Analysis of Risk Factors for Kidney Retransplant Outcomes Associated with Common Induction Regimens: A Study of over Twelve-Thousand Cases in the United States

Predictors of graft function and survival in second kidney transplantation: A single center experience

BACKGROUND

The increasing kidney retransplantation rate has created a parallel field of research, including the risk factors and outcomes of this advanced form of renal replacement therapy. The presentation of experiences from different kidney transplantation centers may help enrich the literature on kidney retransplantation, as a specific topic in the field of kidney transplantation.

AIM

To identify the risk factors affecting primary graft function and graft survival rates after second kidney transplantation (SKT).

METHODS

The records of SKT cases performed between January 1977 and December 2014 at a European tertiary-level kidney transplantation center were retrospectively reviewed and analyzed. Beside the descriptive characteristics, the survivals of patients and both the first and second grafts were described using Kaplan-Meier curves. In addition, Kaplan-Meier analyses were also used to estimate the survival probabilities at 1, 3, 5, and 10 post-operative years, as well as at the longest follow-up duration available. Moreover, bivariate associations between various predictors and the categorical outcomes were assessed, using the suitable biostatistical tests, according to the predictor type.

RESULTS

Out of 1861 cases of kidney transplantation, only 48 cases with SKT were eligible for studying, including 33 men and 15 women with a mean age of 42.1 ± 13 years. The primary non-function (PNF) graft occurred in five patients (10.4%). In bivariate analyses, a high body mass index (P = 0.009) and first graft loss due to acute rejection (P = 0.025) were the only significant predictors of PNF graft. The second graft survival was reduced by delayed graft function in the first (P = 0.008) and second (P < 0.001) grafts. However, the effect of acute rejection within the first year after the first transplant did not reach the threshold of significance (P = 0.053). The mean follow-up period was 59.8 ± 48.6 mo. Censored graft/patient survival rates at 1, 3, 5 and 10 years were 90.5%/97.9%, 79.9%/95.6%, 73.7%/91.9%, and 51.6%/83.0%, respectively.

CONCLUSION

Non-immediate recovery modes of the first and second graft functions were significantly associated with unfavorable second graft survival rates. Patient and graft survival rates of SKT were similar to those of the first kidney transplantation.

Pediatric kidney retransplantation focused on surgical outcomes

INTRODUCTION

Despite survival rates after pediatric kidney transplantation (KT) are on the rise it is still likely that most pediatric recipients will require more than one retransplant in their lifetime. The earlier the age at the first KT the higher is the risk of repeat pediatric kidney transplantation (RPKT).

OBJECTIVE

The current study aims to analyze the outcomes of repeat pediatric kidney transplantation (RPKT) among pediatric kidney transplant recipients focusing on surgical complications and compare the outcomes of second and subsequent grafts with those of the first kidney graft.

MATERIALS AND METHODS

Retrospective study of RPKT (<18 years) undertaken between January 2000-2020. We analyzed primary etiology of renal disease, time to graft loss (GL), etiology of initial graft failure, history of acute rejection, previous delayed graft function, HLA-mismatches at the initial transplant, surgical complications and outcomes. Additionally, we compared the characteristics and outcomes of patients who underwent RPKT (group 1) with those who received a first kidney graft (group 2).

RESULTS

Out of 229 kT, 59 patients underwent RPKT (26 females/33 males). At the time of RPKT median age was 11.37 years (SD:5.7). The most frequent primary renal disease was congenital nephrotic syndrome in 11 (18.6%). Fifty-four (91.5%) were on renal replacement therapy at the time of transplant. Fourty-one patients received their second KT (69.5%), 14 (23.7%) the third, 3 (5.1%) the fourth and 1 (1.7%) the fifth. Transplant graft nephrectomy (GN) was performed in 26 patients (44.1%) prior to retransplantation. Fifty-four (91.5%) received a cadaveric graft and 5 (8.5%) a living-related graft. An extraperitoneal approach was achieved in 53 patients (89.8%), whereas in the remaining 6 (10.2%) the graft was placed intraperitoneally. We observed 10 surgical complications (16.9%): 9 major which required reintervention and 1 minor (perirenal hematoma). No vascular complications were observed and none of the surgical complications were involved in graft loss. Graft survival at 1,3 and 5 years was 91%, 84% and 73% respectively. The most frequent cause of GL was chronic graft nephropathy in 15 (25.4%). After a mean follow-up of 9.40 years (SD: 4.7) only 2 patients died (3.4%), both with functioning grafts.

DISCUSSION

Pediatric recipients of second and subsequent kidney grafts constitute a remarkable high-risk population but are becoming more frequent at reference pediatric transplant centers.

