An Update on Viral Infection-Associated Collapsing Glomerulopathy.

The COVID-19 era has been a reminder to clinicians around the world of the important role that viral infections play in promoting glomerular disease. Several viral infections including human immunodeficiency virus (HIV), severe acute respiratory syndrome coronavirus 2, Epstein-Barr virus, cytomegalovirus, and parvovirus B19 can cause podocyte injury and present with a collapsing glomerulopathy (CG) variant of focal segmental glomerulosclerosis or minimal change disease. CG associated with COVID-19 has been termed COVID-19-associated nephropathy due to its striking resemblance to HIV-associated nephropathy. Host susceptibility is a major determinant of viral infection-associated CG, and the presence of two APOL1 risk variants explains most of the racial predilection to viral-associated CG observed in individuals of African ancestry. Interactions between APOL1 risk variants, viral genes, and the systemic inflammatory response to viral infection all contribute to kidney injury. This review will summarize our current knowledge of viral infection-associated CG, focusing primarily on the clinical presentation, histological features, mechanisms, and disease course of HIV-associated nephropathy and COVID-19-associated nephropathy.

Podocyte density as a predictor of long-term kidney outcome in obesity-related glomerulopathy.

Glomerulomegaly and focal segmental glomerulosclerosis are histopathological hallmarks of obesity-related glomerulopathy (ORG). Podocyte injury and subsequent depletion are regarded as key processes in the development of these glomerular lesions in patients with ORG, but their impact on long-term kidney outcome is undetermined. Here, we correlated clinicopathological findings and podocyte depletion retrospectively in patients with ORG. Relative (podocyte density) and absolute (podocyte number per glomerulus) measures of podocyte depletion were estimated using model-based stereology in 46 patients with ORG. The combined endpoint of kidney outcomes was defined as a 30% decline in estimated glomerular filtration rate (eGFR) or kidney failure. Patients with lower podocyte density were predominantly male and had larger body surface area, greater proteinuria, fewer non-sclerotic glomeruli, larger glomeruli and higher single-nephron eGFR. During a median follow-up of 4.1 years, 18 (39%) patients reached endpoint. Kidney survival in patients with lower podocyte density was significantly worse than in patients with higher podocyte density. However, there was no difference in kidney survival between patient groups based on podocyte number per glomerulus. Cox hazard analysis showed that podocyte density, but not podocyte number per glomerulus, was associated with the kidney outcomes after adjustment for clinicopathological confounders. Thus, our study demonstrates that a relative depletion of podocytes better predicts long-term kidney outcomes than does absolute depletion of podocytes. Hence, the findings implicate mismatch between glomerular enlargement and podocyte number as a crucial determinant of disease progression in ORG.

Clinical Course of Nonresponders With Recurrent Focal Segmental Glomerulosclerosis After Pediatric Kidney Transplantation: A Retrospective Multicenter Study.

BACKGROUND: Primary focal segmental glomerulosclerosis (FSGS) frequently recurs after kidney transplantation and is associated with poor graft survival. Patients who do not achieve remission (nonresponders) have an especially poor graft survival. However, the characteristics that may affect graft survival in nonresponders are unknown. This study aimed to determine the clinical characteristics associated with graft survival in nonresponders. METHODS: We retrospectively collected the clinical records of patients with FSGS and an age at onset <16 years who experienced posttransplant recurrence of FSGS at six hospitals in Japan from 1993 to 2018. RESULTS: Eight nonresponders with recurrent FSGS were enrolled in this study. The median time to recurrence after kidney transplantation was 1 day (interquartile range, 1-2 days). All patients received therapeutic plasma exchange and methylprednisolone pulse therapy. Rituximab was used as an add-on therapy in three patients. Five patients lost their graft within 2 years after kidney transplantation (rapid group). In contrast, three patients had much longer graft survival (nonrapid group). We compared the clinical characteristics of the rapid and nonrapid groups. Proteinuria tended to be lower in the nonrapid group at the third and subsequent months of therapy. The rapid group had persistent nephrotic syndrome. The rate of reduction in proteinuria was lower in the rapid group than in the nonrapid group. CONCLUSIONS: Our study suggests that persistent nephrotic syndrome and a low rate of reduction in proteinuria may predict rapid progression to graft failure in nonresponders.

