Recurrent glomerulonephritis after kidney transplantation

Recurrent disease after pediatric renal transplantation

BACKGROUND

Recurrent disease after kidney transplant remains an important cause of allograft failure, accounting for 7-8% of graft loss and ranking as the fifth most common cause of allograft loss in the pediatric population. Although the pathophysiology of many recurrent diseases is incompletely understood, recent advances in basic science and therapeutics are improving outcomes and changing the course of several of these conditions.

METHODS

Review of the literature.

RESULTS

We discuss the diagnosis and management of recurrent disease.

CONCLUSION

We highlight new insights into the pathophysiology and treatment of post-transplant primary hyperoxaluria, focal segmental glomerulosclerosis, immune complex glomerulonephritis, C3 glomerulopathy, lupus nephritis, atypical hemolytic uremic syndrome, and IgA nephropathy.

Post-transplant recurrence of focal segmental glomerular sclerosis: consensus statements

Focal segmental glomerular sclerosis (FSGS) is 1 of the primary causes of nephrotic syndrome in both pediatric and adult patients, which can lead to end-stage kidney disease. Recurrence of FSGS after kidney transplantation significantly increases allograft loss, leading to morbidity and mortality. Currently, there are no consensus guidelines for identifying those patients who are at risk for recurrence or for the management of recurrent FSGS. Our work group performed a literature search on PubMed/Medline, Embase, and Cochrane, and recommendations were proposed and graded for strength of evidence. Of the 614 initially identified studies, 221 were found suitable to formulate consensus guidelines for recurrent FSGS. These guidelines focus on the definition, epidemiology, risk factors, pathogenesis, and management of recurrent FSGS. We conclude that additional studies are required to strengthen the recommendations proposed in this review.

KDOQI US Commentary on the 2021 KDIGO Clinical Practice Guideline for the Management of Glomerular Diseases

The KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases represents the first update to this set of recommendations since the initial set of KDIGO guideline recommendations was published in 2012. The pace of growth in our molecular understanding of glomerular disease has quickened and a number of newer immunosuppressive and targeted therapies have been introduced since the original set of guideline recommendations, making such an update necessary. Despite these updates, many areas of controversy remain. In addition, further updates since the publication of KDIGO 2021 have occurred which this guideline does not encompass. With this commentary, the KDOQI work group has generated a chapter-by-chapter companion opinion article that provides commentary specific to the implementation of the KDIGO 2021 guideline in the United States.

The podocyte: glomerular sentinel at the crossroads of innate and adaptive immunity

Focal segmental glomerulosclerosis (FSGS) is a common glomerular disorder that manifests clinically with the nephrotic syndrome and has a propensity to recur following kidney transplantation. The pathophysiology and therapies available to treat FSGS currently remain elusive. Since the podocyte appears to be the target of apparent circulating factor(s) that lead to recurrence of proteinuria following kidney transplantation, this article is focused on the podocyte. In the context of kidney transplantation, the performance of pre- and post-reperfusion biopsies, and the establishment of in vitro podocyte liquid biopsies/assays allow for the development of clinically relevant studies of podocyte biology. This has given insight into new pathways, involving novel targets in innate and adaptive immunity, such as SMPDL3b, cGAS-STING, and B7-1. Elegant experimental studies suggest that the successful clinical use of rituximab and abatacept, two immunomodulating agents, in our case series, may be due to direct effects on the podocyte, in addition to, or perhaps distinct from their immunosuppressive functions. Thus, tissue biomarker-directed therapy may provide a rational approach to validate the mechanism of disease and allow for the development of new therapeutics for FSGS. This report highlights recent progress in the field and emphasizes the importance of kidney transplantation and recurrent FSGS (rFSGS) as a platform for the study of primary FSGS.

Membranous nephropathy

Membranous nephropathy is a glomerulopathy, which main affected target is the podocyte, and has consequences on the glomerular basement membrane. It is more common in adults, especially over 50 years of age. The clinical presentation is nephrotic syndrome, but many cases can evolve with asymptomatic non-nephrotic proteinuria. The mechanism consists of the deposition of immune complexes in the subepithelial space of the glomerular capillary loop with subsequent activation of the complement system. Great advances in the identification of potential target antigens have occurred in the last twenty years, and the main one is the protein "M-type phospholipase-A2 receptor" (PLA2R) with the circulating anti-PLA2R antibody, which makes it possible to evaluate the activity and prognosis of this nephropathy. This route of injury corresponds to approximately 70% to 80% of cases of membranous nephropathy characterized as primary. In the last 10 years, several other potential target antigens have been identified. This review proposes to present clinical, etiopathogenic and therapeutic aspects of membranous nephropathy in a didactic manner, including cases that occur during kidney transplantation.

Benefit of B7-1 staining and abatacept for treatment-resistant post-transplant focal segmental glomerulosclerosis in a predominantly pediatric cohort: time for a reappraisal

BACKGROUND

Primary FSGS manifests with nephrotic syndrome and may recur following KT. Failure to respond to conventional therapy after recurrence results in poor outcomes. Evaluation of podocyte B7-1 expression and treatment with abatacept (a B7-1 antagonist) has shown promise but remains controversial.

METHODS

From 2012 to 2020, twelve patients developed post-KT FSGS with nephrotic range proteinuria, failed conventional therapy, and were treated with abatacept. Nine/twelve (< 21 years old) experienced recurrent FSGS; three adults developed de novo FSGS, occurring from immediately, up to 8 years after KT. KT biopsies were stained for B7-1.

RESULTS

Nine KTRs (75%) responded to abatacept. Seven of nine KTRs were B7-1 positive and responded with improvement/resolution of proteinuria. Two patients with rFSGS without biopsies resolved proteinuria after abatacept. Pre-treatment UPCR was 27.0 ± 20.4 (median 13, range 8-56); follow-up UPCR was 0.8 ± 1.3 (median 0.2, range 0.07-3.9, p < 0.004). Two patients who were B7-1 negative on multiple KT biopsies did not respond to abatacept and lost graft function. One patient developed proteinuria while receiving belatacept, stained B7-1 positive, but did not respond to abatacept.

CONCLUSIONS

Podocyte B7-1 staining in biopsies of KTRs with post-transplant FSGS identifies a subset of patients who may benefit from abatacept. A higher resolution version of the Graphical abstract is available as Supplementary information.

