Membranous Lupus Nephritis: The Same, But Different

Effects of remnant cholesterol on adverse renal outcomes in lupus nephritis

BACKGROUND

Remnant cholesterol (RC) causes inflammation and promotes kidney diseases development. However, its role in lupus nephritis (LN) remains unclear. The purpose of this study was to investigate the association between RC and LN.

METHODS

This observational study was conducted among patients enrolled between 2000 and 2018 in the High Quality Evidence of Guangzhou Lupus Nephritis Cohort. The study outcomes were defined as adverse renal outcomes, including serum creatinine doubled and end-stage renal disease. Patients were stratified into lower and higher RC groups based on the optimal cutoff RC value (86.88 mg/dL) for adverse renal outcomes. To explore the association between renal outcomes and RC, survival analyses, multivariate Cox regression analyses, and subgroup analyses were conducted.

RESULTS

Overall, 909 individuals were enrolled. Over a median follow-up of 8.33 (interquartile range, 3.08-12.83) years, 134(14.74%) of them reached renal endpoints. Kaplan-Meier survival analyses indicated that patients with higher RC levels were more susceptible to adverse renal outcomes in LN (P < 0.001). After adjusting for confounding factors, higher RC levels exhibited significant correlations with adverse renal outcomes in LN [hazard ratio (HR):1.98, 95% confidence interval (CI):1.16-3.39; P = 0.012]. Subgroup analyses revealed a strong relationship between the higher RC and adverse renal outcomes, particularly in patients aged < 40 years, with an estimated glomerular filtration rate < 60 ml/min/1.73m2 or proliferative pathological changes or nephrotic syndrome (P < 0.05).

CONCLUSIONS

Higher RC levels were significantly associated with poor renal outcomes in LN, indicating that RC may become a non-invasive prognostic tool in clinical assessment of LN.

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.

Clinicopathological phenotype and outcomes of NCAM-1+ membranous lupus nephritis

BACKGROUND

No studies have explored the long-term outcomes of neural cell adhesion molecule 1 (NCAM1)-associated membranous lupus nephritis (MLN) patients.

METHOD

We performed immunohistochemical studies on kidney biopsy specimens against NCAM1 in consecutive MLN patients. The clinical and histopathological characteristics and outcomes of cases of NCAM1-associated MLN patients are described and compared with NCAM1-negative patients. In addition, we detected serum circulating anti-NCAM1 antibodies through western blotting and indirect immunofluorescence assays.

RESULTS

Among 361 MLN cases, 18 (5.0%) were glomerular NCAM1-positive. NCAM1-positive MLN patients were older [35 years (interquartile range, IQR 27-43) versus 28 (22-37); P = .050] and had lower systemic lupus erythematosus disease activity index [11 (IQR 8-12) versus 14 (10-18); P = .007], serum creatinine [60 μmol/L (IQR 50-70) versus 70 (54-114); P = .029] and activity index [3 (IQR 2-6) versus 6 (3-9); P = .045] at kidney biopsy compared with NCAM1-negative patients. The percentage of positive anti-Sjögren's syndrome-related antigen A antibodies in NCAM1-positive patients was significantly greater (83.3% versus 58.2%; P = .035) than in the NCAM1-negative patients. However, no evidence of neuropsychiatric disorders was found in these 18 patients. There were no significant differences in the treatment response and the risk of end-stage renal diseases between NCAM1-positive and -negative groups (P = .668 and P = .318, respectively). However, the risk of death was much higher in the NCAM1-positive group than the NCAM1-negative group (27.8% vs 8.1%; P = .007). Moreover, the risk of death was also much higher in the NCAM1-positive group than the matched NCAM1-negative group (Log-rank P = .013). Additionally, circulating anti-NCAM1 antibodies can be detected in 1/5 (20%) patients who had serum available.

CONCLUSION

The prevalence of NCAM1 positivity was 5.0% in our cohort of MLN and the high mortality in these subgroup patients are needed to validate in future studies.

