Induction Therapy, Rejection, and Graft Outcomes in Pediatric and Adolescent Kidney Transplant Recipients

Immune monitoring in pediatric kidney transplant

BACKGROUND

Long-term outcomes in pediatric kidney transplantation remain suboptimal, largely related to chronic rejection. Creatinine is a late marker of renal injury, and more sensitive, early markers of allograft injury are an active area of current research.

METHODS

This is an educational review summarizing existing strategies for monitoring for rejection in kidney transplant recipients.

RESULTS

We summarize supporting currently available clinical tests, including surveillance biopsy, donor specific antibodies, and donor-derived cell free DNA, as well as the potential limitations of these studies. In addition, we review the current avenues of active research, including transcriptomics, proteomics, metabolomics, and torque tenovirus levels.

CONCLUSION

Advancing the use of noninvasive immune monitoring will depend on well-designed multicenter trials that include patients with stable graft function, include biopsy results on all patients, and can demonstrate both association with a patient-relevant clinical endpoint such as graft survival or change in glomerular filtration rate and a potential timepoint for intervention.

Outcomes based on induction regimens in pediatric kidney transplantation: a NAPRTCS and PHIS collaborative study

BACKGROUND

Induction agent used at the time of kidney transplant is often based upon center practice and recipient characteristics. We evaluated outcomes across induction therapies among children enrolled in the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) transplant registry with data in the Pediatric Health Information System (PHIS).

METHODS

This is a retrospective study of merged data from NAPRTCS and PHIS. Participants were grouped by induction agent: interleukin-2 receptor blocker (IL-2 RB), anti-thymocyte/anti-lymphocyte globulin (ATG/ALG), and alemtuzumab. Outcomes assessed included 1-, 3-, and 5-year allograft function and survival, rejection, viral infections, malignancy, and death.

RESULTS

A total of 830 children transplanted between 2010 and 2019. At 1 year post-transplant, the alemtuzumab group had higher median eGFR (86 ml/min/1.73 m2) compared to IL-2 RB and ATG/ALG (79 and 75 ml/min/1.73 m2, respectively; P < 0.001); at 3 and 5 years, there was no difference. Adjusted eGFR over time was similar across all induction agents. Rejection rates were lower among the alemtuzumab group vs. IL-2RB and ATG (13.9% vs. 27.3% and 24.6%, respectively; P = 0.006). Adjusted ATG/ALG and alemtuzumab had higher hazard ratio for time to graft failure compared to IL-2 RB (HR 2.48 and HR 2.11, respectively; P < 0.05). Incidence of malignancy, mortality, and time to first viral infection was similar.

CONCLUSION

Although rejection and allograft loss rates were distinct, the incidences of viral infection and malignancy were comparable across induction agents. By 3 years post-transplant, there was no difference in eGFR. A higher resolution version of the Graphical abstract is available as Supplementary information.

Status and Influencing Factors of Social Participation in Renal Transplantation Recipients: A Cross-Sectional Study From a Single Center in China

BACKGROUND

To investigate the social participation (SP) of renal transplantation (RT) recipients and analyze the influencing factors.

DESIGN

Cross-sectional study.

METHODS

Data were collected from RT recipients reviewed within the Urology Outpatient Clinic of a tertiary class-A hospital in Hebei, China between October 2018 and October 2019.

RESULTS

The total mean score of an SP questionnaire for RT recipients was 37.77 ± 2.74. The mean score per item in each dimension showed that the scores for leisure, activity, and voluntary participation in social life were the highest, indicating low participation. Educational level, household income, occupation, preoperative employment, creatinine level in the transplanted kidney, medication compliance, depression, and anxiety could explain 77% of the variation in the SP level.

CONCLUSIONS

There are many factors affecting the SP levels of RT recipients. Clinicians should comprehensively evaluate RT recipients before and after surgery, formulate health education programs, and improve the SP level.