Living Donor Kidney Transplant in Recipients With Glomerulonephritis: Donor Recipient Biologic Relationship and Allograft Outcomes

Using the Scientific Registry of Transplant Recipients, we examined the association between donor-recipient biologic relationship and long-term recipient and allograft survival among glomerulonephritis (GN) patients. Four GN types were studied: membranous nephropathy, IgA, lupus-associated nephritis, and focal segmental glomerulosclerosis (FSGS). We identified all adult primary living-donor recipients between 2000 and 2018 (n = 19,668): related (n = 10,437); unrelated (n = 9,231). Kaplan-Meier curves were generated for the recipient, death-censored graft survival and death with functioning graft through ten years post-transplant. Multivariable Cox proportional hazard models were used to examine the association between the donor-recipient relationship and outcomes of interest. There was an increased risk for acute rejection by 12 months post-transplant among the unrelated compared to the related group in IgA (10.1% vs. 6.5%, p<0.001), FSGS (12.1% vs. 10%, p-0.016), and lupus nephritis (11.8% vs. 9.2%; p-0.049). The biological donor-recipient relationship was not associated with a worse recipient or graft survival or death with functioning graft in the multivariable models. These findings are consistent with the known benefits of living-related-donor kidney transplants and counter the reports of the potential adverse impact of the donor-recipient biologic relationship on allograft outcomes.

Retrospective Diagnosis of Nail-patella Syndrome

A 37 years old female presented with asymptomatic nephrotic range proteinuria due to focal segmental glomerulosclerosis (FSGS). She was treated with steroids and mycophenolate mofetil to which there was no response and progressed to advanced chronic kidney disease. When her brother who was being evaluated as a potential donor, for renal transplant, was found to have proteinuria and a genetic study for the steroid-resistant nephrotic syndrome was done. This revealed mutation in the LMX1B gene. It is then that a diagnosis of nail-patella syndrome (NPS) was made. She underwent a successful renal transplant with her father as a donor and is doing well.

UNOS/OPTN Data-guided Assessment of Focal Segmental Glomerulosclerosis After Kidney Transplantation and Evaluation of Immunosuppressive Protocols in a Steroid-free Center

BACKGROUND

Focal segmental glomerulosclerosis (FSGS) is a common recurrent glomerulopathy associated with graft loss and patient survival after kidney transplantation (KT). However, its natural history, clinical predictors, and treatment response are still poorly understood. Steroid withdrawal regimens in KT have been associated with improvements in cardiovascular risk and patient outcomes. The Scripps Center for Organ Transplantation (SCOT) uses a rapid low-dose steroid withdrawal immunosuppression (IS) protocol for KT maintenance.

METHODS

We assessed the impact of our protocol on FSGS disease recurrence over a 10-y period to reassess our steroid and IS protocols and to evaluate if our patient outcomes diverge from published data. We compared 4 groups: steroids always, steroid free, steroid switch on, and steroid weaned off. We used IS and induction-matched retrospective data from United Network for Organ Sharing (UNOS) to investigate patient and graft survival for FSGS at SCOT.

RESULTS

Our analysis results differ from earlier studies showing that FSGS was associated with a higher risk of graft loss, perhaps because of selection of a UNOS data set filtered to match the SCOT IS protocol for making direct comparisons. Overall outcomes of graft failure and recipient death did not differ between SCOT patients and steroid-free transplant patient data from the UNOS data for FSGS. SCOT recurrence rate for FSGS was 7.5%, which was lower than in most published single-center studies.

CONCLUSIONS

Based on our results, we believe that it is safe to continue the steroid avoidance protocols at SCOT and the steroid-free protocol may not be detrimental when the adverse effects and toxicities associated with steroid use are considered.

Comparative Long-Term Renal Allograft Outcomes of Recurrent Immunoglobulin A with Severe Activity in Kidney Transplant Recipients with and without Rituximab: An Observational Cohort Study

Recurrent IgA nephropathy (IgAN) remains an important cause of allograft loss in renal transplantation. Due to the limited efficacy of corticosteroid in the treatment of recurrent glomerulonephritis, rituximab was used in kidney transplant (KT) recipients with severe recurrent IgAN. A retrospective cohort study was conducted between January 2015 and December 2020. Accordingly, there were 64 KT recipients with biopsy-proven recurrent IgAN with similar baseline characteristics that were treated with the conventional standard therapy alone (controls, n = 43) or together with rituximab (cases, n = 21). All of the recipients had glomerular endocapillary hypercellularity and proteinuria (>1 g/d) with creatinine clearance (CrCl) > 30 mL/min/1.73 m² and well-controlled blood pressure using renin–angiotensin–aldosterone blockers. The treatment outcomes were renal allograft survival rate, proteinuria, and post-treatment allograft pathology. During 3.8 years of follow-up, the rituximab-based regimen rapidly decreased proteinuria within 12 months after rituximab administration and maintained renal allograft function—the primary endpoint—for approximately 3 years. There were eight recipients in the case group (38%), and none in the control group reached a complete remission (proteinuria < 250 mg/d) at 12 months after treatment. Notably, renal allograft histopathology from patients with rituximab-based regimen showed the less severe endocapillary hypercellularity despite the remaining strong IgA deposition. In conclusion, adjunctive treatment with rituximab potentially demonstrated favorable outcomes for treatment of recurrent severe IgAN post-KT as demonstrated by proteinuria reduction and renal allograft function in our cohort. Further in-depth mechanistic studies with the longer follow-up periods are recommended.

Kidney transplantation outcomes in patients with IgA nephropathy and other glomerular and non-glomerular primary diseases in the new era of immunosuppression

OBJECTIVES

Kidney transplant (KTx) recipients with IgAN as primary disease, were compared with recipients with other causes of renal failure, in terms of long-term outcomes.

METHODS

Ninety-nine KTx recipients with end-stage kidney disease (ESKD) due to IgAN, were retrospectively compared to; i/ a matched case-control group of patients with non-glomerular causes of ESKD, and ii/ four control groups with ESKD due to glomerular diseases; 44 patients with primary focal segmental glomerulosclerosis (FSGS), 19 with idiopathic membranous nephropathy (IMN), 22 with lupus nephritis (LN) and 21 with pauci-immune glomerulonephritis (PIGN).

RESULTS

At end of the observation period, graft function and survival, were similar between KTx recipients with IgAN and all other groups, but the rate of disease recurrence in the graft differed significantly across groups. The rate of IgAN recurrence in the graft was 23.2%, compared to 59.1% (p<0.0001) in the FSGS group, 42.1% (p = 0.17) in the IMN group, and 0% in the LN and PIGN groups (p = 0.01). IgAN recipients, who were maintained with a regimen containing tacrolimus, experienced recurrence less frequently, compared to those maintained with cyclosporine (p = 0.01). Graft loss attributed to recurrence was significantly higher in patients with FSGS versus all others.