Lupus-like membranous nephropathy during the postpartum period expressing glomerular antigens exostosin 1/exostosin 2 and phospholipase A2 receptor: a case report

Recently, several target antigens of membranous nephropathy (MN), such as phospholipase A2 receptor (PLA2R) and exostosin 1/exostosin 2 (EXT1/2), have been discovered. A 30-year-old woman was referred to our hospital with nephrotic range proteinuria and microscopic hematuria. She was first noted to have proteinuria before pregnancy, and her proteinuria worsened in the postpartum period. A renal biopsy showed MN. Immunofluorescence microscopy showed IgG, IgA, IgM, C3, C4, and C1q depositions in the mesangial area and glomerular capillary walls (GCWs). Regarding the IgG subclass, IgG1 and IgG3 were detected on glomeruli. Electron microscopy showed subepithelial electron-dense deposits (EDDs). EDDs were also detected in paramesangial and subendothelial areas. The diagnosis of membranous lupus nephritis (MLN) was suspected, but she did not fulfill the criteria for systemic lupus erythematosus. Neither anti-nuclear antibody nor hypocomplementemia were detected. We further evaluated glomerular EXT1/2 expressions, which were evident on GCWs. In addition, PLA2R was also detected on GCWs, although serum antibody for PLA2R was negative. She responded to immunosuppressive therapy with decreased proteinuria. In the present case, glomerular PLA2R expression implied the possibility of primary MN. However, pathological findings with a full-house staining pattern and glomerular EXT1/2 expressions were very similar to those of lupus-associated MN. Glomerular PLA2R expression appeared not to reflect immunocomplexes of PLA2R and autoantibody when considering the results for glomerular IgG subclass and the absence of serum anti-PLA2R antibody. Collectively, it is plausible that this was a case of a relatively young postpartum female who developed latent MLN rather than primary MN.

A Comprehensive and Practical Approach to the Management of Lupus Nephritis in the Current Era

Lupus nephritis (LN) is a severe complication of systemic lupus erythematosus (SLE) and is one of the leading causes of morbidity and mortality in patients with SLE. It is estimated that up to 60% of individuals with SLE will develop LN, which can manifest at any stage of a patient's life; however, it commonly emerges early in the course of SLE and tends to exhibit a more aggressive phenotype in men compared to women. Black and Hispanic patients are more likely to progress to kidney failure than white patients. LN is characterized by kidney inflammation and chronic parenchymal damage, leading to impaired kidney function and potential progression to kidney failure. This article provides a comprehensive overview of the epidemiology, pathogenesis, clinical presentation, diagnosis, and management of LN, highlighting the importance of early recognition and treatment of LN to prevent progressive, irreversible kidney damage and improve patient outcomes. Additionally, the article discusses current and emerging therapies for LN, including traditional immunosuppressive agents, biological agents, and novel therapies targeting specific pathways involved in LN pathogenesis, to provide a practical guide for clinicians in properly diagnosing LN and determining a patient-centered treatment plan.

Non-Full House Membranous Lupus Nephritis Represents a Clinically Distinct Subset

Key Points

Non-full house (NFH) membranous lupus nephritis (MLN) is a minor subset of all MLN cases. Patients with NFH MLN tend to be older when diagnosed with systemic lupus erythematosus, undergo first renal biopsy at an older age, and have fewer extrarenal systemic manifestations. Lower load of C3 glomerular deposits seen in NFH MLN biopsies suggests attenuation of complement-mediated injury, which may have wider systemic implications.

Background

Renal involvement in systemic lupus erythematosus (SLE) is a key predictor of morbidity and mortality. Immunofluorescence (IF) staining of glomeruli is typically positive for IgG, IgA, IgM, C3, and C1q—the full house (FH) pattern. However, a subset of patients with membranous lupus nephritis (MLN) have a Non-FH (NFH) IF pattern more typical of idiopathic membranous nephropathy.

