Dissociation of depletional induction and posttransplant lymphoproliferative disease in kidney recipients treated with alemtuzumab

Mechanistic Understanding of EBV+Lymphoproliferative Disease Development After Transplantation

Posttransplant lymphoproliferative disorders (PTLDs) are among the most common malignant complications after transplantation, leading to a drastic reduction in patient survival rates. The majority of PTLDs are tightly linked to Epstein-Barr virus (EBV+PTLDs) and are the result of an uncontrolled proliferation of EBV-infected cells. However, although EBV infections are a common finding in transplant recipients, most patients with high EBV loads will never develop EBV+PTLD. Natural killer cells and EBV-specific CD8+ T lymphocytes are critical for controlling EBV-infected cells, and the impairment of these cytotoxic immune responses facilitates the unfettered proliferation of EBV-infected cells. Recent years have seen a considerable increase in available literature aiming to describe novel risk factors associated with the development of EBV+PTLD, which may critically relate to the strength of EBV-specific natural killer cell and EBV-CD8+ T lymphocyte responses. The accumulation of risk factors and the increased risk of developing EBV+PTLD go hand in hand. On the one hand, most of these risk factors, such as the level of immunosuppression or the EBV donor and recipient serologic mismatch, and distinct genetic risk factors are host related and affect cytotoxic EBV-specific immune responses. On the other hand, there is growing evidence that distinct EBV variants may have an increased malignant potential and are thus more likely to induce EBV+PTLD. Here, we aim to review, from a mechanistic point of view, the risk factors for EBV+PTLD in the host and the infecting EBV variants that may explain why only a minority of transplant recipients develop EBV+PTLD.

The IPTA Nashville consensus conference on post-transplant lymphoproliferative disorders after solid organ transplantation in children: IV-consensus guidelines for the management of post-transplant lymphoproliferative disorders in children and adolescents

The International Pediatric Transplant Association convened an expert consensus conference to assess current evidence and develop recommendations for various aspects of care relating to post-transplant lymphoproliferative disorders (PTLD) after pediatric solid organ transplantation. This report addresses the outcomes of deliberations by the PTLD Management Working Group. A strong recommendation was made for reduction in immunosuppression as the first step in management. Similarly, strong recommendations were made for the use of the anti-CD20 monoclonal antibody (rituximab) as was the case for chemotherapy in selected scenarios. In some scenarios, there is uncoupling of the strength of the recommendations from the available evidence in situations where such evidence is lacking but collective clinical experiences drive decision-making. Of note, there are no large, randomized phase III trials of any treatment for PTLD in the pediatric age group. Current gaps and future research priorities are highlighted.

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.

Induction immunosuppression strategies and outcomes post-lung transplant: A single center experience

PURPOSE

Currently 80% of lung transplant centers use induction immunosuppression. However, there is a lack of standardization of induction protocols within and across lung transplant centers. This study explores the association of two different induction immunosuppression strategies used at our center [single dose rabbit antithymocyte globulin (rATG) vs. alemtuzumab] compared to no induction with immunologic and clinical outcomes after lung transplantation.

METHODS

A total of 174 consecutive lung transplant recipients (LTR) between 2016 and 2019 were included in the analysis. Twenty nine LTR (16.7%) received no induction, 22 LTR (12.6%) received alemtuzumab, 123 LTR (70.6%) received a single dose of rATG; 1.5 mg/kg within 24 h of transplant for induction. All LTR had a negative flow cytometry crossmatch on the day of the transplant. All LTR were assessed for de novo HLA donor-specific antibodies (DSA) development and clinical outcomes, including the risk of acute cellular rejection (ACR), antibody-mediated rejection (AMR), chronic lung allograft dysfunction (CLAD), and overall survival post-transplant.

RESULTS

The median lung allocation score (LAS) was significantly higher in LTR that did not receive Induction immunosuppression (76; range = 35.3-94.3) compared to induction with rATG (41.6; range = 31.6-91) and alemtuzumab (51; range = 33.1-88.2) (p < 0.001). De novo HLA DSA were detected in 50/174 (28.7%) LTR within 12 months post-transplant. They were detected in 13/29 (44.8%) LTR without induction immunosuppression compared to 28/123 (22.8%) and 9/22 (40.9%) LTR with rATG and alemtuzumab induction, respectively (p = 0.02). The percent freedom from ACR rates between LTR who received alemtuzumab induction was significantly higher compared to LTR who received rATG or no induction at 1 (p = 0.02), 2 (p = 0.01) and 3 (p = 0.05) years post-transplant. In addition, the overall 1-year survival rates were significantly higher in LTR who received rATG or alemtuzumab induction compared to LTR without induction immunosuppression (p = 0.02).

CONCLUSION

Induction immunosuppression strategies utilizing rATG or Alemtuzumab have unique and contrasting benefits in LTR. Combination of alemtuzumab induction and a lower dose of maintenance immunosuppression may reduce the incidence of ACR in LTR. Single-dose rATG or alemtuzumab induction immunosuppression may also improve the 1 year overall LTR survival compared to no induction.

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.

Post-transplant malignancy: Focusing on virus-associated etiologies, pathogenesis, evidence-based management algorithms, present status of adoptive immunotherapy and future directions

Modern immunosuppression has led to a decrease in rejection rates and improved survival rates after solid organ transplantation. Increasing the potency of immunosuppression promotes post-transplant viral infections and associated cancers by impairing immune response against viruses and cancer immunoediting. This review reflects the magnitude, etiology and immunological characteristics of various virus-related post-transplant malignancies, emphasizing the need for future research. A multidisciplinary and strategic approach may serve best but overall literature evidence targeting it is sparse. However, the authors attempted to provide a more detailed update of the literature consensus for the prevention, diagnosis, management and surveillance of post-transplant viral infections and associated malignancies, with a focus on the current role of adoptive immunotherapy and the way forward. In order to achieve long-term patient and graft survival as well as superior post-transplant outcomes, collaborative research on holistic care of organ recipients is imperative.

Case Report: Non-negligible Epstein-Barr virus-associated posttransplant lymphoproliferative disorders in a lung transplant recipient

Background

Posttransplant lymphoproliferative disorders (PTLDs) are uncommon but serious complications in patients following solid organ transplantation. Primary Epstein-Barr virus (EBV) infection is a risk factor for the development of PTLD, especially early-onset PTLD, in EBV-negative recipients. To date, however, there are no specific guidelines on the threshold of EBV-DNA load for therapeutic intervention, the source for measurement (e.g., blood, bronchoalveolar fluid), or the use of antiviral agents as prophylaxis for early PTLD prevention in EBV-mismatched patients.

Methods

The present study describes a 56-year-old male lung transplant recipient diagnosed with EBV-associated PTLD.

Results

This patient had a history of invasive fungal disease and Mucor and Aspergillus fumigatus infections in the early post-transplant period, necessitating antifungal therapy throughout the course of the disease. The patient was EBV-positive 15 days after transplantation, with lung CT showing multiple bilateral nodules of varying sizes beginning 98 days after transplantation. A lung biopsy showed PTLD, and next-generation sequencing (NGS) revealed EBV. This patient, however, did not receive any antiviral therapy for early PTLD prevention or any PTLD-related treatment. He died 204 days after lung transplantation.