CONCLUSION

Recipients with IgAN as primary disease, experienced outcomes comparable to those of recipients with other causes of ESKD. The rate of IgAN recurrence in the graft was significantly lower than the rate of FSGS recurrence, but higher than the one recorded in recipients with LN or PIGN. Tacrolimus, as part of the KTx maintenance therapy, was associated with lower rates of IgAN recurrence in the graft, compared to the rate cyclosporine.

Deconvolution of Focal Segmental Glomerulosclerosis Pathophysiology Using Transcriptomics Techniques

Background

Focal segmental glomerulosclerosis is a histopathological pattern of renal injury and comprises a heterogeneous group of clinical conditions with different pathophysiology, clinical course, prognosis, and treatment. Nevertheless, subtype differentiation in clinical practice often remains challenging, and we currently lack reliable diagnostic, prognostic, and therapeutic biomarkers. The advent of new transcriptomics techniques in kidney research poses great potential in the identification of gene expression biomarkers that can be applied in clinical practice.

Summary

Transcriptomics techniques have been completely revolutionized in the last 2 decades, with the evolution from low-throughput reverse-transcription polymerase chain reaction and in situ hybridization techniques to microarrays and next-generation sequencing techniques, including RNA-sequencing and single-cell transcriptomics. The integration of human gene expression profiles with functional in vitro and in vivo experiments provides a deeper mechanistic insight into the candidate genes, which enable the development of novel-targeted therapies. The correlation of gene expression profiles with clinical outcomes of large patient cohorts allows for the development of clinically applicable biomarkers that can aid in diagnosis and predict prognosis and therapy response. Finally, the integration of transcriptomics with other "omics" modalities creates a holistic view on disease pathophysiology.

Key Messages

New transcriptomics techniques allow high-throughput gene expression profiling of patients with focal segmental glomerulosclerosis (FSGS). The integration with clinical outcomes and fundamental mechanistic studies enables the discovery of new clinically useful biomarkers that will finally improve the clinical outcome of patients with FSGS.

Successful long-term management of recurrent focal segmental glomerulosclerosis after kidney transplantation with costimulation blockade

Recurrence of primary focal segmental glomerulosclerosis (FSGS) occurs in up to 50% of patients after kidney transplantation and is associated with poor allograft outcome. Novel therapeutic concepts directly target podocyte function via B7-1 with inconsistent response. We present the case of a 19-year-old patient with recurrent primary FSGS early after living donor kidney transplantation. Plasmapheresis and rituximab did not induce remission. Repetitive abatacept administration was able to achieve partial remission. Maintenance immunosuppression was subsequently switched to a belatacept-based calcineurin inhibitor-free immunosuppression, resulting in sustained complete remission with excellent allograft function throughout a follow-up of >56 months.

Two-year protocol biopsy after kidney transplantation in clinically stable recipients - a retrospective study

The idea of protocol biopsy is to detect subclinical pathologies, including rejection, recurrent disease, or infection for early intervention and adjustment of immunosuppressants. Nevertheless, it is not adopted by most clinicians because of its low yield rate and uncertain long-term benefits. This retrospective study evaluated the impact of protocol biopsy on renal function and allograft survival. A two-year protocol biopsy was proposed for 190 stable patients; 68 of them accepted [protocol biopsy (PB) group], while 122 did not [nonprotocol biopsy (NPB) group]. The rejection diagnosis was made in 13 patients by protocol biopsy, and 11 of them had borderline rejection. In the following 5 years, graft survival was better in the PB group than in the NPB group (P = 0.0143). A total of 4 and 17 patients in the PB and NPB groups, respectively, had rejection events proven by indication biopsy. Renal function was better preserved in the PB group than in the NPB group (P = 0.0107) for patients with rejection events. Nevertheless, the survival benefit disappeared by a longer follow-up period (12-year, P = 0.2886). In conclusion, 2-year protocol biopsy detects subclinical pathological changes in rejection and preserves renal function by early intervention so as to prolong graft survival within 5 years.

Kidney transplantation for primary glomerulonephritis: Recurrence risk and graft outcomes with related versus unrelated donors

Primary glomerulonephritis can recur after kidney transplantation and may jeopardize the survival of the renal allograft. The risks of living-related kidney transplantation remain controversial in this group of patients. Living related transplantation offers potentially better HLA matching, therefore improve the long-term graft survival. However, the concern for increased rates of recurrence of the primary glomerulonephritis in the transplanted kidney from living related donors complicates the selection of donors. With the recent dramatic rise in the use of paired kidney exchange, there is now often the option of having a living related donor donate through a paired exchange. This raises the question of whether patients with primary glomerulonephritis should receive living donor kidneys through paired kidney exchange programs to obtain the benefits of a living donor kidney transplant while also reducing the risk of recurrent glomerulonephritis. Our review of the literature suggests that although the recurrence of primary glomerulonephritis occurs more often when donation occurs from a living related donor as compared to an unrelated donor, the graft survival advantage of living related donation is generally maintained despite the recurrence. We suggest that despite the increased risk of recurrence, living related donation should not be avoided in patients with primary glomerulonephritis as the cause of their end-stage renal disease.

Recurrent Glomerulonephritis after Renal Transplantation: The Clinical Problem

Glomerulonephritis (GN) continues to be one of the main causes of end-stage kidney disease (ESKD) with an incidence rating from 10.5% to 38.2%. Therefore, recurrent GN, previously considered to be a minor contributor to graft loss, is the third most common cause of graft failure 10 years after renal transplantation. However, the incidence, pathogenesis, and natural course of recurrences are still not completely understood. This review focuses on the most frequent diseases that recur after renal transplantation, analyzing rate of recurrence, epidemiology and risk factors, pathogenesis and bimolecular mechanisms, clinical presentation, diagnosis, and therapy, taking into consideration the limited data available in the literature. First of all, the risk for recurrence depends on the type of glomerulonephritis. For example, recipient patients with anti-glomerular basement membrane (GBM) disease present recurrence rarely, but often exhibit rapid graft loss. On the other hand, recipient patients with C3 glomerulonephritis present recurrence in more than 50% of cases, although the disease is generally slowly progressive. It should not be forgotten that every condition that can lead to chronic graft dysfunction should be considered in the differential diagnosis of recurrence. Therefore, a complete workup of renal biopsy, including light, immunofluorescence and electron microscopy study, is essential to provide the diagnosis, excluding alternative diagnosis that may require different treatment. We will examine in detail the biomolecular mechanisms of both native and transplanted kidney diseases, monitoring the risk of recurrence and optimizing the available treatment options.

