Mesangial proliferative lupus nephritis with podocytopathy: a special entity of lupus nephritis

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 management of lupus nephritis as proposed by EULAR/ERA 2019 versus KDIGO 2021

In 2019 and 2021, the European League for Rheumatism (EULAR) jointly with the European Renal Association (ERA) and the Kidney Disease: Improving Global Outcomes (KDIGO), respectively, released updated guidelines on the management of lupus nephritis (LN). The Immunology Working Group of the ERA reviewed and compared both updates. Recommendations were either consistent or differences were of negligible clinical relevance for: indication for kidney biopsy, kidney biopsy interpretation, treatment targets, hydroxychloroquine dosing, first-line initial immunosuppressive therapy for active class III, IV (±V) LN, pregnancy in LN, LN in paediatric patients and LN patients with kidney failure. Relevant differences in the recommended management relate to the recognition of lupus podocytopathies, uncertainties in steroid dosing, drug preferences in specific populations and maintenance therapy, treatment of pure class V LN, therapy of recurrent LN, evolving alternative drug options and diagnostic work-up of thrombotic microangiopathy. Altogether, both documents provide an excellent guidance to the growing complexity of LN management. This article endeavours to prevent confusion by identifying differences and clarifying discrepancies.

Association of podocyte injury with clinical features and prognosis in patients with mesangial proliferative lupus nephritis

OBJECTIVES

The aim of this study is to explore the association of podocyte injury with clinical features and outcomes in mesangial proliferative (Class II) lupus nephritis (LN).

METHODS

We conducted a retrospective and clinicopathologic analysis with 576 LN patients with renal biopsy and screened 58 patients with Class II LN. Then, the 58 cases were divided into 4 groups based on the degree of podocyte damage and immune complex (IC) deposits on light microscope (histological and immunofluorescence) and electron microscope: Podocyte Injury Group, IC deposits Group, Podocyte Injury and IC Group, and Less-lesion Group. Clinical and pathologic information was collected from the patients' medical records at the time of the kidney biopsy and at follow-up. The data of demography, clinical parameters, therapy, remission, and relapse rates were analyzed and compared across groups.

RESULTS

A significant difference was observed in the ages of patients among four Class II LN groups. The onset age of patients with FPE ≥ 50% was significant later. The frequency of thrombocytopenia was statistically different among the four groups and the patients with FPE ≥ 50% had lower frequency of thrombocytopenia. Patients with FPE ≥ 50% had lower serum albumin, eGFR, and elevated proteinuria and serum lipids. In this study, most patients received glucocorticoids in combination with immunosuppressants. Among the 4 groups, the use of ACEI/ARBs was highest in the podocyte injury group. There was a statistical difference in the renal relapse rates among the 4 Class II LN groups. Moreover, the recurrence rate was higher in the FPE ≥ 50% group.

CONCLUSION

Our data identified Class II LN patients with podocyte injury (FPE ≥ 50%) present prominent renal damage and higher rate of renal relapse, suggesting more aggressive treatment and close follow-up for these patients.

MicroRNA-98-5p inhibits human mesangial cell proliferation and TNF-α and IL-6 secretion by targeting BTB and CNC homology 1

MicroRNA (miR)-98-5p has been reported to be involved in the development of lupus nephritis (LN); however, its specific role in LN remains unclear. The present study aimed to investigate the effect of miR-98-5p on human mesangial cell proliferation and the secretion of TNF-α and IL-6. Reverse transcription-quantitative PCR (RT-qPCR) and western blotting were used to analyze the level of gene and protein expression, respectively. Cellular proliferation was assessed using a Cell Counting Kit-8 (CCK-8) assay. ELISA was used to detect the secretion of TNF-α and IL-6 by human mesangial cells. RT-qPCR analysis revealed that miR-98-5p expression was downregulated in LN renal tissues compared with control renal tissues. Overexpression of miR-98-5p inhibited human mesangial cell proliferation and the secretion of TNF-α and IL-6, whereas miR-98-5p-knockdown demonstrated the opposite effect. Dual luciferase reporter assays demonstrated that miR-98-5p directly targeted BTB and CNC homology 1 (BACH1). BACH1-overexpression promoted human mesangial cell proliferation and the secretion of TNF-α and IL-6, whereas BACH1-knockdown demonstrated the opposite effect. Notably, co-transfection with miR-98-5p mimic inhibited BACH1-overexpression induced human mesangial cell proliferation and the secretion of TNF-α and IL-6. The results of the present study indicated that miR-98-5p inhibited human mesangial cell proliferation and the secretion of TNF-α and IL-6 by targeting BACH1. Therefore, miR-98-5p and BACH1 may represent potential therapeutic targets for LN.

