Lupus nephritis: challenges and progress

New guidelines and therapeutic updates for the management of lupus nephritis

PURPOSE OF REVIEW

Systemic lupus erythematosus (SLE) can be a devastating condition, striking young patients often in their prime reproductive years. Lupus nephritis is a common and serious complication occurring in roughly 50% of SLE cases, indicating a high likelihood of disease progression, morbidity, and mortality. As the early trials of steroid therapy, and later cyclophosphamide (CYC), therapeutic changes had been stagnant. Then came the introduction of mycophenolate mofetil (MMF) in the 2000s. After the Aspreva Lupus Management Study, there had been a dearth of trials showing positive therapy results. Since 2020, new studies have emerged for lupus nephritis involving the use of anti-BLYS agents, novel calcineurin inhibitors, CD20 blockade, and antiinterferon agents. Nephrology and rheumatology society guidelines in the United States and across the world are still catching up.

RECENT FINDINGS

Although therapeutic guidelines are being developed, updates that have come through have focused on improved diagnostic and monitoring guidelines. One theme is the recommendation of increasingly tight proteinuria control and firmer guidelines for the rapid induction of remission. The reality of multitarget therapy and the expectation of rapid induction for a more complete remission are being widely recognized.

SUMMARY

The need for more complete and more rapid induction and control of lupus nephritis is undisputed according to the evidence and guidelines, and the medications to achieve this are growing at a rate not seen over the prior two decades. What remains is a stepwise approach to recognize how to best optimize therapy. Based on available evidence, an algorithm for induction and maintenance treatment of lupus nephritis used by the University of California Irvine Lupus Nephritis clinic, is recommended.

Functional consequence of Iron dyshomeostasis and ferroptosis in systemic lupus erythematosus and lupus nephritis

Systemic lupus erythematosus (SLE) and its renal manifestation Lupus nephritis (LN) are characterized by a dysregulated immune system, autoantibodies, and injury to the renal parenchyma. Iron accumulation and ferroptosis in the immune effectors and renal tubules are recently identified pathological features in SLE and LN. Ferroptosis is an iron dependent non-apoptotic form of regulated cell death and ferroptosis inhibitors have improved disease outcomes in murine models of SLE, identifying it as a novel druggable target. In this review, we discuss novel mechanisms by which iron accumulation and ferroptosis perpetuate immune cell mediated pathology in SLE/LN. We highlight intra-renal dysregulation of iron metabolism and ferroptosis as an underlying pathogenic mechanism of renal tubular injury. The basic concepts of iron biology and ferroptosis are also discussed to expose the links between iron, cell metabolism and ferroptosis, that identify intracellular pro-ferroptotic enzymes and their protein conjugates as potential targets to improve SLE/LN outcomes.

Population-wide long-term study of incidence, renal failure, and mortality rates for lupus nephritis

OBJECTIVE

Given limited regional data, we investigate the state-wide epidemiology, renal and patient outcomes for lupus nephritis (LN) in Western Australia (WA).

METHODS

Patients hospitalized with incident SLE (≥2 diagnostic codes in the state-wide WA Health Hospital Morbidity Data Collection) in the period 1985-2015 were included (n = 1480). LN was defined by the presence of glomerulonephritis and/or raised serum creatinine. Trends over three study decades for annual incidence rate (AIR)/100.000 population, mortality (MR), and end-stage renal disease (ESRD) rates/100 person years were analyzed by least square regression and compared with a matched control group (n = 12 840).

RESULTS

Clinical evidence of LN developed in 366 SLE patients (25.9%) after a median disease duration of 10 months (IQR 0-101) with renal biopsy performed in 308 (84.2%). The AIR for LN (0.63/100.000) did not change significantly over time (R2  = .11, p = .85), while point prevalence reached 11.9/100.000 in 2015. ESRD developed in 14.1% (n = 54) of LN patients vs. 0.2% in non-LN SLE patients and 0.05% in controls (all p ≤ 0.01). ESRD rates increased over time in LN patients (0.4 to 0.7, R2 = .52, p = .26). The odds ratio for death was 8.81 (CI 3.78-22.9) for LN and 6.62 (CI 2.76-17.9) for non-LN SLE patients compared to controls and MR for LN patients increased over time (1.3 to 2.2, R2 = .84, p = .26).

CONCLUSIONS

The incidence rate of LN in WA remained unchanged over 30 years. A lack of improvement in renal failure and mortality rates illustrates the pressing need for better long-term treatment options and/or strategies in LN.

Non-invasive prediction of the chronic degree of lupus nephropathy based on ultrasound radiomics

OBJECTIVE

Through machine learning (ML) analysis of the radiomics features of ultrasound extracted from patients with lupus nephritis (LN), this attempt was made to non-invasively predict the chronicity index (CI)of LN.

METHODS

A retrospective collection of 136 patients with LN who had renal biopsy was retrospectively collected, and the patients were randomly divided into training set and validation set according to 7:3. Radiomics features are extracted from ultrasound images, independent factors are obtained by using LASSO dimensionality reduction, and then seven ML models were used to establish predictive models. At the same time, a clinical model and an US model were established. The diagnostic efficacy of the model is evaluated by analysis of the receiver operating characteristics (ROC) curve, accuracy, specificity, and sensitivity. The performance of the seven machine learning models was compared with each other and with clinical and US models.

