating mutations in this gene have recently been proven to cause SRNS. Here, we present another case of infantile SRNS related to novel compound heterozygous variations of LAMA5 (c.3434G > A, p.Cys1145Tyr and c.6883C > T, p.Gln2295*), the first reported case with one missense and one nonsense allele. A 10-month-old female patient presented with eyelid edema and massive proteinuria without any extrarenal symptoms or family history. The patient was diagnosed with SRNS. Renal biopsy revealed focal segmental glomerulosclerosis with widely effaced epithelial foot processes and a "moth-eaten" appearance. She progressed to end stage kidney disease (ESKD), requiring dialysis at 31 months of age, and underwent a deceased-donor kidney transplant at 6 years of age. Four months after transplantation, she developed Ebstein-Barr Virus (EBV) infection related to post-transplantation lymphoproliferative disorder (PTLD). After chemotherapy, the patient remained healthy with adequate renal function without disease recurrence for the past 7 years. We also identified previous cases of biallelic LAMA5 variants associated with the nephrotic phenotype and analyzed the available clinical and genetic information. All reported patients had an onset of NS ranging from 3 months to 8 years, with no other syndromic features. Response to therapy and renal outcomes varied greatly; most patients exhibited steroid resistance, five progressed to ESKD, and two received kidney transplantation (KT). There was one report of PTLD. Our patient's phenotype was markedly more severe than those with biallelic missense variants and somewhat less severe than those with two truncating variants. LAMA5 defects may also play a role in PTLD, though no conclusions can be made with such limited cases. LAMA5 should be considered a candidate gene for SRNS and should be actively tested in cases with no other genetic diagnosis.

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.

Long-term Outcomes of Sequential Hematopoietic Stem Cell Transplantation and Kidney Transplantation: Single-center Experience

BACKGROUND

Experience with sequential hematopoietic stem cell transplant (HSCT) and kidney transplant (KT) is limited.

METHODS

We conducted a retrospective observational study of adult patients who underwent both HSCT and KT at our center, with a median follow-up of 11 y.

RESULTS

In our 54 patients cohort (94% autologous HSCT), 36 (67%) patients received HSCT first followed by KT, while 18 (33%) received KT before HSCT. In both groups, AL amyloidosis represented 50% of hematologic diagnosis. Only 4 patients expired due to hematologic disease relapse (2 patients in each group) and only 3 allografts were lost due to hematologic disease recurrence (HSCT first n = 1 and KT first n = 2). Overall 1, 5, and 10 y death-censored graft survival rates were 94%, 94%, and 94%, respectively, for the HSCT first group and 89%, 89%, and 75%, respectively, for the KT first group. Overall 1, 5, and 10 y patients survival rates were 100%, 97% and 90%, respectively, for the HSCT first group and 100%, 76%, and 63%, respectively, for the KT first group.

CONCLUSIONS

Our study supports safety of sequential KT and HSCT, with improved overall patient survival compared to recipients of HSCT remaining on dialysis and good long-term kidney allograft outcome.

Sex differences in cancer risk and outcomes after kidney transplantation

Kidney transplant recipients (KTRs) experience a two- to four-fold increased risk of developing and dying from cancer compared with the general population. High cancer risk results from the interaction of both modifiable and non-modifiable factors. This mapping review explores the impact of sex disparity on cancer's increased incidence and mortality after kidney transplantation (KT). In terms of age, population-based studies indicate that younger recipients of both sexes experience a higher risk of cancer, but this is more pronounced in young women. On the contrary, older men are more likely to be diagnosed with cancer, although their increased risk is not statistically significant compared with the general population. Regarding cancer type, studies show an increased risk of Kaposi sarcoma, gynecologic and lung cancer in women, and bladder and kidney cancer in men. Immune-related cancers such as pos-transplant lymphoproliferative disorders and melanoma are increased in both sexes. Mortality also shows differences between sexes. Although cancer is the second cause of death in both male and female KTRs, studies show higher overall mortality in men and elderly recipients. However, the relative risk of cancer mortality compared with the general population is higher at a younger age, with disparate results regarding sex. Female KTRs appear to die at a younger age than males when compared with the general population. Differences in cancer rates by sex after renal transplantation need further studies. A better understanding of sex-specific differences in cancer epidemiology after KT could help nephrologists to better address pre-transplant counseling, to establish early surveillance programs, and to plan modifiable risk factors such as immunosuppression.