[Review on anti-glomerular basement membrane disease or Goodpasture's syndrome]

Anti-glomerular basement membrane (anti-GBM) disease or Goodpasture's syndrome is a small vessel vasculitis affecting the capillary beds of kidneys and lungs. It is an autoimmune disease mediated by autoantibodies targeting the glomerular and alveolar basement membranes, leading to pneumorenal syndrome. It is a rare, monophasic and severe disease, associating rapidly progressive glomerulonephritis and alveolar hemorrhage. The presence of antineutrophil cytoplasmic antibodies (ANCA) is reported in 20 to 60% of cases. Management should be prompt and combine plasma exchange with systemic corticosteroids and immunosuppressive therapy by cyclophosphamide. The objective of this review is: 1) to describe the pathogenesis, clinical and histological features of the disease; 2) to characterize double-positive anti-GBM/ANCA patients; 3) to highlight the prognostic factors of renal and global survival, and 4) to focus on the treatment of anti-GBM disease.

Recurrent and de novo Glomerulonephritis After Kidney Transplantation

The prevalence, pathogenesis, predictors, and natural course of patients with recurrent glomerulonephritis (GN) occurring after kidney transplantation remains incompletely understood, including whether there are differences in the outcomes and advances in the treatment options of specific GN subtypes, including those with de novo GN. Consequently, the treatment options and approaches to recurrent disease are largely extrapolated from the general population, with responses to these treatments in those with recurrent or de novo GN post-transplantation poorly described. Given a greater understanding of the pathogenesis of GN and the development of novel treatment options, it is conceivable that these advances will result in an improved structure in the future management of patients with recurrent or de novo GN. This review focuses on the incidence, genetics, characteristics, clinical course, and risk of allograft failure of patients with recurrent or de novo GN after kidney transplantation, ascertaining potential disparities between “high risk” disease subtypes of IgA nephropathy, idiopathic membranous glomerulonephritis, focal segmental glomerulosclerosis, and membranoproliferative glomerulonephritis. We will examine in detail the management of patients with high risk GN, including the pre-transplant assessment, post-transplant monitoring, and the available treatment options for disease recurrence. Given the relative paucity of data of patients with recurrent and de novo GN after kidney transplantation, a global effort in collecting comprehensive in-depth data of patients with recurrent and de novo GN as well as novel trial design to test the efficacy of specific treatment strategy in large scale multicenter randomized controlled trials are essential to address the knowledge deficiency in this disease.

Membranous Nephropathy (MN) Recurrence After Renal Transplantation

Primary membranous nephropathy (MN) is a frequent cause of NS in adults. In native kidneys the disease may progress to ESRD in the long term, in some 40–50% of untreated patients. The identification of the pathogenic role of anti-podocyte autoantibodies and the development of new therapeutic options has achieved an amelioration in the prognosis of this disease. MN may also develop in renal allograft as a recurrent or a de novo disease. Since the de novo MN may have some different pathogenetic and morphologic features compared to recurrent MN, in the present paper we will deal only with the recurrent disease. The true incidence of the recurrent form is difficult to assess. This is mainly due to the variable graft biopsy policies in kidney transplantation, among the different transplant centers. Anti-phospholipase A2 receptor (PLA2R) autoantibodies are detected in 70–80% of patients. The knowledge of anti-PLA2R status before transplant is useful in predicting the risk of recurrence. In addition, the serial survey of the anti-PLA2R titers is important to assess the rate of disease progression and the response to treatment. Currently, there are no established guidelines for prevention and treatment of recurrent MN. Symptomatic therapy may help to reduce the signs and symptoms related to the nephrotic syndrome. Anecdotal cases of response to cyclical therapy with steroids and cyclophosphamide have been published. Promising results have been reported with rituximab in both prophylaxis and treatment of recurrence. However, these results are based on observational data, and prospective controlled trials are still missing.

Rituximab and Therapeutic Plasma Exchange in Recurrent Focal Segmental Glomerulosclerosis Postkidney Transplantation

BACKGROUND

Focal segmental glomerulosclerosis (FSGS) is a common cause of end-stage renal disease with a high rate of recurrence after kidney transplantation. Several factors, such as white race, rapid progression, and previous allograft failure due to recurrence, were found to be risks of recurrence. Data are limited on the benefits of rituximab and/or therapeutic plasma exchange (TPE) in preventing recurrence. In this study, we sought to assess the efficacy of rituximab and TPE for the prevention and treatment of recurrent FSGS after kidney transplantation.

METHODS

We enrolled 66 patients with FSGS in this prospective observational study and followed their outcomes. Patients with high risk for recurrence received preventative therapy with TPE and/or rituximab.

RESULTS

Twenty-three (62%) of the 37 patients who received preventative therapy developed recurrence compared with 14 (51%) recurrences of the 27 patients who did not receive any therapy (P = 0.21). There was a trend for less relapse when rituximab was used as a therapy for recurrent FSGS (6/22 vs 9/18, P = 0.066). We used a clinical score of 5 values to assess the prediction of FSGS recurrence. A score of 3 or more had a predictive receiver operating characteristic curve of 0.72. Treatment with TPE and/or rituximab resulted in better allograft survival than historical studies. Allograft failure because of recurrent FSGS occurred in only 6 (9%) patients.

CONCLUSIONS

Preventative therapies do not decrease the recurrence rate of recurrent FSGS. However, prompt treatment of recurrence with these therapies may result in improved outcomes.

Use of genomic and functional analysis to characterize patients with steroid-resistant nephrotic syndrome

BACKGROUND

Children with genetic causes of steroid-resistant nephrotic syndrome (SRNS) usually do well after renal transplantation, while some with idiopathic SRNS show recurrence due to a putative podocyte-toxic factor. Distinguishing different forms of SRNS based on clinical criteria has been difficult. The aim of our study was to test a novel approach that allows categorization of patients into clinically useful subgroups.

METHODS

Seventeen patients with clinically confirmed SRNS were analyzed by next-generation sequencing (NGS) of 37 known SRNS genes and a functional assay of cultured human podocytes, which indirectly tests for toxicity of patients' sera by evidenced loss of podocyte focal adhesion complex (FAC) number.

RESULTS

We identified a pathogenic mutation in seven patients (41%). Sera from patients with monogenic SRNS caused mild loss of FAC number down to 73% compared to untreated controls, while sera from seven of the remaining ten patients with idiopathic SRNS caused significant FAC number loss to 43% (non-overlapping difference 30%, 95% CI 26-36%, P < 0.001). All patients with recurrent SRNS (n = 4) in the graft showed absence of podocyte gene mutations but significant FAC loss. Three patients had no mutation nor serum podocyte toxicity.