Delayed Onset Minimal Change Disease as a Manifestation of Lupus Podocytopathy

Lupus podocytopathy (LP) is an uncommon manifestation of systemic lupus erythematosus (SLE) and is not included in the classification of lupus nephritis. The diagnosis of LP is confirmed by the presence of diffuse foot process effacement in the absence of capillary wall deposits with or without mesangial immune deposits in a patient with SLE. Here we describe a 13-year-old female who presented with nephrotic syndrome (NS) seven years after the diagnosis of SLE. The renal function had been stable for seven years since the SLE diagnosis, as manifested by the normal serum creatinine, serum albumin and absence of proteinuria. Renal biopsy showed evidence of minimal change disease without immune complex deposits or features of membranous nephropathy. Renal function was normal. The patient had an excellent response to steroid therapy with remission within two weeks. The patient remained in remission five months later during the most recent follow-up. This report highlights the importance of renal histology to determine the accurate etiology of NS in patients with SLE. Circulating factors, including cytokines such as interleukin 13, may play a role in the pathophysiology of LP and needs to be studied further in future larger studies.

Long-term renal outcomes of mesangial proliferative lupus nephritis in Chinese patients

OBJECTIVE

This study aimed to explore the long-term outcomes of mesangial proliferative lupus nephritis (LN class II) and the factors associated with its relapse and histological transformation in Chinese patients.

METHODS

104 SLE patients with biopsy-proven LN class II were included and divided into proteinuria group (proteinuria ≥ 0.4 g/24 h, with or without microscopic hematuria) and hematuria group (microscopic hematuria with proteinuria < 0.4 g/24 h).Patients were treated with glucocorticoid alone (GC monotherapy) or GC in combination with other immunosuppressant (combination therapy). The rates of remission, relapse, histological transformation, end-stage renal disease (ESRD), adverse events, and risk factors related to the outcomes were analyzed.

RESULTS

During the median follow-up of 77.5 (IQR 58-116.5) months, all the 104 patients achieved remission. Relapse occurred in 69 cases (66.3%), of which 37 were of renal relapse (35.6%). Histological transformation was found in 14 of the 16 (87.5%) cases who received repeated renal biopsy after renal relapse. At the end of follow-up, 3 (2.9%) patients developed ESRD. There were no significant differences in the rates of relapse, histological transformation, adverse events and in the time from remission to relapse between the proteinuria group and the hematuria group. In contrast, the cumulative relapse rate in the GC monotherapy group was much higher than that in the combination group (P < 0.01). Adverse events occurred in 55 (57.3%) patients during follow-up.

CONCLUSIONS

Patients with LN class II have high rates of relapse and renal histological transformation and need optimal maintenance therapy.

KEY POINTS

• The rates of relapse and histological transformation are high in patients with LN class II. • Patients with LN class II are suggested to receive combination therapy and consider repeat renal biopsy after renal relapse.

Starting off on the right foot: A 22-year-old woman with leg swelling

A previously healthy 22-year-old woman was in the second trimester of her first pregnancy when she developed new lower extremity edema. Her pregnancy course had been unremarkable, and she was receiving routine obstetric care from her family physician. One week prior to admission she developed progressive swelling in her legs.

Stellenwert der Nierenbiopsie bei Lupusnephritis

Bei systemischem Lupus erythematodes (SLE) findet sich häufig eine renale Mitbeteiligung, der verschiedene pathogenetische Mechanismen zugrunde liegen. Die Nierenbeteiligung hat einen negativen Einfluss auf die Prognose des SLE, insbesondere bei progredienter Niereninsuffizienz. Eine Nierenbiopsie ist aufgrund der Heterogenität der Nierenbeteiligung und der damit verbundenen therapeutischen Konsequenzen unabdingbar. Sie kann durch nicht-invasive Untersuchungen wie die Urindiagnostik oder Serologie nicht ersetzt werden, da das Ausmaß der Proteinurie oder der Mikrohämaturie keine sicheren Rückschlüsse auf den Schweregrad, die Pathogenese und die Prognose der Nierenbeteiligung erlauben. Die Nierenbiopsie gibt neben der korrekten Klassifikation der Lupusnephritis (LN) Informationen über die Mitbeteiligung des Niereninterstitium, der intrarenalen Gefäße und der Aktivität sowie Chronizität der Nephritis. Auch kann der Pathologe die Frage beantworten, inwieweit mit einer Besserung der Nierenfunktion unter Therapie gerechnet werden kann. Der folgende Beitrag gibt einen Überblick über den Stellenwert der Nierenbiopsie bei SLE, der revidierten Klassifikation der LN von 2018 einschließlich Sonderformen der LN und über die Implikationen des Biopsie-Ergebnisses für die Therapie.

Clinical aspects and risk factors of lupus nephritis: a retrospective study of 156 adult patients

Objective

To analyze the clinical manifestations, laboratory indexes, disease activity, and pathological types of lupus nephritis (LN) in adult patients.