RESULTS

A total of 1314 radiomics features are extracted from ultrasound images, and 5 features are finally screened out by LASSO for model construction, and the average ROC of the seven ML is 0.683, among which the Xgboost model performed the best, and the AUC in the test set is 0.826 (95% CI: 0.681-0.936). For the same test set, the AUC of clinical model constructed based on eGFR is 0.560 (95% CI: 0.357-0.761), and the AUC of US model constructed based on Ultrasound parameters is 0.679 (95% CI: 0.489-0.853). The Xgboost model is significantly more efficient than the clinical and US models.

CONCLUSION

ML model based on ultrasound radiomics features can accurately predict the chronic degree of LN, which can provide a valuable reference for clinicians in the treatment strategy of LN patients.

Autoimmune Responses and Therapeutic Interventions for Systemic Lupus Erythematosus: A Comprehensive Review

Systemic Lupus Erythematosus (SLE) or Lupus is a multifactorial autoimmune disease of multiorgan malfunctioning of extremely heterogeneous and unclear etiology that affects multiple organs and physiological systems. Some racial groups and women of childbearing age are more susceptible to SLE pathogenesis. Impressive progress has been made towards a better understanding of different immune components contributing to SLE pathogenesis. Recent investigations have uncovered the detailed mechanisms of inflammatory responses and organ damage. Various environmental factors, pathogens, and toxicants, including ultraviolet light, drugs, viral pathogens, gut microbiome metabolites, and sex hormones trigger the onset of SLE pathogenesis in genetically susceptible individuals and result in the disruption of immune homeostasis of cytokines, macrophages, T cells, and B cells. Diagnosis and clinical investigations of SLE remain challenging due to its clinical heterogeneity and hitherto only a few approved antimalarials, glucocorticoids, immunosuppressants, and some nonsteroidal anti-inflammatory drugs (NSAIDs) are available for treatment. However, the adverse effects of renal and neuropsychiatric lupus and late diagnosis make therapy challenging. Additionally, SLE is also linked to an increased risk of cardiovascular diseases due to inflammatory responses and the risk of infection from immunosuppressive treatment. Due to the diversity of symptoms and treatment-resistant diseases, SLE management remains a challenging issue. Nevertheless, the use of next-generation therapeutics with stem cell and gene therapy may bring better outcomes to SLE treatment in the future. This review highlights the autoimmune responses as well as potential therapeutic interventions for SLE particularly focusing on the recent therapeutic advancements and challenges.

Cordyceps cicadae ameliorates inflammatory responses, oxidative stress, and fibrosis by targeting the PI3K/mTOR-mediated autophagy pathway in the renal of MRL/lpr mice

BACKGROUND

The vast majority of systemic lupus erythematosus patients develop lupus nephritis (LN) with severe renal manifestations, such as inflammatory responses, oxidative stress, and fibrosis. The purpose of this research was to investigate Cordyceps cicadae as a potential therapeutic target for treating inflammatory responses, oxidative stress, and fibrosis in LN.

METHODS

The effects of C. cicadae on lupus symptoms in mice with LN were determined. MRL/lpr mice were treated with C. cicadae (4 g/kg/day, i.e., CC group, n = 8) or an equal volume of saline (model group, n = 8), and MRL/MP mice were treated with an equal volume of saline (control group, n = 8). Renal function indices, renal pathology, inflammatory markers, oxidative stress markers, and renal interstitial fibrosis levels were evaluated after C. cicadae treatment. Western blot analysis was performed to investigate the effect of C. cicadae on the expression of fibrosis biomarkers and the phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR)-mediated autophagy pathway in the renal tissues of mice.

RESULTS

C. cicadae ameliorated renal lesions, the inflammatory response, and oxidative stress damage in MRL/lpr mice. C. cicadae treatment inhibited renal fibrosis (16.31 ± 4.16 vs. 31.25 ± 5.61) and downregulated the expression of the fibrosis biomarkers alpha-smooth muscle actin, fibronectin, and collagen I (COL I) in the kidneys of MRL/lpr mice. In addition, further research showed that the PI3K/mTOR-mediated autophagy pathway was involved in C. cicadae-mediated effects on renal fibrosis in MRL/lpr mice. Furthermore, the therapeutic effect of C. cicadae on repairing renal fibrosis and damage in MRL/lpr mice was abolished by the PI3K agonist 740 Y-P.

CONCLUSIONS

The findings of the present research showed that C. cicadae could alleviate inflammatory responses, oxidative stress, and fibrosis in the renal tissues of mice with LN by targeting the PI3K/mTOR-mediated autophagy pathway.

Gbp3 is associated with the progression of lupus nephritis by regulating cell proliferation, inflammation and pyroptosis

Lupus nephritis (LN) is a major cause death in patients with systemic lupus erythematosus. We aimed to find the differentially expressed genes (DEGs) in LN and confirm the regulatory mechanism on LN. The mouse model of LN was constructed by subcutaneous injection of pristane. RNA-seq screened 392 up-regulated and 447 down-regulated DEGs in LN mouse model, and KEGG analysis found that the top 20 DEGs were enriched in arachidonic acid metabolism, tryptophan metabolism, etc. The hub genes, Kynu, Spidr, Gbp3, Cbr1, Cyp4b1, and Cndp2 were identified, in which Gbp3 was selected for following study. Afterwards, the function of Gbp3 on the proliferation, inflammation, and pyroptosis of LN was verified by CCK-8, ELISA, and WB in vitro. The results demonstrated that si-Gbp3 promoted cell proliferation and inhibited the levels of inflammatory factors (IL-1β, TNF-α and IL-8) and pyroptosis-related proteins (GSDMD, Caspase-1 and NLRP3) in a cell model of LN. In constrast, Gbp3 overexpression played an opposite role. In summary, Gbp3 promoted the progression of LN via inhibiting cell proliferation and facilitating inflammation and pyroptosis.