CONCLUSIONS

Our approach allowed categorization of patients into three subgroups: (1) patients with monogenic SRNS; (2) patients with idiopathic SRNS and marked serum podocyte toxicity; and (3) patients without identifiable genetic cause nor evidence of serum podocyte toxicity. Post-transplant SRNS recurrence risk appears to be low in groups 1 and 3, but high in group 2.

A large, international study on post-transplant glomerular diseases: the TANGO project

Background

Long-term outcomes in kidney transplantation (KT) have not significantly improved during the past twenty years. Despite being a leading cause of graft failure, glomerular disease (GD) recurrence remains poorly understood, due to heterogeneity in disease pathogenesis and clinical presentation, reliance on histopathology to confirm disease recurrence, and the low incidence of individual GD subtypes. Large, international cohorts of patients with GD are urgently needed to better understand the disease pathophysiology, predictors of recurrence, and response to therapy.

Methods

The Post-TrANsplant GlOmerular Disease (TANGO) study is an observational, multicenter cohort study initiated in January 2017 that aims to: 1) characterize the natural history of GD after KT, 2) create a biorepository of saliva, blood, urine, stools and kidney tissue samples, and 3) establish a network of patients and centers to support novel therapeutic trials. The study includes 15 centers in America and Europe. Enrollment is open to patients with biopsy-proven GD prior to transplantation, including IgA nephropathy, membranous nephropathy, focal and segmental glomerulosclerosis, atypical hemolytic uremic syndrome, dense-deposit disease, C3 glomerulopathy, complement- and IgG-positive membranoproliferative glomerulonephritis or membranoproliferative glomerulonephritis type I-III (old classification). During phase 1, patient data will be collected in an online database. The biorepository (phase 2) will involve collection of samples from patients for identification of predictors of recurrence, biomarkers of disease activity or response to therapy, and novel pathogenic mechanisms. Finally, through phase 3, we will use our multicenter network of patients and centers to launch interventional studies.

Discussion

Most prior studies of post-transplant GD recurrence are single-center and retrospective, or rely upon registry data that frequently misclassify the cause of kidney disease. Systematically determining GD recurrence rates and predictors of clinical outcomes is essential to improving post-transplant outcomes. Furthermore, accurate molecular phenotyping and biomarker development will allow better understanding of individual GD pathogenesis, and potentially identify novel drug targets for GD in both native and transplanted kidneys. The TANGO study has the potential to tackle GD recurrence through a multicenter design and a comprehensive biorepository.

Utility of Oxford Classification in Post-Transplant Immunoglobulin A Nephropathy

BACKGROUND

With increasing graft survival, post-transplant immunoglobulin A nephropathy (IgAN) has emerged as an important cause of chronic graft dysfunction in renal allograft recipients. We studied the clinico-pathological features of post-transplant IgAN regardless of the primary disease. The aim was to study the usefulness of the Oxford classification in predicting survival.

METHODS

Indication graft biopsy specimens (n = 915) were received during a 10-year period; 27 biopsy specimens from 22 patients were diagnosed as IgAN.

RESULTS

Post-transplant IgAN was seen in 2.6% of biopsy specimens. Mean time to occurrence was 71.6 ± 47.6 months (range, 6.8 months to 16 years), occurring most commonly 4 to 8 years after transplant. Associated rejection was present in 4 biopsies; 72.7% (16/22), 91% (20/22), and 31.8% (7/22) presented with rise in serum creatinine, proteinuria, and hematuria, respectively. Four (21%) patients had nephrotic range proteinuria. Mesangial hypercelullarity (M1), endocapillary hypercelullarity (E1), segmental glomerulosclerosis (S1), and tubulo-interstitial fibrosis (T1-2) was present in 36.6%, 22.7%, 54.5%, and 31.8% biopsies, respectively. The most frequent Haas class was III (n = 7; 29.1%), followed by classes IV and I (n = 5; 20.8% each). The 2- and 5-year graft survival rates were 75% and 56%, respectively. High serum creatinine, low estimated glomerular filtration rate, E1 and T lesions, and degree of interstitial inflammation predicted graft survival. Interestingly, percentage (>25%) of segmentally sclerosed glomeruli and not S1 correlated with graft outcome.

CONCLUSIONS

The Oxford MEST scheme is useful in predicting graft survival in post-transplant IgAN. The degree of interstitial inflammation is also an important feature for determining graft outcomes in post-transplant IgAN.

Recurrent glomerular disease after kidney transplantation

PURPOSE OF REVIEW

With improving short-term kidney transplant outcomes, recurrent glomerular disease is being increasingly recognized as an important cause of chronic allograft failure. Further understanding of the risks and pathogenesis of recurrent glomerular disease enable informed transplant decisions, along with the development of preventive and treatment strategies.

RECENT FINDINGS

Multiple observational studies have highlighted differences in rates and outcomes for various recurrent glomerular diseases, although these rates have not markedly improved over the last decade. Emerging evidence supports use of rituximab to treat recurrent primary membranous nephropathy and possibly focal segmental glomerulosclerosis (FSGS), whereas eculizumab is effective in glomerular diseases associated with complement dysregulation [C3 glomerulopathy (C3G) and atypical hemolytic uremic syndrome (aHUS)].

SUMMARY

Despite the potential for recurrence in the allograft, transplant remains the optimal therapy for patients with advanced chronic kidney disease (CKD) secondary to primary glomerular disease. Biomarkers and therapeutic options necessitate accurate pretransplant diagnoses with opportunities for improved surveillance and treatment of recurrent glomerular disease posttransplant.

[Current insights about recurrence of glomerular diseases after renal transplantation]

Recurrence of glomerular disease after renal transplantation is a frequent cause of graft loss. Incidence, risk factors and outcome of recurrence are widely due to the underlying glomerular disease. Graft biopsy analysis is required to confirm the definitive diagnosis of recurrence and to start an appropriate therapy that, in some cases, remains challenging to prevent graft failure. Increased use of protocol biopsy and recent advances in our understanding of the pathogenesis of some glomerular diseases with the identification of some relevant biomarkers provide a unique opportunity to initiate kidney-protective therapy at early stages of recurrence on the graft. This review summarizes our current knowledge on the management of many recurrent primary and secondary glomerulonephritis after kidney transplantation.

Preoperative Low-Density Lipoprotein Apheresis for Preventing Recurrence of Focal Segmental Glomerulosclerosis after Kidney Transplantation

Background

Focal segmental glomerulosclerosis (FSGS) often develops rapidly and frequently progresses to renal failure, while the recurrence rate after kidney transplantation is 20–50%. We performed low-density lipoprotein (LDL) apheresis before kidney transplantation in FSGS patients to prevent recurrence.

Methods

Five adult patients with chronic renal failure due to FSGS undergoing living related donor kidney transplantation were investigated retrospectively. LDL apheresis was done 1-2 times before transplantation. Postoperative renal function and recurrence of FSGS were assessed.