Inflammasome, the Constitutive Heterochromatin Machinery, and Replication of an Oncogenic Herpesvirus

The success of long-term host–virus partnerships is predicated on the ability of the host to limit the destructive potential of the virus and the virus’s skill in manipulating its host to persist undetected yet replicate efficiently when needed. By mastering such skills, herpesviruses persist silently in their hosts, though perturbations in this host–virus equilibrium can result in disease. The heterochromatin machinery that tightly regulates endogenous retroviral elements and pericentromeric repeats also silences invading genomes of alpha-, beta-, and gammaherpesviruses. That said, how these viruses disrupt this constitutive heterochromatin machinery to replicate and spread, particularly in response to disparate lytic triggers, is unclear. Here, we review how the cancer-causing gammaherpesvirus Epstein–Barr virus (EBV) uses the inflammasome as a security system to alert itself of threats to its cellular home as well as to flip the virus-encoded lytic switch, allowing it to replicate and escape in response to a variety of lytic triggers. EBV provides the first example of an infectious agent able to actively exploit the inflammasome to spark its replication. Revealing an unexpected link between the inflammasome and the epigenome, this further brings insights into how the heterochromatin machinery uses differential strategies to maintain the integrity of the cellular genome whilst guarding against invading pathogens. These recent insights into EBV biology and host–viral epigenetic regulation ultimately point to the NLRP3 inflammasome as an attractive target to thwart herpesvirus reactivation.

Posttransplant Lymphoproliferative Disorder Following Kidney Transplantation: A Review

Posttransplant lymphoproliferative disorder (PTLD) is one of the most feared complications following kidney transplantation. Over a 10-year period, the risk of PTLD in kidney transplant recipients (KTRs) is 12-fold higher than in a matched nontransplanted population. Given the number of kidney transplants performed, KTRs who experience PTLD outnumber other organ transplant recipients who experience PTLD. Epstein-Barr virus infection is one of the most important risk factors for PTLD, even though 40% of PTLD cases in contemporary series are not Epstein-Barr virus-associated. The overall level of immunosuppression seems to be the most important driver of the increased occurrence of PTLD in solid organ transplant recipients. Reduction in immunosuppression is commonly accepted to prevent and treat PTLD. Although the cornerstone of PTLD treatment had been chemotherapy (typically cyclophosphamide-doxorubicin-vincristinr-prednisone), the availability of rituximab has changed the treatment landscape in the past 2 decades. The outcome of PTLD in KTRs has clearly improved as a result of the introduction of more uniform treatment protocols, improved supportive care, and increased awareness and use of positron emission tomography combined with computed tomography in staging and response monitoring. In this review, we will focus on the most recent data on epidemiology, presentation, risk factors, and management of PTLD in KTRs.

Post-transplant malignancies in pediatric organ transplant recipients

The majority of cancer diagnoses in pediatric solid organ transplant recipients (SOTRs) are post-transplantation lymphoproliferative disorders (PTLD) or skin cancers. However, pediatric SOTRs are also at significantly elevated risk for multiple other solid and hematological cancers. The risks of specific cancers vary by transplanted organ, underlying disease, and immunosuppression factors. More than one-quarter of pediatric SOTRs develop cancer within 30 years of transplantation and their risk of solid cancer is 14 times greater than the general population. Pediatric SOTRs are at significantly higher risk of cancer-associated death. Improving patient survival among pediatric SOTRs puts them at risk of adult epithelial cancers associated with environmental carcinogenic exposures. Vaccination against oncogenic viruses and avoidance of excessive immunosuppression may reduce the risk of solid cancers following transplantation. Patient and family education regarding photoprotection is an essential component of skin cancer prevention. There is significant variability in cancer screening recommendations for SOTRs and general population approaches are typically not validated for transplant populations. An individualized approach to cancer screening should be developed based on estimated cancer risk, patient life expectancy, and screening test performance.

Outcomes of kidney retransplantation in recipients with prior posttransplant lymphoproliferative disorders: An analysis of the 2000-2019 UNOS/OPTN database

This study utilized the UNOS database to assess clinical outcomes after kidney retransplantation in patients with a history of posttransplant lymphoproliferative disease (PTLD). Among second kidney transplant patients from 2000 to 2019, 254 had history of PTLD in their first kidney transplant, whereas 28,113 did not. After a second kidney transplant, PTLD occurred in 2.8% and 0.8% of patients with and without history of PTLD, respectively (p = .001). Over a median follow-up time of 4.5 years after a second kidney transplant, 5-year death-censored graft failure was 9.5% vs. 12.6% (p = .21), all-cause mortality was 8.3% vs. 11.8% (p = .51), and 1-year acute rejection was 11.0% vs. 9.3% (p = .36) in the PTLD vs. non-PTLD groups, respectively. There was no significant difference in death-censored graft failure, mortality, and acute rejection between PTLD and non-PTLD groups in adjusted analysis and after propensity score matching. We conclude that graft survival, patient survival, and acute rejection after kidney retransplantation are comparable between patients with and without history of PTLD, but PTLD occurrence after kidney retransplantation remains higher in patients with history of PTLD.