Identification of a circRNA-miRNA-mRNA network to explore the effects of circRNAs on renal injury in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease. At present, the mechanism of non-coding RNA in renal injury in SLE patients is still unclear. A total of 64 DEcircRNAs, 75 DEmiRNAs, and 249 DEmRNAs were identified. We integrated 10 circRNAs, 10 miRNAs, and 88 target mRNAs into a circRNA-miRNA-mRNA network and obtained 9 hub genes (circ-0000006, miR-766-3p, miR-409-3p, miR-339-3p, miR-331-3p, miR-140-3p, miR-186-5p, miR-149-5p, PSME3). The ROC curve results showed that the diagnostic efficiency of 6 hub miRNA was higher than that of has_circ_0000006 and PSEME3. SsGSEA analysis revealed immune cell composition in SLE and control renal tissues, including 3 types of immune cells up-regulated (gamma delta T cell, effector memory CD4 T cell, central memory CD8 T cell) and 4 types down-regulated (memory B cell, mast cell, macrophage, immature dendritic cell, eosinophil) in SLE patients. In addition, PSME3 was negatively correlated with 3 up-regulated immune cells and positively correlated with 4 down-regulated immune cells in SLE patients. Our study provides a deeper understanding of the circRNA-related competing endogenous RNA regulatory mechanism in the renal injury of systemic lupus erythematosus.

Clinical research progress of novel biologics for the treatment of lupus nephritis

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the loss of immune tolerance. Lupus nephritis (LN) is one of the most common manifestations of severe organ damage in SLE, and also an important cause of disability and death. Its pathogenesis is associated with immune abnormalities such as immune cells, cytokines, and immune complex deposition. Traditional immunosuppressive therapy has been unable to meet the treatment needs of patients while bringing them toxic effects. In recent years, targeted therapies have emerged, and several novel biologics have gradually entered people's sight. This review will briefly introduce the pathogenesis of LN and the mechanism of biological targets, and summarize and analyze the clinical trials of new biologics for treating LN. Although not all biologics show positive results in clinical trials, the experience learned from these trials can help researchers adjust and plan future trial programs to seek better treatment methods.

SMURF1 activates the cGAS/STING/IFN-1 signal axis by mediating YY1 ubiquitination to accelerate the progression of lupus nephritis

Aggravated endoplasmic reticulum stress (ERS) and apoptosis in podocytes play an important role in lupus nephritis (LN) progression, but its mechanism is still unclear. Herein, the role of SMURF1 in regulating podocytes apoptosis and ERS during LN progression were investigated. MRL/lpr mice was used as LN model in vivo. HE staining was performed to analyze histopathological changes. Mouse podocytes (MPC5 cells) were treated with serum IgG from LN patients (LN-IgG) to construct LN model in vitro. CCK8 assay was adopted to determine the viability. Cell apoptosis was measured using flow cytometry and TUNEL staining. The interactions between SMURF1, YY1 and cGAS were analyzed using ChIP and/or dual-luciferase reporter gene and/or Co-IP assays. YY1 ubiquitination was analyzed by ubiquitination analysis. Our results found that SMURF1, cGAS and STING mRNA levels were markedly increased in serum samples of LN patients, while YY1 was downregulated. YY1 upregulation reduced LN-IgG-induced ERS and apoptosis in podocytes. Moreover, SMURF1 upregulation reduced YY1 protein stability and expression by ubiquitinating YY1 in podocytes. Rescue studies revealed that YY1 knockdown abrogated the inhibition of SMURF1 downregulation on LN-IgG-induced ERS and apoptosis in podocytes. It was also turned out that YY1 alleviated podocytes injury in LN by transcriptional inhibition cGAS/STING/IFN-1 signal axis. Finally, SMURF1 knockdown inhibited LN progression in vivo. In short, SMURF1 upregulation activated the cGAS/STING/IFN-1 signal axis by regulating YY1 ubiquitination to facilitate apoptosis in podocytes during LN progression.

Integrative analysis of the association between circadian rhythm and lupus nephritis

Background

Lupus nephritis (LN) is an autoimmune nephropathy associated with systemic lupus erythematosus. Circadian rhythms are involved in the development of several diseases, especially inflammation-related diseases, but their relationship with LN is unclear.

Methods

This was an integrative bioinformatics study. The expression profile from glomeruli, tubular interstitium and renal whole tissue samples was used to assess the expression levels and relevance of circadian rhythm-related genes. To screen for circadian rhythm-related signatures, we employed the LASSO and SVM-RFE algorithms. A consensus clustering algorithm was used to classify LN patients into two circadian rhythm patterns (cluster A and cluster B). We made immune cell infiltration analysis. We used the weighted gene co-expression network analysis (WGCNA) algorithm to identify cluster-specific differentially expressed genes. Nephroseq data were used to observe the relationship between genes and renal function.