Results

The patients were two men and three women aged 24 to 41 years. The observation period ranged from 60 days to 22 months. Preoperative LDL apheresis was performed once in one patient and twice in four patients. Blood LDL cholesterol levels were normal before LDL apheresis and remained normal both after LDL apheresis and after kidney transplantation. Additional LDL apheresis was performed once in one patient with mild proteinuria after transplantation. The renal graft survived in all patients and there was no evidence of recurrent FSGS.

Conclusions

Although the observation period was short, FSGS did not recur in all 5 patients receiving preoperative LDL apheresis. These results suggest that LDL apheresis can be effective in preventing recurrence of FSGS after kidney transplantation.

Higher Incidence of Renal Allograft Glomerulonephritis in Living-Related Donor Kidney Transplantation

Glomerulonephritis recurrence has emerged as one of the leading causes of allograft loss. We aimed to investigate the effect of living-related and deceased donation on the incidence of renal allograft glomerulonephritis and its effect on renal allograft survival.

METHODS

Adult renal allograft recipients with primary glomerulonephritis were enrolled. Transplantation date was from Feb 2004 to Dec 2015. Exclusion criteria included combined organ transplantation, structural abnormality, diabetic nephropathy, hypertension nephropathy, obstructive nephropathy, and primary uric acid nephropathy. The incidence of biopsy-proven allograft glomerulonephritis was compared between the living-related donor group and the deceased donor group. Graft survival was assessed with Kaplan-Meier method, and Cox proportional hazard model was used to evaluate the effect of posttransplant glomerulonephritis on graft outcome.

RESULTS

There were 525 living-related donor kidney transplant recipients (LRKTx) and 456 deceased donor kidney transplant recipients (DDKTx) enrolled. The incidence of IgA nephropathy was 8.8% in the LRKTx group and 1.3% in the DDKTx group (P < .001); the incidence of focal segmental glomerulosclerosis (FSGS) was 3.8% in the LRKTx group and 1.5% in the DDKTx group (P = .03). FSGS increased the risk of graft failure compared with non-FSGS (hazard ratio [HR], 3.703 [1.459-9.397]; P = .006). IgA nephropathy increased the risk of graft failure by over 5 times 5 years after kidney transplantation compared with non-IgA nephropathy, but it did not affect early allograft survival (HR for ≥5 years, 6.139; 95% CI, 1.766-21.345; P = .004; HR for <5 years, 0.385 [0.053-2.814]; P = .35).

CONCLUSIONS

Higher incidence of IgA nephropathy and FSGS in renal allograft was observed in living-related donor kidney transplantation compared with deceased donor kidney transplantation. De novo or recurrent IgA nephropathy and FSGS impaired long-term renal allograft survival.

Graft survival of pediatric kidney transplant recipients selected for de novo steroid avoidance-a propensity score-matched study

Background

Steroid-avoidance protocols have gained popularity in pediatric kidney transplant recipients at low immunologic risk. The long-term safety of steroid avoidance in children with immunologic risk factors remains unknown.

Methods

Pediatric kidney transplant recipients from 2004 to 2014 in the Organ Procurement and Transplantation Network database who received tacrolimus and mycophenolate immunosuppression were investigated. Propensity score matching was used to compare graft survival in 1624 children who received steroid avoidance with 1624 children who received steroid-based immunosuppression. The effect of steroid avoidance on graft failure among immunologic risk strata was estimated using Cox proportional hazards regression in this propensity score-matched cohort.

Results

It was observed that 5-year graft survival was mildly improved in children receiving steroid avoidance (84.8% versus 81.2%, P = 0.03). This improvement in graft survival occurred in the first 2 years following transplant, when the hazard ratio (HR) for allograft failure in children receiving steroid avoidance was 0.62 [95% confidence interval (CI) 0.45-0.86]. In contrast, steroid avoidance was not associated with improved allograft survival during Years 2-10 following transplant (HR = 0.93; 95% CI 0.75-1.15). During this time period, HRs (95% CIs) for allograft failure within immunologic risk strata were not significantly different from the null value of 1: repeat kidney transplants, 1.84 (0.84-4.05); African-Americans, 1.02 (0.67-1.56); sensitized recipients, 1.24 (0.63-2.43); recipients of deceased donor kidneys, 1.02 (0.79-1.32); recipients of completely human leukocyte antigen-mismatched kidneys, 0.80 (0.47-1.37); and recipients with pretransplant glomerular disease, 0.94 (0.71-1.23).

Conclusions

In pediatric kidney transplant recipients receiving tacrolimus- and mycophenolate-based immunosuppression, steroid avoidance can be safely practiced in children with immunologic risk factors.

Recurrent IgA nephropathy after renal transplantation and steroid withdrawal

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis; the reported recurrence rate of IgAN after renal transplantation is as high as 13%-50%. The impact of immunosuppressive therapy and steroid withdrawal on the risk of recurrence of IgAN is still under debate. We performed a retrospective single-center study, selecting 123 kidney transplants (rtx) in 120 patients, between January 1995 and December 2012, with IgAN on the native kidney. In 51 of 123 transplants, at least one post-transplantation biopsy for clinical indication was performed; in 28 of 51 transplants, IgAN recurrence (IgANr) was demonstrated. This group (G1; N = 28) was compared with a group without IgANr (G2; N = 23). In our study, clinically evident IgANr rate was 54.9% (28/51) on biopsied patients. At discharge, the use of the immunosuppressant drugs (tacrolimus, cyclosporine A, mycophenolate mofetil, azathioprine, mTor inhibitors) was not associated with an increased risk of IgANr (P = NS). At discharge, all patients were steroid treated. Neither the use of tacrolimus, mycophenolate mofetil, nor mTor inhibitors (mTori) at biopsy time were associated with IgANr. However, IgANr was significantly higher in patients who experienced steroid withdrawal at any post-transplantation time (OR 7.7 P = .03). The median time to recurrence after steroid withdrawal was 59 months (min 4.18, max 113.2).

Recurrence of primary glomerulonephritis: Review of the current evidence

In view of the availability of new immunosuppression strategies, the recurrence of allograft glomerulonephritis (GN) are reported to be increasing with time post transplantation. Recent advances in understanding the pathogenesis of the GN recurrent disease provided a better chance to develop new strategies to deal with the GN recurrence. Recurrent GN diseases manifest with a variable course, stubborn behavior, and poor response to therapy. Some types of GN lead to rapid decline of kidney function resulting in a frustrating return to maintenance dialysis. This subgroup of aggressive diseases actually requires intensive efforts to ascertain their pathogenesis so that strategy could be implemented for better allograft survival. Epidemiology of native glomerulonephritis as the cause of end-stage renal failure and subsequent recurrence of individual glomerulonephritis after renal transplantation was evaluated using data from various registries, and pathogenesis of individual glomerulonephritis is discussed. The following review is aimed to define current protocols of the recurrent primary glomerulonephritis therapy.

