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

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.