Methods

From a multi-institutional cohort of 113 MLN cases, we identified 29 NFH MLN biopsies. NFH MLN was defined by IF criteria: ≥1+ glomerular capillary loop IgG staining and<1+ IgA, IgM, and C1q. FH MLN was defined as ≥1+ staining for all five antibodies. Intermediate (Int) cases did not meet criteria for FH or NFH. We compared the pathological and clinical characteristics and outcomes among patients with FH, NFH, and Int IF patterns on kidney biopsy.

Results

NFH MLN represents a subset of MLN biopsies (13.4%). Compared with patients with FH MLN, patients with NFH MLN were older at SLE diagnosis (29 versus 22.5 years), had a longer time to initial kidney biopsy (8 versus 3.16 years), and had fewer SLE manifestations (2.5 versus 3.36 involved systems). NFH MLN biopsies showed lower C3 IF intensity (1.16+ versus 2.38+). Int biopsies had findings intermediate between those of NFH and FH groups.

Conclusions

NFH IF pattern defines a small subset of MLN biopsies and appears to be associated with milder clinical manifestations and slower disease progression. Less robust C3 deposition in NFH MLN may suggest a pathophysiology distinct from that of FH MLN.

Efficacy and safety of intravenous immunoglobulin in patients with lupus nephritis: A systematic review of the literature

INTRODUCTION AND OBJECTIVE

Intravenous immunoglobulin (IVIg) is an anti-inflammatory drug with an unclear role in the treatment of patients with lupus nephritis (LN). This systematic review evaluates the evidence for IVIg in the care of patients with LN.

METHODOLOGY

A systematic search was done in the PubMed, EMBASE, BVS and OVID databases - All EBM Reviews following the PRISMA methodology (registration in PROSPERO CRD42021236662). The variables were extracted: indications for use, dosage, partial or complete response, adverse reactions, initiation of renal replacement therapy, reduction of proteinuria, and mortality. The quality assessment was done with the "The Joanna Briggs Institute (JBI) Critical Appraisal tools for use in Systematic Reviews Checklist". In addition, synthesis reports were prepared through the Synthesis Without Meta-analysis - SWiM guide.

RESULTS

A total of 2328 articles were obtained (28 were considered for inclusion). When the studies were evaluated, IVIg therapy was found to be between 60% to 70% effective (except for patients with class V LN) with overall responses (complete + partial) even for patients who are refractory to first line treatment. Normalization (<0.5 g) of nephrotic proteinuria occurred in 24% of cases with infrequent adverse events and a mortality plus dialysis composite of 11.5% and 24.1% (most representative study).

CONCLUSION

In patients with LN refractory to conventional treatment or co-infection situations, the reported data seem to demonstrate effectiveness of IVIg therapy. There are few adverse reactions and caution is exercised when using it on patients with class V NL. However, given the lack of controlled studies with long-term follow-up, these data should be interpreted cautiously thus encouraging the development of high-quality RCTs.

Lupus nephritis diagnosis using enhanced moth flame algorithm with support vector machines

Systemic lupus erythematosus is a chronic autoimmune disease that affects the kidney in most patients. Lupus nephritis (LN) is divided into six categories by the International Society of Nephrology/Renal Pathology Society (ISN/RPS). The purpose of this research is to build a framework for discriminating between ISN/RPS pure class V(MLN) and classes III ± V or IV ± V (PLN) using real clinical data. The framework is developed by merging a hybrid stochastic optimizer, moth-flame algorithm (HMFO), with a support vector machine (SVM), dubbed HMFO-SVM. The HMFO is constructed by enhancing the original moth-flame algorithm (MFO) with a bee-foraging learning operator, which guarantees that the algorithm speeds convergence and departs from the local optimum. The HMFO is used to optimize parameters and select features simultaneously for SVM on clinical SLE data. On 23 benchmark tests, the suggested HMFO method is validated. Finally, clinical data from LN patients are analyzed to determine the efficacy of HMFO-SVM over other SVM rivals. The statistical findings indicate that all measures have predictive capabilities and that the suggested HMFO-SVM is more stable for analyzing systemic LN. HMFO-SVM may be used to analyze LN as a feasible computer-assisted technique.