Monitoring of Renal Allograft Function with Different Equations: What are the Differences?

Introduction. Monitoring of graft function by creatinine concentrations in serum and calculated glomerular filtration rate (GFR) is recommended after kidney transplantation. KDIGO recommendations on the treatment of transplant patients advocate usage of one of the existing mathematical equations based on serum creatinine. We compared clinical application of three equations based on serum creatinine in monitoring the function of transplanted kidney. Methods. A total number of 55 adult patients who received their first renal allograft from living donors at our transplant center in between 2011-2014 were included into the study. Renal allograft GFR was estimated by the Cockroft-Gault, Nankivell and MDRD formula, and correlated with clinical parameters of donors and recipients. Results. The mean age of recipients was 35.7±9.5 (range 16-58), and the mean age of donors was 55.5±9.0 (34- 77) years. Out of this group of 55 transplant patients, 50(90.91%) were on hemodialysis (HD) prior to transplantation. HD treatment was shorter than 24 months in 37(74%) transplant patients. The calculated GFR with MDRD equation showed the highest mean value at 6 and 12 months (68.46±21.5; 68.39±24.6, respectively) and the lowest at 48 months (42.79±12.9). According to the Cockroft&Gault equation GFR was the highest at 12 months (88.91±24.9) and the lowest at 48 months (66.53±18.1 ml/min). The highest mean level (80.53±17.7) of the calculated GFR with the Nankivell equation was obtained at 12 months and the lowest (67.81±16.7 ml/min) at 48 months. The values of Pearson’s correlation coefficient between the calculated GFR and the MDRD at 2 years after transplantation according to donor’s age of r=-0.3224, correlation between GFR and the Cockfroft & Gault at 6 and 12 months and donor’s age (r=-0.2735 and r=-0.2818), and correlation between GFR and the Nankivell at 2 years and donor’s age of r=-0.2681, suggested a conclusion that calculated GFR was lower in recipients who had an older donors. Conclusion. Our analysis showed difference in the calculated GFR with different equations at the same time points. Using one mathematical equation during the total post-transplantation period would be a recommended method in order to eliminate the discrepancy in determining the stage of kidney failure.

Recommendations for the treatment of hepatitis C virus infection in chronic kidney disease: a position statement by the Spanish association of the liver and the kidney

Hepatitis C virus (HCV) infection is one of the main causes of liver cirrhosis worldwide. The long-term impact of HCV infection is highly variable, ranging from minimal histological changes to extensive fibrosis with hepatocellular carcinoma. The development of HCV drugs has increased dramatically in recent years, even in special populations such as chronic kidney disease patients. Classical treatment of chronic hepatitis C was based on the administration of interferon and ribavirin for 24-48 weeks, which was associated with a poor viral response and a high rate of side effects, especially in patients with a lower estimated glomerular filtration rate. The current high availability of the new direct-acting antivirals renders the classification of these agents for this special population necessary. The Spanish Association of the Liver and the Kidney has produced a position statement on the treatment of HCV infection in chronic kidney disease patients since the evidence to guide this treatment is scant and what evidence does exist is weak. The recommendations are based on the results of clinical trials and controlled studies conducted to date, with data published hitherto by the authors of these studies. Since the indications for treatment have been evaluated by other societies or are dependent on internal clinical protocols, the main goal of this position statement is to assist in decision-making when choosing a therapeutic option.

Anti-Glomerular Basement Membrane Disease

Anti-glomerular basement membrane (anti-GBM) disease is a rare small vessel vasculitis that affects the capillary beds of the kidneys and lungs. It is an archetypic autoimmune disease, caused by the development of directly pathogenic autoantibodies targeting a well characterized autoantigen expressed in the basement membranes of these organs, although the inciting events that induce the autoimmune response are not fully understood. The recent confirmation of spatial and temporal clustering of cases suggests that environmental factors, including infection, may trigger disease in genetically susceptible individuals. The majority of patients develop widespread glomerular crescent formation, presenting with features of rapidly progressive GN, and 40%-60% will have concurrent alveolar hemorrhage. Treatment aims to rapidly remove pathogenic autoantibody, typically with the use of plasma exchange, along with steroids and cytotoxic therapy to prevent ongoing autoantibody production and tissue inflammation. Retrospective cohort studies suggest that when this combination of treatment is started early, the majority of patients will have good renal outcome, although presentation with oligoanuria, a high proportion of glomerular crescents, or kidney failure requiring dialysis augur badly for renal prognosis. Relapse and recurrent disease after kidney transplantation are both uncommon, although de novo anti-GBM disease after transplantation for Alport syndrome is a recognized phenomenon. Copresentation with other kidney diseases such as ANCA-associated vasculitis and membranous nephropathy seems to occur at a higher frequency than would be expected by chance alone, and in addition atypical presentations of anti-GBM disease are increasingly reported. These observations highlight the need for future work to further delineate the immunopathogenic mechanisms of anti-GBM disease, and how to better refine and improve treatments, particularly for patients presenting with adverse prognostic factors.

Rituximab for recurrent IgA nephropathy in kidney transplantation: A report of three cases and proposed mechanisms

AIM

Recurrent IgA nephropathy (IgAN) is a common recurrent glomerular disease after kidney transplantation. Recurrent IgAN, in particular, with crescent formation or endocapillary proliferation might result in kidney allograft loss. However, the current treatment options of recurrent IgAN are conflicting.

METHODS

We have reported three kidney-transplanted recipients with biopsy-proven recurrent IgAN treated with four consecutive months of rituximab at the dose of 375 mg/1.73m² without corticosteroids.

RESULTS

At median follow-up 20 months following rituximab administration, all three recipients demonstrated decrease in proteinuria severity, slow disease progression with a well-tolerated condition. This therapeutic effect is most probably mediated by the B cell depletion.

CONCLUSION

Our three case reports suggest that the disease severity of recurrent IgAN with endocapillary proliferation regardless of crescent formation can be minimized by the four doses of monthly rituximab regimen.