Anuria after kidney transplantation diagnosed as early recurrence of focal segmental glomerulosclerosis combined with acute calcineurin inhibitor nephrotoxicity: a case report and literature review.

BACKGROUND: Primary focal segmental glomerulosclerosis (FSGS) is a glomerular disease that sometimes recurs in patients after kidney transplantation (KT) and increases the risk of graft loss. Proteinuria is a common early sign of recurrent FSGS, but an abrupt decrease in urine volume is rare. Herein, we report a patient with early recurrence of FSGS with anuria following KT. CASE PRESENTATION: A 55-year-old man with end-stage kidney disease caused by primary FSGS experienced anuria on postoperative day 2 following deceased donor KT. Laboratory results revealed that serum tacrolimus trough levels were consistently elevated at the time of anuria. At first, we considered acute calcineurin inhibitor (CNI) nephrotoxicity based on graft biopsy on light microscopy, laboratory findings, and clinical courses. However, the allograft function did not recover even after discontinuation of CNI, and recurrent FSGS was diagnosed 2 weeks later on electron microscopy. A total of 13 sessions of plasmapheresis and two administrations of rituximab (375 mg/m2) were required to treat recurrent FSGS. The patient achieved a partial response, and the spot urine protein-to-creatinine ratio decreased from 15.5 g/g creatinine to 5.2 g/g creatinine. At 5 months following KT, the serum creatinine level was stable at 1.15 mg/dL. CONCLUSIONS: These findings highlight that anuria can occur in cases of early recurrence of FSGS combined with acute CNI nephrotoxicity.

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.

Current approaches to overcome recurrent focal segmental glomerulosclerosis after kidney transplantation.

PURPOSE OF REVIEW: Recurrent focal segmental glomerulosclerosis (FSGS) presents with nephrotic syndrome shortly after kidney transplantation. This review will overview the role of circulating permeability factors in disease pathogenesis and treatment options for recurrent FSGS. RECENT FINDINGS: Novel circulating permeability factors have been identified in serum samples. Current research is focused on detection of permeability factors as a marker of treatment response. Furthermore, novel monoclonal antibodies are being utilized to further induce remission. SUMMARY: Posttransplant recurrent FSGS can have a deleterious effect on allograft. Early detection of disease recurrence with prompt treatment is optimal for clinical remission. Plasmapheresis with anti-B cell therapy is considered the mainstay of treatment. Newer B cell therapies and detection of circulating factors in serum may help in providing targeted treatment in a subset of patients.

Efficacy of combined rituximab and daratumumab treatment in posttransplant recurrent focal segmental glomerulosclerosis.

Focal segmental glomerulosclerosis (FSGS) is one of the leading causes of kidney failure and it is characterized by a high rate of recurrence after kidney transplant. Moreover, FSGS recurrence is worsened by an increased risk of graft failure. Common therapies for FSGS recurrence mostly consist of plasma exchange treatments, also for prolonged time, and rituximab, with variable efficacy. We report 5 cases of early FSGS recurrence after kidney transplant, resistant to plasma exchange and rituximab treatment that subsequently resolved after combined therapy with rituximab and daratumumab. All cases were negative for genetic FSGS. The combined treatment induced a complete response in all the cases and was well tolerated. We also performed a comprehensive flow cytometry analysis in 2 subjects that may suggest a mechanistic link between plasma cells and disease activity. In conclusion, given the lack of viable treatments for recurrent FSGS, our reports support the rationale for a pilot trial testing the safety/efficacy profile of combined rituximab and daratumumab in posttransplant FSGS recurrence.

Incidence, risk factors, and outcomes of recurrent focal segmental glomerulosclerosis in pediatric kidney transplant recipients: A systematic review and meta-analysis.