Conclusion

The present study describes a lung transplant recipient who developed EBV-associated PTLD, a non-negligible disease, after solid organ transplantation. Monitoring EBV-DNA load is important, as a sudden increase may be a sensitive indicator of PTLD. An earlier diagnosis may increase the likelihood of successful treatment.

Second Kidney Transplant Outcomes in Dialysis Dependent Recipients by Induction Type in the United States

BACKGROUND

We examined the association between induction type for a second kidney transplant in dialysis-dependent recipients and the long-term outcomes.

METHODS

Using the Scientific Registry of Transplant Recipients, we identified all second kidney transplant recipients who returned to dialysis before re-transplantation. Exclusion criteria included: missing, unusual, or no-induction regimens, maintenance regimens other than tacrolimus and mycophenolate, and positive crossmatch status. We grouped recipients by induction type into 3 groups: the anti-thymocyte group (N = 9899), the alemtuzumab group (N = 1982), and the interleukin 2 receptor antagonist group (N = 1904). We analyzed recipient and death-censored graft survival (DCGS) using the Kaplan-Meier survival function with follow-up censored at 10 years post-transplant. We used Cox proportional hazard models to examine the association between induction and the outcomes of interest. To account for the center-specific effect, we included the center as a random effect. We adjusted the models for the pertinent recipient and organ variables.

RESULTS

In the Kaplan-Meier analyses, induction type did not alter recipient survival (log-rank P = .419) or DCGS (log-rank P = .146). Similarly, in the adjusted models, induction type was not a predictor of recipient or graft survival. Live-donor kidneys were associated with better recipient survival (HR 0.73, 95% CI [0.65, 0.83], P < .001) and graft survival (HR 0.72, 95% CI [0.64, 0.82], P < .001). Publicly insured recipients had worse recipient and allograft outcomes.

CONCLUSION

In this large cohort of average immunologic-risk dialysis-dependent second kidney transplant recipients, who were discharged on tacrolimus and mycophenolate maintenance, induction type did not influence the long-term outcomes of recipient or graft survival. Live-donor kidneys improved recipient and graft survival.

Post-transplant lymphoproliferative disorder: Update on treatment and novel therapies

Post-transplant lymphoproliferative disorder (PTLD) is rare and heterogeneous lymphoid proliferations that occur as a result of immunosuppression following solid organ transplant (SOT) and haematopoietic stem cell transplant (HSCT) with the majority being driven by EBV. Although some histologies are similar to lymphoid neoplasms seen in immunocompetent patients, treatment of PTLD may be different due to difference in pathobiology and higher risk of treatment complications. The most common treatment approach in SOT PTLD after failing immunosuppression reduction (RIS) takes into consideration a risk-stratified sequential algorithm with rituximab +/- chemotherapy based on phase 2 studies. In HSCT PTLD, RIS alone and chemotherapy are usually ineffective making rituximab +/- RIS as the gold standard of frontline treatment. In this review, we give an update on the treatment of PTLD beyond RIS. We highlight the most recent studies that attempted to incorporate more aggressive chemotherapy regimens and novel treatments into the traditional risk-stratified sequential approach. We also discuss the role of EBV-cytotoxic T lymphocytes in treatment of EBV-driven PTLD. Other novel agents with potential role in PTLD will be discussed in addition to the challenges that could arise with chimeric antigen receptor T-cell therapy and immune checkpoint inhibitors in this population.

In vitro and in vivo evidence that the switch from calcineurin to mTOR inhibitors may be a strategy for immunosuppression in Epstein-Barr virus-associated post-transplant lymphoproliferative disorder

Post-transplant lymphoproliferative disorder is a life-threatening complication of immunosuppression following transplantation mediated by failure of T cells to control Epstein-Barr virus (EBV)-infected and transformed B cells. Typically, a modification or reduction of immunosuppression is recommended, but insufficiently defined thus far. In order to help delineate this, we characterized EBV-antigen-specific T cells and lymphoblastoid cell lines from healthy donors and in patients with a kidney transplant in the absence or presence of the standard immunosuppressants tacrolimus, cyclosporin A, prednisolone, rapamycin, and mycophenolic acid. Phenotypes of lymphoblastoid cell-lines and T cells, T cell-receptor-repertoire diversity, and T-cell reactivity upon co-culture with autologous lymphoblastoid cell lines were analyzed. Rapamycin and mycophenolic acid inhibited lymphoblastoid cell-line proliferation. T cells treated with prednisolone and rapamycin showed nearly normal cytokine production. Proliferation and the viability of T cells were decreased by mycophenolic acid, while tacrolimus and cyclosporin A were strong suppressors of T-cell function including their killing activity. Overall, our study provides a basis for the clinical decision for the modification and reduction of immunosuppression and adds information to the complex balance of maintaining anti-viral immunity while preventing acute rejection. Thus, an immunosuppressive regime based on mTOR inhibition and reduced or withdrawn calcineurin inhibitors could be a promising strategy for patients with increased risk of or manifested EBV-associated post-transplant lymphoproliferative disorder.

The Impact of Human Microbiotas in Hematopoietic Stem Cell and Organ Transplantation

The human microbiota heavily influences most vital aspects of human physiology including organ transplantation outcomes and transplant rejection risk. A variety of organ transplantation scenarios such as lung and heart transplantation as well as hematopoietic stem cell transplantation is heavily influenced by the human microbiotas. The human microbiota refers to a rich, diverse, and complex ecosystem of bacteria, fungi, archaea, helminths, protozoans, parasites, and viruses. Research accumulating over the past decade has established the existence of complex cross-species, cross-kingdom interactions between the residents of the various human microbiotas and the human body. Since the gut microbiota is the densest, most popular, and most studied human microbiota, the impact of other human microbiotas such as the oral, lung, urinary, and genital microbiotas is often overshadowed. However, these microbiotas also provide critical and unique insights pertaining to transplantation success, rejection risk, and overall host health, across multiple different transplantation scenarios. Organ transplantation as well as the pre-, peri-, and post-transplant pharmacological regimens patients undergo is known to adversely impact the microbiotas, thereby increasing the risk of adverse patient outcomes. Over the past decade, holistic approaches to post-transplant patient care such as the administration of clinical and dietary interventions aiming at restoring deranged microbiota community structures have been gaining momentum. Examples of these include prebiotic and probiotic administration, fecal microbial transplantation, and bacteriophage-mediated multidrug-resistant bacterial decolonization. This review will discuss these perspectives and explore the role of different human microbiotas in the context of various transplantation scenarios.

