Current management of lupus nephritis

Predictive modeling of co-infection in lupus nephritis using multiple machine learning algorithms

This study aimed to analyze peripheral blood lymphocyte subsets in lupus nephritis (LN) patients and use machine learning (ML) methods to establish an effective algorithm for predicting co-infection in LN. This study included 111 non-infected LN patients, 72 infected LN patients, and 206 healthy controls (HCs). Patient information, infection characteristics, medication, and laboratory indexes were recorded. Eight ML methods were compared to establish a model through a training group and verify the results in a test group. We trained the ML models, including Logistic Regression, Decision Tree, K-Nearest Neighbors, Support Vector Machine, Multi-Layer Perceptron, Random Forest, Ada boost, Extreme Gradient Boosting (XGB), and further evaluated potential predictors of infection. Infected LN patients had significantly decreased levels of T, B, helper T, suppressor T, and natural killer cells compared to non-infected LN patients and HCs. The number of regulatory T cells (Tregs) in LN patients was significantly lower than in HCs, with infected patients having the lowest Tregs count. Among the ML algorithms, XGB demonstrated the highest accuracy and precision for predicting LN infections. The innate and adaptive immune systems are disrupted in LN patients, and monitoring lymphocyte subsets can help prevent and treat infections. The XGB algorithm was recommended for predicting co-infection in LN.

MAIT cells altered phenotype and cytotoxicity in lupus patients are linked to renal disease severity and outcome

Introduction

Systemic lupus erythematosus (SLE) is an autoimmune disease in which circulating immune complexes can cause different types of glomerulonephritis, according to immune deposits and to the type of glomerular cell injury. Proliferative lesions represent the most severe form of lupus nephritis (LN) and often lead to kidney failure and death. Mucosal-associated invariant T (MAIT) cells are a subset of innate-like T cells that recognize microbial-derived ligands from the riboflavin synthesis pathway. Although abundant in peripheral blood, MAIT cells are enriched in mucosal and inflamed tissues. While previous studies have reported concordant results concerning lower MAIT cell frequencies in the blood of SLE patients, no information is known about MAIT cell function and LN severity and outcome.

Methods

In the current study, we analyzed the baseline phenotype and function of peripheral blood MAIT cells by flow cytometry in 26 patients with LN and in a control group of 16 healthy individuals.

Results

We observe that MAIT cell frequencies are markedly reduced in blood of LN patients. MAIT cells from patients have an altered phenotype in terms of migration, proliferation and differentiation markers, notably in most severe forms of LN. Frequencies of PMA/ionomycin stimulated MAIT cells secreting effector molecules, such as proinflammatory IL-17 and cytotoxic protein granzyme B, are higher in LN patients. Patients undergoing a complete renal remission after immunosuppressive therapy had higher MAIT cell frequency, lower expression of proliferation marker Ki-67 and granzyme B (GzB) at inclusion. Remarkably, GzB production defines a predictive model for complete remission.

Discussion

We report here that blood MAIT cells display proinflammatory and cytotoxic function in severe lupus nephritis which may play a pathogenesis role, but without association with systemic lupus activity. Finally, low cytotoxic profile of MAIT cells may represent a promising prognostic factor of lupus nephritis remission one year after induction therapy.

A Preliminary Predictive Model for Proliferative Lupus Nephritis in Juvenile Systemic Lupus Erythematosus

Proliferative lupus nephritis, which is diagnosed by renal biopsy, has significant impact on the treatment choices and long-term prognosis of juvenile SLE (jSLE). Renal biopsies are however not always possible or available, thus leading to an ongoing search for alternative biomarkers. This study aimed to develop a clinical predictive machine learning model using routine standard parameters as an alternative tool to evaluate the probability of proliferative lupus nephritis (ISN/RPS Class III or IV). Data were collected retrospectively from jSLE patients seen at Selayang Hospital from 2004 to 2021. A total of 22 variables including demographic, clinical and laboratory features were analyzed. A recursive feature elimination technique was used to identify factors to predict pediatric proliferative lupus nephritis. Various models were then used to build predictive machine learning models and assessed for sensitivity, specificity and accuracy. There were 194 jSLE patients (165 females), of which 111 had lupus nephritis (54 proliferative pattern). A combination of 11 variables consisting of gender, ethnicity, fever, nephrotic state, hypertension, urine red blood cells (RBC), C3, C4, duration of illness, serum albumin, and proteinuria demonstrated the highest accuracy of 79.4% in predicting proliferative lupus nephritis. A decision-tree model performed the best with an AROC of 69.9%, accuracy of 73.85%, sensitivity of 78.72% and specificity of 61.11%. A potential clinically useful predictive model using a combination of 11 non-invasive variables to collectively predict pediatric proliferative lupus nephritis in daily practice was developed.

