Membranous nephropathy in systemic lupus erythematosus: a therapeutic enigma

Short- and long-term outcomes of patients with pure membranous lupus nephritis compared with patients with proliferative disease

OBJECTIVES

Membranous LN (MLN) is thought to have a more benign course than proliferative LN (PLN). We aimed to determine the differences in short- and long-term outcomes between patients with MLN and PLN.

METHODS

We included patients with first biopsy-proven MLN and PLN. Short-term outcomes included complete proteinuria recovery (CPR), complete renal response (CRR) and primary efficacy renal response (PERR). Long-term outcomes included a sustained ≥40% reduction in baseline estimated glomerular filtration rate, end-stage kidney disease (ESKD), cardiovascular (CV) events, ≥2 increase in SLICC/ACR Damage Index and death. Univariable and multivariable Cox proportional hazard models were used to examine the effect of baseline characteristics on long-term outcomes.

RESULTS

Of 215 patients, 51 had pure MLN and 164 had PLN. We found no significant differences between the two groups in achieving CPR, CRR and PERR at 1 and 2 years. Median time to outcomes was slightly, but insignificantly, longer in the MLN group. For long-term outcomes, PLN was associated with worse renal and non-renal outcomes, but this was not statistically significant. In the multivariable Cox proportional hazard models, ESKD was associated with the following baseline variables: younger age [hazard ratio (HR) 0.92, 95% confidence interval (CI) 0.87-0.97], higher creatinine (HR 1.01, 95% CI 1.01-1.02), low complement (HR 4.0, 95% CI 1.04-11.10) and higher chronicity index (HR 1.28, 95% CI 1.08-1.51).

CONCLUSION

The resolution of proteinuria in LN is slow. MLN is not a benign disease and may be associated with deterioration of renal function, ESKD, damage, CV events and death.

The fate of immune complexes in membranous nephropathy

The most characteristic feature of membranous nephropathy (MN) is the presence of subepithelial electron dense deposits and the consequential thickening of the glomerular basement membrane. There have been great advances in the understanding of the destiny of immune complexes in MN by the benefit of experimental models represented by Heymann nephritis. Subepithelial immune complexes are formed in situ by autoantibodies targeting native autoantigens or exogenous planted antigens such as the phospholipase A2 receptor (PLA2R) and cationic BSA respectively. The nascent immune complexes would not be pathogenic until they develop into immune deposits. Podocytes are the major source of autoantigens in idiopathic membranous nephropathy. They also participate in the modulation and removal of the immune complexes to a large extent. The balance between deposition and clearance is regulated by a wide range of factors such as the composition and physicochemical properties of the immune complexes and the complement system. Complement components such as C3 and C1q have been reported to be precipitated with the deposits whereas a complement regulatory protein CR1 expressed by podocytes is involved in the phagocytosis of immune complexes by podocytes. Podocytes regulate the dynamic change of immune complexes which is disturbed in membranous nephropathy. To elucidate the precise fate of the immune complexes is essential for developing more rational and novel therapies for membranous nephropathy.

II Brazilian Society of Rheumatology consensus for lupus nephritis diagnosis and treatment

OBJECTIVE

To develop the second evidence-based Brazilian Society of Rheumatology consensus for diagnosis and treatment of lupus nephritis (LN).

METHODS

Two methodologists and 20 rheumatologists from Lupus Comittee of Brazilian Society of Rheumatology participate in the development of this guideline. Fourteen PICO questions were defined and a systematic review was performed. Eligible randomized controlled trials were analyzed regarding complete renal remission, partial renal remission, serum creatinine, proteinuria, serum creatinine doubling, progression to end-stage renal disease, renal relapse, and severe adverse events (infections and mortality). The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to develop these recommendations. Recommendations required ≥82% of agreement among the voting members and were classified as strongly in favor, weakly in favor, conditional, weakly against or strongly against a particular intervention. Other aspects of LN management (diagnosis, general principles of treatment, treatment of comorbidities and refractory cases) were evaluated through literature review and expert opinion.

RESULTS

All SLE patients should undergo creatinine and urinalysis tests to assess renal involvement. Kidney biopsy is considered the gold standard for diagnosing LN but, if it is not available or there is a contraindication to the procedure, therapeutic decisions should be based on clinical and laboratory parameters. Fourteen recommendations were developed. Target Renal response (TRR) was defined as improvement or maintenance of renal function (±10% at baseline of treatment) combined with a decrease in 24-h proteinuria or 24-h UPCR of 25% at 3 months, a decrease of 50% at 6 months, and proteinuria < 0.8 g/24 h at 12 months. Hydroxychloroquine should be prescribed to all SLE patients, except in cases of contraindication. Glucocorticoids should be used at the lowest dose and for the minimal necessary period. In class III or IV (±V), mycophenolate (MMF), cyclophosphamide, MMF plus tacrolimus (TAC), MMF plus belimumab or TAC can be used as induction therapy. For maintenance therapy, MMF or azathioprine (AZA) are the first choice and TAC or cyclosporin or leflunomide can be used in patients who cannot use MMF or AZA. Rituximab can be prescribed in cases of refractory disease. In cases of failure in achieving TRR, it is important to assess adherence, immunosuppressant dosage, adjuvant therapy, comorbidities, and consider biopsy/rebiopsy.

CONCLUSION

This consensus provides evidence-based data to guide LN diagnosis and treatment, supporting the development of public and supplementary health policies in Brazil.

The clinicopathological features and renal prognostic factors in pure membranous lupus nephritis-a large series cohort study from China

BACKGROUND

Membranous lupus nephritis (MLN) is a subepithelial immune deposition or its morphological sequelae with or without mesangial changes. Previous studies on the prognosis of MLN have shown relatively small sample sizes and short follow-up periods.

METHODS

Our study was a retrospective analysis of biopsy-proven MLN patients from January 2010 to January 2020 at Jinling Hospital in China. The clinical manifestations, pathological features, and renal outcomes of MLN patients were collected. The endpoint was defined as end-stage kidney disease (eGFR≤15 mL/min·1.73 m2 or need for renal replacement therapy) or a doubling of serum creatinine or an eGFR decline of more than 40%. We used Cox regression to analyze the risk factors for renal outcome and Kaplan-Meier curves were used to analyze renal survival rate.

