Antibody-mediated rejection diagnosed in early protocol biopsies in high immunological risk kidney transplant recipients.

BACKGROUND: Renal transplant recipients with donor-specific anti-HLA antibodies are at an increased risk of antibody-mediated rejection (AMR). Early protocolized renal biopsies may serve as a strategy to improve diagnosis in this patient population. METHODS: We evaluated 155 highly sensitized renal transplant recipients with cPRA class I + II > 90% pre-transplant from 2015 to 2022. Patients with protocol biopsies within the first two weeks post-transplant were included. RESULTS: A total of 122 patients were included in the study. Of these, 13 (10.6%) were diagnosed with very early antibody-mediated rejection (veABMR) within the first two weeks post-transplant. This corresponds to 52% (13/25 patients) of all ABMR cases reported during the follow-up of this population. The graft survival rates at one and three years were significantly lower in patients with veABMR (p < 0.001) compared to patients without rejection in the early protocol biopsy. In terms of severity, the veABMR cohort exhibited a hazard ratio (HR) of 10.33 (95% CI 3.23-33.06; p < 0.001) for graft failure. The presence of donor-specific antibodies (DSA) class II on the day of transplantation and a higher percentage of eplet mismatch (EpMM), particularly EpMM DQA1, correlated with the development of veABMR. CONCLUSION: Early protocol biopsies play a pivotal role in the early detection of veABMR in high-risk immunological patients. Patients with veABMR face significant risks of graft loss, despite early treatment of rejection.

Early kinetics of donor-derived cell-free DNA after transplantation predicts renal graft recovery and long-term function.

BACKGROUND: Ischemia-reperfusion injury (IRI) upon transplantation is one of the most impactful events that the kidney graft suffers during its life. Its clinical manifestation in the recipient, delayed graft function (DGF), has serious prognostic consequences. However, the different definitions of DGF are subject to physicians' choices and centers' policies, and a more objective tool to quantify IRI is needed. Here, we propose the use of donor-derived cell-free DNA (ddcfDNA) for this scope. METHODS: ddcfDNA was assessed in 61 kidney transplant recipients of either living or deceased donors at 24 h, and 7, 14 and 30 days after transplantation using the AlloSeq cfDNA Kit (CareDx, San Francisco, CA, USA). Patients were followed-up for 6 months and 7-year graft survival was estimated through the complete and functional iBox tool. RESULTS: Twenty-four-hour ddcfDNA was associated with functional DGF [7.20% (2.35%-15.50%) in patients with functional DGF versus 2.70% (1.55%-4.05%) in patients without it, P = .023] and 6-month estimated glomerular filtration rate (r = -0.311, P = .023). At Day 7 after transplantation, ddcfDNA was associated with dialysis duration in DGF patients (r = 0.612, P = .005) and worse 7-year iBox-estimated graft survival probability (ß -0.42, P = .001) at multivariable analysis. Patients with early normalization of ddcfDNA (<0.5% at 1 week) had improved functional iBox-estimated probability of graft survival (79.5 ± 16.8%) in comparison with patients with 7-day ddcfDNA ≥0.5% (67.7 ± 24.1%) (P = .047). CONCLUSIONS: ddcfDNA early kinetics after transplantation reflect recovery from IRI and are associated with short-, medium- and long-term graft outcome. This may provide a more objective estimate of IRI severity in comparison with the clinical-based definitions of DGF.

Preemptive simultaneous pancreas kidney transplantation has survival benefit to patients.