Results

We found more significant differences in circadian rhythm-related gene expression in LN glomeruli compared with tubulointerstitial and whole-kidney tissues. We established a circadian rhythm-related signature consisting of eight genes that can easily distinguish LN from healthy individuals. Patients in cluster A were associated with B-cell-dominated immunity, whereas patients in cluster B were associated with T-cell-dominated immunity. As most of the patients with proliferative LN combined with membranous LN belonged to cluster B, patients in cluster B may have more severe renal pathology compared with patients in cluster A. Fifteen circadian rhythm-related genes associated with LN and LN typing were screened using the WGCNA algorithm, with COL1A2 and DOCK2 associated with renal prognosis.

Conclusions

This study found that circadian rhythms are associated with the occurrence of LN, providing new ideas for the development of new LN treatment options from the perspective of circadian rhythms.

Anifrolumab in lupus nephritis: results from second-year extension of a randomised phase II trial

OBJECTIVE

To characterise the safety and efficacy of anifrolumab in active lupus nephritis (LN) through year 2 of the phase II randomised, double-blind Treatment of Uncontrolled Lupus via the Interferon Pathway (TULIP)-LN trial (NCT02547922) of 2 anifrolumab dosing regimens versus placebo.

METHODS

Patients received intravenous anifrolumab 900 mg for the first 3 doses followed by 300 mg anifrolumab (intensified regimen (IR)), 300 mg anifrolumab (basic regimen (BR)) or placebo every 4 weeks throughout. To continue into Year 2, patients must have achieved at least partial renal response and a glucocorticoid tapering target.

RESULTS

Of 147 randomised patients, 101 completed Year 1 study treatment; of these, 75 (74%) continued into Year 2 (anifrolumab IR: n=29, BR: n=23 and placebo: n=23). During Year 2, 72% of patients reported ≥1 adverse event (AE); serious AEs were reported in 6.9%, 8.7% and 8.7% of patients (anifrolumab IR, BR and placebo, respectively); 3 patients discontinued treatment due to an AE (anifrolumab IR: n=2 and placebo: n=1) and herpes zoster was reported in 2 patients (anifrolumab IR: n=1 and BR: n=1). The study was ongoing at the start of the pandemic, but no COVID-19 cases were reported. Of the 145 patients receiving treatment, more patients on the IR attained complete renal response at Week 104 compared with those on BR or placebo (27.3% vs 18.6% and 17.8%) and simultaneously achieved sustained glucocorticoid tapering (IR: 25.0%; BR: 18.6% and placebo: 17.8%). The improvements in estimated glomerular filtration rate were numerically larger in both anifrolumab groups versus placebo.

CONCLUSIONS

The safety and tolerability profile through Year 2 of TULIP-LN was generally consistent with Year 1, with promising efficacy results for the anifrolumab IR regimen. Collectively, the results support further investigation of an anifrolumab intensified dosing regimen in larger populations of patients with active proliferative LN.

TRIAL REGISTRATION NUMBER

NCT02547922.

Renal interferon-inducible protein 16 expression is associated with disease activity and prognosis in lupus nephritis

BACKGROUND

Lupus nephritis (LN) is one of the most severe complications of systemic lupus erythematosus (SLE). However, the current management of LN remains unsatisfactory due to sneaky symptoms during early stages and lack of reliable predictors of disease progression.

METHODS

Bioinformatics and machine learning algorithms were initially used to explore the potential biomarkers for LN development. Identified biomarker expression was evaluated by immunohistochemistry (IHC) and multiplex immunofluorescence (IF) in 104 LN patients, 12 diabetic kidney disease (DKD) patients, 12 minimal change disease (MCD) patients, 12 IgA nephropathy (IgAN) patients and 14 normal controls (NC). The association of biomarker expression with clinicopathologic indices and prognosis was analyzed. Gene Set Enrichment Analysis (GSEA) and Gene Set Variation Analysis (GSVA) were utilized to explore potential mechanisms.

RESULTS

Interferon-inducible protein 16 (IFI16) was identified as a potential biomarker for LN. IFI16 was highly expressed in the kidneys of LN patients compared to those with MCD, DKD, IgAN or NC. IFI16 co-localized with certain renal and inflammatory cells. Glomerular IFI16 expression was correlated with pathological activity indices of LN, while tubulointerstitial IFI16 expression was correlated with pathological chronicity indices. Renal IFI16 expression was positively associated with systemic lupus erythematosus disease activity index (SLEDAI) and serum creatinine while negatively related to baseline eGFR and serum complement C3. Additionally, higher IFI16 expression was closely related to poorer prognosis of LN patients. GSEA and GSVA suggested that IFI16 expression was involved in adaptive immune-related processes of LN.

CONCLUSION

Renal IFI16 expression is a potential biomarker for disease activity and clinical prognosis in LN patients. Renal IFI16 levels may be used to shed light on predicting the renal response and develop precise therapy for LN.

Knockdown of KLF5 ameliorates renal fibrosis in MRL/lpr mice via inhibition of MX1 transcription

OBJECTIVE

This study aims to elucidate the role of Kruppel-like factor (KLF5) and myxovirus resistance 1 (MX1) in the progression of renal fibrosis in lupus nephritis (LN).