RESULTS

In the total of 2884 lupus patients, we screened 535 MLN patients. 456 MLN patients were recruited with an average age of 34 ± 12 years, 87.8% for female patients and 62.1% patients of nephrotic syndrome with proteinuria of 2.67 g/24h. After follow-up of 78 (IQR, 47.3-113.0) months, 37 (8.1%) patients reached the renal endpoint. The 5-year and 10-year renal survival rates were 95.8% and 89.4%, respectively. 370 patients (81.1%) achieved complete remission, 43 patients (9.4%) had partial remission, and only 43 had no response. 34.4% MLN experienced a relapse. The Cox regression showed the risk factors that affect the renal prognosis include male, hypertension history, anemia, high uric acid, acute kidney injury, and interstitial fibrosis in the renal pathology.

CONCLUSIONS

MLN mostly manifested as nephrotic syndrome, with few renal dysfunctions. Although MLN had a high relapse rate, most patients had a response to immunosuppressants and had a good renal outcome.

Renal Vein Thrombosis as an Initial Presentation for Systemic Lupus Erythematosus in a 32-Year-Old Sudanese Male: A Case Report in Palestine

Systemic lupus erythematosus (SLE) is a complex autoimmune disease known for its diverse clinical presentations, and one severe complication is lupus nephritis (LN), which significantly contributes to morbidity and mortality. While LN often presents within the first 5 years of SLE diagnosis, renal vein thrombosis (RVT) is a rare vascular complication with a high risk of mortality and morbidity. This case report discusses the rare occurrence of RVT as the initial presentation of SLE in a 32-year-old Sudanese male patient, currently working in Palestine, presenting with flank pain, hematuria, fever, and lower limb edema. The case details the patient's symptoms, examination findings, and extensive laboratory and imaging workup leading to the diagnosis. This report highlights the rare association between RVT and SLE, emphasizing the importance of maintaining a high index of suspicion for SLE in patients with multisystem involvement, especially in males, where the diagnosis may be overlooked due to its lower prevalence. Early recognition can improve patient outcomes and reduce the risk of complications. Further research is needed to better understand the connection between RVT and SLE and to develop more effective treatment strategies.

Membranous nephropathy: Mechanistic insights and therapeutic perspectives

Membranous nephropathy (MN) is one of the most common causes of non-diabetic nephrotic syndrome in adults. About 80% of cases are renal limited (primary MN) and 20% are associated with other systemic diseases or exposures (secondary MN). Autoimmune reaction is the main pathogenic factor of MN, and the discovery of autoantigens including the phospholipase A2 receptor and thrombospondin type-1 domain-containing protein 7A has led to new insights into the pathogenesis, they can induce humoral immune responses led by IgG4 makes them suitable for the diagnosis and monitoring of MN. In addition, complement activation, genetic susceptibility genes and environmental pollution are also involved in MN immune response. In clinical practice, due to the spontaneous remission of MN, the combination of supportive therapy and pharmacological treatment is widely used. Immunosuppressive drugs are the cornerstone of MN treatment, and the dangers and benefits of this approach vary from person to person. In summary, this review provides a more comprehensive review of the immune pathogenesis, interventions and unresolved issues of MN in the hope of providing some new ideas for clinical and scientific researchers in the treatment of MN.

New Insights Into an Overlooked Entity: Long-Term Outcomes of Membranous Lupus Nephritis From a Single Institution Inception Cohort

Introduction

Pure membranous lupus nephritis (MLN) accounts for 10–20% of total cases of lupus nephritis and is generally associated with a better patient and renal survival compared to proliferative classes. Studies of MLN are limited by small sample size and heterogeneity of included populations since patients with pure MLN and those with mixed classes are usually examined together.

Aim of the Study

To describe clinical and laboratory characteristics of patients with pure MLN, therapeutic regimens, response to treatment, renal relapses, and their long-term renal survival and to define prognostic factors of remission and relapse.

Methods

We retrospectively studied an inception cohort of 27 patients with histologically proven pure MLN. Clinical, laboratory and therapeutical parameters were recorded at diagnosis, at different time points (3–6–9–12–18–24–36–72 months) during the course of the disease, at time of renal flare, and at last follow up visit.

Results

48.1% (13/27) of patients were treated with mycophenolic acid (MPA), 29.6% (8/27) with cyclophosphamide (CYC), and 3.7% (1/27) with cyclosporine (all in combination with corticosteroids). Five patients (18.5%) did not receive any immunosuppressive treatment. Mean duration of treatment was 4.7 ± 2.3 years. Median time to complete remission was 9 months (IQR = 7) and median time to partial remission was 4 months (IQR = 4). No clinical or laboratory parameter was found to be significantly associated with time to remission. Time to remission was not significantly affected by either of the two treatment regimens (CYC and MPA) (p = 0.43). Renal flare was observed in 6 (22%) of the 27 patients in a median time of 51 months (IQR = 63). Proteinuria >1 g/24 h at 1 year significantly correlated with risk of flare (OR 20, p = 0.02). After a median follow up period of 77 months, all patients had an eGFR > 60 ml/min/1.73 m² (mean eGFR 100 ± 32 ml/min/1.73 m²).

Conclusions

In a small cohort of patients with pure MLN, long-term renal survival was very good. With the limitation of the small sample size, we could not find any baseline clinical, biochemical or therapeutic factor that could predict time to remission. Proteinuria > 1 g/24 h at 1 year should be further examined in larger cohorts as a possible predictor of flare.