Several organ allocation protocols give priority to wait-listed simultaneous kidney-pancreas (SPK) transplant recipients to mitigate the higher cardiovascular risk of patients with diabetes mellitus on dialysis. The available information regarding the impact of preemptive simultaneous kidney-pancreas transplantation on recipient and graft outcomes is nonetheless controversial. To help resolve this, we explored the influence of preemptive simultaneous kidney-pancreas transplants on patient and graft survival through a retrospective analysis of the OPTN/UNOS database, encompassing 9690 simultaneous transplant recipients between 2000 and 2017. Statistical analysis was performed applying a propensity score analysis to minimize bias. Of these patients, 1796 (19%) were transplanted preemptively. At ten years, recipient survival was significantly superior in the preemptive group when compared to the non-preemptive group (78.9% vs 71.8%). Dialysis at simultaneous kidney-pancreas transplantation was an independent significant risk for patient survival (hazard ratio 1.66 [95% confidence interval 1.32-2.09]), especially if the dialysis duration was 12 months or longer. Preemptive transplantation was also associated with significant superior kidney graft survival compared to those on dialysis (death-censored: 84.3% vs 75.4%, respectively; estimated half-life of 38.57 [38.33 -38.81] vs 22.35 [22.17 - 22.53] years, respectively). No differences were observed between both groups neither for pancreas graft survival nor for post-transplant surgical complications. Thus, our results sustain the relevance of early referral for pancreas transplantation and the importance of pancreas allocation priority in reducing patient mortality after simultaneous kidney-pancreas transplantation.

Antiphospholipase A2 receptor antibody-positive membranous nephropathy in the kidney donor: Lessons from a serendipitous transplantation.

Primary membranous nephropathy (PMN) is an autoimmune disease limited to the kidney that is characterized by the presence of circulating PLAR2 antibodies in 70% of the cases and usually positivity for PLA2R and IgG4 by immunohistochemistry (IHC) staining. We report the first documented case of PMN (PLA2R positive) in a deceased kidney donor, transplanted to two different recipients and their clinical and immunological evolution through serial biopsies. Recipient A's first allograft biopsy (Day 26) was compatible with a MN with both positive PLA2R and IgG4 subepithelial deposits in IHC. The donor's preimplantation kidney biopsies were retrieved and reexamined, revealing MN, with high intensity for PLA2R and IgG4 in IHC. Recipient B's protocol allograft biopsy, performed later at 3 months, also revealed histology compatible with MN but without the presence of PLA2R nor IgG4 in IHC. At 1-year follow-up, both recipients maintain graft function. Serial protocol biopsies were performed in both patients showing disappearance of IgG4 in recipient A but the persistence of PLA2R in IHC. We can conclude that, given the reversal of PMN changes in the grafts, it could be considered to transplant a patient from an asymptomatic deceased donor with PMN as long as he maintains unaltered renal function.

Kidney Transplantation in Monoclonal Immunoglobulin Deposition Disease: A Report of 6 Cases.

Monoclonal immunoglobulin deposition disease (MIDD) usually leads to kidney failure. Treatment of patients with a bortezomib-based regimen followed by autologous stem cell transplantation (SCT) has been increasingly used, with improvements in the response rates and allograft outcomes in kidney transplant recipients. The objective of this report was to analyze the outcomes of 6 patients who underwent kidney transplantation in our institution after treatment of MIDD between 2010 and 2019. Monoclonal immunoglobulin deposition disease was initially treated with bortezomib-based therapy followed by high-dose melphalan and autologous SCT with complete hematologic response, although all patients remained on dialysis. During a median follow-up of 20.5 months from kidney transplant (54 months from SCT), 1 patient experienced hematologic relapse and 2 had hematologic progression (one of them with MIDD relapse in the allograft) requiring treatment. The patient with organ relapse received daratumumab monotherapy, achieving complete hematologic response but with graft failure. The other 5 patients had functional grafts with median serum creatinine 1.68 mg/dL. These results support that, in patients with MIDD and sustained complete hematologic response, a kidney transplant can be considered. The optimal approach to treatment of hematologic relapse or recurrence of MIDD after kidney transplant remains to be determined.

Increasing kidney grafts for transplantation.