METHODS

First, the expression of KLF5 and MX1 was assessed in the peripheral blood of LN patients and healthy participants. Next, the pathological changes in renal tissues were evaluated and compared in BALB/c and MRL/lpr mice, by detecting the expression of fibrosis marker proteins (transforming growth factor-β [TGF-β] and CTGF) and α-SMA, the content of urine protein, and the levels of serum creatinine, blood urea nitrogen, and serum double-stranded DNA antibody. In TGF-β1-induced HK-2 cells, the messenger RNA levels of KLF5 and MX1 were tested by qRT-PCR, and the protein expression of α-SMA, type I collagen (Col I), fibronectin (FN), and matrix metalloproteinase 9 (MMP9) was measured by western blot analysis. Moreover, the relationship between KLF5 and MX1 was predicted and verified.

RESULTS

In renal tissues of MRL/lpr mice and the peripheral blood of LN patients, KLF5 and MX1 were highly expressed. Pearson analysis revealed that KLF5 was positively correlated with MX1. Furthermore, KLF5 bound to MX1 promoter and promoted its transcription level. MRL/lpr mice showed substantial renal injury, accompanied by increased expression of α-SMA, TGF-β, CTGF, Col I, FN, and MMP9. Injection of sh-KLF5 or sh-MX1 alone in MRL/lpr mice reduced renal fibrosis in LN, while simultaneous injection of sh-KLF5 and ad-MX1 exacerbated renal injury and fibrosis. Furthermore, we obtained the same results in TGF-β1-induced HK-2 cells.

CONCLUSION

Knockdown of KLF5 alleviated renal fibrosis in LN through repressing the transcription of MX1.

Brensocatib, an oral, reversible inhibitor of dipeptidyl peptidase 1, mitigates interferon-α-accelerated lupus nephritis in mice

Neutrophils have been implicated in initiating and perpetuating systemic lupus erythematosus and the resultant kidney damage in lupus nephritis (LN) patients, in part through an excessive release of neutrophil serine proteases (NSPs). NSP zymogens are activated by dipeptidyl peptidase 1 (DPP1) during neutrophil maturation and released by mature neutrophils in response to inflammatory stimuli. Thus, a potential strategy to attenuate disease progression in LN would be to inhibit DPP1. We tested whether brensocatib, a highly selective and reversible DPP1 inhibitor, could mitigate LN progression in an interferon-alpha (IFNα)-accelerated NZB/W F1 mouse model. To confirm brensocatib's pharmacodynamic effect on NSPs in this mouse strain, repeated dose studies were conducted for 7 and 14 days in naïve NZB/W F1 mice via oral gavage twice a day. Brensocatib at 2 and 20 mg/kg/day achieved a significant reduction in bone marrow NSP activities after 7 days of daily administration. To initiate LN disease progression, the mice were injected with an IFNα-expressing adenovirus. After 2 weeks, three brensocatib doses (or vehicle) were administered for 6 more weeks. Throughout the 8-week study, brensocatib treatment (20 mg/kg/day) significantly reduced the occurrence of severe proteinuria compared to the vehicle control. Brensocatib treatment also entailed a significant reduction in the urine albumin-to-creatinine ratio, indicating decreased kidney damage, as well as a significant reduction in blood urea nitrogen level, suggesting improved renal function. Based on kidney histopathology analysis, brensocatib treatment significantly lowered both the renal tubular protein score and the nephropathy score compared to the vehicle group. A trend towards reduced glomerulonephritis score with brensocatib treatment was also observed. Lastly, brensocatib significantly reduced LN mouse kidney infiltration by various inflammatory cells. In conclusion, these results suggest that brensocatib alters disease progression in LN mice and warrant further evaluation of DPP1 inhibition in LN.

Amelioration of nephritis in receptor for advanced glycation end-products (RAGE)-deficient lupus-prone mice through neutrophil extracellular traps

The receptor for advanced glycation end-products (RAGE) is a pattern recognition receptor that regulates inflammation, cell migration, and cell fate. Systemic lupus erythematosus (SLE) is a chronic multiorgan autoimmune disease. To understand the function of RAGE in SLE, we generated RAGE-deficient (Ager-/-) lupus-prone mice by backcrossing MRL/MpJ-Faslpr/J (MRL-lpr) mice with Ager-/- C57BL/6 mice. In 18-week-old Ager-/- MRL-lpr, the weights of the spleen and lymph nodes, as well as the frequency of CD3+CD4-CD8- cells, were significantly decreased. Ager-/- MRL-lpr mice had significantly reduced urine albumin/creatinine ratios and markedly improved renal pathological scores. Moreover, neutrophil infiltration and neutrophil extracellular trap formation in the glomerulus were significantly reduced in Ager-/- MRL-lpr. Our study is the first to reveal that RAGE can have a pathologic role in immune cells, particularly neutrophils and T cells, in inflammatory tissues and suggests that the inhibition of RAGE may be a potential therapeutic strategy for SLE.