Rapamycin attenuates PLA2R activation-mediated podocyte apoptosis via the PI3K/AKT/mTOR pathway

Membranous nephropathy (MN) is the most common cause of nephrotic syndrome in adults without diabetes. Primary MN has been associated with circulating antibodies against native podocyte antigens, including phospholipase A2 receptor (PLA2R); however, precision therapy targeting the signaling cascade of PLA2R activation is lacking. Both PLA2R and the mammalian target of rapamycin (mTOR) exist in podocytes, but the interplay between these two proteins and their roles in MN warrants further exploration. This study aimed to investigate the crosstalk between PLA2R activation and mTOR signaling in a human podocyte cell line. We demonstrated that podocyte apoptosis was induced by Group IB secretory phospholipase A2 (sPLA2IB) in a concentration- and time-dependent manner via upregulation of phosphoinositide 3-kinase (PI3K), protein kinase B (AKT), and mTOR, and inhibited by rapamycin or LY294002. Furthermore, aberrant activation of the PI3K/AKT/mTOR pathway triggers both extrinsic (caspase-8 and caspase-3) and intrinsic (Bcl-2-associated X protein [BAX], B-cell lymphoma 2 [BCL-2], cytochrome c, caspase-9, and caspase-3) apoptotic cascades in podocytes. The therapeutic implications of our findings are that strategies to reduce PLA2R activation and PI3K/AKT/mTOR pathway inhibition in PLA2R-activated podocytes help protect podocytes from apoptosis. The therapeutic potential of rapamycin shown in this study provides cellular evidence supporting the repurposing of rapamycin for MN treatment.

Resorption of immune deposits in membranous lupus nephritis following rituximab vs conventional immunosuppressive treatment

OBJECTIVES

Studies on repeat renal biopsies in membranous LN (MLN) are limited, and evaluation of treatment response is mainly based on proteinuria. EM of renal biopsies from rituximab (RTX)-treated MLN patients has revealed resorption of sub-epithelial ICs. Whether resorption phenomena are useful for treatment evaluation, or differs between treatment regimens is not known. We studied EM findings and clinical treatment response in MLN patients after RTX vs conventional immunosuppressive treatment.

METHODS

Twenty-four patients with MLN and renal biopsies performed before and after treatment were included in this retrospective observational study. Laboratory data were collected at both biopsy occasions. Seven patients had received RTX and 17 had received conventional treatment (CYC, MMF or AZA). Electron micrographs of renal tissue were scored using an arbitrary scale (0-3) for the level of sub-epithelial ICs, resorption of ICs and podocyte fusion.

RESULTS

Sub-epithelial ICs decreased after treatment, however not significantly and with no difference between treatments. The resorption phenomena increased after RTX (P = 0.028), but not after conventional therapy (P = 0.29). Six out of seven (86%) RTX-treated patients had increased resorption vs 7/17 (41%) after conventional therapies (P = 0.047). Clinical responders had more pronounced resorption of ICs vs non-responders (P = 0.022).

CONCLUSIONS

We report increased resorption of ICs in repeat renal biopsies in MLN, especially after RTX treatment. Increased resorption phenomena were associated with clinical response, suggesting that EM findings may be useful for treatment evaluation in MLN. Although of limited size, the study indicates that RTX is effective both clinically and at a tissue level.

Outcomes of membranous and proliferative lupus nephritis - analysis of a single-centre cohort with more than 30 years of follow-up

Objectives

To compare membranous lupus nephritis (MLN) and proliferative lupus nephritis (PLN) with respect to survival, demographic, clinical and laboratory characteristics; and to investigate predictors of renal and patient survival.

Methods

Single-centre retrospective observational study. Patients with biopsy-proven PLN, MLN and mixed lupus nephritis were included. Groups were compared using appropriate statistical tests and survival was analysed through the Kaplan-Meier method. Cox regression analysis was performed to investigate predictors of renal and patient survival.

Results

A total of 187 patients with biopsy-proven lupus nephritis (135 with PLN, 38 with MLN and 14 with mixed LN) were followed for up to 42 years (median 12 years). There was a higher proportion of MLN amongst Afro-Caribbeans than amongst Caucasians (31% vs 15%, P = 0.010). Patients with MLN had significantly lower anti-dsDNA antibodies (P = 0.001) and higher C3 levels (P = 0.018) at diagnosis. Cumulative renal survival rates at 5, 10, 15 and 20 years were 91, 81, 75 and 66% for PLN and 100, 97, 92 and 84% for MLN, respectively (P = 0.028). Cumulative patient survival at 5, 10, 15 and 20 years was 94, 86, 80 and 76%, with no difference between PLN and MLN. Urinary protein-creatinine ratio above 42 mg/mmol and eGFR below 76 ml/min/1.73 m², one year after the diagnosis of LN, were the strongest predictors of progression to end-stage renal disease. eGFR below 77 ml/min/1.73 m², at one year, development of end-stage renal disease and Afro-Caribbean ethnicity were associated with higher mortality.

Conclusion

Patients with MLN and PLN differ significantly regarding serological profiles and renal survival, suggesting different pathogenesis. Renal function at year one predicts renal and patient survival.

Secondary Membranous Nephropathy. A Narrative Review

Membranous nephropathy (MN) is a common cause of proteinuria and nephrotic syndrome all over the world. It can be subdivided into primary and secondary forms. Primary form is an autoimmune disease clinically characterized by nephrotic syndrome and slow progression. It accounts for ~70% cases of MN. In the remaining cases MN may be secondary to well-defined causes, including infections, drugs, cancer, or autoimmune diseases, such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), urticarial vasculitis, sarcoidosis, thyroiditis, Sjogren syndrome, systemic sclerosis, or ankylosing spondylitis. The clinical presentation is similar in primary and secondary MN. However, the outcome may be different, being often related to that of the original disease in secondary MN. Also, the treatment may be different, being targeted to the etiologic cause in secondary MN. Thus, the differential diagnosis between primary and secondary MN is critical and should be based not only on history and clinical features of the patient but also on immunofluorescence and electron microscopy analysis of renal biopsy as well as on the research of circulating antibodies. The identification of the pathologic events underlying a secondary MN is of paramount importance, since the eradication of the etiologic factors may be followed by remission or definitive cure of MN. In this review we report the main diseases and drugs responsible of secondary MN, the outcome and the pathogenesis of renal disease in different settings and the possible treatments.

Delayed lupus nephritis in the course of systemic lupus erythematosus is associated with a poorer treatment response: a multicentre, retrospective cohort study in Japan

Objective

The objective of this study was to investigate possible differences in treatment responses between two categories for the onset of lupus nephritis.