Silent Lupus Nephritis: Renal Histopathological Profile and Early Detection with Urinary Monocyte Chemotactic Protein 1

Objective

Lupus nephritis (LN) affects almost half of all individuals with systemic lupus erythematosus (SLE). Overt LN (OLN) symptoms might vary from asymptomatic microscopic hematuria to renal failure. However, when there are no clinical or laboratory indicators of renal involvement, some people with silent LN (SLN) may have pathological evidence of renal involvement identified by renal biopsy. Monocyte Chemotactic Protein 1 (MCP-1) is a chemotactic factor that promotes leukocyte migration to the kidney. MCP-1 urine levels (uMCP-1) have been demonstrated to be high in individuals with active LN. The purpose of this study was to discover the occurrence of SLN, as well as the possible variations between overt LN (OLN) and SLN across SLE patients based on the histopathological assessment, as well as the role of uMCP-1 in the early detection of SLN.

Methods

An overall of 144 patients with SLE were included in the current research. Patients were subsequently divided into two groups: individuals who did not have clinical evidence of LN (84 patients) and those with OLN (60 patients). All the patients were subjected to the following investigations: uMCP-1, erythrocyte sedimentation rate (ESR), complement C3 (C3), complement C4 (C4), creatinine, albumin/creatinine ratio (uACR), creatinine clearance, quantitative assessment of proteinuria by 24-hour urine proteinuria (24hr UP) and percutaneous renal biopsy.

Results

Sixty patients from group I (71.4%) showed glomerular lesions on renal biopsy (SLN), and class II was the predominant class. uMCP-1 had a sensitivity of 95.2% and a specificity of 98% in the detection of SLN, and uMCP-1 values were markedly higher in patients with OLN in comparison to SLN.

Conclusion

The actual frequency of SLN may be higher than expected. High levels of uMCP-1 may have warranted the early activity of LN. uMCP-1 can be used as a non-invasive, useful tool for the prediction of LN.

Pediatric lupus nephritis - An evil cousin of its adult counterpart: A single-center based experience from a tertiary care hospital of Eastern India

Context

Systemic lupus erythematosus is an autoimmune multisystem disease with a high predilection for renal involvement. Lupus nephritis develops in 20% to 75% within the first two years. Presentation varies from subnephrotic proteinuria to end-stage renal disease.

Aims

To study clinical features, biochemical, and serological parameters and correlate with histological activity and chronicity score [modified National Institute of Health (NIH) score].

Settings and Design

Retrospective, cross-sectional, single-center based study in a tertiary care hospital of Eastern India.

Subjects and Methods

We incuded 36 children with lupus nephritis diagnosed from February 2018 to March 2019. Laboratory data included were complete blood count (CBC), blood glucose, urine analysis, serum urea, creatinine, blood urea nitrogen (BUN), albumin, cholesterol, HBsAg, antihepatitis C virus (HCV) antibody, antistreptolysin O (ASO) titer, antinuclear antibody (ANA), myeloperoxidase antineutrophil cytoplasmic antibody (MPO ANCA), proteinase 3 antineutrophil cytoplasmic antibody (PR3 ANCA), double-stranded DNA (dsDNA), C3, and C4. Clinical parameters were age, sex, blood pressure (BP), skin lesions, arthralgia, edema, obesity. Renal biopsies examined with light microscopy, hematoxylin and eosin (H and E), periodic acid-Schiff (PAS), silver methanamine, Masson's trichrome (MT) stains. Immunofluorescence microscopy done with IgG, IgM, IgA, C3c, C1q, kappa, lambda antibodies.

Statistical Analysis Used

Kruskal-Wallis and χ² tests.