INTRODUCTION: The current pool of organs available for transplantation does not cover requirements, for this reason non-standard risk donors need to be incorporated into the pool. In this way, donors with small renal tumour are considered for transplantation after bench tumour excision. The aim of our study was to analyse our experience in using these grafts for transplantation. MATERIALS AND METHODS: Retrospective analysis from our prospective accrued database of donors with incidental renal mass used for kidney transplantation between January 2007 and August 2018. RESULTS: Twenty kidney transplantations were performed, thirteen cases received the affected kidney (after tumour removal) and seven the contralateral kidney; from six living and eleven deceased donors. Donor and recipient median age was 58 years (range 22-82) and 56.5 years (range 38-74), respectively. Mean tumour diameter was 12.7 mm (SD 9.5). Tumours resulted in two benign lesions and fifteen renal cell carcinoma. Surgical margins were negative. Two cases presented with bleeding after reperfusion was solved without repercussion. One case presented with immediate vein thrombosis. None of them present delayed graft function. After a 69 month follow-up none of the donors or the recipients presented tumour recurrence. CONCLUSIONS: Kidneys with small incidental tumours seem to be a good option for kidney transplantation in selected patients after bench surgery excision with good functional and oncologic results. More studies and longer follow-up are needed to confirm these results.

The impact of functional delayed graft function in the modern era of kidney transplantation - A retrospective study.

The dialysis-based definition of Delayed Graft Function (dDGF) is not necessarily objective as it depends on the individual physician's decision. The functional definition of DGF (fDGF, the failure of serum creatinine to decrease by at least 10% daily on 3 consecutive days during the first week post-transplant), may be more sensitive to reflect recovery after the ischemia-reperfusion injury. We retrospectively analyzed both definitions in 253 deceased donor kidney transplant recipients for predicting death-censored graft failure as primary outcome, using eGFR < 25 ml/min/1.73 m2 as a surrogate end-point for graft failure. Secondary outcome was a composite outcome that included graft failure as above and also patient's death. Median follow-up was 3.22 [2.38-4.21] years. Seventy-nine patients developed dDGF (31.2%) and 127 developed fDGF (50.2%). Sixty-three patients fulfilled criteria for both definitions (24.9%). At multivariable analysis, the two definitions were significantly associated with the primary [HR (95%CI) 2.07 (1.09-3.94), P = 0.026 for fDGF and HR (95%CI) 2.41 (1.33-4.37), P = 0.004 for dDGF] and the secondary composite outcome [HR (95%CI) 1.58 (1.01-2.51), P = 0.047 for fDGF and HR (95%CI) 1.67 (1.05-2.66), P = 0.028 for dDGF]. Patients who met criteria for both definitions had the worst prognosis, with a three-year estimates (95%CI) of survival from the primary and secondary outcomes of 2.31 (2.02-2.59) and 2.20 (1.91-2.49) years for fDGF+/dDGF+, in comparison with the other groups (P < 0.01 for trend). fDGF provides supplementary information about graft outcomes on top of the dDGF definition in a modern series of kidney transplantation.

Mucormycosis associated with COVID-19 in two kidney transplant patients.

Coronavirus disease 2019 (COVID-19) predisposes patients to bacterial and fungal superinfections due to the impairment of the immunological system. Among the associated opportunistic fungal infections, mucormycosis is one of the least frequent but with the highest mortality. We describe two cases of mucormycosis in two kidney transplant recipients, while they were hospitalized for SARS-CoV-2 pneumonia, with rhinosinusal and musculoskeletal involvement, respectively.

Kidney Graft Outcomes in High Immunological Risk Simultaneous Liver-Kidney Transplants.

Recipients of simultaneous liver-kidney transplantations (SLKTs) have a lower risk of rejection compared with recipients of kidney transplants alone. However, there is disagreement about the impact of pretransplant anti-human leukocyte antigen sensitization on patient and kidney graft survival in the long term. The aim of the study was to evaluate the impact of the recipient immunological risk and comorbidities in renal graft outcomes on SLKT. We reviewed the SLKTs performed in our center from May 1993 until September 2017. Patient and graft survival were analyzed according to the immunological risk, comorbidities, liver and kidney rejection episodes, immunosuppression, and infections. A total of 20 recipients of SLKT were considered in the high immunological risk (HIR) group, and 68 recipients were included in the low immunological risk (LIR) control group. The prevalence of hepatitis C virus infection, second renal transplant, and time on dialysis prior to transplantation were significantly higher in the HIR group. The incidence of acute kidney rejection was higher in the HIR group (P<0.01). However, death-censored kidney graft survival as well as the estimated glomerular filtration rate at follow-up were not different between the 2 groups. Comorbidities, but not the immunological risk, impact negatively on patient survival. Despite the higher incidence of rejection in the HIR SLKT group, longterm renal function and graft survival were similar to the LIR group.