CONCLUSIONS

RPKT is technically challenging but can yield good results. In our series overall the incidence of surgical complications and particularly vascular complications was low.

The Role of Donor Sex in Females Undergoing Repeat Kidney Transplant: Does Prior Donor Sex Matter?

Female recipients of male donor kidneys are at increased risk for graft failure because of the HY antigen effect. However, whether prior transplant with a male donor impacts subsequent transplant outcomes is unknown. Therefore, the purpose of this study was to determine whether prior male-current male donor sex is associated with an increased risk of graft failure in female recipients.

Methods

We performed a cohort study of adult female recipients undergoing a second kidney transplant (2000-2017), identified using the Scientific Registry of Transplant Recipients. Using multivariable Cox models, we analyzed the risk of death-censored graft loss (DCGL) if the second transplant was from a male versus female kidney donor, conditional on donor sex at the time of the first transplant. In a secondary analysis, we stratified results by recipient age (>50 or ≤50 y) at the time of retransplant.

Results

Of 5594 repeat kidney transplants, 1397 (25.0%) developed DCGL. Overall, there was no association between first and second donor sex pairing and DCGL. A prior and current female donor (FD₁FD₂) posed a higher risk for DCGL in recipients aged >50 y at second transplant (hazard ratio,≤0.67, confidence interval 0.46-0.98, for all other donor combinations), but posed a lower risk if aged ≤50 y at retransplant (hazard ratio, ≥1.37, confidence interval 1.04-1.80, for all other donor combinations).

Conclusions

Overall, past-current donor sex pairing was not associated with DCGL in female recipients undergoing second kidney transplant; however, the risk with a past and current female donor was increased in older, and decreased in younger, female recipients at retransplant.

Kidney Retransplantation after Graft Failure: Variables Influencing Long-Term Survival

Background

There is an increasing demand for kidney retransplantation. Most studies report inferior outcomes compared to primary transplantation, consequently feeding an ethical dilemma in the context of chronic organ shortage.

Objective

To assess variables influencing long-term graft survival after kidney retransplantation. Material and Methods. All patients transplanted at our center between 2000 and 2016 were analyzed retrospectively. Survival was estimated with the Kaplan–Meier method, and risk factors were identified using multiple Cox regression.

Results

We performed 1,376 primary kidney transplantations and 222 retransplantations. The rate of retransplantation was 67.8% after the first graft loss, with a comparable 10-year graft survival compared to primary transplantation (67% vs. 64%, p=0.104) but an inferior graft survival thereafter (log-rank p=0.026). Independent risk factors for graft survival in retransplantation were age ≥ 50 years, time on dialysis ≥1 year, previous graft survival <2 years, ≥1 mild comorbidity in the Charlson–Deyo index, active smoking, and life-threatening complications (Clavien–Dindo grade IV) at first transplantation.

Conclusion

Graft survival is comparable for first and second kidney transplantation within the first 10 years. Risk factors for poor outcomes after retransplantation are previous graft survival, dialysis time after graft failure, recipient age, comorbidities, and smoking. Patients with transplant failure should have access to retransplantation as early as possible.

Risk Factors of Rejection in Renal Transplant Recipients: A Narrative Review

Multiple factors influence graft rejection after kidney transplantation. Pre-operative factors affecting graft function and survival include donor and recipient characteristics such as age, gender, race, and immunologic compatibility. In addition, several peri- and post-operative parameters affect graft function and rejection, such as cold and warm ischemia times, and post-operative immunosuppressive treatment. Exposure to non-self-human leucocyte antigens (HLAs) prior to transplantation up-regulates the recipient’s immune system. A higher rate of acute rejection is observed in transplant recipients with a history of pregnancies or significant exposure to blood products because these patients have higher panel reactive antibody (PRA) levels. Identifying these risk factors will help physicians to reduce the risk of allograft rejection, thereby promoting graft survival. In the current review, we summarize the existing literature on donor- and recipient-related risk factors of graft rejection and graft loss following kidney transplantation.

Urinary Proteomics in Kidney Transplantation

Although kidney transplantation is the best treatment option for end stage kidney disease, it is still associated with long-term graft failure. One of the greater challenges for transplant professionals is the ability to identify grafts with a high risk of failure before initial decline of eGFR with irreversible graft changes. Transplantation medicine is facing an emerging need for novel disease end point-specific biomarkers, with practical application in preventive screening, early diagnostic, and improved prognostic and therapeutic utility. The aim of our review was to evaluate the clinical application of urinary proteomics in kidney transplant recipients at risk for any type of future graft failure.