Results

Mean age was 15.12 ± 3.49 and 12.5 ± 1.73 years for lupus nephritis (LN) with activity and LN without activity, respectively. Mean dsDNA was higher and mean C3 was lower (52.35 ± 22.21 mg/dl) in active LN. Mean 24-hour urinary protein was higher in LN without activity. Serum creatinine was raised in active LN. LN class III and IV showed higher activity than chronicity.

Conclusions

Pediatric LN is proliferative and more active as compared with adult counterparts. Activity scores are much higher than chronicity scores.

Non-histologic factors discriminating proliferative lupus nephritis from membranous lupus nephritis

BACKGROUND

To investigate non-histologic factors that can discriminate proliferative lupus nephritis (LN) from membranous LN in patients with systemic lupus erythematosus with renal manifestations.

METHODS

Patients with biopsy-proven proliferative LN (class III ± V and class IV ± V) and membranous LN (class V) were included. Non-histologic factors were compared between the two groups. A logistic regression analysis was performed to identify the factors associated with proliferative LN. To assess the accuracy of these factors in discriminating between proliferative LN and membranous LN, we performed a receiver-operating characteristic analysis.

RESULTS

Of the total 168 patients with biopsy-proven LN, 150 patients (89.3%) had proliferative LN, and 18 patients (10.7%) had membranous LN. In the multivariable logistic regression analysis, positive anti-double-stranded DNA (anti-dsDNA) antibody (adjusted OR = 11.200, 95% CI = 2.202-56.957, p = 0.004) was associated with proliferative LN, while positive anti-U1RNP antibody (adjusted OR = 0.176, 95% CI = 0.040-0.769, p = 0.021) and higher glomerular filtration rate (GFR) (adjusted OR = 0.973, 95% CI = 0.951-0.994, p = 0.013) were inversely associated with proliferative LN. Among these covariates, the anti-dsDNA antibody (area under the curve = 0.806, 95% CI = 0.695-0.916) had the highest accuracy in discriminating between proliferative LN and membranous LN.

CONCLUSION

The positivity of anti-dsDNA antibody was associated with proliferative LN, while the positivity of anti-U1RNP antibody and GFR were inversely associated with proliferative LN. The anti-dsDNA antibody had a good accuracy in discriminating proliferative LN from membranous LN.

Urinary biomarkers in lupus nephritis

Systemic lupus erythematosus (SLE) is the prototypical autoimmune disease that can affect any organ of the body. Multiple mechanisms may contribute to the pathophysiology of systemic lupus, including failure to remove apoptotic bodies, hyperactivity of self-reactive B and T lymphocytes, abnormal exposure to autoantigens, and increased levels of B-cell stimulatory cytokines. The involvement of the kidney, called lupus nephritis (LN), during the course of the disease affects between 30% and 60% of adult SLE patients, and up to 70% of children. LN is an immune-mediated glomerulonephritis that is a common and serious finding in patients with SLE. Nowadays, renal biopsy is considered the gold standard for classifying LN, besides its degree of activity or chronicity. Nevertheless, renal biopsy lacks the ability to predict which patients will respond to immunosuppressive therapy and is a costly and risky procedure that is not practical in the monitoring of LN because serial repetitions would be necessary. Consequently, many serum and urinary biomarkers have been studied in SLE patients for the complementary study of LN, existing conventional biomarkers like proteinuria, protein/creatinine ratio in spot urine, 24 ​h urine proteinuria, creatinine clearance, among others and non-conventional biomarkers, like Monocyte chemoattractant protein-1 (MCP-1), have been correlated with the histological findings of the different types of LN. In this article, we review the advances in lupus nephritis urinary biomarkers. Such markers ideally should be capable of predicting early sub-clinical flares and could be used to follow response to therapy. In addition, some of these markers have been found to be involved in the pathogenesis of lupus nephritis.

Chinese patent medicine Bailing capsule for treating lupus nephritis: A protocol for systematic review and meta-analysis

BACKGROUND

Treatment of lupus nephritis (LN) remains challenging. LN remains the primary source of morbidity and mortality in patients with systemic lupus erythematosus. Chinese patent medicine Bailing capsule is commonly used for the treatment of LN. However, there is no consensus on the difference in clinical efficacy compared with routine treatment. Therefore, we plan to perform a systematic review and meta-analysis to review the clinical efficacy and safety of Bailing capsule for LN.