Hepatitis C viremia as a risk factor for opportunistic infections in kidney transplant recipients.

The aim of the present study was to determine the clinical characteristics, frequency of opportunistic infections (OI) in HCV-positive kidney recipients, and to evaluate HCV replication as a risk factor for developing an OI. We conducted a retrospective study of all kidney recipients from 2003 to 2014. A total of 1203 kidney transplants were performed during the study period. Opportunistic infections were recorded in 251 patients (21%) and nucleic acid amplification testing (NAAT) positivity in 75 (6%). Patients who are HCV NAAT positive were more likely to present an OI than those who are HCV NAAT negative (45% vs 20%, P < 0.001). Multivariate analysis showed the factors that were independently associated with the development of OI to be acute rejection, graft loss, post-transplantation hemodialysis, and HCV replication. Liver cirrhosis after transplantation could not be considered a risk factor to develop OI. To conclude, a high index of suspicion of OI must be maintained in the case of kidney recipients with HCV replication. Active surveillance of cytomegalovirus infection and other prophylactic strategies against OI should be considered after 6 month post-transplantation. Prompt initiation of DAA therapies may be a useful option aiming to decrease the incidence of OI after transplantation.

Efficacy and tolerability of interferon-free antiviral therapy in kidney transplant recipients with chronic hepatitis C.

BACKGROUND & AIMS: The development of direct-acting antiviral agents (DAAs) is a major step forward in the treatment of hepatitis C (HCV). The aims of the study were to evaluate the efficacy and tolerability of DAAs in kidney transplant (KT) recipients. METHODS: Hepa-C is a Spanish registry of patients treated with DAAs in which clinical, virological and analytical data were prospectively included. We report on the data from 103 KT recipients who received DAAs. RESULTS: The most commonly used DAAs combinations were sofosbuvir/ledipasvir (n=59, 57%) and sofosbuvir+daclatasvir (n=18, 17%). Ribavirin was used in 41% of patients. Sustained viral response after 12weeks (SVR12) rate was 98%. Grade 2 or 3 anemia appeared in 14 (33%) of patients receiving ribavirin and in 9 (15%) without (p=0.03). There were three episodes of acute humoral graft rejection. No patient discontinued therapy due to adverse events. Importantly, 57 (55%) patients required immunosuppression dose adjustment. Overall, there were no statistically significant differences in the mean level of serum creatinine, eGFR and proteinuria before and after treatment. Nonetheless, seventeen (16%) patients experienced renal dysfunction (increase in serum creatinine >25%) during antiviral therapy, of whom 65% were cirrhotic in comparison with only 29% cirrhotic patients who did not develop significant renal dysfunction (p=0.004). CONCLUSIONS: Antiviral therapy with DAAs was highly efficacious and safe in KT recipients. Nevertheless, a non-negligible number of patients, most of them cirrhotic, developed mild allograft dysfunction and a significant proportion of patients required immunosuppression dose adjustment, warranting a close follow-up during therapy. LAY SUMMARY: Infection by hepatitis C virus is often found in kidney transplant patients and its presence increases mortality and graft failure. We investigated the efficacy and safety of the new direct-acting hepatitis C antivirals in this population, in which previous information is scarce. Our data shows that, as occurs in the non-transplant setting, new anti-HCV antivirals are highly efficacious kidney transplant patients. Overall, this therapy is also quite safe, although worsening of renal function is observed in 16% of patients warranting a close follow-up observation of graft function during antiviral therapy.

Borderline rejection in ABO-incompatible kidney transplantation.