Predicting lupus membranous nephritis using reduced picolinic acid to tryptophan ratio as a urinary biomarker

The current gold standard for classifying lupus nephritis (LN) progression is a renal biopsy, which is an invasive procedure. Undergoing a series of biopsies for monitoring disease progression and treatments is unlikely suitable for patients with LN. Thus, there is an urgent need for non-invasive alternative biomarkers that can facilitate LN class diagnosis. Such biomarkers will be very useful in guiding intervention strategies to mitigate or treat patients with LN. Urine samples were collected from two independent cohorts. Patients with LN were classified into proliferative (class III/IV) and membranous (class V) by kidney histopathology. Metabolomics was performed to identify potential metabolites, which could be specific for the classification of membranous LN. The ratio of picolinic acid (Pic) to tryptophan (Trp) ([Pic/Trp] ratio) was found to be a promising candidate for LN diagnostic and membranous classification. It has high potential as an alternative biomarker for the non-invasive diagnosis of LN.

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.

Immunopathological analysis of the expression of glomerular exostosin 1 and exostosin 2 in Japanese patients with lupus nephritis

Exostosin 1 and exostosin 2 (EXT1/EXT2) on glomerular basement membrane (GBM) were recently reported as novel putative antigens in secondary membranous nephropathy with autoimmune disease. However, the clinical significance of glomerular EXT1/EXT2 remains elusive in patients with lupus nephritis (LN). The immunofluorescence staining pattern of glomerular EXT1/EXT2 is also undetermined in membranous LN (MLN) or proliferative LN (PLN). We cross-sectionally analyzed patients with MLN (pure class V, n = 11) and PLN (class III, IV, and mixed class III/IV + V, n = 22) who underwent renal biopsies between 2010 and 2020 at Showa University Hospital. Glomerular EXT1/EXT2 expressions were evaluated by immunofluorescence. T-helper (Th) cell-related serum inflammatory cytokines were measured using enzyme-linked immunosorbent assay. The positivity for both EXT1/EXT2 was higher in patients with MLN than PLN (90.9% vs 63.6%, P = 0.212). MLN showed global and bright granular EXT1/EXT2 expressions along GBM, while PLN showed segmental and moderate expressions on GBM. Additionally, glomerular EXT1/EXT2 positivity was not associated with the degree of proteinuria or renal function in MLN and PLN patients, but the levels of serum anti-dsDNA antibody and circulating immune complexes were lower in patients with EXT1/EXT2-positive MLN than EXT1/EXT2-negative PLN. Moreover, serum complement levels and IL-4/IFN-γ ratios were elevated in EXT1/EXT2-positive MLN than EXT1/EXT2-negative PLN. Collectively, immunofluorescence staining for glomerular EXT1/EXT2 had characteristic patterns between MLN and PLN. Glomerular EXT1/EXT2 expressions tended to be high in Th2-dominant MLN patients without severe hypocomplementemia and elevated autoantibodies. Thus, EXT1/EXT2 might be involved in the unique developmental mechanism of MLN.

Life prognosis and renal relapse after induction therapy in Japanese patients with proliferative and pure membranous lupus nephritis

OBJECTIVE

We aimed to compare life prognosis and renal relapse after induction therapy in proliferative (PLN) and pure membranous LN (MLN).

METHODS

We retrospectively analysed the cases of 140 of 172 patients with LN who underwent a renal biopsy at our hospital or community hospitals from 1993 to 2016. We determined the complete response (CR) rate at 12 months after the patients had started induction therapy, and we evaluated the predictive factors for CR, life prognosis and renal relapse in PLN and pure MLN. We defined PLN as International Society of Neurology and the Renal Pathology Society (ISN/RPS) Class III or IV and MLN as ISN/RPS Class V.