METHODS

Cochrane Central Register of Controlled Trials, PubMed, EMBASE, Chinese National Knowledge Infrastructure, Chinese Biomedical Database, Wanfang database, and VIP information database will be searched from their inception until January 2019. The meta-analysis will be conducted with Review Manager 5.3 software to systematically review the clinical efficacy and safety of Bailing capsule for LN. The primary outcome will include clinical effective rate, and the secondary outcomes will include Systemic Lupus Erythematosus Disease Activity Index, serum creatinine, 24-hour urine protein quantity, complement 3, and adverse effects.

RESULTS

This analysis will provide useful information about clinical efficacy and safety of Bailing capsule for LN.

CONCLUSIONS

Our study will generate strong evidence of Bailing capsule for patients with LN and provide suggestions for clinical practice.

Accelerated Glomerular Cell Senescence in Experimental Lupus Nephritis

BACKGROUND The aim of this study was to determine whether senescence in renal glomeruli is involved in lupus nephritis (LN); the expression of senescence-associated β-galactosidase (SA-β-Gal) and its association with glomerular lesions were investigated in a mouse model of LN. MATERIAL AND METHODS Eighteen MRL/lpr mice with severe proteinuria were randomly divided into 2 equal groups and intraperitoneally injected with dexamethasone (DEX) or saline; 4 age-matched mice with mild proteinuria served as controls. Serum creatinine and urinary protein levels were analyzed, and kidney histological changes were observed by periodic acid-Schiff and Sirius Red staining. SA-β-Gal was detected via histochemistry. Glomerular expression of collagen IV, α-SMA, and nephrin was analyzed by immunohistochemistry, and glomerular complement C3 deposition was tested by immunofluorescence. The relationships between SA-β-Gal expression and renal function or glomerular lesion markers were determined by Spearman's correlation analysis. RESULTS Mice with severe proteinuria exhibited glomerular segmental sclerosis and endothelial cell proliferation. DEX administration suppressed these lesions but had no significant effect on 24-hour urinary protein levels. The elevated glomerular expression of SA-β-Gal in proteinuric mice was attenuated by DEX treatment. In addition, DEX treatment markedly downregulated glomerular C3 deposition and collagen IV and α-SMA expression, while significantly increasing nephrin expression. Furthermore, SA-β-Gal expression was positively correlated with urinary protein levels and expression of α-SMA. CONCLUSIONS Accelerated senescence of glomerular cells may contribute to glomerular injury in LN.

Intrarenal activation of adaptive immune effectors is associated with tubular damage and impaired renal function in lupus nephritis

Objectives

Chronic renal impairment remains a feared complication of lupus nephritis (LN). The present work aimed at identifying mechanisms and markers of disease severity in renal tissue samples from patients with LN.

Methods

We performed high-throughput transcriptomic studies (Illumina HumanHT-12 v4 Expression BeadChip) on archived kidney biopsies from 32 patients with LN and eight controls (pretransplant donors). Histological staging (glomerular and tubular scores) and immunohistochemistry experiments were performed on the same and on a replication set of 37 LN kidney biopsy samples.

Results

A group of LN samples was identified by unsupervised clustering studies based on their gene expression features, that is, the overexpression of transcripts involved in antigen presentation, T and B cell activation. These samples were characterised by a significantly lower estimated glomerular filtration rate (eGFR) at the time of biopsy (T0) compared with the other systemic lupus erythematosus samples. Yet, apparent disease duration at T0, double-stranded DNA antibody titres at T0 and other relevant characteristics (serum C3, proteinuria, histological scores, numbers of previous flares) were not different between groups.

Immunohistochemistry studies confirmed the association between interstitial infiltration by adaptive immune effectors and decreased renal function in the same and in a replication group of LN kidney biopsies. This was associated with transcriptomic, histological and immunohistochemical evidence of renal tubular cell involvement.

Conclusion

Interstitial infiltration of LN kidney biopsies by adaptive immune effectors is associated with impaired renal tubular cell function and decreased eGFR. These results open new perspectives in evaluating and treating patients with LN, focusing on intrarenal mechanisms of immune cell activation.

Glucocorticoid use and factors associated with variability in this use in the Systemic Lupus International Collaborating Clinics Inception Cohort

Objectives

To describe glucocorticoid (GC) use in the SLICC inception cohort and to explore factors associated with GC use. In particular we aimed to assess temporal trends in GC use and to what extent physician-related factors may influence use.