Methods

We performed a multicentre, retrospective cohort study of class III–V lupus nephritis patients diagnosed between 1997 and 2014. The renal responses to initial induction therapy were compared between patients who developed lupus nephritis within one year from diagnosis of systemic lupus erythematosus (early (E-) LN) and the remainder (delayed (D-) LN) using the Kaplan–Meier method. We determined the predictors of renal response as well as renal flares and long-term renal outcomes using multivariate Cox regression analyses.

Results

A total of 107 E-LN and 70 D-LN patients were followed up for a median of 10.2 years. Log-rank tests showed a lower cumulative incidence of complete response in D-LN compared with E-LN patients. Multivariate analysis identified D-LN (hazard ratio (HR) 0.48, 95% confidence interval (CI) 0.33–0.70), nephrotic syndrome at baseline, and a chronicity index greater than 2 as negative predictors of complete response. D-LN patients were more likely to experience renal flares. D-LN (HR 2.54, 95% CI 1.10–5.83) and decreased renal function were significant predictors of chronic kidney disease at baseline.

Conclusion

D-LN was a predictor of poorer treatment outcomes, in addition to renal histology and severity of nephritis at lupus nephritis onset.

[Lupus nephritis]

Systemic lupus erythematosus is the most characteristic of auto-immune disorders that can lead to tissue damage in many organs, including kidney. Lupus nephritis occurs in 10 to 40% of lupus patients. Its clinical hallmark is the appearance of a proteinuria as soon as a 0.5 g/g or 0.5 g/d threshold, which calls for a renal histological evaluation in order to determine the lupus nephritis severity and the need for specific therapy. More than half of renal biopsies lead to the diagnosis of active lupus nephritis-class III or class IV A according to the ISN/RPS classification-that are the most severe in regards to renal prognosis and mortality. Their treatment aims to their clinical remission and to the prevention of relapse with minimal adverse effects for eventually the preservation of renal function, the prevention of other irreversible damage, and the reduction of risk of death. The remission is obtained through induction therapies of which the association of high dose steroids and cyclophosphamide is the most experienced. When this association must be challenged by the prevention of side-effect, in particular infertility, mycophenolate can be given instead of cyclophosphamide. Maintenance therapy, for the prevention of relapse, consists in mycophenolate or in azathioprine, mycophenolate being the most efficient however associated with a high risk of teratogenicity. Withdrawal of maintenance therapy is possible after two to three years in absence of high risk factors of relapse of lupus nephritis, however a reliable assessment of the risk of relapse is still lacking. Only pure membranous lupus nephritis (pure class V) associated with high level proteinuria requires specific therapies that usually associates steroids and an immunosuppressive drug. However, their choice hierarchy and even the use of less immunosuppressive strategies remain to be determined in terms of benefice over risk ratios. In spite of its trigger effect on lupus activity, pregnancy can be safe and successful if scheduled in the lowest risk periods with close multidisciplinary monitoring before, during and after. When necessary, renal replacement therapy does not require specific adaptation, renal transplantation is the best option when possible, as early as possible.

Membranous Nephropathy in a Patient with Charcot-Marie-Tooth Disease: Association of Myelin Mutations

A 40-year-old female presented to the neurologist with gradually progressive weakness of distal and proximal muscles of both lower limbs and cramps for 2 years. She gave a history of similar illness in her paternal grandmother and her father. Her examination revealed bilateral foot drop and mild proximal muscle weakness. She was diagnosed to have peripheral neuropathy and subsequently treated conservatively. Over the next year, she noticed progressive swelling of both lower limb and frothy urine. A nephrology consultation was obtained, and a renal biopsy was done, which showed membranous nephropathy. She was started on steroids and subsequently on tacrolimus as the proteinuria progressively worsened. Her anti-phospholipase A2 receptor antibody was negative both in blood and in the kidney biopsy tissue. A search for a genetic basis of this rare clinical condition was made, and heterozygous mutation was detected in the myelin gene. This mutation was confirmed with genetic sequencing. The mutation is associated with MPZ gene and is associated with multiple hereditary sensorimotor neuropathy. MPZ knockout mice have been shown to have increased glomerular permeability and proteinuria.

Membranous Nephropathy and Anti-Podocytes Antibodies: Implications for the Diagnostic Workup and Disease Management

The discovery of circulating antibodies specific for native podocyte antigens has transformed the diagnostic workup and greatly improved management of idiopathic membranous nephropathy (iMN). In addition, their identification has clearly characterized iMN as a largely autoimmune disorder. Anti-PLA2R1 antibodies are detected in approximately 70% to 80% and anti-THSD7A antibodies in only 2% of adult patients with iMN. The presence of anti-THSD7A antibodies is associated with increased risk of malignancy. The assessment of PLA2R1 and THSD7A antigen expression in glomerular immune deposits has a better sensitivity than measurement of the corresponding autoantibodies. Therefore, in the presence of circulating anti-podocytes autoantibodies and/or enhanced expression of PLA2R1 and THSD7A antigens MN should be considered as primary MN (pMN). Anti-PLA2R1 or anti-THSD7A autoantibodies have been proposed as biomarkers of autoimmune disease activity and their blood levels should be regularly monitored in pMN to evaluate disease activity and predict outcomes. We propose a revised clinical workup flow for patients with MN that recommends assessment of kidney biopsy for PLA2R1 and THSD7A antigen expression, screening for circulating anti-podocytes antibodies, and assessment for secondary causes, especially cancer, in patients with THSD7A antibodies. Persistence of anti-podocyte antibodies for 6 months or their increase in association with nephrotic proteinuria should lead to the introduction of immunosuppressive therapies. Recent data have reported the efficacy and safety of new specific therapies targeting B cells (anti-CD20 antibodies, inhibitors of proteasome) in pMN which should lead to an update of currently outdated treatment guidelines.

Urine angiostatin and VCAM-1 surpass conventional metrics in predicting elevated renal pathology activity indices in lupus nephritis

AIM

The goal of this study is to investigate how urinary angiostatin, vascular cell adhesion molecule 1 (VCAM-1) and established measures of renal function relate to specific histologic findings in paired kidney biopsy samples from patients with lupus nephritis (LN).