Pediatric Onco-Nephrology: Time to Spread the Word-Part II: Long-Term Kidney Outcomes in Survivors of Childhood Malignancy and Malignancy after Kidney Transplant

Onco-nephrology is a recent and evolving medical subspecialty devoted to the care of patients with kidney disease and unique kidney-related complications in the context of cancer and its treatments, recognizing that management of kidney disease as well as the cancer itself will improve survival and quality of life. While this area has received much attention in the adult medicine sphere, similar emphasis in the pediatric realm has not yet been realized. As in adults, kidney involvement in children with cancer extends beyond the time of initial diagnosis and treatment. Many interventions, such as chemotherapy, stem cell transplant, radiation, and nephrectomy, have long-term kidney effects, including the development of chronic kidney disease (CKD) with subsequent need for dialysis and/or kidney transplant. Thus, with the improved survival of children with malignancy comes the need for ongoing monitoring of kidney function and early mitigation of kidney-related comorbidities. In addition, children with kidney transplant are at higher risk of developing malignancies than their age-matched peers. Pediatric nephrologists thus need to be aware of issues related to cancer and its treatments as they impact their own patients. These facts emphasize the necessity of pediatric nephrologists and oncologists working closely together in managing these children and highlight the importance of bringing the onco-nephrology field to our growing list of pediatric nephrology subspecialties.

Kidney Allograft and Recipient Survival After Heart Transplantation by Induction Type in the United States

BACKGROUND

Induction choices for kidney-after-heart transplant recipients are variable. We examined the impact of kidney induction types on kidney graft and patient survival in heart transplant recipients.

METHODS

We analyzed the Scientific Registry of Transplant Recipient database from inception through the end of 2018 to study kidney and patient outcomes in the United States after heart transplantation. We only included recipients who were discharged on tacrolimus and mycophenolate maintenance. We grouped recipients by induction type into 3 groups: depletional (N = 307), nondepletional (n = 253), and no-induction (steroid only) (n = 57). We studied patients and kidney survival using Cox PH regression, with transplant centers included as a random effect. We adjusted the models for heart induction, recipient and donor age, gender, time between heart and kidney transplant, heart transplant indication, HLA mismatches, payor, live-donor kidney, transplant year, dialysis status, and diabetes mellitus at the time of kidney transplant.

RESULTS

The 1-y kidney rejection rates and creatinine levels were similar in all groups. The 1-y rehospitalization rate was higher in the depletional group (51.7%) and nondepletional group (50.7%) than in the no-induction group (39.1%) although this was not statistically significant. There were no differences in recipient or kidney survival by kidney induction type. Live-donor kidney was associated with improved patient (hazard ratio, 0.74; 95% confidence interval, 0.54-1.0; P = 0.05) and kidney survival (hazard ratio, 0.45; 95% confidence interval, 0.24-0.84; P = 0.012].

CONCLUSIONS

Type of kidney induction did not influence patient or kidney graft survival in heart transplant recipients. No-induction may be the preferred choice due to the lack of clinical benefits associated with induction use.

Post-transplant lymphoproliferative disease after pediatric kidney transplant

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

Post-transplant lymphoproliferative disorders (PTLD)-from clinical to metabolic profiles-a single center experience and review of literature

Post-transplant lymphoproliferative disorders (PTLD) are among the most serious complications after solid organ transplantation (SOT). Monomorphic diffuse large B-cell lymphoma (DLBCL) is the most common subtype of PTLD. Historically, outcomes of PTLD have been poor with high mortality rates and allograft loss, although this has improved in the last 10 years. Most of our understanding about PTLD DLBCL is extrapolated from studies in non-PTLD DLBCL, and while several clinical factors have been identified and validated for predicting non-PTLD DLBCL outcomes, the molecular profile of PTLD DLBCL has not yet been characterized. Compartment-specific metabolic reprograming has been described in non-PTLD DLBCL with a lactate uptake metabolic phenotype with high monocarboxylate transporter 1 (MCT1) expression associated with worse outcomes. The aim of our study was to compare the outcomes of PTLD in our transplant center to historic cohorts, as well as study a subgroup of our PTLD DLBCL tumors and compare metabolic profiles with non-PTLD DLBCL. We performed a retrospective single institution study of all adult patients who underwent a SOT between the years 1992-2018, who were later diagnosed with PTLD. All available clinical information was extracted from the patients' medical records. Tumor metabolic markers were studied in a subgroup of PTLD DLBCL and compared to a group of non-PTLD DLBCL. Thirty patients were diagnosed with PTLD following SOT in our center. Median time from SOT to PTLD diagnosis was 62.8 months (IQR 7.6; 134.4), with 37% of patients diagnosed with early PTLD, and 63% with late PTLD. The most common PTLD subtype was DLBCL. Most patients were treated with reduction of their immunosuppression (RIS) including a group who were switched from calcineurin inhibitor (CNI) to mTOR inhibitor based IS, in conjunction with standard anti-lymphoma chemoimmunotherapy. Progression free survival of the PTLD DLBCL cohort was calculated at 86% at 1 year, and 77% at 3 and 5-years, with overall survival of 86% at 1 and 3-years, and 75% at 5 years. Death censored allograft survival in the kidney cohort was 100% at 1 year, and 93% at 3, 5 and 10 years. MCT1 H scores were significantly higher in a subset of the non-PTLD DLBCL patients than in a PTLD DLBCL cohort. Our data is concordant with improved PTLD outcomes in the last 10 years. mTOR inhibitors could be an alternative to CNI as a RIS strategy. Finally, PTLD DLBCL may have a distinct metabolic profile with reduced MCT1 expression compared to non-PTLD DLBCL, but further studies are needed to corroborate our limited cohort findings and to determine if a specific metabolic profile is associated with outcomes.

Malignancies after pediatric solid organ transplantation

As life expectancy among pediatric solid organ transplant recipients (SOTRs) improves, the risk of comorbid conditions such as malignancy post-transplantation has also increased. SOTRs are at elevated risks of post-transplantation lymphoproliferative disorders (PTLDs), and skin and solid cancers. PTLDs typically occur early following transplantation, while skin and solid cancers frequently arise in young adulthood (25-40 years). By 30 years following transplantation, 26-41% of pediatric SOTRs have developed cancer. Different risk factors exist for PTLD, and skin and solid cancers, which are modified by cumulative immunosuppression, infections, transplanted organ, and the underlying disease process associated with initial organ failure (e.g., kidney failure). Optimal cancer treatment strategies depend on the specific cancer type, stage, and patient comorbidities. Immunosuppression reduction may be beneficial for certain cancers but must be considered against the risks of acute and chronic rejection and allograft loss. Lifestyle counseling regarding smoking avoidance and sun protection, as well as human papillomavirus vaccination, is an important aspect of cancer prevention. Currently, no cancer screening guidelines exist specifically for pediatric SOTRs. Adult population screening guidelines have not been validated in transplant populations. Therefore, an individualized approach should be taken to cancer screening for pediatric SOTRs, accounting for other cancer risk factors.

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.

Induction with ATG in DCD kidney transplantation; efficacy and relation of dose and cell markers on delayed graft function and renal function

AIM

We aimed to analyse the efficacy of the Thymoglobulin dose used for induction in controlled DCD kidneys, and its initial impact on blood cell and CD3 count, as predictors of efficacy.

METHODS

140 DCD patients who received ATG induction, were analysed. Intended dose was 1.25 mg/kg/day over 5 days, rounded to nearest 25 mg and not exceeding 125 mg/dose. Outcomes included the total dose in relation with rejection, DGF, graft survival, eGFR. The cell count response to ATG was assessed as predictors of outcome.