Methods

Patients were recruited within 15 months of diagnosis of SLE from 33 centres between 1999 and 2011 and continue to be reviewed annually. Descriptive statistics were used to detail oral and parenteral GC use. Cross sectional and longitudinal analyses were performed to explore factors associated with GC use at enrolment and over time.

Results

We studied 1700 patients with a mean (s.d.) follow-up duration of 7.26 (3.82) years. Over the entire study period, 1365 (81.3%) patients received oral GCs and 447 (26.3%) received parenteral GCs at some point. GC use was strongly associated with treatment centre, age, race/ethnicity, sex, disease duration and disease activity. There was no change in the proportion of patients on GCs or the average doses of GC used over time according to year of diagnosis.

Conclusion

GCs remain a cornerstone in SLE management and there have been no significant changes in their use over the past 10-15 years. While patient and disease factors contribute to the variation in GC use, between-centre differences suggest that physician-related factors also contribute. Evidence-based treatment algorithms are needed to inform a more standardized approach to GC use in SLE.

[Lupus nephropathy: Insight in new treatments]

Systemic lupus erythematosus is a chronic autoimmune disease. Both acquired and innate immune systems are involved in the development of this systemic disease. Lupus nephritis usually is the most serious manifestation of systemic lupus erythematosus, with significant morbidity and mortality. The physiopathological development of the renal involvement of lupus has been increasingly elucidated over the years and various target therapies have recently been developed. After some physiopathological reminders, we discuss the conventional treatment of lupus nephritis as well as the various therapeutic advances, in particular the contribution and the place of the new target therapies in the treatment of the lupus nephritis.

A Systematic Review and Meta-analysis of Prevalence of Biopsy-Proven Lupus Nephritis

Objectives

This study aims to conduct a meta-analysis to clarify the epidemiologic characteristics of biopsy-proven lupus nephritis (BPLN), including those relating to its prevalence and prognosis.

Patients and methods

A literature search for relevant studies was conducted in the electronic databases of PubMed, Google Scholar, Embase, and Cochrane trial register. The following search terms were used for original articles published between January 1982 and April 2016: "lupus nephritis" or systemic lupus erythematosus ('SLE') or 'systemic lupus erythematous' and "pathology" or 'epidemiology' or prevalence or incidence. Pooled estimates with 95% confidence intervals were calculated.

Results

Nineteen studies were included (mean age of SLE patients at renal biopsy: ~30 years). Of total BPLN patients, 85% were females. BPLN developed in 29% of SLE patients, and accounted for 60% of secondary glomerular diseases in renal biopsy databases. BPLN prevalence among SLE patients was higher in Saudi Arabia compared with pooled Europe/USA data (43% vs 26%, p<0.05). Pooled BPLN prevalence among secondary glomerular diseases patients was higher in Asian/Latin American countries than in Europe (63% vs 34%, p<0.05). Overall five-, 10- and 20-year survival rates of BPLN patients were 94%, 86%, and 71%, respectively, which were higher than those before 1995 (84%, 72%, and 52%, respectively) and lower than those after 1995 (96%, 89%, and 80%, respectively) (all p<0.05). Class IV nephritis, present in 40% of BPLN patients, was a risk factor for renal failure that contributed to poor prognosis.

Conclusion

Lupus nephritis is a common complication of young female patients with SLE, and the most prevalent etiology of secondary glomerular diseases. Attention should be paid to class IV nephritis due to its high frequency and association with poor prognosis.

The contribution of the programmed cell death machinery in innate immune cells to lupus nephritis

Systemic lupus erythematosus (SLE) is a chronic multi-factorial autoimmune disease initiated by genetic and environmental factors, which in combination trigger disease onset in susceptible individuals. Damage to the kidney as a consequence of lupus nephritis (LN) is one of the most prevalent and severe outcomes, as LN affects up to 60% of SLE patients and accounts for much of SLE-associated morbidity and mortality. As remarkable strides have been made in unlocking new inflammatory mechanisms associated with signaling molecules of programmed cell death pathways, this review explores the available evidence implicating the action of these pathways specifically within dendritic cells and macrophages in the control of kidney disease. Although advancements into the underlying mechanisms responsible for inducing cell death inflammatory pathways have been made, there still exist areas of unmet need. By understanding the molecular mechanisms by which dendritic cells and macrophages contribute to LN pathogenesis, we can improve their viability as potential therapeutic targets to promote remission.