Reduced Renal CSE/CBS/H2S Contributes to the Progress of Lupus Nephritis

The molecular mechanisms underlying lupus nephritis (LN) pathogenesis are not fully understood. Hydrogen sulfide (H2S) is involved in many pathological and physiological processes. We sought to investigate the roles of H2S in LN pathogenesis. H2S synthase cystathionine-lyase (CSE) and cystathionine-synthetase (CBS) expression was downregulated in renal tissues of patients with LN and their levels were associated with LN's prognosis using the Nephroseq database. Reduced CSE and CBS protein expression in kidney tissues of LN patients and MRL/lpr mice were confirmed by immunohistochemistry. CSE and CBS mRNA levels were reduced in MRL/lpr and pristine- and R848-induced lupus mice. Given that H2S exerts an anti-inflammatory role partly via regulating inflammatory transcription factors (TFs), we analyzed hub TFs by using a bioinformatics approach. It showed that STAT1, RELA, and T-cell-related signaling pathways were enriched in LN. Increased STAT1 and RELA expression were confirmed in renal tissues of LN patients. Treatment of MRL/lpr and pristine mice with H2S donors alleviated systemic lupus erythematosus (SLE) phenotypes and renal injury. H2S donors inhibited RELA level and T-cell infiltration in the kidneys of MRL/lpr and pristine mice. Our data indicated that CSE/CBS/H2S contributes to LN pathogenesis. Supplementation of H2S would be a potential therapeutic strategy for LN.

Identification of potential biomarkers for systemic lupus erythematosus by integrated analysis of gene expression and methylation data

INTRODUCTION

Systemic lupus erythematosus (SLE) is a heterogeneous and chronic autoimmune disease. Aberrant DNA methylation occurs during various processes of SLE development regulating the mRNA expression of interrelated genes. This study aims to screen potential DNA methylation markers for SLE.

METHODS

Gene expression and methylation datasets were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) between SLE patients and healthy controls were screened using the limma R package, and differentially methylated positions (DMPs) and regions (DMRs) were identified using dmpfinder and bumphunter (minfi). Additionally, the DNA methylation markers to distinguish SLE patients from healthy controls were explored through receiver operating characteristic (ROC) curves and logistic regression analyses. Finally, we validated the results of the bioinformatic analysis by pyrosequencing.

RESULTS

In total, 91 DEGs, 90,092 DMPs, 15 DMRs, and 13 DMR-associated genes were identified. Through the integrative analysis of DEG- and DMR-associated genes, we identified five type I interferon (IFN)-related genes as key epigenetic-driven genes in SLE. GO enrichment analysis showed that the five SLE-associated epigenetic-driven genes were mainly enriched in the type I IFN signaling pathway involved in immune response and defense response to virus. Moreover, we identified two SLE-specific DNA methylation markers, three SLE without lupus nephritis (SLE-LN^-)-specific DNA methylation markers, and two SLE with lupus nephritis (SLE-LN⁺)-specific DNA methylation markers by stepwise logistic regression.

CONCLUSIONS

Overall, our study demonstrates potential DNA methylation markers of SLE, SLE-LN^-, and SLE-LN⁺, which may help the diagnosis, boost the development of new epigenetic therapy, and contribute to individualized treatment. Key Points • This study identified five type I IFN-related genes as key epigenetic-driven genes in SLE, which support the importance of the type I IFN pathway in the pathogenesis of SLE • We identified novel DNA methylation biomarkers in SLE, SLE-LN-, and SLE-LN+ by a comprehensive analysis of bioinformatics methods and executed experimental validation, and binary logistic regression analysis showed that they have excellent potential • These results may provide new insights into the biological mechanisms of SLE, and identify reliable biomarkers for SLE, SLE-LN-, and SLE-LN+, which may contribute to diagnosis and individualized treatment.

Transcriptional expression of CXCL10 and STAT1 in lupus nephritis and the intervention effect of triptolide

OBJECTIVE

This study screened out the key genes associated with the occurrence and development of lupus nephritis (LN) using bioinformatics methods, and then explored the expression of key genes in LN and the inhibitory effect of triptolide.

METHODS

The GEO2R online tool in the GEO database was used to perform differential analysis of gene expression in LN tissues and normal kidney tissues. The GO function and KEGG pathway enrichment analysis of differentially expressed genes (DEGs), STRING, and Cytoscape software were used to build a protein-protein interaction network (PPI) to screen out the Hub gene. Mouse glomerular mesangial cells (MMC) were randomly divided into a control group, an interferon-γ (IFN-γ) stimulation group, and a triptolide intervention group. The relative expression of CXCL10 mRNA in each group was detected by real-time fluorescent quantitative PCR (RT-PCR). CXCL10 secretion was detected by enzyme-linked immunosorbent assay (ELISA), and Western blot was used to detect the expression of the JAK/STAT1 signaling pathway-related proteins STAT1 and p-STAT1 in each group.

RESULTS

Bioinformatics showed that there were 22 DEGs expression differences in the GEO database. The GO enrichment analysis showed that biological process (BP) such as the type I interferon signaling pathway, innate immune response, IFN-γ-mediated signaling pathway, virus defense response, and immune response were significantly regulated by DEGs. Through the combination of String database analysis and cytoscape software, it was found that STAT1 and CXCL10 are closely related to LN. Experimental results showed that IFN-γ induces the expression of CXCL10 mRNA and protein by activating the JAK/STAT1 signaling pathway, while triptolide inhibits the expression of CXCL10 mRNA and protein by inhibiting the JAK/STAT1 signaling pathway.