Methods

We retrospectively analyzed the clinical manifestations, laboratory indexes, and pathological classifications of 156 adult patients first diagnosed with LN between July 2013 and November 2017. Patients were categorized according to the following criteria: active or inactive LN, LN with or without renal damage, and mild or severe LN.

Results

Immunoglobulin G and A levels, 24-hour proteinuria, and anti-dsDNA, anti-Sm, and anti-ribosomal P protein antibody positivity rates were all significantly increased in patients with active LN compared with inactive LN. Anti-dsDNA antibody positivity and 24-hour proteinuria were significantly increased, whereas hemoglobin, serum albumin, and C3 and C4 levels were significantly decreased in patients with LN and renal damage compared with those without renal damage. Anti-dsDNA and anti-Sm antibody positivity rates and 24-hour proteinuria were significantly increased, while hemoglobin, serum albumin, C3 and C4 levels, and estimated glomerular filtration rate were significantly decreased in patients with severe LN compared with patients with mild LN.

Conclusions

LN can display various clinical manifestations, laboratory indexes, levels of disease activity, and pathological types in adult patients.

The Kidney Biopsy in Systemic Lupus Erythematosus: A View of the Past and a Vision of the Future

The kidney biopsy advanced our understanding of kidney disease in systemic lupus erythematosus. It allowed for better recognition and classification of lupus nephritis (LN). Several LN classifications have been devised in an effort to inform treatment decision and predict prognosis, and these are being further updated. In this review, we will examine the role of diagnostic as well as repeat kidney biopsy in the management of LN, including the potential role of molecular interrogation as a step forward beyond conventional histology to guide the discovery of novel biomarkers and a precision medicine approach to the management of LN.

Lupus Podocytopathy: An Overview

In systemic lupus erythematosus, nephrotic-range proteinuria typically signals the presence of a proliferative lupus nephritis (class III/IV) and/or membranous lupus nephritis (class V, with or without concomitant class III or IV lesions). However, in rare instances, systemic lupus erythematosus patients with nephrotic syndrome have kidney biopsy findings of normal glomeruli or focal segmental glomerulosclerosis lesions, with or without mesangial proliferation, on light microscopy; the absence of subepithelial or subendothelial deposits on immunofluorescence and electron microscopy; and diffuse foot process effacement on electron microscopy. This pattern, termed lupus podocytopathy, is a unique form of lupus nephritis that mimics minimal change disease or primary focal segmental glomerulosclerosis and represents approximately 1% of lupus nephritis biopsies. Here we review the clinical features, histological manifestations, diagnostic criteria and classification, pathogenesis, treatment, and prognosis of lupus podocytopathy.

Podocyte Injury in Lupus Nephritis

Systemic lupus erythematosus (SLE) is characterized by a broad spectrum of renal lesions. In lupus glomerulonephritis, histological classifications are based on immune-complex (IC) deposits and hypercellularity lesions (mesangial and/or endocapillary) in the glomeruli. However, there is compelling evidence to suggest that glomerular epithelial cells, and podocytes in particular, are also involved in glomerular injury in patients with SLE. Podocytes now appear to be not only subject to collateral damage due to glomerular capillary lesions secondary to IC and inflammatory processes, but they are also a potential direct target in lupus nephritis. Improvements in our understanding of podocyte injury could improve the classification of lupus glomerulonephritis. Indeed, podocyte injury may be prominent in two major presentations: lupus podocytopathy and glomerular crescent formation, in which glomerular parietal epithelial cells play also a key role. We review here the contribution of podocyte impairment to different presentations of lupus nephritis, focusing on the podocyte signaling pathways involved in these lesions.

Lupus podocytopathy: a distinct entity of lupus nephritis

Systemic lupus erythematosus (SLE) patients clinically presenting with nephrotic syndrome demonstrating minimal change disease (MCD), mesangial proliferation (MsP) or focal segmental glomerulosclerosis (FSGS), while on electronic microscopy, diffuse podocyte foot process effacement in absence of sub-epithelial or sub-endothelial deposition is the only morphological feature and now diagnosed as lupus podocytopathy. Lupus podocytopathy with glomerular morphology of MCD or MsP usually presents with typical nephrotic syndrome and sensitive to glucocorticoid treatment, but the relapse rate could reach up to 90% on maintenance treatment with glucocorticoid alone. Glucocorticoid plus other immunosuppressive agents could significantly decrease the relapse rate. Lupus podocytopathy with FSGS presents with a higher rate of acute kidney injury and less sensitivity to glucocorticoid treatment. The long-term outcomes of lupus podocytopathy are optimistic, but pathological transition could occur after renal relapses. The unique clinical and morphological features of lupus podocytopathy indicate that this special SLE-associated glomerulopathy should be included in the upcoming revised pathological classification of lupus nephritis.