METHOD

Urine samples were collected from 54 LN patients together with paired kidney biopsy samples and examined for urinary angiostatin and VCAM-1 protein levels. Nonparametric tests were used to examine the association of both urinary biomarkers and established traditional laboratory markers of renal function with nine specific renal histologic features seen in LN, including glomerular leukocyte infiltration, endocapillary proliferation, cellular crescents, fibrinoid necrosis, wire loops, interstitial inflammation, glomerulosclerosis, fibrous crescents, tubular atrophy and interstitial fibrosis.

RESULTS

Compared to traditional renal disease metrics, both urinary angiostatin and VCAM-1 exhibited outstanding potential (area under the curve 0.97, 0.98, respectively) to predict renal biopsy activity index score ≥ 7, which is associated with poor long-term prognosis. Whereas urine VCAM-1 was most significantly associated with fibrous crescents, urine angiostatin was most significantly associated with endocapillary proliferation, cellular crescents, fibrinoid necrosis and fibrous crescents in concurrent renal biopsies.

CONCLUSION

Urinary angiostatin and VCAM-1 are predictive of specific histological changes in concurrent LN renal biopsies. Both urinary biomarkers are good candidates for use as noninvasive measures of renal pathology activity changes in LN.

Calcineurin inhibitors in systemic lupus erythematosus

The calcineurin inhibitors (CNIs) belong to a group of immunosuppressive agents that block T-cell activation through the suppression of the calcium/calcimodulin-dependent phosphatase calcineurin. Agents such as cyclosporine A (CSA) and tacrolimus (TAC) have long been used in patients with systemic lupus erythematosus (SLE). TAC is preferred to CSA in SLE because of the lower frequency of cosmetic, hypertensive and dyslipidemic adverse effects. Recent randomised controlled trials have demonstrated noninferiority of TAC to mycophenolate mofetil (MMF) or cyclophosphamide (CYC) for induction therapy of lupus nephritis. Low-dose combination of TAC and MMF has also been shown to outperform CYC pulses in inducing remission of lupus nephritis in Chinese patients. TAC does not affect fertility and is relatively safe in pregnancy. In SLE patients who are intolerant or refractory to conventional immunosuppressives, or where contraindications to other immunosuppressive agents exist, TAC is an alternative option. However, the therapeutic window of TAC is narrow, and drug level monitoring is required to ensure drug exposure and minimise toxicities. Current evidence of TAC in lupus nephritis is limited to 6 months, and its long-term safety as maintenance therapy of SLE is yet to be determined. Newer chemical analogues of CNIs, such as voclosporin, with less variable plasma concentration are being tested in lupus nephritis.

Redefining lupus nephritis: clinical implications of pathophysiologic subtypes

Systemic lupus erythematosus (SLE) is associated with a broad spectrum of clinical and immunologic manifestations, of which lupus nephritis is the most common cause of morbidity and mortality. The development of nephritis in patients with SLE involves multiple pathogenic pathways including aberrant apoptosis, autoantibody production, immune complex deposition and complement activation. The 2003 International Society of Nephrology/Renal Pathology Society (ISN/RPS) classification system for lupus nephritis was widely accepted with high intraobserver and interobserver concordance to guide therapeutic strategy and provide prognostic information. However, this classification system is not based on the underlying disease pathophysiology. Some additional lesions that contribute to disease presentation, including glomerular crescents, podocyte injury, tubulointerstitial lesions and vascular injury, should be recognized. Although outcomes for patients with lupus nephritis have improved over the past 30 years, treatment of this disease remains challenging and is best approached on the basis of the underlying pathogenesis, which is only partially represented by the various pathological phenotypes defined by the ISN/RPS classification. Here, we discuss the heterogeneous mechanisms involved in the pathogenesis of lupus nephritis and how improved understanding of underlying disease mechanisms might help guide therapeutic strategies.

Rituximab alone as induction therapy for membranous lupus nephritis: A multicenter retrospective study

The optimal treatment for pure membranous lupus nephritis (MLN) remains undetermined. Rituximab constitutes a promising therapeutic option for lupus nephritis and is currently being evaluated for use in idiopathic membranous nephritis. We retrospectively analysed the efficacy and tolerance of rituximab as a monotherapy in the induction treatment of pure MLN.We retrospectively investigated SLE patients with biopsy-proven pure class V lupus nephritis presenting with a protein-to-creatinine ratio of at least 2 g/g and treated with rituximab as monotherapy. A background low dose of corticosteroids (≤20 mg/day) was allowed, as was hydroxychloroquine; higher doses of steroids and/or immunosuppressive drugs fell under the exclusion criteria. Remission status was evaluated at baseline and 6, 12, and 24 months after rituximab.The study included 15 patients (13 women, median age 37 years, 27% with extra-renal manifestations, median SLE duration 1.5 years). The median protein-to-creatinine ratio was 4.9 g/g, 80% of the patients had nephrotic-range proteinuria, the median serum albumin was 24 g/L, the median serum creatinine was 0.7 mg/dL, and the median eGFR was 122 mL/min/1.73 m. The median follow-up was 29 months (6-112 months). Treatment failure occurred in 2 patients. However, remission was recorded in the remaining 13 (87%, complete remission in 8 patients) with a median time to remission of 5 months. Median proteinuria decreased from 4.9 g/g to 0.16 g/g at month 12 and to 0.11 g/g at month 24. Median serum albumin increased to 36.5 g/L at month 24, and all patients had serum albumin levels greater than 30 g/L at month 12. Renal function remained stable in all patients. Relapse of proteinuria was recorded in 3 patients (at 12, 29, and 34 months). No patients experienced serious adverse events.Rituximab as monotherapy may represent an effective treatment for pure MLN with an excellent tolerance profile.