RESULTS

Graft survival, was 96.2%, 92.4%, 85% at 1, 3 and 5 years. Rejection was 7% at 1 year and associated with eGFR at 3 (p = 0.003) and 5 years. ATG dose was not predictive of rejection but was associated with the day5 leucocyte and lymphocyte count (p < 0.001) and negatively with DGF (p = 0.05). In 31 patients day3 CD3 count was available and it was associated with rejection (p = 0.002), less DGF (p = 0.09), and 3 years eGFR (p = 0.01).

CONCLUSION

Thymoglobulin provides excellent results in DCD kidneys that do not significantly differ with small dose variations. In higher doses it reduces DGF. Lymphocytes and CD3 count, may be useful surrogate markers of efficacy and outcome.

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 lymphoproliferative disorder in adult renal transplant recipients: case series and review of literature

Post-transplant lymphoproliferative disorder (PTLD) is serious life-threating complication of transplantation. The clinical picture differs from lymphomas observed in the general population, with different manifestation, histopathology, higher aggressiveness with involvement of sites beyond the primary lymph node, and poorer outcome.

The objective of the study was to present nine cases of PTLD observed in our centre among the kidney transplant recipient population and discuss the results with up-to-date literature. We performed a retrospective single-centre assessment of PTLD incidence in the cohorts of kidney transplant recipients followed by our centre. We found nine cases of PTLD, five men and four woman, aged from 26 to 67 years at the time of diagnosis (mean [SD] 48 [5] years), transplanted between 1997 and 2013.

The disease was diagnosed between 2002 and 2017, from 6 to 440 months after transplantation (mean [SD] 96 [137] months). A diffuse large B-cell lymphoma was found in seven cases early as well as late after transplantation, and two patients presented T-cell lymphoma. Five patients achieved complete remission with no relapses after 6 to 13 months of treatment. In three cases the remission was achieved by switching to mammalian target of rapamycin inhibitors (mTORi) only. Four recipients died from 2 weeks to 15 months after PTLD was diagnosed.

Although the diagnostic criteria of different forms of PTLD are commonly known, rapid and correct diagnosis is not easy. PTLD is a relatively a rare disease, so there are too few studies and little consensus on the optimal treatment.

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

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

Induction regimens and post-transplantation lymphoproliferative disorder after pediatric intestinal transplantation: Single-center experience

Pediatric recipients of intestinal transplants have a high incidence of PTLD, but the impact of specific induction immunosuppression agents is unclear. In this single-center retrospective review from 2000 to 2017, we describe the incidence, characteristics, and outcomes of PTLD after primary intestinal transplantation in 173 children with or without liver, after induction with rATG, alemtuzumab, or anti-IL-2R agents. Thirty cases of PTLD occurred among 28 children, 28 EBV+ and 2 EBV-. Although not statistically significant, the PTLD incidence was higher after isolated intestinal transplant compared with liver-inclusive allograft (19.3% vs 13.3%, P = .393) and after induction with anti-IL-2R antibody and alemtuzumab compared with rATG (28.6% and 27.3% vs 13.3%, P = .076). The 30 PTLD cases included 13 monomorphic PTLD, 13 polymorphic PTLD, one spindle cell, one Burkitt lymphoma, and two cases too necrotic to classify. After reduction of immunosuppression, management was based on disease histology and extent. Resection with or without rituximab was used for polymorphic tumors and limited disease extent, whereas chemotherapy was used for diffuse disease. Of the 28 patients, 11 recovered with functioning allografts (39.3%), 10 recovered after enterectomy (35.7%), and seven patients died (25%), three due to PTLD and four due to other causes. All who died of progressive PTLD had received chemotherapy, highlighting the mortality of PTLD, toxicity of treatment and need for novel agents. Alemtuzumab is no longer used for induction at our center.

Relationship between rabbit anti-thymocyte globulin and development of PTLD and its aggressive form in renal transplant population

Introduction

The aim of our study is to explore the relationship of rabbit anti-thymocyte globulin (R-ATG) on development of post-transplant lymphoproliferative disease (PTLD) and its aggressive forms (monomorphic PTLD and Hodgkin lymphoma) in renal transplant recipients.

Methodology

All patients diagnosed with PTLD post-renal transplant in the United States’ Organ Procurement and Transplantation Network from 2003 till 2013 and followed up till 2017 were retrospectively reviewed. Multi-variable logistic regression analysis assessed association of R-ATG to development of PTLD and its aggressive form.

Results

Risk of developing PTLD post renal transplant is 1.35%. In comparison to interleukin-2 blocker induction therapy, R-ATG is associated with increased risk of development of PTLD (Odds Ratio = 1.48, confidence interval ranges from 1.04 to 2.11, p = .02) and is associated with higher risk of development of aggressive PTLD (Odds Ratio = 1.83, confidence interval ranges from 1.001 to 3.34, p = .04).

Conclusion

We conclude that R-ATG induction is associated with a higher risk of PTLD and its aggressive form (monomorphic PTLD and Hodgkin lymphoma). Careful monitoring for development of PTLD in renal transplant recipients receiving R-ATG induction therapy is advised.

Lymphoproliferative disorder in a lung transplant recipient

Post-transplantation lymphoproliferative disorder (PTLD) is uncommon following solid organ transplantation. We present a case of PTLD presenting as hematochezia and abdominal pain in a 66-year-old man, who had undergone bilateral lung transplantation with alemtuzumab induction 7 months prior to presentation. The transplant serologic status was "high-risk" for the presence of both Epstein-Barr virus (EBV) serologies in the donor and negative serologies in the recipient. Biopsies taken during colonoscopy stained strongly positive for EBV-encoded RNA. Mediastinal lymph node biopsies also showed atypical, EBV-positive lymphohistiocytic infiltration with focal necrosis. The patient's hospital course was complicated by treatment side effects, most notably bowel perforation following rituximab. In this case report the topic of PTLD is reviewed and consideration is given to whether alemtuzumab induction may have contributed to the patient's development of PTLD.

Immunosuppressive strategies in lung transplantation

Lung transplantation is a viable option for those with end-stage lung disease which is evidenced by the continued increase in the number of lung transplantations worldwide. However, patients and clinicians are constantly faced with acute and chronic rejection, infectious complications, drug toxicities, and malignancies throughout the lifetime of the lung transplant recipient. Conventional maintenance immunosuppression therapy consisting of a calcineurin inhibitor (CNI), anti-metabolite, and corticosteroids have become the standard regimen but newer agents and modalities continue to be developed. Here we will review induction agents, maintenance immunosuppressives, adjunctive therapies and other strategies to improve long-term outcomes.

Epstein-Barr virus-positive post-transplant lymphoproliferative disordepresenting as hematochezia and enterobrosis in renal transplant recipients in China: A report of two cases

BACKGROUND

Post-transplant lymphoproliferative disorder (PTLD) is a rare severe complication after renal transplantation, with an incidence of approximately 0.3%-2.0% in patients undergoing renal transplantation. The clinical manifestations of PTLD are often nonspecific, leading to tremendous challenges in the clinical diagnosis and treatment of PTLD.

CASE SUMMARY

We report two Epstein-Barr virus (EBV)-positive PTLD cases whose main clinical manifestations were digestive tract symptoms. Both of them admitted to our hospital because of extranodal infiltration symptoms and we did not suspect of PTLD until the pathology confirmation. Luckily, they responded well to the treatment of rituximab. We also discuss the virological monitoring, clinical characteristics, diagnosis, and treatment of PTLD.

