Poor allograft outcome in Indian patients with post-transplant C3 glomerulopathy

C3 glomerulopathy post kidney transplantation: A single center experience

BACKGROUND

C3 glomerulopathies (C3G) are a rare cause of kidney failure resulting from complement dysregulation. Small studies demonstrate a high rate of recurrence and poor outcomes in kidney transplantation. Treatment efficacy in this setting with eculizumab, a terminal complement inhibitor, is largely unknown.

AIM

To determine the outcomes of kidney transplantation in patients with C3G and the potential impact of eculizumab.

METHODS

We retrospectively studied kidney transplant recipients who underwent a post-transplant biopsy confirming C3G between January 1, 1993 and December 31, 2023 at a single center. Only the first episode of kidney transplant was reviewed. The electronic medical records were reviewed for post-transplant allograft function, indication for biopsy, time to biopsy from transplant, time to allograft failure from transplantation, post-C3G treatment, complement laboratory testing, and concurrent malignancy/infection. Reports, and when available slides and immunofluorescence/electron microscopic images, were re-reviewed by a renal pathologist.

RESULTS

A total of fifteen patients were included in this study. Fourteen patients had suspected recurrent disease, with a pre-transplant native kidney report of C3G. One patient developed de novo C3G. Median post kidney transplant clinical follow up time was 91 months. Median time to recurrence was 7 months with median graft survival of 48 months post kidney transplantation. The most common index biopsy pattern of injury was endocapillary proliferative glomerulonephritis (often with exudative features) with or without mesangial hypercellularity (56%) followed by membranoproliferative glomerulonephritis (25%). Most patients developed membranoproliferative glomerulonephritis pattern of injury on follow up biopsies (63%). Seven patients with recurrent disease received treatment with eculizumab with a median graft survival of 73 months, with five functioning grafts by the end of the study period. Seven patients with recurrent disease did not receive therapy, and all lost their graft with a median graft survival of 22 months (P = 0.003).

CONCLUSION

C3G following kidney transplantation is mostly a recurrent disorder with a poor prognosis in untreated patients. Untreated recurrence has a poor prognosis with median allograft survival < 2 years. Early treatment with eculizumab may improve transplant outcomes in patients with recurrent C3G.

Outcome of Patients Transplanted for C3 Glomerulopathy and Primary Immune Complex-Mediated Membranoproliferative Glomerulonephritis

Introduction

Approximately 50% of patients with C3 glomerulopathy (C3G) and primary immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) reach kidney failure 10 years after diagnosis. Because these patients are generally young, the majority will be listed for kidney transplantation (KTx). However, reported outcomes in patients transplanted for C3G and IC-MPGN are heterogeneous and conflicting, because they are mainly based on retrospective monocentric studies. We thus aimed to provide detailed multicenter data on these patients, taking advantage of the ongoing nationwide Swiss Transplant Cohort Study (STCS).

Methods

We analyzed patient and graft outcomes, including the risk of graft loss in relation to recurrence of glomerulopathy.

Results

Forty-one (10 C3G and 31 IC-MPGN) transplanted recipients were included with a mean age at transplantation of 48 ± 16 years. Living donors provided 53% of the organs. During a mean follow-up of 4.7 years, 7 patients (4 C3G and 3 IC-MPGN) presented disease recurrence with a mean time to recurrence of 1.2 years. New-onset or rapidly increasing proteinuria was an early marker of recurrence, preceding significant decline in estimated glomerular filtration rate (eGFR). Following recurrence, 28% lost their graft, compared to 11% of patients without recurrence. Disease recurrence was the primary cause of graft loss in all patients. Finally, 14% of patients died during follow-up.

Conclusion

This study provides important insights into the epidemiology and outcome of patients with C3G and IC-MPGN and their grafts after KTx. The data also suggest that proteinuria may serve as an early biomarker of disease recurrence and should be considered in patient management as well as an endpoint in current clinical trials using novel complement modulators.

Childhood onset C3 glomerulopathy: recurrence after kidney transplantation-a case series

Background

C3 Glomerulopathy (C3G) is a complement-mediated disease, with predominant C3 deposits, where pathogenic genetic variants in complement system components and circulating autoantibodies result in loss of control of the alternative pathway, have been described. A high incidence of disease recurrence including graft failure has been reported after kidney transplantation (KTx). Currently treatment modalities for preventing and treating post KTx C3G recurrence (plasma exchange, rituximab and eculizumab) in adults have yielded inconsistent results. Data on post KTx C3G recurrence in childhood-onset C3G is still unknown.

Methods

A comprehensive case study of patients diagnosed with C3G as children or adolescents, who underwent KTx between the years 2015-2023. Data collected included complement workup, treatment modalities, and outcomes.

Results

19 patients with C3G were identified during the study period. Five patients developed ESRD and received a kidney transplant. C3G recurrence was diagnosed post KTx in 100% of patients. Graft function improved in 3 of these patients (two with anti-factor H antibodies) after eculizumab treatment, one patient reached graft failure 9 months after transplantation despite eculizumab, recieved a second successful transplantation with pre-emptive eculizumab treatment and one patient showed histologic signs of disease recurrence without clinical signs.