INTRODUCTION: The clinical results of ABO-incompatible (ABOi) and ABO-compatible (ABOc) kidney transplantation (KT) are similar. Protocol kidney biopsies (PKB) of ABOi transplant recipients show positivity for C4d without evidence of antibody-mediated rejection (ABMR), but little is known about the histologic progression. METHOD: We evaluated histologic parameters in PKB at 12 months and also compared clinical outcome at 1 year. This is a prospective observational study conducted between 2009 and 2013. We performed 146/30 ABOc/ABOi consecutive living-donor KT with PKB as well as additional indication biopsies. In the ABOi group, the desensitization protocol consisted of rituximab, plasma exchange or immunoadsorption, and immunoglobulins. RESULTS: In indication biopsies during the first year, T-cell-mediated rejection Banff ≥immunoadsorption was 8.2% vs 6.7% (P=.561) and ABMR 4.8% vs 13.3% (P=.095). At 1 year, PKB (ABOc/ABOi) showed differences in borderline rejection lesions (6.8% vs 23.3% [P=.012]) and in C4d positivity in the ABOi group (P=.001). Interstitial fibrosis and tubular atrophy (IFTA) lesions (ABOc/ABOi) were 68.4% vs 63.2% (P=.348). Transplant glomerulopathy was 0.7% vs 3.3% (P=.373) at 1 year. CONCLUSIONS: Our PKB ABOi series shows at 1 year more borderline lesions independent of ABO titers, HLA incompatibility, and the presence of antidonor antibody, but do not show more IFTA nor transplant glomerulopathy. No clinical differences were observed between ABOi and ABO transplants.

An mTOR-inhibitor-based protocol and calcineurin inhibitor (CNI)-free treatment in kidney transplant recipients from donors after cardiac death: good renal function, but high incidence of conversion to CNI.

Donor after cardiac death (DCD) grafts have excellent survival despite the high incidence of delayed graft function (DGF). We assessed the feasibility of a mammalian target of rapamycin inhibitor (mTOR-I) protocol in uncontrolled DCD kidney transplantation and compared it with brain-dead donor (DBD) transplantation under calcineurin inhibitor (CNI) treatment. This retrospective study (2002-2011) included 109 Maastricht category II DCD patients and 218 standard-criteria DBD as controls. Immunosuppression consisted of polyclonal antibody induction, mycophenolate mofetil, prednisone, and mTOR-I (starting on day 6) in the DCD group and tacrolimus in the DBD group. DGF occurred in 72.5% of the DCD group vs. 26.1% of the DBD group (P = 0.001). Patient survival at 1 year was 99.1% vs. 95.9% (P = 0.112), and graft survival was 89% vs. 92.2% (P = 0.253). Patient survival at 5 years was 85.3% vs. 90.1% (P = 0.340) and graft survival was 85.5% vs. 78.8% (P = 0.166). During the first year, 46.8% (n = 51) of DCD patients were converted to CNI therapy. Serum creatinine at 1 year was 1.5(1.26-2) mg/dl vs. 1.4(1.16-1.8) mg/dl (P = 0.078). At 1 year, the acute rejection rate was 7.3% vs. 12.5% (P = 0.766). mTOR-I-based therapy was not associated with inferior graft function or higher rejection rates than standard CNI therapy. DCD kidney transplantation with an mTOR-I-based protocol is feasible but is associated with a high conversion rate to CNI-based therapy.

Antiviral treatment with sofosbuvir and simeprevir in a kidney transplant recipient with HCV-decompensated cirrhosis: viral eradication and removal from the liver transplant waiting list.

Hepatitis C positive kidney transplant (KT) recipients are a difficult-to-treat subpopulation. Interferon-based therapies are contraindicated (or at least not used) in KT patients, due to the risk of allograft rejection, its poor tolerability and the low rates of sustained virological response (SVR) achieved with these therapies. Nevertheless, the use of direct-acting antiviral drugs (DAAs) will certainly provide new opportunities for hepatitis C treatment in the KT setting. Here, we report the case of a KT recipient with decompensated cirrhosis who received antiviral therapy with sofosbuvir, simeprevir, and ribavirin during 24 weeks while awaiting liver transplantation. Hepatitis C was eradicated, and the patient was removed from the transplant list. Although there is no safety and efficacy data regarding the use of DAAs in the KT setting, this case suggests that KT recipients may benefit from the use of new antiviral drugs with high SVR rates and an excellent safety profile.