CONCLUSION

PTLD is a deceptive disease and difficult to diagnose. Once patients are confirmed with PTLD, immune suppressant dosage should be immediately reduced and rituximab should be used as first-line therapy.

Induction type and outcomes for kidney graft and patient survival in recipients with prior lung transplantation in the United States

BACKGROUND

Induction immunosuppression regimens for kidney transplants in lung transplant recipients vary widely. We studied the impact of induction types for kidney after lung transplant recipients.

METHODS

Using the Scientific Registry of Transplant Recipients database between 1994 and 2015, we studied outcomes of patients and kidney grafts for 330 kidney after lung transplant recipients for whom induction before kidney transplant included depletional (n = 115), non-depletional (n = 170), or no induction (steroids only; n = 45). We studied risk factors for recipient and graft survival using Cox proportional hazards model adjusted for kidney and lung induction, kidney donor type, dialysis status, recipient and donor ages, time from lung to kidney transplant, cause of lung disease, bilateral vs single lung transplant, diabetes, and human leukocyte antigen mismatches before kidney transplant, with transplant center as a random effect.

RESULTS

There was no difference between groups in patient survival or death-censored kidney allograft survival. The 1-year kidney acute rejection rates were 15.5%, 7.14%, and 0% in depletional, non-depletional, and no induction groups, respectively. In the Cox model for patient survival, living kidney donor recipients and bilateral lung transplant recipients were favorable predictors. For death-censored graft survival, kidney induction type did not predict graft survival. Results did not change when models only included recipients on tacrolimus and mycophenolate based maintenance.

CONCLUSIONS

The type of kidney induction did not influence patient or kidney graft survival following kidney transplants for those with previous lung transplants. No induction may be the preferred choice for kidney after lung transplant because of the lack of benefits from biologic induction in this large cohort.

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

Background

Differences in the epidemiology of post-transplant lymphoproliferative disease (PTLD) between adult and paediatric kidney transplant recipients remain unclear.

Methods

Using the Australian and New Zealand Dialysis and Transplant Registry (1963-2015), the cumulative incidences of PTLD in children (age <20 years) and adults were calculated using a competing risk of death model and compared with age-matched population-based data using standardized incidence ratios (SIRs). Risk factors for PTLD were assessed using Cox proportional hazards regression.

Results

Among 23 477 patients (92% adult, 60% male), 505 developed PTLD, with 50 (10%) occurring in childhood recipients. The 25-year cumulative incidence of PTLD was 3.3% [95% confidence interval (CI) 2.9-3.6] for adult recipients and 3.6% (95% CI 2.7-4.8) for childhood recipients. Childhood recipients had a 30-fold increased risk of lymphoma compared with the age-matched general population [SIR 29.5 (95% CI 21.9-38.8)], higher than adult recipients [SIR 8.4 (95% CI 7.7-9.2)]. Epstein-Barr virus (EBV)-negative recipient serology [adjusted hazard ratio (aHR) 3.33 (95% CI 2.21-5.01), P < 0.001], year of transplantation [aHR 0.93 for each year after the year 2000 (95% CI 0.88-0.99), P = 0.02], induction with an agent other than anti-CD25 monoclonal antibody [aHR 2.07 (95% CI 1.16-3.70), P = 0.01] and having diabetes [aHR 3.49 (95% CI 2.26-5.38), P < 0.001] were independently associated with PTLD.

Conclusions

Lymphoma occurs at similar rates in adult and paediatric recipients, but has been decreasing since the year 2000. EBV-negative patients and those with diabetes or induction agent other than anti-CD25 monoclonal antibody are at substantially increased risk of PTLD.

Dual blockade of the PI3K/Akt/mTOR pathway inhibits posttransplant Epstein-Barr virus B cell lymphomas and promotes allograft survival

Posttransplant lymphoproliferative disorder (PTLD) is a serious complication of organ transplantation that often manifests as Epstein-Barr virus (EBV)-associated B cell lymphomas. Current treatments for PTLD have limited efficacy and can be associated with graft rejection or systemic toxicities. The mTOR inhibitor, rapamycin, suppresses tumor growth of EBV+ B cell lymphoma cells in vitro and in vivo; however, the efficacy is limited and clinical benefits of mTOR inhibitors for PTLD are variable. Here, we show constitutive activation of multiple nodes within the PI3K/Akt/mTOR pathway in EBV+ PTLD-derived cell lines. Inhibition of either PI3K or Akt, with specific inhibitors CAL-101 and MK-2206, respectively, diminished growth of EBV+ B cell lines from PTLD patients in a dose-dependent manner. Importantly, rapamycin combined with CAL-101 or MK-2206 had a synergistic effect in suppressing cell growth as determined by IC₅₀ isobolographic analysis and Loewe indices. Moreover, these combinations were significantly more effective than rapamycin alone in inhibiting tumor xenograft growth in NOD-SCID mice. Finally, both CAL-101 and MK-2206 also prolonged survival of heterotopic cardiac allografts in C57BL/6 mice. Thus, combination therapy with rapamycin and a PI3K inhibitor, or an Akt inhibitor, can be an efficacious treatment for EBV-associated PTLD, while simultaneously promoting allograft survival.

Metagenomic analysis of DNA viruses from posttransplant lymphoproliferative disorders

Posttransplant lymphoproliferative disorders (PTLDs), 50%-80% of which are strongly associated with Epstein-Barr virus (EBV), carry a high morbidity and mortality. Most clinical/epidemiological/tumor characteristics do not consistently associate with worse patient survival, so our aim was to identify if other viral genomic characteristics associated better with survival. We extracted DNA from stored paraffin-embedded PTLD tissues at our center, identified viral sequences by metagenomic shotgun sequencing (MSS), and analyzed the data in relation to clinical outcomes. Our study population comprised 69 PTLD tissue samples collected between 1991 and 2015 from 60 subjects. Nucleotide sequences from at least one virus were detected by MSS in 86% (59/69) of the tissues (EBV in 61%, anelloviruses 52%, gammapapillomaviruses 14%, CMV 7%, and HSV in 3%). No viruses were present in higher proportion in EBV-negative PTLD (compared to EBV-positive PTLD). In univariable analysis, death within 5 years of PTLD diagnosis was associated with anellovirus (P = 0.037) and gammapapillomavirus (P = 0.036) detection by MSS, higher tissue qPCR levels of the predominant human anellovirus species torque teno virus (TTV; P = 0.016), T cell type PTLD, liver, brain or bone marrow location. In multivariable analyses, T cell PTLD (P = 0.006) and TTV PCR level (P = 0.012) remained significant. In EBV-positive PTLD, EBNA-LP, EBNA1 and EBNA3C had significantly higher levels of nonsynonymous gene variants compared to the other EBV genes. Multiple viruses are detectable in PTLD tissues by MSS. Anellovirus positivity, not EBV positivity,was associated with worse patient survival in our series. Confirmation and extension of this work in larger multicenter studies is desirable.