Conclusions

C3G recurrence after KTx in patients diagnosed as children or adolescents may be higher than previously described. Treatment with eculizumab is beneficial in some patients. New treatments are needed for improving post-transplant outcome in patients with C3G.

C3 Glomerulopathy Recurs Early after Kidney Transplantation in Serial Biopsies Performed within the First 2 Years after Transplantation

Background

C3 glomerulopathy (C3G), which encompasses C3GN and dense deposit disease (DDD), results from dysregulation of the alternative complement pathway. Data on disease recurrence after kidney transplantation are limited, and details on histologic features of recurrent C3G are scarce. We aimed to evaluate C3G recurrence in the allograft, with a focus on histologic presentation and progression.

Methods

We retrospectively analyzed 18 patients with native kidney failure attributed to C3G (12 C3GN and six DDD), who received a kidney transplant from January 2016 to January 2023. Demographic, genetic, clinical, and histologic data were studied. The NanoString 770 genes PanCancer Immune Profiling Panel was used for transcriptomic analysis. Disease recurrence was the primary outcome.

Results

During a median (interquartile range) follow-up period of 37 (18–56) months, C3G recurrence occurred in 16 (89%) patients (11 with C3GN and five with DDD) at a median (interquartile range) of 33 (13–141) days after transplantation. Over a third (38%) of recurrent cases were detected in protocol biopsies, and only 31% of patients presented with >300 mg/g of proteinuria. Recurrence in index biopsies was mainly established through a combination of immunofluorescence and electron microscopy findings, while it showed only subtle histologic alterations and no characteristic transcriptomic signals. Over time, histologic chronicity indices increased, but all the allografts were functioning at the end of follow-up. Patients with recurrence of C3GN and DDD showed overlapping immunofluorescence and electron microscopy findings and had similar recurrence rate and time to recurrence.

Conclusions

Most of the patients with native kidney failure attributed to C3G developed disease recurrence very early after kidney transplantation, usually with minimal proteinuria, mild histologic alterations, and favorable short-term allograft survival. Immunofluorescence and electron microscopy played a crucial role in detecting early, subclinical recurrence of C3GN and DDD, which showed significant overlapping features.

Recurrence of immune complex and complement-mediated membranoproliferative glomerulonephritis in kidney transplantation

INTRODUCTION

Membranoproliferative glomerulonephritis (MPGN) represents a histologic pattern of glomerular injury that may be due to several aetiologies. Few studies have comprehensively analysed the recurrence of MPGN according to the current classification system.

METHODS

We collected a multicentre, retrospective cohort of 220 kidney graft recipients with biopsy-proven native kidney disease due to MPGN between 1981 and 2021 in 11 hospitals. Demographic, clinical and histologic parameters of prognostic interest were collected. The main outcomes were time to kidney failure, time to recurrence of MPGN and disease remission after recurrence.

RESULTS

The study group included 34 complement-mediated and 186 immune complex-mediated MPGN. A total of 81 patients (37%) reached kidney failure in a median follow-up of 79 months. The main predictors of this event were the development of rejection episodes and disease recurrence. In all, 54 patients (25%) had a disease recurrence in a median of 16 months after kidney transplantation. The incidence of recurrence was higher in patients with dysproteinaemia (67%) and complement-mediated MPGN (62%). In the multivariable model, complement-mediated MPGN emerged as a predictor of recurrence. A total of 33 patients reached kidney failure after recurrence. The main determinants of no remission were early time to recurrence (<15 months), estimated glomerular filtration rate <30 mL/min/1.73 m2 and serum albumin <3.5 g/dL at the time of recurrence.

CONCLUSIONS

One-fourth of the patients with native kidney disease due to MPGN developed clinical recurrence in the allograft, especially in cases with complement-mediated disease or in those associated with dysproteinaemia. The kidney outcomes of disease recurrence with currently available therapies are heterogeneous and thus more effective and individualized therapies are needed.

C3 glomerulopathy: Understanding an ultra-rare complement-mediated renal disease

C3 glomerulopathy (C3G) describes a pathologic pattern of injury diagnosed by renal biopsy. It is characterized by the dominant deposition of the third component of complement (C3) in the renal glomerulus as resolved by immunofluorescence microscopy. The underlying pathophysiology is driven by dysregulation of the alternative pathway of complement in the fluid-phase and in the glomerular microenvironment. Characterization of clinical features and a targeted evaluation for indices and drivers of complement dysregulation are necessary for optimal patient care. Autoantibodies to the C3 and C5 convertases of complement are the most commonly detected drivers of complement dysregulation, although genetic mutations in complement genes can also be found. Approximately half of patients progress to end-stage renal disease within 10 years of diagnosis, and, while transplantation is a viable option, there is high risk for disease recurrence and allograft failure. This poor outcome reflects the lack of disease-specific therapy for C3G, relegating patients to symptomatic treatment to minimize proteinuria and suppress renal inflammation. Fortunately, the future is bright as several anti-complement drugs are currently in clinical trials.