Membranous nephropathy-one morphologic pattern with different diseases

Since the discovery of the phospholipase A₂ receptor 1 (PLA₂R1) and thrombospondin type-1 domain-containing 7A (THSD7A) as endogenous antigens involved in the development of membranous nephropathy (MN) in over 80% of adult patients, substantial progress in the diagnosis, prognosis, and therapy of MN has been made. In most cases of patients with MN, it is now possible to specifically define the responsible pathogenic mechanisms of disease and make a diagnosis even without a renal biopsy. Moreover, the presence of antibodies in the blood and the detection of the antigens in renal biopsies allow the definite diagnosis without the morphologic uncertainties, which now still apply for only about 20% of all renal biopsies showing MN. The discovery that the expression of THSD7A in malignant tumors might serve as the site of primary antigen recognition for the immune system to start MN might lead to a better understanding of not only tumor-associated MN, which accounts for up to 10% of all patients with MN, but also of the pathomechanisms relevant for MN development in general.

Con: Cyclophosphamide for the treatment of lupus nephritis

Kidney involvement is a major determinant for morbidity and mortality in patients with systemic lupus erythematosus. The treatment target of lupus renal disease is to induce and maintain remission and to minimize disease or treatment-related comorbidities. Cyclophosphamide (CYC), in conjunction with glucocorticoids, has conventionally been used for the initial treatment of lupus nephritis. However, the major concerns of CYC are its toxicities, such as infertility, urotoxicity and oncogenicity, which are particularly relevant in women of childbearing age. As a result, maintenance therapy of lupus nephritis with an extended course of CYC pulses has largely been replaced by other immunosuppressive agents such as mycophenolate mofetil (MMF) and azathioprine. Recent randomized controlled trials have demonstrated non-inferiority of MMF to pulse CYC as induction therapy of lupus nephritis. Although MMF as induction-maintenance therapy has been increasingly used in lupus nephritis, its efficacy in the long-term preservation of renal function remains to be elucidated. MMF is not necessarily less toxic than CYC. Meta-analyses of clinical trials show similar incidence of infective complications and gastrointestinal adverse events in both MMF- and CYC-based regimens. However, considering the reduction in gonadal toxicity and the risk of oncogenicity, MMF may be used as first-line therapy of lupus nephritis. Tacrolimus (TAC) has recently been shown to be equivalent to either MMF or CYC for inducing remission of lupus nephritis and may be considered as another non-CYC alternative. Combined low-dose MMF and TAC appears to be more effective than CYC pulses in Chinese patients with lupus nephritis and has the potential to replace the more toxic CYC regimens in high-risk patients. Currently, CYC still plays an important role in the management of lupus nephritis patients with impaired or rapidly deteriorating renal function, crescentic glomerulonephritis or as salvage therapy for recalcitrant disease.

Towards new avenues in the management of lupus glomerulonephritis

Renal involvement in systemic lupus erythematosus (SLE) carries substantial morbidity and mortality. Conventional immunosuppressive agents (cyclophosphamide and azathioprine) have suboptimal efficacy and substantial toxicity. Mycophenolate mofetil has emerged as an alternative agent for both induction and maintenance therapy in lupus nephritis because of its reduced gonadal toxicity, despite its failure to demonstrate superiority over cyclophosphamide in pivotal studies. The calcineurin inhibitor tacrolimus has equivalent efficacy to cyclophosphamide and mycophenolate mofetil for inducing remission of lupus nephritis. Although rituximab has shown promise in refractory lupus nephritis, combining rituximab with mycophenolate mofetil as initial therapy offers no additional benefit. Considerable interethnic variation is evident in the efficacy and tolerability of the various immunosuppressive regimens, which necessitates individualized treatment and comparison of the efficacy of new regimens across different ethnic groups. For example, low-dose combinations of tacrolimus and mycophenolate mofetil seem to be more effective than pulse cyclophosphamide as induction therapy in Chinese patients. The same regimen has also been used successfully to treat refractory proliferative and membranous lupus nephritis in patients of various ethnic groups. Finally, novel serum and urinary biomarkers are being validated for diagnosis, prognostic stratification and early recognition of flares in lupus nephritis.

Comparison of Lupus Nephritis Induction Treatments in a Hispanic Population: A Single-center Cohort Analysis

OBJECTIVE

To evaluate response rates in an adult lupus nephritis (LN) cohort in Mexico City, Mexico.

METHODS

We analyzed 165 patients with biopsy-proven LN histological International Society of Nephrology/Renal Pathology Society classes III, IV, or V, distributed by treatment drug in 3 groups: mycophenolate mofetil (MMF; dosage > 2 g/day per 6 mos, n = 63), intravenous cyclophosphamide (IVC; 0.7 g/m(2) body surface area monthly per 6 pulses, n = 66), or azathioprine (AZA; dosage > 1.5 mg/kg/day per 6 mos, n = 36). Median followup was 31 ± 18 months. The primary endpoint was the proportion of patients achieving complete renal response (CR). Secondary endpoints included the proportion of patients achieving renal response (complete or partial), renal flare-free survival, doubling of serum creatinine, and progression to endstage renal disease (ESRD).

RESULTS

MMF induction was superior to IVC (HR 2.00, 95% CI 1.23-3.25, p = 0.005) and AZA (HR 2.12, 95% CI 1.23-3.66, p = 0.007) in the primary endpoint. Censored CR rates at 6, 12, 24, and 36 months were 32.6%, 56.1%, 76.6%, and 94.1% for MMF; 24.2%, 34.4%, 57.9%, and 62.1% for IVC; and 8.4%, 39.8%, 49.7%, and 49.7% for AZA. MMF was also superior in renal response to treatment and renal flare-free survival outcomes. There were no differences between groups in doubling of serum creatinine or progression to ESRD. The induction treatment with MMF (HR 2.04, 95% CI 1.25-3.33, p = 0.005) and absence of vascular lesions on renal biopsy (HR 2.05, 95% CI 1.25-3.37, p = 0.004) were associated with CR, whereas proteinuria at the time of presentation was negatively associated with CR (HR 0.91, 95% CI 0.84-0.98, p = 0.013).

CONCLUSION

MMF induction therapy is superior to IVC and AZA in patients with LN of Mexican-mestizo race.