Non-immunological complications following kidney transplantation

Kidney transplantation (KT) is the most effective way to decrease the high morbidity and mortality of patients with end-stage renal disease. However, KT does not completely reverse the damage done by years of decreased kidney function and dialysis. Furthermore, new offending agents (in particular, immunosuppression) added in the post-transplant period increase the risk of complications. Cardiovascular (CV) disease, the leading cause of death in KT recipients, warrants pre-transplant screening based on risk factors. Nevertheless, the screening methods currently used have many shortcomings and a perfect screening modality does not exist. Risk factor modification in the pre- and post-transplant periods is of paramount importance to decrease the rate of CV complications post-transplant, either by lifestyle modification (for example, diet, exercise, and smoking cessation) or by pharmacological means (for example, statins, anti-hyperglycemics, and so on). Post-transplantation diabetes mellitus (PTDM) is a major contributor to mortality in this patient population. Although tacrolimus is a major contributor to PTDM development, changes in immunosuppression are limited by the higher risk of rejection with other agents. Immunosuppression has also been implicated in higher risk of malignancy; therefore, proper cancer screening is needed. Cancer immunotherapy is drastically changing the way certain types of cancer are treated in the general population; however, its use post-transplant is limited by the risk of allograft rejection. As expected, higher risk of infections is also encountered in transplant recipients. When caring for KT recipients, special attention is needed in screening methods, preventive measures, and treatment of infection with BK virus and cytomegalovirus. Hepatitis C virus infection is common in transplant candidates and in the deceased donor pool; however, newly developed direct-acting antivirals have been proven safe and effective in the pre- and post-transplant periods. The most important and recent developments on complications following KT are reviewed in this article.

Posttransplant Malignancy

Posttransplant malignancy is a leading cause of death after solid organ transplantation (SOT). Recipients of SOT are at significantly higher risk of multiple cancers compared with the general population, most notably nonmelanoma skin cancer and posttransplant lymphoproliferative disorders. Risk factors for posttransplant malignancy include history of malignancy, immunosuppression, oncogenic viral infections, sun exposure, and disease-specific associations. Early detection and treatment of malignancies can improve survival.

Etiology of increased cancer incidence after solid organ transplantation

Over the past decades, there has been an encouraging increase in survival after solid organ transplantation. However, with longer life spans, more transplant recipients are at risk of dying with functioning grafts from illnesses such as cancer and cardiovascular conditions. Malignancy has emerged as an important cause of death in transplant recipients and is expected to become the leading cause of death in transplanted patients within the next decade. While it is known that solid organ transplant recipients have a three to five-fold increased risk of developing cancer compared with the general population, the mechanisms that lead to the observed excess risk in transplant recipients are less clear. This review explores the etiology of the increased cancer incidence in solid organ transplant including the effect of immunosuppressants on immunosurveillance and activation of oncogenic viruses, and carcinogenic effects of these medications; the role of chronic stimulation of the immune system on the development of cancer; and the impact of pre-existing cancer risk factors and factors related to end-stage organ disease on the cancer excess incidence in solid organ transplant recipients.

Risk factors associated with post-kidney transplant malignancies: an article from the Cancer-Kidney International Network

In kidney transplant recipients, cancer is one of the leading causes of death with a functioning graft beyond the first year of kidney transplantation, and malignancies account for 8-10% of all deaths in the USA (2.6 deaths/1000 patient-years) and exceed 30% of deaths in Australia (5/1000 patient-years) in kidney transplant recipients. Patient-, transplant- and medication-related factors contribute to the increased cancer risk following kidney transplantation. While it is well established that the overall immunosuppressive dose is associated with an increased risk for cancer following transplantation, the contributive effect of different immunosuppressive agents is not well established. In this review we will discuss the different risk factors for malignancies after kidney transplantation.

A Review of Induction with Rabbit Antithymocyte Globulin in Pediatric Heart Transplant Recipients

Pediatric heart transplantation (pHTx) represents only a small proportion of cardiac transplants. Due to these low numbers, clinical data relating to induction therapy in this special population are far less extensive than for adults. Induction is used more widely in pHTx than in adults, mainly because of early steroid withdrawal or complete steroid avoidance. Antithymocyte globulin (ATG) is the most frequent choice for induction in pHTx, and rabbit antithymocyte globulin (rATG, Thymoglobulin^®) (Sanofi Genzyme) is the most widely-used ATG preparation. In the absence of large, prospective, blinded trials, we aimed to review the current literature and databases for evidence regarding the use, complications, and dosages of rATG. Analyses from registry databases suggest that, overall, ATG preparations are associated with improved graft survival compared to interleukin-2 receptor antagonists. Advantages for the use of rATG have been shown in low-risk patients given tacrolimus and mycophenolate mofetil in a steroid-free regimen, in sensitized patients with pre-formed alloantibodies and/or a positive donor-specific crossmatch, and in ABO-incompatible pHTx. Registry and clinical data have indicated no increased risk of infection or post-transplant lymphoproliferative disorder in children given rATG after pHTx. A total rATG dose in the range 3.5–7.5 mg/kg is advisable.

Impact of the posttransplant lymphoproliferative disorder subtype on survival

BACKGROUND

Posttransplant lymphoproliferative disorder (PTLD) is a life-threatening complication of solid organ transplantation. Histologic heterogeneity and a lack of treatment standards have made evaluating clinical outcomes in specific patient populations difficult. This systematic literature review investigated the impact of the PTLD histologic subtype on survival in a large data set.

METHODS

Case series were identified on PubMed with the search terms post-transplant lymphoproliferative disorder/disease, PTLD, and solid organ transplantation, with additional publications identified through reference lists. The patient characteristics, immunosuppressive regimen, treatment, survival, and follow-up time for 306 cases were extracted from 94 articles, and these cases were combined with 11 cases from Emory University Hospital. Patients with a recorded subtype were included in a Kaplan-Meier survival analysis (n = 234). Cox proportional hazards regression analyses identified predictors of overall survival (OS) for each subtype and B-cell subgroup.

RESULTS

OS differed significantly between monomorphic T-cell neoplasms (median, 9 months) and polymorphic, monomorphic B-cell, and Hodgkin-type neoplasms, for which the median OS was not reached (P = .0001). Significant differences in OS among B subgroups were not detected, but there was a trend toward decreased survival for patients with Burkitt-type PTLD. Kidney transplantation and a reduction of immunosuppression were associated with increased OS for patients with B-cell neoplasms in a multivariate analysis. Immunosuppression with azathioprine was associated with decreased OS for patients with T-cell neoplasms, whereas radiotherapy was associated with improved OS for patients with that subtype.

CONCLUSIONS

The histologic subtype represents an important prognostic factor in PTLD, with patients with T-cell neoplasms exhibiting very poor OS. Possibly lower survival for certain subsets of patients with B-cell PTLD should be explored further and suggests the need for subtype-specific therapies to improve outcomes. Cancer 2018;124:2327-36. © 2018 American Cancer Society.