Induction and maintenance immunosuppression in pediatric kidney transplantation-Advances and controversies

Advances in immunosuppression have improved graft survival in pediatric kidney transplant recipients; however, treatment-related toxicities need to be balanced against the possibility of graft rejection. Several immunosuppressive agents are available for use in transplant recipients; however, the optimal combinations of agents remain unclear, resulting in variations in institutional protocols. Lymphocyte-depleting antibodies, specifically ATG, are the most common induction agent used for pediatric kidney transplantation in the US. Basiliximab may be used for induction in immunologically low-risk children; however, pediatric data are scarce. CNIs and antiproliferative agents (mostly Tac and mycophenolate in recent years) constitute the backbone of maintenance immunosuppression. Steroid-avoidance maintenance regimens remain controversial. Belatacept and mTOR inhibitors are used in children under specific circumstances such as non-adherence or CNI toxicity. This article reviews the indications, mechanism of action, efficacy, dosing, and side effect profiles of various immunosuppressive agents available for pediatric kidney transplantation.

Primary pediatric live-donor-kidney transplant-recipients' outcomes by immunosuppression induction received in the United States

OBJECTIVE

We examined the association between induction type and outcomes of live-donor pediatric kidney recipients on tacrolimus and mycophenolate maintenance.

MATERIAL AND METHODS

We analyzed the SRTR standard analysis file to evaluate primary live-donor pediatric kidney recipients between 2000 and 2018. Recipients were grouped by induction type into three groups: alemtuzumab n = 289, anti-thymocyte n = 1197, and IL-2RA n = 1625. Kaplan-Meier curves were generated for recipient and death-censored graft survival. Predictors of recipient and allograft survival were examined using Cox proportional hazards models. Models were adjusted for age, sex, ethnicity, renal failure etiology, HLA-mismatches, transplant year, steroid maintenance, preemptive transplantation, payor type, and donor factors such as age, sex, and donor-recipient relationship. The transplant center was included as a random effect to account for inter-center variability.

RESULTS

Rejection rates at 6 months (Alemtuzumab 9.5% vs. r-ATG 5.7% vs. IL2-RA 5.3%; P: .023) and 12 months (Alemtuzumab 14.5% vs. r-ATG 10.8% vs. IL2-RA 9%; P: .028) were significantly higher in the alemtuzumab group. PTLD rate (Alemtuzumab 0.8% vs. r-ATG 2.2% vs. IL2-RA 1%; P: .028) was significantly higher in the anti-thymocyte group. In the multivariable models, induction type did not influence patient or death-censored graft survival within ten years post-transplant.

CONCLUSION

In this large cohort of standard immunological risk primary pediatric live-donor kidney recipients, as compared to IL-2RA, neither alemtuzumab nor anti-thymocyte globulin was associated with improved long-term graft or recipient survival. In the first year post-transplant, recipients of alemtuzumab induction had a higher rejection rate, while PTLD was more frequently observed in the anti-thymocyte recipients.

Primary pediatric deceased-donor kidney transplant recipients outcomes by immunosuppression induction received in the United States

BACKGROUND

We studied the association of induction immunosuppression and pediatric deceased-donor kidney recipient and graft survival.

METHODS

We utilized the SRTR to evaluate all primary pediatric deceased-donor kidney transplants from January 1st, 2000, through December 2018. We included only recipients who were maintained on tacrolimus and mycophenolate. Recipients were grouped by induction type: alemtuzumab n = 320, r-ATG n = 2091 and IL-2RA n = 2165. Recipient and allograft survival, and their predictors, were examined. Models were adjusted for age, sex, ethnicity, HLA-antigen mismatches, transplant year, steroid maintenance, pre-emptive transplantation and payor type, with the transplant center included as a random effect.

RESULTS

Rejection rates at 6 months (alemtuzumab 8.6% vs r-ATG 7.8% vs IL2-RA 9.2%; P = .30) and 12 months (alemtuzumab 17.2% vs r-ATG 15.7% vs IL2-RA 16.5%; P = .70) were not significantly different between induction groups. In the multivariable models, compared to IL-2RA neither alemtuzumab nor r-ATG was associated with improved recipient [alemtuzumab (HR 1.06, P = .88); r-ATG (HR 1.03, P = .84)] or graft survival [alemtuzumab (HR 1.18, P = .32); r-ATG (HR 1.10, P = .21)].

CONCLUSION

In this large cohort of standard immunological risk primary pediatric deceased-donor kidney recipients on tacrolimus and mycophenolate maintenance, depletional induction regimens were not associated with better rejection rates, recipient, or graft survival compared to IL-2RA induction. Racial, payor type, and sex-related outcome disparities were significant in this group independent of the induction choice.