[Early detection, prevention and management of renal failure in liver transplantation]. / Detección precoz, prevención y manejo de la insuficiencia renal en el trasplante hepático.

Renal failure is a frequent complication in liver transplant recipients and is associated with increased morbidity and mortality. A variety of risk factors for the development of renal failure in the pre- and post-transplantation periods have been described, as well as at the time of surgery. To reduce the negative impact of renal failure in this population, an active approach is required for the identification of those patients with risk factors, the implementation of preventive strategies, and the early detection of progressive deterioration of renal function. Based on published evidence and on clinical experience, this document presents a series of recommendations on monitoring RF in LT recipients, as well as on the prevention and management of acute and chronic renal failure after LT and referral of these patients to the nephrologist. In addition, this document also provides an update of the various immunosuppressive regimens tested in this population for the prevention and control of post-transplantation deterioration of renal function.

Long-Term Outcomes of Incidental Liver Malignancies in Simultaneous Liver-Kidney Transplant Recipients.

BACKGROUND: The pretransplant diagnosis of liver malignancies in nodular cirrhotic livers remains a diagnostic challenge despite current advances. Although the prognostic impact of incidental hepatocellular carcinoma (HCC) or intrahepatic cholangiocarcinoma (iCC) in liver transplant recipients is well documented, there are no data on the impact in simultaneous liver kidney transplant (LKT) recipients. METHODS: This is a single-center observational, retrospective study of all LKT performed from May 1993 to April 2022. Among these patients, demographic data, immunosuppressive therapy, rejection episodes, and prevalence of incidental HCC or iCC were evaluated. RESULTS: One hundred eight LKTs were performed and 6 were excluded. There were 13 patients with incidental carcinomas in the explanted liver: one of them with both an HCC and iCC, one with an iCC, and the remaining with an HCC. One case of iCC died. No other recurrences occurred. There were no cases of incidental HCC nor iCC in patients with a hereditary or metabolic LKT indication. We found no differences in the 5-year patient survival, and death-censored kidney and liver graft survival rates for those LKT with an incidental HCC and those without it (76.9% vs 84.2%, P = .5; 100% vs 91.6%, P = .28; and 100% vs 94.7%, P = 0.39, respectively). Finally, there were no significant associations between explant carcinoma and rejections of the liver (7.7% vs 17.9%, P = .34) or kidney graft (0% vs 16.8%, P = 0.11). CONCLUSION: Despite a high prevalence of incidental HCC or iCC, patient, kidney, and liver graft 5-year survival were unaffected by incidental HCC.

Factor B Inhibition with Iptacopan in Recurrent C3 Glomerulopathy Following Kidney Transplant: A Report of Two Cases.

C3 glomerulopathy is a rare disease caused by fluid phase dysregulation of the alternative complement pathway. Currently, treatment depends on clinical and histological severity and includes nephroprotection, unspecific immunosuppression, and terminal complement blockers (C5), without having an etiological treatment approved. C3 glomerulopathy has high recurrence rates after kidney transplantation with a high risk of graft loss. Fortunately, new molecules are being developed that specifically target the proximal alternative complement pathway, such as iptacopan, a factor B inhibitor that showed promising results in native kidneys and cases of transplant recurrence in a phase 2 clinical trial. We present 2 "real-world" cases of C3 glomerulopathy recurrence in kidney allografts treated with iptacopan, with initial excellent clinical response and safety profile, especially with early introduction. We also present follow-up biopsies that showed no C3 deposition during factor B inhibition. Our cases suggest that proximal blockade of the alternative complement pathway can be effective and safe in the treatment of C3 glomerulopathy recurrence in kidney transplantation, bringing other questions such as dual blockade (eg, in C3 and C5), the optimal patient profile to benefit from factor B inhibition or treatment duration and its potential use in other forms of membranoproliferative glomerulonephritis (eg, immune complex-mediated).