Increased glomerulonephritis recurrence after living related donation

Background

Kidney transplantation confers superior outcomes for patients with end stage kidney disease, and live donor kidneys associate with superior outcomes compared to deceased donor kidneys. Modern immunosuppression has improved rejection rates and transplant survival and, as a result, recurrence of glomerulonephritis has emerged as a major cause of allograft loss. However, many glomerulonephritides have significant genetic risk which may manifest through kidney intrinsic or systemic mechanisms. We hypothesise that heritable kidney intrinsic predisposition to glomerulonephritis will result in increased risk of glomerulonephritis recurrence in kidneys transplanted from genetically related donors.

Methods

We investigated the effect of living related donation on rates of recurrence and subsequent graft outcomes in 7236 patient from 28 years of ANZDATA transplant registry data. Data were analysed in R, using Kaplan Meier Survival analysis and adjusted analyses performed using Cox Proportional Hazards methods. A competing risk model was also analysed.

Results

Glomerulonephritis recurrence rates were significantly higher in living related donor grafts compared to either living unrelated or deceased donor grafts (p < 0 · 001). In IgA nephropathy, transplantation from living related donor kidneys demonstrated a 10 year recurrence rate of 16 · 7% compared to 7 · 1% in living unrelated donors and 9 · 2% in deceased donors (HR:1 · 7, 95% CI:1 · 26–2 · 26, p = 0 · 0005 for living related vs deceased donors). In focal segmental glomerulosclerosis, risk of recurrence at 10 years was 14 · 6% in living related donors compared to 10 · 8% in living unrelated donors and 6 · 6% in deceased donors (HR:2 · 2, 95% CI 1 · 34–3 · 64, p = 0 · 002) for living related vs deceased donors. Primary glomerulonephritis death censored graft survival was superior for living donor grafts, related or unrelated, compared to deceased donor grafts.

Conclusions

We identified a significant increase in the risk of glomerulonephritis recurrence in IgA Nephropathy and Focal Segmental Glomerulosclerosis in living related donors compared to a deceased donors.

Recent advances in our understanding of recurrent primary glomerulonephritis after kidney transplantation

Recurrent glomerulonephritis (GN) is an important cause of kidney allograft failure, particularly in younger recipients. Approximately 15% of death-censored graft failures are due to recurrent GN, but this incidence is likely an underestimation of the magnitude of the problem. Overall, 18% to 22% of kidney allografts are lost due to GN, either recurrent or presumed de novo. The impact of recurrent GN on allograft survival was recognized from the earliest times in kidney transplantation. However, progress in this area has been slow, and our understanding of GN recurrence remains limited, in large part due to incomplete understanding of the pathogenesis of these diseases. This review focuses on recent advances in our general understanding of the pathophysiology of primary GN, the risk of recurrence in the allograft, and the consequences for kidney graft survival. We focus specifically on the most common forms of primary GN, including focal segmental glomerulosclerosis, membranous nephropathy, membranoproliferative glomerulonephritis, and IgA nephropathy. New understanding of the pathogenesis of these diseases has had direct clinical implications for transplantation, allowing better identification of candidates at high risk of recurrence and earlier diagnoses, and it is expected to lead to significance improvements in the therapy and perhaps even prevention of GN recurrence. More than ever, it is essential to fully characterize GN before transplantation as this information will direct our management posttransplantation. Further, the relative rarity of recurrent GN dictates the need for multicenter studies in order to evaluate, test, and validate recent advances and therapies.

Immune-mediated nephropathies in kidney transplants: recurrent or de novo diseases

IMN contribute to ESRD in 13% children with renal transplant (txp). Recurrent or de novo IMN can cause graft dysfunction and/or failure, but the details regarding incidence, therapy, and outcome remain poorly understood. Retrospective single-center study of all pediatric kidney txp was carried out since 1998. Clinical presentation, pathology, therapy, and graft outcomes of children with recurrent or de novo IMN were reviewed. IMN was the primary etiology of ESRD in 28 of the 149 txp recipients. Eleven children had biopsy-proven post-txp IMN-six were recurrent and five had de novo. Presentation varied with changes in SCr and/or proteinuria. Initial therapy included higher doses of steroids, MMF, and tacrolimus. Outcome was excellent with only one late graft loss. Full remission was achieved in all other patients, but some had re-recurrence of the IMN. Median follow-up time was 11.8 years. IMN (recurrent or de novo) occurred in 7.4% (11 of 149) of all kidney txp performed at our center. IMN post-txp was often seen late post-txp, usually asymptomatic and noted to have relapsing pattern. Early diagnosis and prompt therapy resulted in excellent long-term outcome in children diagnosed with post-txp IMN.

The importance of non-HLA antibodies in transplantation

The development of post-transplantation antibodies against non-HLA autoantigens is associated with rejection and decreased long-term graft survival. Although our knowledge of non-HLA antibodies is incomplete, compelling experimental and clinical findings demonstrate that antibodies directed against autoantigens such as angiotensin type 1 receptor, perlecan and collagen, contribute to the process of antibody-mediated acute and chronic rejection. The mechanisms that underlie the production of autoantibodies in the setting of organ transplantation is an important area of ongoing investigation. Ischaemia-reperfusion injury, surgical trauma and/or alloimmune responses can result in the release of organ-derived autoantigens (such as soluble antigens, extracellular vesicles or apoptotic bodies) that are presented to B cells in the context of the transplant recipient's antigen presenting cells and stimulate autoantibody production. Type 17 T helper cells orchestrate autoantibody production by supporting the proliferation and maturation of autoreactive B cells within ectopic tertiary lymphoid tissue. Conversely, autoantibody-mediated graft damage can trigger alloimmunity and the development of donor-specific HLA antibodies that can act in synergy to promote allograft rejection. Identification of the immunologic phenotypes of transplant recipients at risk of non-HLA antibody-mediated rejection, and the development of targeted therapies to treat such rejection, are sorely needed to improve both graft and patient survival.

FSGS Recurrence in Adults after Renal Transplantation

Recurrence of focal segmental glomerulosclerosis (FSGS) in the allograft occurs in 30–50% of patients, and it is associated with poor renal allograft survival. Major risk factors for recurrence are younger age at diagnosis, rapid progression to end-stage renal disease, white race, and the loss of previous allografts due to recurrence. Recent data support the hypothesis that circulating permeability factors play a crucial role in podocyte injury and progression of FSGS. Due to lack of controlled trials, the management of recurrent FSGS is inconsistent and highly empirical. Prophylactic and perioperative treatment with plasmapheresis and high-dose (intravenous) cyclosporine represent the main cornerstones of immunosuppressive therapy. In recent years, therapy with rituximab has shown promising results. Despite evidence of activation of the renin-angiotensin system (RAS) in recurrent FSGS and its association with progression, only limited data exist on the renoprotective role of RAS blockade in this setting. Further well designed studies are needed on pathogenesis risk factors and therapeutical options in FSGS and its recurrence after transplantation.