Acute rejection in pediatric renal transplantation: Retrospective study of epidemiology, risk factors, and impact on renal function

AR is a major relevant and challenging topic in pediatric kidney transplantation. Our objective was to evaluate cumulative incidence of AR in pediatric kidney transplant patient, risk factors for this outcome, and impact on allograft function and survival. A retrospective cohort including pediatric patients that underwent kidney transplantation between 2011 and 2015 was designed. Risk factors for AR were tested by competing risk analysis. To estimate its impact, graft survival and difference in GFR were evaluated. Two hundred thirty patients were included. As a whole, the incidence of AR episodes was 0.16 (95% CI = 0.12-0.20) per person-year of follow-up. And cumulative incidence of AR was 23% in 1 year and 39% in 5 years. Risk factors for AR were number of MM (SHR 1.36 CI 1.14-1.63 P = .001); ISS with CSA, PRED, and AZA (SHR 2.22 CI 1.14-4.33 P = .018); DGF (SHR 2.49 CI 1.57-3.93 P < .001); CMV infection (SHR 5.52 CI 2.27-11.0 P < .001); and poor adherence (SHR 2.28 CI 1.70-4.66 P < .001). Death-censored graft survival in 1 and 5 years was 92.5% and 72.1%. Risk factors for graft loss were number of MM (HR 1.51 CI 1.07-2.13 P = .01), >12 years (HR 2.66 CI 1.07-6.59 P = .03), and PRA 1%-50% (HR 2.67 CI 1.24-5.73 P = .01). Although occurrence of AR did not influence 5-year graft survival, it negatively impacted GFR. AR was frequent in patients assessed and associated with number of MM, ISS regimen, DGF, CMV infection, and poor adherence, and had deleterious effect on GFR.

Considerations and controversies of pharmacologic management of the pediatric kidney transplant recipient

Pediatric kidney transplantation has experienced considerable growth and improvement in patient and allograft outcomes over the past 20 years, in part due to advancements in immunosuppressive regimens and management. Despite this progress, care for this unique population can be challenging due to limited pediatric transplant data and trials, intricacies related to differences in children and adolescents compared with their adult counterparts, and limitations to long-term survival facing all solid organ transplant populations. Immunosuppression and infection prevention practices vary from one pediatric transplant center to another and clinical controversies exist surrounding treatment and dosing. This review aims to summarize key aspects of pharmacologic management in this population and present pertinent data that describe the influence of practice to serve as a resource for practitioners caring for this unique specialty patient population. Additionally, this review highlights select controversies that exist within pediatric kidney transplantation.

Kidney transplantation in children with CAKUT and non-CAKUT causes of chronic kidney disease: Do they have the same outcomes?

Almost half the children who undergo kidney transplantation (KTx) have congenital abnormalities of the kidney and urinary tract (CAKUT). We compared patient, graft survival, and kidney function at last follow-up between CAKUT and non-CAKUT patients after KTx. We divided the analysis into two eras: 1988-2000 and 2001-2019. Of 923 patients, 52% had CAKUT and 48% non-CAKUT chronic kidney disease (CKD). Of the latter, 341 (77%) had glomerular disease, most frequently typical HUS (32%) and primary FSGS (27%); 102 had non-glomerular disease. CAKUT patients were more often boys, younger at KTx, transplanted more frequently preemptively, but with longer time on chronic dialysis. They had less delayed graft function (DGF) and better eGFR, but higher incidence of urinary tract infection (1 year post-KTx). In both eras, 1-, 5-, and 10-year patient survival was similar in the groups, but graft survival was better in CAKUT recipients vs those with primary glomerular and primary recurrent glomerular disease: Era 1, 92.3%, 80.7%, and 63.6% vs 86.9%, 70.6%, and 49.5% (P = .02), and 76.7%, 56.6%, and 34% (P = .0003); Era 2, 96.2%, 88%, and 73.5% vs 90.3%, 76.1%, and 61% (P = .0075) and 75.4%, 54%, and 25.2% (P < .0001), respectively. Main predictors of graft loss were DGF, late acute rejection (AR), and age at KTx in CAKUT group and disease relapse, DGF, early AR, and number of HLA mismatches in recipients with glomerular disease. Graft survival was better in CAKUT patients. DGF was the main predictor of graft loss in all groups. Disease recurrence and early AR predicted graft failure in patients with glomerular disease.

Special Considerations in Pediatric Kidney Transplantation

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