RESULTS

The renal pathology of 99 (70.7%) patients was classified as PLN, and that of the other 41 (29.3%) patients as MLN. Fifty patients (50.5%) with PLN and 22 patients (53.7%) with MLN achieved a CR at 12 months. A multivariate analysis showed that a lower index of chronicity in PLN and a higher total haemolytic complement (CH50) level in MLN were predictive factors for achieving a CR at 12 months. A Kaplan-Meier analysis showed that the life prognosis (P = 0.93) and renal relapse (P = 0.52) were not significantly different between PLN and MLN.

CONCLUSIONS

The predictive factors for a CR at 12 months post-induction therapy were index of chronicity in PLN and CH50 level in MLN. There were no significant differences in life prognosis or renal relapse between PLN and MLN in the achievement of a CR at 12 months post-induction therapy.

Lupus-like membranous nephropathy. Is it lupus? Report of 5 cases in a reference hospital in Mexico

INTRODUCTION

Lupus nephritis requires antinuclear antibodies as classification criteria. There is a group of patients with nephrotic syndrome and conclusive histopathological findings for lupus nephritis, without classification criteria for systemic lupus erythematosus (SLE) or extrarenal manifestations. These groups of patients have been described as "lupus-like" nephritis or "renal-limited lupus nephritis".

METHODS

Renal biopsy with histopathological evaluation with "full-house" immune-reactants in patients with negative antinuclear antibodies.

RESULTS

We report four cases with nephrotic syndrome and one with hematuria-proteinuria syndrome: two with impaired glomerular filtration rate and three with preserved renal function; urinary sediment with hematuria without dysmorphia and without extrarenal manifestations for autoimmune disease, negative antinuclear antibodies (ANA) and anti-double stranded DNA (anti-dsDNA); normal C3 and C4 complement levels. Renal biopsy in all cases was consistent for lupus nephritis class V. All patients received treatment as lupus nephritis protocol; only one case received induction with cyclophosphamide and methylprednisolone boluses, the rest received mycophenolic acid and prednisone as induction and maintenance. Two of the cases induced with mycophenolic acid relapsed, requiring cyclophosphamide for 6 months, achieving complete remission. All patients received renin-angiotensin-aldosterone system blockade and hydroxychloroquine. At follow-up, 4 cases still have negative antibodies and are without extrarenal manifestations for SLE classification criteria. The other case, during pregnancy several years after initial diagnosis, had preeclampsia with nephrotic proteinuria and a new determination of positive ANA and anti-dsDNA antibodies, complement levels below normal limits.

CONCLUSION

The follow-up of patients with membranous glomerulopathy must be close; lupus like nephritis may be the first manifestation of the disease.

Association of coexisting anti-ribosomal P and anti-dsDNA antibodies with histology and renal prognosis in lupus nephritis patients

OBJECTIVES

Anti-ribosomal P protein autoantibodies (anti-P) specifically develop in patients with systemic lupus erythematosus. Associations of anti-P with lupus nephritis (LN) histological subclass and renal outcome remain inconclusive. We sought to determine the association of anti-P and anti-double-stranded DNA antibody (anti-dsDNA) with renal histology and prognosis in LN patients.

METHODS

Thirty-four patients with LN, having undergone kidney biopsy, were included. The 2018 revised ISN/RPS classification system was used for pathophysiological evaluation. Chronic kidney disease (CKD) was defined as an estimated glomerular filtration rate < 60 mL/min/1.73 m² for > 3 months.

RESULTS

Six patients (17.6%) were positive for anti-P and 26 (76.5%) for anti-dsDNA. Among the six patients with anti-P, one did not have anti-dsDNA, but did have anti-Sm antibody, and showed a histological subtype of class V. This patient maintained good renal function for over 14 years. The remaining five patients, who had both anti-P and anti-dsDNA, exhibited proliferative nephritis and were associated with prolonged hypocomplementemia, and the incidence of CKD did not differ from patients without anti-P.