BACKGROUND: Focal segmental glomerulosclerosis is the most prevalent acquired kidney disease leading to end-stage renal disease in children and has a propensity for recurring in the transplanted kidney. The recurrence of FSGS after kidney transplantation in children varies greatly. In addition, the risk factors and outcomes of recurrence of FSGS remain controversial. This study evaluated the recurrence rate, risk factors, and prognosis of FSGS after kidney transplantation in order to provide advice and assistance in clinical decision-making for pediatric kidney transplantation. METHODS: PubMed, Embase, Web of Science, CNKI, and other databases were searched from the establishment of the repository to March 2022. We extracted data on incidence, risk factors, and outcomes. RESULTS: The results showed that the recurrence rate of primary FSGS in children after renal transplantation was 48% (95% CI 36%-59%) and the recurrence rate of FSGS (all forms) was 35% (95% CI 17%-52%). The graft loss rate of primary FSGS in children after kidney transplantation was 29% (95% CI 17%-42%) and the graft loss rate of FSGS (all forms) was 29% (95% CI 4%-62%). 57% (95% CI 42%-73%) of pediatric patients with recurrent primary FSGS showed complete remission. Risk factor analyses showed that age of onset (SMD .69, 95% CI .20-1.19, p = .006) was related to the recurrence of primary FSGS, whereas the living related donor was not a risk factor for recurrent primary FSGS in pediatrics after kidney transplantation (OR 1.22, 95% CI .48-3.10, p = .674). CONCLUSIONS: The recurrence rate and graft loss rate of FSGS in children after kidney transplantation were relatively high. Age at onset was associated with a risk for recurrent primary FSGS, whereas the living related donor was not a risk factor for recurrent FSGS in pediatric kidney recipients.

Stage lighting on PAR-1: a step further in the understanding of acquired focal and segmental glomerulosclerosis.

The pathogenic mechanisms of acquired focal and segmental glomerular sclerosis are only partially known and represent a medical challenge in nephrology. The article by May et al. sheds additional light on previous data indicating the key role of the protease-activated receptor 1. The new evidence is based on in vivo studies in relevant animal models and on patient biopsies and represents a significant step forward in the understanding of this pathologic condition.

Incidence and risk factors for recurrent focal segmental glomerulosclerosis after kidney transplantation: a meta-analysis.

AIMS: To systematically review the incidence and risk factors for recurrent FSGS after kidney transplantation. METHODS: We searched PubMed, Embase, Medline, Web of Science, the Cochrane Library, CNKI, CBMdisc, Wanfang, and Weipu for case-control studies related to recurrent FSGS from the establishment until October 2022. The protocol was registered on PROSPERO (CRD42022315448). Data were analyzed using Stata 12.0, with odds ratios (counting data) and standardized mean difference (continuous data) being considered as effect sizes. If the I2 value was greater than 50%, the random-effects model was used; otherwise, a fixed-effects model was used. A meta-analysis on the incidence and risk factors for recurrent FSGS after kidney transplantation was performed. RESULTS: A total of 22 studies with 966 patients and 12 factors were included in the meta-analysis. There were 358 patients with recurrent FSGS and 608 patients without FSGS after kidney transplantation. The results showed that the recurrence rate of FSGS after kidney transplantation was 38% (95% CI: 31%-44%). Age at transplantation (SMD = -0.47, 95% CI -0.73 to -0.20, p = .001), age at onset (SMD = -0.31, 95% CI -0.54 to -0.08, p = .008), time from diagnosis to kidney failure (SMD = -0.24, 95% CI -0.43 to -0.04, p = .018), proteinuria before KT (SMD = 2.04, 95% CI 0.91 - 3.17, p < .001), related donor (OR 1.99, 95% CI 1.20 - 3.30, p = .007) and nephrectomy of native kidneys (OR 6.53, 95% CI 2.68 - 15.92, p < .001) were associated with recurrent FSGS, whereas HLA mismatches, duration of dialysis before KT, sex, living donor, tacrolimus use and previous transplantation were not associated with recurrent FSGS after kidney transplantation. CONCLUSIONS: The recurrence of FSGS after kidney transplantation remains high. Clinical decision-making should warrant further consideration of these factors, including age, original disease progression, proteinuria, related donor, and nephrectomy of native kidneys.

Computational drug repositioning of clopidogrel as a novel therapeutic option for focal segmental glomerulosclerosis.