CONCLUSION

STAT1 and CXCL10 are the key genes in the occurrence and development of LN. IFN-γ induces the expression of CXCL10 by activating the JAK/STAT1 signaling pathway, while triptolide inhibits the expression of CXCL10 by blocking the JAK/STAT1 signaling pathway. Inhibition of the JAK/STAT1 signaling pathway and CXCL10 expression is expected to become a potential target for the treatment of LN. Key Points • Bioinformatics showed that there were 22 DEGs expression differences in the GEO database. • Through the combination of String database analysis and Cytoscape software, it was found that STAT1 and CXCL10 are closely related to LN. • Experimental results showed that IFN-γ induces the expression of CXCL10 mRNA and protein by activating the JAK/STAT1 signaling pathway, while triptolide inhibits the expression of CXCL10 mRNA and protein by inhibiting the JAK/STAT1 signaling pathway.

Research progress of single-cell transcriptome sequencing in autoimmune diseases and autoinflammatory disease: A review

Autoimmunity refers to the phenomenon that the body's immune system produces antibodies or sensitized lymphocytes to its own tissues to cause an immune response. Immune disorders caused by autoimmunity can mediate autoimmune diseases. Autoimmune diseases have complicated pathogenesis due to the many types of cells involved, and the mechanism is still unclear. The emergence of single-cell research technology can solve the problem that ordinary transcriptome technology cannot be accurate to cell type. It provides unbiased results through independent analysis of cells in tissues and provides more mRNA information for identifying cell subpopulations, which provides a novel approach to study disruption of immune tolerance and disturbance of pro-inflammatory pathways on a cellular basis. It may fundamentally change the understanding of molecular pathways in the pathogenesis of autoimmune diseases and develop targeted drugs. Single-cell transcriptome sequencing (scRNA-seq) has been widely applied in autoimmune diseases, which provides a powerful tool for demonstrating the cellular heterogeneity of tissues involved in various immune inflammations, identifying pathogenic cell populations, and revealing the mechanism of disease occurrence and development. This review describes the principles of scRNA-seq, introduces common sequencing platforms and practical procedures, and focuses on the progress of scRNA-seq in 41 autoimmune diseases, which include 9 systemic autoimmune diseases and autoinflammatory diseases (rheumatoid arthritis, systemic lupus erythematosus, etc.) and 32 organ-specific autoimmune diseases (5 Skin diseases, 3 Nervous system diseases, 4 Eye diseases, 2 Respiratory system diseases, 2 Circulatory system diseases, 6 Liver, Gallbladder and Pancreas diseases, 2 Gastrointestinal system diseases, 3 Muscle, Bones and joint diseases, 3 Urinary system diseases, 2 Reproductive system diseases). This review also prospects the molecular mechanism targets of autoimmune diseases from the multi-molecular level and multi-dimensional analysis combined with single-cell multi-omics sequencing technology (such as scRNA-seq, Single cell ATAC-seq and single cell immune group library sequencing), which provides a reference for further exploring the pathogenesis and marker screening of autoimmune diseases and autoimmune inflammatory diseases in the future.

Artificial neural network - an effective tool for predicting the lupus nephritis outcome

Background

Lupus nephropathy (LN) occurs in approximately 50% of patients with systemic lupus erythematosus (SLE), and 20% of them will eventually progress into end-stage renal disease (ESRD). A clinical tool predicting remission of proteinuria might be of utmost importance. In our work, we focused on predicting the chance of complete remission achievement in LN patients, using artificial intelligence models, especially an artificial neural network, called the multi-layer perceptron.

Methods

It was a single centre retrospective study, including 58 individuals, with diagnosed systemic lupus erythematous and biopsy proven lupus nephritis. Patients were assigned into the study cohort, between 1st January 2010 and 31st December 2020, and eventually randomly allocated either to the training set (N = 46) or testing set (N = 12). The end point was remission achievement. We have selected an array of variables, subsequently reduced to the optimal minimum set, providing the best performance.

Results

We have obtained satisfactory results creating predictive models allowing to assess, with accuracy of 91.67%, a chance of achieving a complete remission, with a high discriminant ability (AUROC 0.9375).

Conclusion

Our solution allows an accurate assessment of complete remission achievement and monitoring of patients from the group with a lower probability of complete remission. The obtained models are scalable and can be improved by introducing new patient records.

Application of herbal traditional Chinese medicine in the treatment of lupus nephritis

Lupus nephritis (LN) is a secondary renal disease caused by systemic lupus erythematosus affecting the kidneys. It is one of the main causes of end-stage renal disease and a serious risk factor for early mortality and disability of systemic lupus erythematosus patients. Existing LN treatment is mainly based on hormones, cytotoxic drugs, and biological agents. Nevertheless, the prognosis of LN patients remains poor because of frequent recurrence and exacerbation of adverse drug reactions. Hence, LN is still the most important cause of end-stage renal disease. In recent years, traditional Chinese medicine (TCM) has attracted increasing attention because of encouraging evidence that it alleviates LN and the well-described mechanisms underlying renal injury. TCM has therapeutic benefits for treating LN patients. This review article elucidates TCM preparations, TCM monomers, and herbal or natural extraction for LN treatment to provide effective supplementary evidence for promoting the development of TCM treatment for LN and reference for future research and clinical practice.

Mer-tyrosine kinase: a novel susceptibility gene for SLE related end-stage renal disease

OBJECTIVE

Lupus nephritis (LN) is a common and severe manifestation of SLE. The genetic risk for nephritis and progression to end-stage renal disease (ESRD) in patients with LN remains unclear. Herein, we aimed to identify novel genetic associations with LN, focusing on subphenotypes and ESRD.