Individualizing immunosuppression in lung transplantation

Immunosuppression management after lung transplantation continues to evolve, with an increasing number of agents available for use in various combinations allowing for more choice and individualization of immunosuppressive therapy. Therapeutic developments have led to improved outcomes including lower acute rejection rates and improved survival. However, a one size fits all approach for any immunosuppressive strategy may not be best suited to the individual patient and ultimately patient specific factors must be considered when designing the immunosuppressive regimen. Recipient factors including age, race, co-morbidities, immunologic risk, genetic polymorphisms, concomitant and previous pharmacotherapy, and overall immunosuppression burden should be considered. There are several significant drug-drug interactions with select immunosuppressive agents utilized in lung transplant pharmacotherapy that must be considered when choosing and devising a dosing strategy for an individual immunosuppressive agent. Herein, considerations for immunosuppression management in the individual patient will be reviewed.

Graft survival of pediatric kidney transplant recipients selected for de novo steroid avoidance-a propensity score-matched study

Background

Steroid-avoidance protocols have gained popularity in pediatric kidney transplant recipients at low immunologic risk. The long-term safety of steroid avoidance in children with immunologic risk factors remains unknown.

Methods

Pediatric kidney transplant recipients from 2004 to 2014 in the Organ Procurement and Transplantation Network database who received tacrolimus and mycophenolate immunosuppression were investigated. Propensity score matching was used to compare graft survival in 1624 children who received steroid avoidance with 1624 children who received steroid-based immunosuppression. The effect of steroid avoidance on graft failure among immunologic risk strata was estimated using Cox proportional hazards regression in this propensity score-matched cohort.

Results

It was observed that 5-year graft survival was mildly improved in children receiving steroid avoidance (84.8% versus 81.2%, P = 0.03). This improvement in graft survival occurred in the first 2 years following transplant, when the hazard ratio (HR) for allograft failure in children receiving steroid avoidance was 0.62 [95% confidence interval (CI) 0.45-0.86]. In contrast, steroid avoidance was not associated with improved allograft survival during Years 2-10 following transplant (HR = 0.93; 95% CI 0.75-1.15). During this time period, HRs (95% CIs) for allograft failure within immunologic risk strata were not significantly different from the null value of 1: repeat kidney transplants, 1.84 (0.84-4.05); African-Americans, 1.02 (0.67-1.56); sensitized recipients, 1.24 (0.63-2.43); recipients of deceased donor kidneys, 1.02 (0.79-1.32); recipients of completely human leukocyte antigen-mismatched kidneys, 0.80 (0.47-1.37); and recipients with pretransplant glomerular disease, 0.94 (0.71-1.23).

Conclusions

In pediatric kidney transplant recipients receiving tacrolimus- and mycophenolate-based immunosuppression, steroid avoidance can be safely practiced in children with immunologic risk factors.

Comprehensive review of post-organ transplant hematologic cancers

A higher risk for a variety of cancers is among the major complications of posttransplantation immunosuppression. In this part of a continuing series on cancers posttransplantation, this review focuses on the hematologic cancers after solid organ transplantation. Posttransplantation lymphoproliferative disorders (PTLDs), which comprise the great majority of hematologic cancers, represent a spectrum of conditions that include, but are not limited to, the Hodgkin and non-Hodgkin lymphomas. The oncogenic Epstein-Barr virus is a key pathogenic driver in many PTLD cases, through known and unknown mechanisms. The other hematologic cancers include leukemias and plasma cell neoplasms (multiple myeloma and plasmacytoma). Clinical features vary across malignancies and location. Preventive screening strategies have been attempted mainly for PTLDs. Treatments include the chemotherapy regimens for the specific cancers, but also include reduction of immunosuppression, rituximab, and other therapies.

No Increased Risk of Posttransplant Lymphoproliferative Disorder Following Alemtuzumab Induction in Kidney Transplant

OBJECTIVES

Posttransplant lymphoproliferative disorder is a known complication of solid-organ transplant. The use of depleting induction agents has demonstrated varying associations with incidence of posttransplant lymphoproliferative disorder. Alemtuzumab, a depleting induction agent for kidney transplant patients, has shown promising results in reducing the risk of acute rejection and graft loss in the first year. Its unique mechanism of depleting both T-cell and B-cell populations may be beneficial in preventing the occurrence of posttransplant lymphoproliferative disorder.

MATERIALS AND METHODS

We examined the known risk factors for posttransplant lymphoproliferative disorder in the setting of alemtuzumab induction to determine whether incidence increases with this induction agent. We reviewed medical records of all alemtuzumab-induced kidney transplants from March 2006 to November 2015.

RESULTS

Of the 675 transplant patients who received alemtuzumab induction, 10 developed posttransplant lymphoproliferative disorder, with a cumulative incidence rate of 1.5%. All diagnosed patients had several known risk factors associated with posttransplant lymphoproliferative disorder: 7 with advanced age over 60 years, 5 being cytomegalovirus-negative recipients, and all 10 donor kidneys being male patients and Epstein-Barr virus positive before transplant.

CONCLUSIONS

The incidence rate seen in our patient population was within the range of the average in the United States but far lower than the incidence rates associated with other induction agents. Alemtuzumab is associated with a lower cumulative incidence rate of posttransplant lymphoproliferative disorder compared with published reports of other induction treatments.

Hepatocellular cancer and recurrence after liver transplantation: what about the impact of immunosuppression?

Liver transplantation (LT) has originally been designed to treat hepatobiliary malignancies. The initial results of LT for hepatocellular cancer (HCC) were, however, dismal this mainly due to the poor patient selection procedure. Better surgical and perioperative care and, especially, the refinement of selection criteria led to a major improvement of results, making HCC nowadays (again!) one of the leading indications for LT. This evolution is clearly shown by the innumerable reports aiming to further extend inclusion criteria for LT in HCC patients. Nonetheless, the vast majority of papers only deals with morphologic (tumour diameter and number) and (only recently) biologic (tumour markers and response to locoregional treatment) parameters to do so. Curiously enough, the role of both the immune competent state of the recipient as well as the impact of both immunosuppression (IS) type and load has been very poorly addressed in this context, even if it has been shown for a long time, based on both basic and clinical research, that they all play a key role in the outcome of any oncologic treatment and in the development of de novo as well as recurrent tumours. This chapter aims to give, after a short introductive note about the currently used inclusion criteria of HCC patients for LT and about the role of IS in carcinogenesis, a comprehensive overview of the actual literature related to the impact of different immunosuppressive drugs and schemes on outcome of LT in HCC recipients. Unfortunately, up to now solid conclusions cannot be drawn due to the lack of high-level evidence studies caused by the heterogeneity of the studied patient cohorts and the lack of prospectively designed and randomized studies. Based on long-term personal experience with immunosuppressive handling in LT some proposals for further clinical research and practice are put forward. The strategy of curtailing and minimising IS should be explored in the growing field of transplant oncology taking thereby into account the immunological privilege of the liver allograft. These strategies will become more and more compelling when further extending the indications in which adjuvant chemotherapy will probably become an inherent part of the therapeutic scheme of HCC liver recipients.