Risk of serious infections with immunosuppressive drugs and glucocorticoids for lupus nephritis: a systematic review and network meta-analysis

BACKGROUND

To perform a systematic review and network meta-analysis (NMA) to compare the risk of serious infections with immunosuppressive medications and glucocorticoids in lupus nephritis.

METHODS

A trained librarian performed two searches: (1) PubMed for all lupus nephritis trials from the end dates for the systematic review for the 2012 American College of Rheumatology (ACR) lupus nephritis treatment guidelines and the 2012 Cochrane Systematic Review on treatments for lupus nephritis, to September 2013; and (2) PubMed and SCOPUS for all lupus trials (excluding lupus nephritis) from inception to February 2014, to obtain additional trials for harms data in any lupus patient. The search was updated to May 2016. Duplicate title/abstract review and duplicate data abstractions by two abstractors independently was performed for all eligible studies, including those studies abstracted for the 2012 ACR lupus nephritis treatment guidelines and the 2012 Cochrane Systematic Review on lupus nephritis treatments. We performed a systematic review and a Bayesian NMA, including randomized controlled trials (RCTs) of immunosuppressive drugs or glucocorticoids in patients with lupus nephritis assessing serious infection risk. Markov chain Monte Carlo methods were used to model 95 % credible intervals (CrI). Sensitivity analyses examined the robustness of estimates.

RESULTS

A total of 32 RCTs with 2611 patients provided data. There were 26 two-arm, five three-arm, and one four-arm trials. We found that tacrolimus was associated with significantly lower risk of serious infections compared to glucocorticoids, cyclophosphamide (CYC), mycophenolate mofetil (MMF), and azathioprine (AZA) with odds ratios (95 % CrI) of 0.33 (0.12-0.88), 0.37 (0.15-0.87), 0.340 (0.18-0.81), and 0.32 (0.12-0.81), respectively. Conversely, CYC low dose (LD), CYC high dose (HD), and HD glucocorticoids were associated with higher odds of serious infections compared to tacrolimus, ranging from 4.84 to 12.83. We also found that MMF followed by AZA (MMF-AZA) was associated with significantly lower risk of serious infections as compared to CYC LD, CYC HD, CYC-AZA, or HD glucocorticoids with odds ratios (95 % CrI) of 0.09 (0.01-0.76), 0.07 (0.01-0.54), 0.14 (0.02-0.71), and 0.03 (0.00-0.56), respectively. Estimates were similar to pair-wise meta-analyses. Sensitivity analyses that varied estimate (odds ratio vs. Peto's odds ratio), method (random vs. fixed effects model), data (sepsis vs. serious infection data; exclusion of observational studies), treatment grouping (CYC and CYC HD as a combined treatment group vs. separate), made little/no difference to these estimates.

CONCLUSIONS

Tacrolimus and MMF-AZA combination were associated with lower risk of serious infections compared to other immunosuppressive drugs or glucocorticoids for lupus nephritis. In conjunction with comparative efficacy data, these data can help patients make informed decisions about treatment options for lupus nephritis.

PROSPERO REGISTRATION

CRD42016032965.

A systems approach to renal inflammation in SLE

Lupus disease and its complications including lupus nephritis (LN) are very disabling and significantly impact the quality of life and longevity of patients. Broadly immunosuppressive treatments do not always provide the expected clinical benefits and have significant side effects that contribute to patient morbidity. In the era of systems biology, new strategies are being deployed integrating diverse sources of information (molecular and clinical) so as to identify individual disease specificities and select less aggressive treatments. In this review, we summarize integrative approaches linking molecular disease profiles (mainly tissue transcriptomics) and clinical phenotypes. The main goals are to better understand the pathogenesis of lupus nephritis, to identify the risk factors for renal flare and to find the predictors of both short and long-term clinical outcome. Identification of common key drivers and additional patient-specific key drivers can open the door to improved and individualized therapy to prevent and treat LN.

What is damaging the kidney in lupus nephritis?