Focal segmental glomerulosclerosis (FSGS) is a glomerular lesion often associated with nephrotic syndrome. It is also associated with a high risk of progression to end-stage kidney disease. Current treatment of FSGS is limited to systemic corticosteroids or calcineurin inhibition, along with inhibitors of the renin-angiotensin-aldosterone system. FSGS is heterogeneous in etiology, and novel therapies targeting specific, dysregulated molecular pathways represent a major unmet medical need. We have generated a network-based molecular model of FSGS pathophysiology using previously established systems biology workflows to allow computational evaluation of compounds for their predicted interference with molecular processes contributing to FSGS. We identified the anti-platelet drug clopidogrel as a therapeutic option to counterbalance dysregulated FSGS pathways. This prediction of our computational screen was validated by testing clopidogrel in the adriamycin FSGS mouse model. Clopidogrel improved key FSGS outcome parameters and significantly reduced urinary albumin to creatinine ratio (P < 0.01) and weight loss (P < 0.01), and ameliorated histopathological damage (P < 0.05). Clopidogrel is used to treat several cardiovascular diseases linked to chronic kidney disease. Clopidogrel's favorable safety profile and its efficacy in the adriamycin mouse FSGS model thus recommend it as an attractive drug repositioning candidate for clinical trial in FSGS.

Post-operative recurrence of focal segmental glomerulosclerosis according to pre-transplant treatment after kidney transplantation.

BACKGROUND: Recurrent focal segmental glomerulosclerosis (FSGS) after kidney transplantation (KT) is a serious complication and a significant risk factor for graft failure. However, there is no clear evidence of the effectiveness of pre-transplant treatment using plasmapheresis (PP) or rituximab in preventing post-operative FSGS recurrence after KT. METHODS: This single-center retrospective study included 99 adult patients with biopsy-proven primary FSGS who underwent KT between 2007 and 2018. The patients were divided into the pre-treatment group (N = 53, 53.5%) and no pre-treatment group (N = 46, 46.5%). In the pre-transplant group, prophylactic PP was administered before KT in patients undergoing living donor transplantation and the day after KT in those undergoing deceased donor transplantation. RESULTS: The rate of immediate post-operative recurrence was significantly higher in the no pre-treatment group (16 [34.8%]) than in the pre-treatment group (5 [9.4%]; P = 0.002). There were three cases of graft failure due to recurrent FSGS, all of which were in the no pre-treatment group. After adjusting for possible confounding factors, age (per 10-year increase; OR = 0.61, CI, 0.42-0.90; P = 0.012) and pre-transplant treatment (vs. no pre-transplant treatment; OR = 0.17, CI, 0.05-0.54; P = 0.003) were identified as significant factors associated with FSGS recurrence. The rate of death-censored graft survival was significantly superior in the pretransplant treatment group (P = 0.042). CONCLUSION: Pre-transplant treatment with PP was associated with beneficial effects on preventing FSGS recurrence after KT.

Clinical and histopathologic predictors of recurrent glomerulonephritis after kidney transplantation.

INTRODUCTION: We evaluated the long-term outcomes of recurrent glomerulonephritis (RGN) using clinical, histopathological, and demographic predictors. METHODS: A retrospective cohort study of kidney transplant recipients (KTR) in two renal centers between 2005 and 2020. Clinical and native kidney histological data were analyzed. The risk factors and outcomes of each primary glomerulonephritis subtype were assessed using Cox methods. RESULT: 336 recipients with primary glomerulonephritis were analyzed. RGN was diagnosed in 17%, 20%, 25%, and 13% of recipients with IgA nephropathy (IgAN), focal segmental glomerulosclerosis (FSGS), membranous nephropathy (MN) and membranoproliferative glomerulonephritis (MPGN), respectively. Median time to recurrence was shortest in FSGS (.6 years IQR .2-2.9) and longest in MN (6.3 years IQR 3.3-8.0) whereas time to graft loss after diagnosis was shortest in MPGN (.3 years IQR .1-1.7) and longest in IgAN (2.9 year IQR 1.3-4.3). Recipients with recurrent IgAN were likely to be younger, have higher proteinuria at diagnosis, receive living donor allografts, receive cyclosporine treatment, have a history of acute rejection, and have segmental sclerosis in native glomeruli. Younger age of the donors, higher proteinuria at diagnosis, alemtuzumab, proteinuria within the first 12 months, acute rejection, low baseline eGFR, mesangial proliferation, and IgG and IgA deposits were associated with FSGS recurrence. MPGN recurrence was predicted by lower BMI at transplantation, and crescentic native disease. Death-censored graft survival at 5-, 10-, and 15-years was 83%, 51%, and 29% in the RGN group and 95%, 93%, and 84%, respectively in the non-RGN group. Over 15 years, recipients with RGN are nine times more likely than those without RGN to lose their grafts, regardless of donor type, acute rejection, and baseline eGFR. Transplant recipients of related donor allograft were not more likely to have recurrent GN than non-related donors.