[Renal diseases in rheumatology]

Renal involvement and renal function disorders are commonplace in patients with rheumatic diseases and are often decisive for the prognosis. Typical nephrological complications in rheumatology are renal manifestations or delayed sequelae of the underlying disease in addition to drug-induced renal failure, e.g. by nonsteroidal anti-inflammatory drugs (NSAIDs). The differentiation from other common causes of disturbed renal function (e.g. diabetes and hypertension) is important and often difficult in individual cases. Renal involvement can be clinically manifested in many different ways. The spectrum ranges from slight functional disorders with, for example discrete erythrocyturia/proteinuria and normal renal function up to rapidly progressive renal failure. The probability of renal damage also varies greatly between different underlying diseases. For example, renal involvement in rheumatoid arthritis is a rarity but in contrast relatively normal in systemic lupus erythematosus. In the course of the differential diagnostics urine sediment, protein values and sonography are still the most important factors and the indications for kidney biopsy should be generously applied. Early initiation of immunosuppression can substantially improve the renal prognosis of inflammatory systemic diseases.

Immunoadsorption: a new strategy to induce remission in membranous lupus nephritis

We report the case of an 11-year-old previously healthy girl who presented for microscopic hematuria and nephrotic proteinuria with normal renal function, which persisted after 6 months of steroids, angiotensin-converting enzyme inhibitors (ACEi)/angiotensin receptor blockers, hydroxychloroquine, mycophenolic acid and a low-salt diet. A serum investigation suggested lupus nephritis and a renal biopsy, performed 2 weeks after the first proteinuria detection, revealed membranous lupus nephritis. We decided to perform ten sessions of daily immunoadsorption. Proteinuria decreased significantly over these ten sessions from 8 to 0.12 g/l. After the tenth immunoadsorption session, the patient received the first rituximab (RTX) infusion leading to complete B-cell depletion. The patient was maintained on ACEi associated with mycophenolic acid and hydroxychloroquine. Three RTX reinjections were performed when CD19-positive cells reappeared in peripheral blood. Despite complete B-cell recovery and positive anti-dsDNA-Ab, the patient remained in complete remission 18 months after the initial diagnosis with negative proteinuria and a normal renal function.

[Membranous nephropathy]

Membranous nephropathy is characterized by immune complex deposits on the outer side of the glomerular basement membrane. Activation of complement and of oxidation lead to basement membrane lesions. The most frequent form is idiopathic. At 5 and 10 years, renal survival is around 90 and 65% respectively. A prognostic model based on proteinuria, level and duration, progression of renal failure in a few months can refine prognosis. The urinary excretion of C5b-9, β2 and α1 microglobuline and IgG are strong predictors of outcome. Symptomatic treatment is based on anticoagulation in case of nephrotic syndrome, angiotensin conversion enzyme inhibitors, angiotensin II receptor blockers and statins. Immunosuppressive therapy should be discussed for patients having a high risk of progression. Corticoids alone has no indication. Treatment should include a simultaneous association or more often alternating corticoids and alkylant agent for a minimum of 6 months. Adrenocorticoid stimulating hormone and steroids plus mycophenolate mofetil may be equally effective. Steroids plus alkylant decrease the risk of end stage renal failure. Cyclosporine and tacrolimus decrease proteinuria but are associated with a high risk of recurrence at time of withdrawal and are nephrotoxic. Rituximab evaluated on open studies needs further evaluations to define its use.

Association of noninvasively measured renal protein biomarkers with histologic features of lupus nephritis

OBJECTIVE

To investigate the relationship of urinary biomarkers and established measures of renal function to histologic findings in lupus nephritis (LN), and to test whether certain combinations of the above-mentioned laboratory measures are diagnostic for specific histologic features of LN.

METHODS

Urine samples from 76 patients were collected within 2 months of kidney biopsy and assayed for the urinary biomarkers lipocalin-like prostaglandin D synthase (L-PGDS), α(1) -acid glycoprotein (AAG), transferrin (TF), ceruloplasmin (CP), neutrophil gelatinase-associated lipocalin (NGAL), and monocyte chemotactic protein 1 (MCP-1). Using nonparametric analyses, levels of urinary biomarkers and established markers of renal function were compared with histologic features seen in LN, i.e., mesangial expansion, capillary proliferation, crescent formation, necrosis, wire loops, fibrosis, tubular atrophy, and epimembranous deposits. The area under the receiver operating characteristic curve (AUC) was calculated to predict LN activity, chronicity, or membranous LN.

RESULTS

There was a differential increase in levels of urinary biomarkers that formed a pattern reflective of specific histologic features seen in active LN. The combination of MCP-1, AAG, and CP levels plus protein:creatinine ratio was excellent in predicting LN activity (AUC 0.85). NGAL together with creatinine clearance plus MCP-1 was an excellent diagnostic test for LN chronicity (AUC 0.83), and the combination of MCP-1, AAG, TF, and creatinine clearance plus C4 was a good diagnostic test for membranous LN (AUC 0.75).

CONCLUSION

Specific urinary biomarkers are associated with specific tissue changes observed in conjunction with LN activity and chronicity. Especially in combination with select established markers of renal function, urinary biomarkers are well-suited for use in noninvasive measurement of LN activity, LN chronicity, and the presence of membranous LN.

[Renal emergencies in cases of collagenosis and vasculitis]

Renal involvement or complications in systemic diseases occur frequently and crucially influence patient outcomes. In addition to functional renal failure caused by medications (especially nonsteroidal antirheumatic agents), typical nephrological complications in rheumatology include manifestations of the underlying condition which range from mild disorders of renal function to severe and partially irreversible disease progression. The primary physician thus plays a key role in ensuring rapid and specific diagnostic workup and initiating appropriate treatment measures. Sonography and examination of urine sediment still take priority in the differential diagnosis. The indication for kidney biopsy should be broadly defined. Early initiation of immunosuppression in systemic diseases can decisively improve renal prognosis. Despite the current availability of considerably improved pharmacological options, numerous questions about the ideal therapeutic regimen still remain open.