Epstein-Barr virus lymphoproliferative disease after solid organ transplantation

Epstein-Barr virus (EBV) was the first identified human oncovirus and is also one of the most ubiquitous viral infections known with established infections in more than 90% of individuals by early adulthood. EBV establishes latency by controlling expression of the viral genome making it silent to immune surveillance. In immunocompetent individuals, up to 1% of circulating T cells are directed at maintaining control over EBV replication. In addition to being involved in oncogenesis of lymphoid and epithelial tumors in immune-competent individuals, loss of immune surveillance over EBV predisposes individuals to EBV malignancies. Lymphoid proliferations from EBV-infected B cells arise in up to 20% of recipients of solid organ transplants (SOTs). One question not answered is why, when EBV requires such active immune surveillance, EBV malignancies are not even more prevalent in severely immune-compromised individuals. A better understanding of who develops complications related to EBV and what the immunologic risks are will ultimately make it feasible to perform prophylactic trials in those at highest risk. This review summarizes our current understanding of factors in SOT recipients that predispose them to the development of an EBV malignancy and that predict response to initial therapy. We then review the current landscape of those therapies, focusing on the goal of restoring long-term EBV-directed immunity to patients at risk.

Association Between Pretransplant Cancer and Survival in Kidney Transplant Recipients

BACKGROUND

Kidney transplantation in recipients with a previous malignancy is often deferred 2 to 5 years after cancer treatment due to fear of cancer recurrence. In Norway, the required waiting period has been 1 year.

METHODS

We compared patient and graft survival of recipients with pretransplant cancer to the outcomes of matched recipients without such cancer (comparators) using Cox regression.

RESULTS

From 1963 to 2010, 377 (6.4%) of 5867 recipients had a pretransplant cancer. During a median follow-up of 6.8 years, 256 recipients died, 35 (13.7%) from recurrent cancer and 27 (10.5%) from de novo cancer. Uncensored and death-censored graft loss occurred in 263 and 46 recipients, respectively. All-cause mortality was similar as in comparators (hazard ratio [HR], 1.06; 95% confidence interval [CI], 0.93-1.20]; P = 0.40), death-censored graft loss was lower (HR, 0.63; 95% CI, 0.47-0.84; P = 0.002), and uncensored graft loss was similar (HR, 0.99; 95% CI, 0.87-1.12; P = 0.87). Cancer mortality was higher than in comparators (HR, 1.97; 95% CI, 1.51-2.56; P < 0.001), particularly during the first 5 years of follow-up (HR, 3.44; 95% CI, 2.36-5.03; P < 0.01). Waiting period was not associated with recurrent cancer mortality or all-cause mortality (both P > 0.45). Results were similar within cancer subgroups, with most data in patients with a history of kidney cancer, prostate cancer, urothelial cancer, and skin squamous cell carcinoma.

CONCLUSIONS

Kidney transplant recipients with a pretransplant cancer had a similar overall patient and graft survival as recipients without such cancer. Cancer mortality was increased, particularly during the first 5 years after transplantation. A short waiting period was not associated with mortality.

Posttransplant Lymphoproliferative Disorder After Clinical Islet Transplantation: Report of the First Two Cases

We report the first two cases of posttransplant lymphoproliferative disorder (PTLD) in recipients of islet transplants worldwide. First, a 44-year-old recipient of three islet infusions developed PTLD 80 months after his initial transplantation, presenting with abdominal pain and diffuse terminal ileum thickening on imaging. He was treated with surgical excision, reduction of immunosuppression, and rituximab. Seven months later, he developed central nervous system PTLD, presenting with vertigo and diplopia; immunosuppression was discontinued, resulting in graft loss, and he was given high-dose methotrexate and underwent consolidative autologous stem cell transplantation. He remains in remission 37 months after the initial diagnosis. Second, a 58-year-old female recipient of two islet infusions developed PTLD 24 months after initial islet infusion, presenting with pancytopenia secondary to extensive bone marrow involvement. Immunosuppression was discontinued, resulting in graft loss, and she received rituximab and chemotherapy, achieving complete remission. Both patients were monomorphic B cell PTLD subtype by histology and negative for Epstein-Barr virus in tissue or blood. These cases document the first occurrences of this rare complication in islet transplantation, likely secondary to prolonged, intensive immunosuppression, and highlight the varying clinical manifestations of PTLD. Further studies are needed to determine incidence rate and risk factors in islet transplantation.

Eight-year follow-up in pediatric living donor kidney recipients receiving alemtuzumab induction

Recipient lymphocytes are crucial for direct and indirect pathways of allorecognition. We proposed that the administration of alemtuzumab several weeks pretransplantation could eradicate peripheral lymphatic cells and promote donor-specific acceptance. This was a single-center, retrospective review of 101 consecutive living donor kidney transplantations in pediatric patients (age 7 months-18 years), performed between September 2006 and April 2010. IS protocol included two 30 mg doses of alemtuzumab: The first was given 12-29 days prior to transplantation, and the second at the time of transplantation. Maintenance IS was based on combination of low-dose CNI and mycophenolate, with steroids tapered over the first 5 days post-transplantation. Patients were followed for 7.8±1.3 years, and protocol biopsies were taken 1 month, 1, 3, and 5 years post-transplant. The Kaplan-Meier 8-year patient and graft survival rates in the cyclosporine-treated patients were 82.0±7.3% and 71.6±7.3, and in the tacrolimus-treated patients were 97.2±5.4 and 83.8±6.0%. Biopsy-proven acute rejection developed in 35% of cyclosporine-treated patients and in 8% of tacrolimus-treated patients. Alemtuzumab pretreatment prior to LRD kidney transplantation, followed by maintenance immunosuppression with tacrolimus and MMF, is associated with reasonable long-term results in pediatric patients.

Daunting but Worthy Goal: Reducing the De Novo Cancer Incidence After Transplantation

Solid-organ transplant recipients are at increased risk of developing de novo malignancies compared with the general population, and malignancies become a major limitation in achieving optimal outcomes. The prevention and the management of posttransplant malignancies must be considered as a main goal in our transplant programs. For these patients, immunosuppression plays a major role in oncogenesis by both impairement of immunosurveillance, enhancement of chronic viral infection, and by direct prooncogenic effects. It is essential to manage the recipient with a long-term adapted screening program beginning before transplantation to use a prophylaxis to decrease infection-related cancer, to propose a viral monitoring, and to modulate the immunosuppression toward lower doses especially for calcineurin inhibitors. Indeed, strategies to induce tolerance or to allow a dramatic reduction of the immunosuppression burden are the more promising approaches for the reduction of the posttransplant malignancies.

Renal association clinical practice guideline in post-operative care in the kidney transplant recipient

These guidelines cover the care of patients from the period following kidney transplantation until the transplant is no longer working or the patient dies. During the early phase prevention of acute rejection and infection are the priority. After around 3-6 months, the priorities change to preservation of transplant function and avoiding the long-term complications of immunosuppressive medication (the medication used to suppress the immune system to prevent rejection). The topics discussed include organization of outpatient follow up, immunosuppressive medication, treatment of acute and chronic rejection, and prevention of complications. The potential complications discussed include heart disease, infection, cancer, bone disease and blood disorders. There is also a section on contraception and reproductive issues.Immediately after the introduction there is a statement of all the recommendations. These recommendations are written in a language that we think should be understandable by many patients, relatives, carers and other interested people. Consequently we have not reworded or restated them in this lay summary. They are graded 1 or 2 depending on the strength of the recommendation by the authors, and AD depending on the quality of the evidence that the recommendation is based on.