Haematological disorders following kidney transplantation

Transplantation offers cure for some haematological cancers, end-stage organ failure, but at the cost of long-term complications. Renal transplantation is the best-known kidney replacement therapy and it can prolong end-stage renal disease patient lives for decades. However, patients after renal transplantation are at a higher risk of developing different complications connected not only with surgical procedure but also with immunosuppressive treatment, chronic kidney disease progression and rejection processes. Various blood disorders can develop in post-transplant patients ranging from relatively benign anaemia through cytopenias to therapy-related myelodysplasia and acute myeloid leukaemia (AML) and post-transplant lymphoproliferative disorders followed by a rare and fatal condition of thrombotic microangiopathy and haemophagocytic syndrome. So far literature mainly focused on the post-transplant lymphoproliferative disease. In this review, a variety of haematological problems after transplantation ranging from rare disorders such as myelodysplasia and AML to relatively common conditions such as anaemia and iron deficiency are presented with up-to-date diagnosis and management.

Pediatric kidney transplantation in Egypt: Results of 10-year single-center experience

Pediatric kidney transplantation is a multidisciplinary therapy that needs special consideration and experience. In this study, we aimed to present CUCH experience; over a 10-year period, as a specialized center of kidney transplantation in children. We studied 148 transplantations performed at a single center from 2009 to 2018. Pretransplant and follow-up data were collected and graft/patient survival rates were evaluated. A total of 48 patients developed at least one rejection episode during 688 patient-years of follow-up. Infections, recurrence of original disease, and malignancy were the most important encountered medical complications (20%, 2%, and 1.4%, respectively). One-year patient survival was 94.1%, while graft and patient survival was 91.9%. Graft/patient survival at 5, 7, and 9 years was 90%, 77%, and 58%, respectively. Infections were the main cause (69%) of mortality. Death with a functioning graft and CR were the main causes of graft loss (48% and 33%, respectively). Pediatric kidney transplantation in Egypt is still a challenging yet successful experience. Rejections and infections are the most frequent complications. Short-term outcomes surpass long-term ones and graft survival rates are similar to the international standard.

Perioperative antibiotics for preventing post-surgical site infections in solid organ transplant recipients

BACKGROUND

Solid organ transplant recipients are at high risk for infections due to the complexity of surgical procedures combined with the impact of immunosuppression. No consensus exists on the role of antibiotics for surgical site infections in solid organ transplant recipients.

OBJECTIVES

To assess the benefits and harms of prophylactic antimicrobial agents for preventing surgical site infections in solid organ transplant recipients.

SEARCH METHODS

The Cochrane Kidney and Transplant Register of Studies was searched up to 21 April 2020 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs in any language assessing prophylactic antibiotics in preventing surgical site infections in solid organ transplant recipients at any time point after transplantation.

DATA COLLECTION AND ANALYSIS

Two authors independently determined study eligibility, assessed quality, and extracted data. Primary outcomes were surgical site infections and antimicrobial resistance. Other outcomes included urinary tract infections, pneumonias and septicaemia, death (any cause), graft loss, graft rejection, graft function, adverse reactions to antimicrobial agents, and outcomes identified by the Standardised Outcomes of Nephrology Group (SONG), specifically graft health, cardiovascular disease, cancer and life participation. Summary effect estimates were obtained using a random-effects model and results were expressed as risk ratios (RR) and 95% confidence intervals (CI). The quality of the evidence was assessed using the risk of bias and the GRADE approach.