Understanding lupus nephritis: diagnosis, management, and treatment options

Systemic lupus erythematosus (SLE) predominantly affects women in their reproductive years. Renal disease (glomerulonephritis) is one of the most frequent and serious manifestations of SLE. Of the various histological types of lupus glomerulonephritis, diffuse proliferative nephritis carries the worst prognosis. Combined with high-dose prednisone, mycophenolate mofetil (MMF) has emerged as a first-line immunosuppressive treatment, although data regarding the efficacy of MMF on the long-term preservation of renal function are forthcoming. Cyclophosphamide is reserved for more severe forms of lupus nephritis, such as crescentic glomerulonephritis with rapidly deteriorating renal function, patients with significant renal function impairment at presentation, and refractory renal disease. Evidence for the calcineurin inhibitors in the treatment of lupus nephritis is weaker, and it concerns patients who are intolerant or recalcitrant to other agents. While further controlled trials are mandatory, B cell modulation therapies, such as rituximab, belimumab and epratuzumab are confined to refractory disease. Non-immunosuppressive measures, such as angiotensin-converting enzyme inhibitors, vigorous blood pressure control, prevention and treatment of hyperlipidemia and osteoporosis, are equally important.

Identification of urinary metabolites that distinguish membranous lupus nephritis from proliferative lupus nephritis and focal segmental glomerulosclerosis

Introduction

Systemic lupus erythematosus (SLE or lupus) is a chronic autoimmune disease, and kidney involvement with SLE, a.k.a. lupus nephritis (LN), is a frequent and severe complication of SLE that increases patient morbidity and mortality. About 50% of patients with SLE encounter renal abnormalities which, if left untreated, can lead to end-stage renal disease. Kidney biopsy is considered the criterion standard for diagnosis and staging of LN using the International Society of Nephrology/Renal Pathology Society (ISN/RPS) classification, which was developed to help predict renal outcomes and assist with medical decision-making. However, kidney biopsy-based classification of LN is highly invasive and impractical for real-time monitoring of LN status. Here, nuclear magnetic resonance (NMR) spectroscopy-based metabolic profiling was used to identify urinary metabolites that discriminated between proliferative and pure membranous LN as defined by the ISN/RPS classification, and between LN and primary focal segmental glomerulosclerosis (FSGS).

Methods

Metabolic profiling was conducted using urine samples of patients with proliferative LN without membranous features (Class III/IV; n = 7) or pure membranous LN (Class V; n = 7). Patients with primary FSGS and proteinuria (n = 10) served as disease controls. For each patient, demographic information and clinical data was obtained and a random urine sample collected to measure NMR spectra. Data and sample collection for patients with LN occurred around the time of kidney biopsy. Metabolic profiling analysis was done by visual inspection and principal component analysis.

Results

Urinary citrate levels were 8-fold lower in Class V LN compared to Class III/IV patients, who had normal levels of urinary citrate (P < 0.05). Class III/IV LN patients had > 10-fold lower levels of urinary taurine compared to Class V patients, who had mostly normal levels (P < 0.01). Class V LN patients had normal urinary hippurate levels compared to FSGS patients, who completely lacked urinary hippurate (P < 0.001).

Conclusions

This pilot study indicated differences in urinary metabolites between proliferative LN and pure membranous LN patients, and between LN and FSGS patients. If confirmed in larger studies, these urine metabolites may serve as biomarkers to help discriminate between different classes of LN, and between LN and FSGS.

Lack of association between transient receptor potential cation channel 6 polymorphisms and primary membranous glomerulonephritis

Membranous glomerulonephritis (MGN) is one common cause of idiopathic nephrotic syndrome. Transient receptor potential cation channel 6 (TRPC6) has been identified as causing a familial form of progressive focal and segmental glomerulosclerosis. The objective was to clarify the relationship between TRPC6 polymorphisms and MGN. We recruited a cohort of 134 biopsy-diagnosed MGN patients and 265 healthy subjects. Genotyping of TRPC6 polymorphisms was performed using allele-specific polymerase chain reaction methods. We then analyzed associations between TRPC6 gene polymorphisms and clinical manifestations and pathogenesis of MGN. There was no statistically significant difference of TRPC6 gene rs3824935 C/T, rs17096918 C/T, and rs4326755 A/G polymorphisms between controls and patients with MGN. There was no statistical significance of allele frequencies in these two groups. The characteristics of clinical parameters in TRPC6 gene (rs3284935) C/T polymorphism revealed no difference except proteinuria (p < 0.0005) between CC and non-CC genotype in MGN patients. Besides, no apparent statistically significant differences of rs17096918 C/T (TT and non-TT) and rs4326755 A/G (AA and non-AA) polymorphisms between genotypes were found in the clinical parameters. There is no different genotype distribution between normal controls and patients with MGN of TRPC6 gene. The data also show that TRPC6 gene may not be associated with disease clinical course of MGN.

The development of membranous lupus nephritis during treatment with mycophenolate mofetil for proliferative renal disease

The transformation of lupus nephritis from one histologic pattern to another is well described. We report a case of a patient who initially presented with diffuse proliferative glomerulonephritis and was treated with prednisone and mycophenolate mofetil (MMF). She initially responded well to therapy, but later developed high-grade proteinuria while still on MMF and low-dose steroids. A repeat biopsy performed after the increase in proteinuria demonstrated that she had focal proliferative disease but that she had also developed membranous lupus nephritis. Our case is unique in that we report a patient who developed membranous lupus nephritis while receiving MMF.

Lupus nephritis: where are we now?

PURPOSE OF REVIEW

To consider the challenges in the management of lupus nephritis with respect to diagnosis and optimal therapy for induction and maintenance of response.

RECENT FINDINGS

Despite several large clinical trials in lupus nephritis, no second line drug is licensed for use in induction of remission in lupus nephritis. An important issue is how remission and flare are defined and the role of repeat renal biopsies. On the background of negative trials with mycophenolate mofetil and rituximab, there are recent data demonstrating superiority of mycophenolate mofetil in certain subgroups. New data suggest a role for tacrolimus in the treatment of lupus nephritis. Additionally, dogma is being challenged by data showing very low and even no oral steroids can be used in mycophenolate mofetil and rituximab-based regimes.

SUMMARY

Despite the negative outcome of recent trials there is growing evidence that there are increasing opportunities in patients with lupus nephritis to offer treatments tailored to the individual needs of the patient based not only on the class and severity of their nephritis but also on their ethnicity, their desire to have children and their predictors of outcome.