Can Kunxian Capsule, a Novel Tripterygium Preparation be Used as an Adjuvant Treatment of Early Recurrent Focal Segmental Glomerular Sclerosis After Renal Transplantation? A Case Report.

Focal segmental glomerular sclerosis (FSGS) tends to recur after kidney transplantation, particularly when genetic testing is negative. Once the recurrence happens, the renal graft function can rapidly become impaired, following a massive urine protein loss. Despite intensive plasmapheresis and high-dose rituximab treatment, the complete remission rate remains below 50%. The Kunxian capsule, representing a new generation of tripterygium preparation, has shown promising results in controlling proteinuria in patients with IgA nephropathy. It is unclear whether Kunxian capsule treatment would also produce a favorable response in cases of FSGS recurrence. Here we report favorable results with this approach in a patient with early recurrent FSGS after kidney transplantation; we treated this patient successfully with a Kunxian capsule, a low dose of rituximab (200 mg), and reduced sessions of plasmapheresis. Complete remission, with a 90% reduction in total urine protein (0.81 g/24 h vs 8.3 g/24 h), was achieved within 2 weeks post-treatment. Of interest, the complete remission state in this patient has been maintained over 20 months with continuous administration of Kunxian capsules after the cessation of plasmapheresis. The potential mechanisms involved here include direct podocyte protection and the anti-inflammatory and immunosuppressive properties of triptolide in the Kunxian capsule. Our case may offer a new reference option for treating recurrent FSGS in the future.

Unexpected Late Response to Ofatumumab in Adult Post-Transplantation Recurrent Focal Segmental Glomerulosclerosis, Case Report.

BACKGROUND: Idiopathic focal segmental glomerulosclerosis is an important cause of kidney failure in adults, which is associated with a high risk of disease recurrence after transplantation. Plasmapheresis, rituximab, immunoadsorption, and high-dose cyclosporine are used to treat post-transplant recurrent focal segmental glomerulosclerosis (rFSGS). However, the response rate is variable, and few options remain for unresponsive patients. CASE REPORT: We present a 44-year-old man with an early post-transplant rFSGS. After peritransplant plasmapheresis, rituximab, and abatacept treatments failed, we employed ofatumumab. After 9 months without apparent benefit, we observed an unexpected partial remission thereafter, without severe side effects. Furthermore, remission has been sustained in 30-month follow-up. CONCLUSIONS: We believe ofatumumab can be considered an alternative for patients with plasmapheresis and rituximab-resistant post-transplant rFSGS.

Early recurrence of focal segmental glomerulosclerosis as an unusual cause of primary kidney transplant malfunction.

Recurrence of the primary disease is one of the most common causes of graft failure in the first decade after kidney transplantation. We present a case of a patient with an unusually rapid recurrence of focal segmental glomerulonephritis in the graft, the recognition of its occurrence was hampered by the primary graft affection and oligoanuria and by insignificant histological changes in the first two biopsy samples in the early post-transplant period, as well as by unawareness of the disease leading to terminal renal failure, as no renal biopsy was performed due to grade 3 obesity. Only worsening of hypoalbuminemia and finding of massive proteinuria despite oligoanuria were crucial for further management. Disease recurrence in the graft was confirmed by electron microscopy. However, complex targeted therapy did not result in restoration of graft function and decrease in proteinuria. This case history was aimed to draw attention to the knowledge of the importance of the primary disease confirmed by renal biopsy and early (so called pre-emptive) treatment in case of diseases with a high potential of recurrence (Fig. 7, Ref. 10). Text in PDF www.elis.sk Keywords: kidney transplantation, recurrence, minimal changes in glomeruli, focal segmental glomerulosclerosis.