CONCLUSION

Although this study included a small number of patients, the results indicated that histology class and renal prognosis associated with anti-P depend on the coexistence of anti-dsDNA. Further studies with a large number of patients are required to confirm this conclusion.

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.

Prediction of prognosis and renal outcome in lupus nephritis

Lupus nephritis (LN) is a severe manifestation of SLE, characterised by subendothelial and/or subepithelial immune complex depositions in the afflicted kidney, resulting in extensive injury and nephron loss during the acute phase and eventually chronic irreversible damage and renal function impairment if not treated effectively. The therapeutic management of LN has improved during the last decades, but the imperative need for consensual outcome measures remains. In order to design trials with success potentiality, it is important to define clinically important short-term and long-term targets of therapeutic and non-therapeutic intervention. While it is known that early response to treatment is coupled with favourable renal outcomes, early predictors of renal function impairment are lacking. The information gleaned from kidney biopsies may provide important insights in this direction. Alas, baseline clinical and histopathological information has not been shown to be informative. By contrast, accumulating evidence of pronounced discrepancies between clinical and histopathological outcomes after the initial phase of immunosuppression has prompted investigations of the potential usefulness of per-protocol repeat kidney biopsies as an integral part of treatment evaluation, including patients showing adequate clinical response. This approach appears to have merit. Hopefully, clinical, molecular or genetic markers that reliably reflect kidney histopathology and portend the long-term prognosis will be identified. Novel non-invasive imaging methods and employment of the evolving artificial intelligence in pattern recognition may also be helpful towards these goals. The molecular and cellular characterisation of SLE and LN will hopefully result in novel therapeutic modalities, maybe new taxonomy perspectives, and ultimately personalised management.

Idiopathic membranous nephropathy preceding membranous lupus nephritis: a case report

Membranous nephropathy is one of the most common causes of nephrotic syndrome in the adult population. According to the underlying etiology, membranous nephropathy is classified as either primary or secondary. Systemic lupus erythematosus is an autoimmune disease that can affect the kidneys in 50% of patients in the course of the disease. Renal disease may be the first manifestation of systemic lupus erythematosus and the development of systemic findings may be delayed for about 1-5 years following the diagnosis of lupus nephritis. We present a 59-year-old male patient who had a diagnosis of idiopathic membranous nephropathy since 2007 and developed membranous lupus nephritis during the 12-year follow-up without any extrarenal systemic lupus erythematosus findings.

Antibodies to M-type phospholipase A2 receptor (PLA2R) in membranous lupus nephritis

BACKGROUND

Antibodies to M-type phospholipase A2 receptor (a-PLA₂R) have been identified in most patients with idiopathic membranous nephropathy, but the prevalence in membranous lupus nephritis (MLN) is still unclear. The objective of this study was to assess the prevalence of a-PLA₂R antibodies in a large cohort of patients with lupus nephritis.

METHODS

a-PLA₂R antibodies were measured by ELISA in serum from patients with systemic lupus erythematosus ( n = 190), of whom 37 had a biopsy-proven MLN. Positive samples were confirmed by commercial ELISA kit, Western blot and immunohistochemistry in renal tissue.

RESULTS

A total of 10 from 190 patients (5.3%) with systemic lupus erythematosus had circulating a-PLA₂R measured by in-house ELISA assay. The antibodies were detected in 7 patients with MLN (18.9%) and 3 patients with non-renal lupus disease (3.2%). PLA₂R staining was detected in the kidney biopsy of 5 of the 7 (71.4%) patients with MLN. a-PLA₂R levels were associated with active disease but not proteinuria levels. Presence of a-PLA₂R antibodies at baseline was associated with worse remission rates and longer time to remission compared to those patients serologically negative.

CONCLUSIONS

a-PLA₂R antibodies can be detected with low prevalence in MLN patients, but their detection is associated with a worse renal prognosis.