MAIN RESULTS

We identified eight eligible studies (718 randomised participants). Overall, five studies (248 randomised participants) compared antibiotics versus no antibiotics, and three studies (470 randomised participants) compared extended duration versus short duration antibiotics. Risk of bias was assessed as high for performance bias (eight studies), detection bias (eight studies) and attrition bias (two studies). It is uncertain whether antibiotics reduce the incidence of surgical site infections as the certainty of the evidence has been assessed as very low (RR 0.42, 95% CI 0.21 to 0.85; 5 studies, 226 participants; I² = 25%). The certainty of the evidence was very low for all other reported outcomes (death, graft loss, and other infections). It is uncertain whether extended duration antibiotics reduces the incidence of surgical site infections in either solid organ transplant recipients (RR 1.19, 95% CI 0.58 to 2.48; 2 studies, 302 participants; I² = 0%) or kidney-only transplant recipients (RR 0.50, 95% CI 0.05 to 5.48; 1 study, 205 participants) as the certainty of the evidence has been assessed as very low. The certainty of the evidence was very low for all other reported outcomes (death, graft loss, and other infections). None of the eight included studies evaluated antimicrobial agent adverse reactions, graft health, cardiovascular disease, cancer, life participation, biochemical and haematological parameters, intervention cost, hospitalisation length, or overall hospitalisation costs.

AUTHORS' CONCLUSIONS

Due to methodological limitations, risk of bias and significant heterogeneity, the current evidence for the use of prophylactic perioperative antibiotics in transplantation is of very low quality. Further high quality, adequately powered RCTs would help better inform clinical practice.

Biomarkers for PTLD diagnosis and therapies

Post-transplant lymphoproliferative disorder (PTLD) represents a spectrum of lymphoproliferative disorders and is a serious complication of pediatric transplantation. The majority of PTLD are associated with Epstein Barr virus (EBV) and the characteristic EBV+ B cell lymphomas are the leading post-transplant malignancy in children. EBV+ PTLD remains a formidable issue in pediatric transplantation and is thought to result from impaired immunity to EBV as a result of immunosuppression. However, the key viral and immune factors that determine whether EBV+ PTLD develops remain unknown. Recently, there has been much interest in developing biomarkers in order to improve and achieve more personalized approaches, in the clinical diagnosis, management, and treatment of EBV+ PTLD. Here, we review the status of immune-, viral-, and B cell lymphoma-derived candidates for biomarkers of EBV+ PTLD.

Immunosuppression-induced clonal T-cell lymphoproliferative disease causing severe diarrhoea mimicking coeliac disease following renal transplantation: a case report

Background

Post-transplant lymphoproliferative disease is a recognized complication following solid organ transplantation. This is usually a B cell disease and frequently associated with Epstein Barr virus infection, although T cell PTLD can occur. T cell PTLD is usually a monomorphic, lymphomatous disease associated with an adverse prognosis.

Case report

We report a 52 year old male pre-emptive renal transplant recipient who developed severe diarrhea with weight loss following intensification of his immunosuppression due to antibody mediated rejection 3 years after transplantation. Duodenal biopsy demonstrated monoclonal CD8+ T cell duodenitis leading to increased intraepithlieal lymphocytes and sub-total villous atrophy mimicking coeliac disease. Coeliac disease was excluded by negative anti-tissue transglutaminase antibody, HLA-DQ2 and HLA-DQ8 testing. There was no evidence of lymphoma either on biopsy or CT enterography and no FDG avid disease on PET. Symptoms did not improve with reduction of immunosuppression, but resolved fully on complete withdrawal of treatment. The transplant failed and he was established on dialysis. The diagnosis was early PTLD.

Conclusions

Oesophagogastroduodenoscopy with small bowel biopsies is a useful investigation for determining the cause of diarrhoea in renal transplant patients when more common causes have been excluded. This is the first report that we are aware of clonal T cell PTLD mimicking coeliac disease which only resolved after complete withdrawal of immunosuppression. As treatments for lymphoma are aggressive they are only initiated in the malignant phase and management of early stage PTLD is to minimise risk of progression by reducing immunosuppression. Any plans to retransplant will have to take into consideration the possibility that PTLD will recur.

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

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

Post-transplant Lymphoproliferative Disorder of Naso-orbital Region in Adult Renal Transplant Recipients: A Case Report and Literature Review

Post-transplant lymphoproliferative disorder (PTLD) is an uncommon but fatal complication following both solid organ and hematologic stem cell transplantations. Epstein-Barr virus (EBV) has been considered a main etiologic agent causing PTLD, especially in the first year after transplantation. Extranodal manifestations are frequently found in PTLD; however, naso-orbital involvement in adults is rare. We report a case of EBV-associated PTLD of the naso-orbital region in a 72-year-old patient that occurred 10 years after kidney transplant. Six additional adults with naso-orbital PTLD were identified after completing this literature review, including 2 cases with eyelid swelling, 3 cases with proptosis, and 1 case with facial numbness. The majority of cases occurred after 1 year of transplantation and were associated with EBV. This report emphasizes recognizing PTLD as differential diagnosis in transplant recipients who present with naso-orbital symptoms.