Alemtuzumab in Renal Retransplantation - Transplant Outcomes and Associated Infections

Renal retransplant patients have decreased graft survival compared with primary renal transplant patients. Alemtuzumab induction is often used at the time of retransplant; however, the literature surrounding alemtuzumab induction in renal retransplant patients is limited. In this single-center, retrospective, observational study, we aimed to determine the 1-year incidence of infections and transplant outcomes in renal retransplant patients who received alemtuzumab induction. Thirty-four patients who received alemtuzumab met inclusion criteria and were included in the final analysis. Twenty-two (64.7%) of these patients acquired infections. Of these, 7 patients (31.8%) acquired infections that resulted in hospitalization or intravenous antibiotics. The most common infections were urinary tract infections (n = 10; 29.4%), cytomegalovirus DNAemia (n = 7; 20.6%), and BK virus (n = 6; 17.6%). The use of steroid maintenance therapy after alemtuzumab induction did not increase the number of infections compared with patients with a steroid-free interval after alemtuzumab induction. The number of patients who developed de novo donor-specific antibodies (DSA) was 11 (32.4%) with only 1 of these patients having DSA before retransplantation. The incidence of acute cellular rejection was 2.9% (n = 1). There was no graft loss, and patient survival was 97% (n = 33). There were no significant differences in infection rate or DSA development between alemtuzumab and the other induction agents, antithymocyte globulin and basiliximab, among retransplanted patients. Alemtuzumab induction in renal retransplant patients resulted in similar bacterial and viral infection rates as previously reported in the literature and did not negatively impact graft and patient survival.

The Aquaporin3 Promoter Polymorphism -1431 A/G is Associated with Acute Graft Rejection and Cytomegalovirus Infection in Kidney Recipients Due to Altered Immune Cell Migration

Major complications after kidney transplantation are graft rejection and cytomegalovirus (CMV) infection, which are related to T-cell function, which depends on aquaporin 3 (AQP3) expression. The impact of the AQP3 A(−1431)G promoter polymorphism in kidney transplant recipients was unelucidated and we explored the effect of AQP3 polymorphism on immune cell function and its association with graft rejection and CMV infection in 237 adult patients within 12 months after transplantation. AQP3 promoter polymorphism was molecular and functional characterized. Kaplan–Meier plots evaluated the relationship between genotypes and the incidence of CMV infection and graft rejection. AQP3 A(−1431)G A-allele was associated with enhanced immune cell migration and AQP3 expression in T-cells. The incidences of rejection were 45.4% for the A-allele and 27.1% for G-allele carriers (p = 0.005) and the A-allele was a strong risk factor (hazard ratio (HR): 1.95; 95% CI: 1.216 to 3.127; p = 0.006). The incidences for CMV infection were 21% for A-allele and 35% for G-allele carriers (p = 0.013) and G-allele was an independent risk factor (p = 0.023), with a doubled risk for CMV infection (HR: 1.9; 95% CI: 1.154 to 3.128; p = 0.012). Hence, A-allele confers more resistance against CMV infection, but susceptibility to graft rejection mediated by T-cells. Thus, AQP3-genotype adapted management of immunosuppression and antiviral prophylaxis after kidney transplantation seems prudent.

Low-dose alemtuzumab induction in a tailored immunosuppression protocol for sensitized kidney transplant recipients

Background

Induction therapy is crucial in kidney transplantation and constitutes an important cornerstone for long-term allograft survival. Alemtuzumab is a depleting CD52-specific antibody with T- and B-cell activity, leading to prolonged lymphocyte depletion for up to 12 months, with profound immunosuppression and an associated risk of serious infections. Current concepts aim to optimize dosing strategies to reduce side effects. Here we present data from an ongoing centre protocol consisting of low-dose alemtuzumab induction and tailored immunosuppression in sensitized patients undergoing kidney transplantation.

Methods

10-year results of the protocol were analysed. Low-dose alemtuzumab induction consisted of a single dose of 20 mg intraoperatively, followed by tacrolimus and corticosteroids for initial immunosuppression, with mycophenolate mofetil suspended until a total lymphocyte count (TLC) >5% or 200/μl was reached.

Results

Between 01/2007 and 04/2017, 46 patients were treated in accordance with the protocol in 48 kidney transplantations. Median PRA_max was 43 [22-76; IQR] %; all patients had negative CDC-crossmatch prior to transplantation. Low-dose alemtuzumab was well tolerated. Median time to TLC recovery was 77 [62-127; IQR] d. Within a median follow-up of 3.3 [1.5-5.6; IQR] years, 12 (25%) patients developed BPAR, 10 of which were antibody-mediated (3 acute, 7 chronic ABMR). Death-censored 5-year allograft survival was 79.2%, with an excellent allograft function at the end of follow-up. There was no increased rate of infections, in particular viral infections.