Despite marked improvements in the survival of patients with severe lupus nephritis over the past 50 years, the rate of complete clinical remission after immune suppression therapy is <50% and renal impairment still occurs in 40% of affected patients. An appreciation of the factors that lead to the development of chronic kidney disease following acute or subacute renal injury in patients with systemic lupus erythematosus is beginning to emerge. Processes that contribute to end-stage renal injury include continuing inflammation, activation of intrinsic renal cells, cell stress and hypoxia, metabolic abnormalities, aberrant tissue repair and tissue fibrosis. A deeper understanding of these processes is leading to the development of novel or adjunctive therapies that could protect the kidney from the secondary non-immune consequences of acute injury. Approaches based on a molecular-proteomic-lipidomic classification of disease should yield new information about the functional basis of disease heterogeneity so that the most effective and least toxic treatment regimens can be formulated for individual patients.

Lupus nephritis: an update

Lupus nephritis (LN) is an inflammatory condition of the kidneys that encompasses various patterns of renal disease including glomerular and tubulointerstitial pathology. It is a major predictor of poor prognosis in patients with systemic lupus erythematosus (SLE). Genetic factors, including several predisposing loci, and environmental factors, such as EBV and ultraviolet light, have been implicated in the pathogenesis. It carries a high morbidity and mortality if left untreated. Renal biopsy findings are utilized to guide treatment. Optimizing risk factors such as proteinuria and hypertension with renin-angiotensin receptor blockade is crucial. Immunosuppressive therapy is recommended for patients with focal or diffuse proliferative lupus nephritis (Class III or IV) disease, and certain patients with membranous LN (Class V) disease. Over the past decade, immunosuppressive therapies have significantly improved long-term outcomes, but the optimal therapy for LN remains to be elucidated. Cyclophosphamide-based regimens, given concomitantly with corticosteroids, have improved survival significantly. Even though many patients achieve remission, the risk of relapse remains considerably high. Other treatments include hydroxychloroquine, mycofenolate mofetil, and biologic therapies such as Belimumab, Rituximab, and Abatacept. In this paper, we provide a review of LN, including pathogenesis, classification, and clinical manifestations. We will focus, though, on discussion of the established as well as emerging therapies for patients with proliferative and membranous lupus nephritis.

Comparison and evaluation of lupus nephritis response criteria in lupus activity indices and clinical trials

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease with diverse manifestations. Although the approval of new therapies includes only one agent in 50 years, a number of promising new drugs are in development. Lupus nephritis is a dreaded complication of SLE as it is associated with significant morbidity and mortality. Advancing the treatment of lupus nephritis requires well-designed clinical trials and this can be challenging in SLE. The major obstacles involve identifying the correct population of patients to enroll and ensuring that a clinically appropriate and patient-centered endpoint is being measured. In this review, we will first discuss the clinical utility of endpoints chosen to represent lupus nephritis in global disease activity scales. Second, we will review completed and active trials focused on lupus nephritis and discuss the endpoints chosen. There are many important lessons to be learned from existing assessment tools and clinical trials. Reviewing these points will help ensure that future efforts will yield meaningful disease activity measures and well-designed clinical trials to advance our understanding of lupus management.

Incidence and disease severity of anti-neutrophil cytoplasmic antibody-associated nephritis are higher than in lupus nephritis in Sweden

OBJECTIVES

The objectives of this study were to compare incidence rates, renal and patient survival between lupus nephritis (LN) and anti-neutrophil cytoplasmic antibody-associated nephritis (AAN) during a 12-year period in two geographically defined populations in Sweden.

METHODS

In the health care districts surrounding the Skåne University Hospital in Lund [mean population ≥18 years (1997-2008), 188 400] and the University Hospital in Linköping [mean population ≥18 years (1997-2008), 328 900] all patients with biopsy-proven LN and AAN during the period 1997-2008 were included in the study if they (i) were residing within the study areas at the time of onset of nephritis, (ii) had a clinical diagnosis of either SLE or ANCA-associated vasculitis (AAV) and (iii) experienced a first flare of biopsy-proven nephritis during the study period.

RESULTS

Eighty-two patients (Lund 44 + Linköping 38) with biopsy-proven AAN were identified and 27 patients with LN (Lund 13 + Linköping 14). The annual incidence rate per million inhabitants aged ≥18 years in both study areas was estimated to be 13.2 (95% CI 10.4-16.1) for AAN and 4.3 (95% CI 2.7-6.0) for LN, P < 0.001. The patients were followed until January 2013. During the follow-up time 38 patients died (AAN 36, LN 2; P = 0.001), and 20 patients went into end-stage renal disease (AAN 19 and LN 1), P = 0.020.