Conclusions

Our protocol, comprising low-dose alemtuzumab induction, initial suspension of mycophenolate mofetil and triple maintenance immunosuppression, provides excellent patient and allograft outcome in sensitized renal allograft recipients.

Comparing the effect of induction therapy with or without antithymocyte globulin on renal allograft outcomes in live-donor kidney transplant recipients

Background: This study aimed to investigate the effectiveness of antithymocyte globulin (ATG) in low-risk live-donor kidney transplant recipients (LDKTRs).

Methods: In this cohort study, 114 LDKTRs were analyzed in 2 groups of ATG induction therapy (n=77) and control (n=37). In this study, 500 mg pulse therapy with methylprednisolone was provided for both groups for 3 days. In addition, one mg/kg of daily ATG was prescribed for 4 days in ATG induction group. Serum creatinine (Cr) was measured at 3, 7, 30, 90, and 180 days after surgery and discharge day. Acute rejection (AR) was confirmed based on biopsy or rise in serum Cr by three-tenths from baseline if other causes had been ruled out. Survival analysis was used by Stata14 and p < 0.05 was considered significant.

Results: Cr changes were not significantly different between ATG induction therapy and control group in all follow-up periods (2.26 and 1.07 in ATG vs 2.26 and 1.03 in control group from the third day; (p=0.999) to the sixth month (p=0.735)). There was no significant difference between the 2 study groups in AR incidence (11.7% in ATG vs 10.8% in control group, P = 0.890) and its time (9.6 in ATG vs 9.8 in control group, p=0.695). Recipients factors were baseline Cr >10 mg/dL (p=0.055), blood group AB (p=0.007), no postoperative pulse therapy with methylprednisolone (PM) (p=0.005); and donors’ factors were age ≤ 30 years (p=0.022) and blood group AB (p=0.006). Also, based on the log rank analysis, recipient-donor weight difference of 0 to 5 kg (p=0.047) had a significant association with earlier AR. Exploring these effects simultaneously by Cox regression analysis showed only significant results for recipients' baseline Cr (p=0.040) and postoperative therapy with PM (p=0.014).

Conclusion: Both strategies of induction therapy had the same good results based on Cr decrease. Recipients' baseline Cr and postoperative therapy with PM were the predictors of survival time of the kidney (AR).

Outcomes of induction antibody therapies in the nonbroadly sensitized adult deceased donor kidney transplant recipients: a retrospective cohort registry analysis

The outcomes of lymphocyte-depleting antibody induction therapy (LDAIT), [thymoglobulin (ATG) or alemtuzumab (ALM)] versus interleukin-2 receptor antagonist (IL-2RA) in the nonbroadly-sensitized [pretransplant calculated panel reactive antibody (cPRA), <80%] adult deceased donor kidney transplant recipients (adult-DDKTRs) are understudied. In this registry, study of 55 593 adult-DD-KTRs, outcomes of LDAIT [(ATG, N = 32 985) and (ALM, N = 9429)], and IL-2RA (N = 13 179) in <10% and 10-79% cPRA groups was analyzed. Adjusted odds ratio (aOR) of one-year biopsy-proven acute rejection (BPAR) was lower; while, aOR of 1-year composite of re-hospitalization, graft loss, or death was higher with LDAIT than IL2-RA in both cPRA groups. Adjusted odds ratio (aOR) of delayed graft function was higher with LDAIT than IL-2RA in the <10% cPRA group. Adjusted hazard ratio (aHR) of 5-year death-censored graft loss (DCGL) in both <80% cPRA groups seemed higher with ALM than other inductions [(<10% cPRA: ALM versus IL2RA, aHR = 1.11, 95% CI = 1.00-1.23 and ATG versus ALM: aHR = 0.84, 95% CI = 0.77-0.91; 10-79% cPRA: ALM versus IL2RA, aHR = 1.29, 95% CI = 1.02-1.64; and ATG versus ALM, aHR = 0.83, 95% CI = 0.70-0.98)]. Five-year aHR of death did not differ among induction therapies in both cPRA groups. In nonbroadly sensitized adult-DDKTRs, LDAIT is more protective against 1-year BPAR (not 5-year mortality) than IL-2RA; the trend of a higher 5-year DCGL risk with ALM than ATG or IL-2RA needs further investigation.