CONCLUSIONS

In Sweden, AAN was three times more common than LN, and the outcome was considerably worse. SLE is often diagnosed before the onset of nephritis leading to earlier treatment, while AAN is still often diagnosed at a later stage.

AGS, SLE, and RNASEH2 mutations: translating insights into therapeutic advances

Systemic lupus erythematosus (SLE) is a severe autoimmune disease characterized by the presence of nucleic acid- and protein-targeting autoantibodies and an aberrant type I IFN expression signature. Aicardi-Goutières syndrome (AGS) is an autosomal-recessive encephalopathy in children that is characterized by mutations in numerous nucleic acid repair enzymes and elevated IFN levels. Phenotypically, patients with AGS and SLE share many similarities. Ribonuclease H2 (RNase H2) is a nucleic acid repair enzyme that removes unwanted ribonucleotides from DNA. In this issue of the JCI, Günther and colleagues provide an in-depth investigation of the mechanisms underlying the link between defective removal of ribonucleotides in AGS and SLE, and these findings will likely serve as a strong springboard to provide novel therapeutic inroads.

Biologic therapy in lupus nephritis

This position paper critically analyzes the available controlled data regarding biologic therapy in lupus nephritis (LN). Rather than an exhaustive review of all published evidence, the stress is put on the unmet medical needs in LN, the design of trials aimed at testing the effect of a biologic in LN, the possible reasons for LN trial failures and the future of biological therapy in LN.

sIL7R concentrations in the serum reflect disease activity in the lupus kidney

OBJECTIVES

Evaluation of disease activity in systemic lupus erythematosus (SLE) nephritis is a challenge, and repeated renal biopsies are usually needed in order to confirm a suspicion of flare. In a previous cross-sectional study, we reported that serum soluble form of the interleukin-7 receptor (sIL7R) levels is strongly associated with nephritis in SLE patients. In the present study, we wanted to confirm the association between changes in serum sIL7R concentrations and renal disease activity in a large longitudinal cohort of SLE nephritis patients.

METHODS

Sera were harvested longitudinally in 105 SLE nephritis patients. Serum sIL7R cut-off value for the detection of SLE nephritis activity was determined as the mean sIL7R concentration in non-nephritis SLE patients + 2 SDs using data collected in our previous study. Patients with glomerular filtration rate (GFR) <60 mL/min/1.73 m(2) (n=17) were excluded from the study due to persistently elevated serum sIL7R values.

RESULTS

Serum sIL7R concentrations above the renal cut-off value were observed in 25 (out of 88) patients with a normal GFR. These patients had significantly higher serum double-stranded DNA (dsDNA) Ab and urinary protein to creatinine (UPC) ratio. Strikingly, 12 of them developed a renal British Isles Lupus Assessment Group index (BILAG) A within the next 3 months, while this was only the case in four out of the 63 other patients (p<0.0001). The test had 75.0% sensitivity and 81.9% specificity for the detection of a renal BILAG A. Combination of serum sIL7R with any of the classical tests (anti-dsDNA Ab titres, UPC ratio, serum C3) resulted in an increased specificity for the detection of a renal flare. Administration of immunosuppressive therapy resulted in a significant decrease in serum sIL7R concentrations.

CONCLUSIONS

Serum sIL7R is a sensitive and specific marker of renal disease activity in SLE. Elevated serum sIL7R values in SLE patients are associated with or predict the occurrence of an SLE nephritis flare.

When biologics should be used in systemic lupus erythematosus?

Recently, the use and evaluation of biologics increased in systemic lupus erythematosus (SLE). However, no international recommendation is available concerning the use of biologics with regards to the subset of patients who should be treated, the optimal time to treat, the objective of treatment and the manner to discontinue it. To address these complex questions, we focused on biologics already evaluated in at least two published randomized controlled trials. We summarized the results of these trials and available observational data in registries. Taking into account the clinical evidence, we proposed some guidance on the way biologics could be used in SLE. Many areas of uncertainty persist and require intensifying efforts from the academic world to set up new trials, and develop international recommendations.