METHODS

We analysed genomic data on 958 patients with SLE (discovery cohort: LN=338) with targeted sequencing data from 1832 immunological pathway genes. We used an independent multiethnic cohort comprising 1226 patients with SLE (LN=603) as a replication dataset. Detailed functional annotation and functional epigenomic enrichment analyses were applied to predict functional effects of the candidate variants.

RESULTS

A genetic variant (rs56097910) within the MERTK gene was associated with ESRD in both cohorts, meta-analysis OR=5.4 (2.8 to 10.6); p=1.0×10-6. We observed decreased methylation levels in peripheral blood cells from SLE patients with ESRD, compared with patients without renal SLE (p=2.7×10-4), at one CpG site (cg16333401) in close vicinity to the transcription start site of MERTK and located in a DNAse hypersensitivity region in T and B cells. Rs56097910 is linked to altered MERTK expression in kidney tissue in public eQTL databases. Two loci were replicated for association with proliferative LN: PRDM1 (rs6924535, pmeta=1.6×10-5, OR=0.58) and APOA1BP (NAXE) (rs942960, pmeta=1.2×10-5, OR=2.64).

CONCLUSION

We identified a novel genetic risk locus, MERTK, associated with SLE-ESRD using the data from two large SLE cohorts. Through DNA methylation analysis and functional annotation, we showed that the risk could be mediated through regulation of gene expression. Our results suggest that variants in the MERTK gene are important for the risk of developing SLE-ESRD and suggest a role for PRDM1 and APOA1BP in proliferative LN.

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.

Lupus nephritis in the XXI century

Lupus nephritis (LN) is the most common organ lesion in systemic lupus erythematosus (SLE), developing in 4050% of patients. Due to immunosuppressive therapy, the survival of patients with SLE has increased significantly over the past 50 years, and the proportion of severe kidney damage in the death structure has decreased. However, LN relapses and complications of immunosuppression, accelerated atherogenesis, concomitant diseases lead to the accumulation of organ damage and an increased risk of death. The article consideres the place of kidney damage in the SLE, the risk factors for LN development, the main renal histopathological changes, it identifies a number of issues that need to be addressed to optimize treatment and improve LN long-term outcomes, including, the revision of pathogenetic therapy regimens with restriction of glucocorticosteroids and prescribing drugs with steroid-sparing activity, the integration of new drugs for LN treatment, wider use of modern nephroprotection capabilities.

Pregnancy-related complications in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune inflammatory disease that predominantly affects women of childbearing age and results in various adverse pregnancy outcomes (APOs). Pregnancy was formerly discouraged in patients with SLE because of unstable disease activity during the gestation period, increased thrombosis risk, severe organ damage, and inevitable side effects of immunosuppressive agents. Currently, most patients with SLE have successful pregnancies due to preconception counselling, strict monitoring, and improved therapy with minimised complications for both the mother and foetus. Hydroxychloroquine (HCQ) is extensively used and is beneficial for improving pregnancy outcomes. However, pregnant women with SLE have a high-risk of APOs, such as disease flare, preterm birth, intrauterine growth restriction (IUGR), preeclampsia, and pregnancy loss. Better understanding of the changes in maternal immunity and serum biomarkers, as well as their relationships with SLE-related APOs progression, would facilitate the investigation of molecular mechanisms for triggering and ameliorating APOs. Furthermore, it would enable us to explore and develop novel and effective therapeutic strategies to prevent disease activation. Therefore, this review briefly introduces the interaction between pregnancy outcomes and SLE, elucidates pathophysiological and immunological changes during SLE pregnancy. Furthermore, this review systematically expounds on the effective predictors of APOs and the molecular mechanisms underlying the SLE-related APOs to provide a solid foundation for the advanced management of lupus pregnancy.

Renal response and its predictive factors of lupus nephritis: a 2-year real-world study of 56 hospital-based patients

OBJECTIVES

Our aim was to evaluate the renal response rate of patients with lupus nephritis (LN) undergoing standard treatment during a 2-year follow-up and to investigate its predictive factors.

METHODS

A prospective cohort study that enrolled 56 clinically diagnosed LN patients with urinary protein positivity was carried out. All patients underwent standard treatment. All patients were followed up at 6-month intervals for 2 years. Data on renal response and clinical characteristics were collected and analyzed.

RESULTS

Among 56 patients, 27 (48.2%) and 13 (23.2%) patients achieved complete renal response (CR) and partial renal response (PR) at 6 months after induction therapy, respectively, and 42 (75.0%) and 4 (7.1%) patients developed CR and PR at 2 years. Among patients who achieved PR at 6 months, 90.0% achieved CR at 24 months, while only 37.5% of the patients who were unresponsive at 6 months achieved CR. In the multivariable Cox proportional-hazards model, female (OR 6.51, 95% CI 1.23-34.52, p = 0.028), disease duration (OR 0.84, 95% CI 0.73-0.98, p = 0.021), achieving PR within 6 months (OR 8.09, 95% CI 2.06-31.73, p = 0.003), and urine protein/creatinine ratio (UPCR) (OR 0.998, 95% CI 0.996-1.000, p = 0.025) were found to be predictive factors of CR.

CONCLUSION

A total of 48.2% of patients achieved CR at 6 months of induction therapy, and the response rates gradually increased to 60.7%, 64.3%, and 75.0% at 12, 18, and 24 months. Besides, female, disease duration, partial response within 6 months, and UPCR were predictive factors for a complete renal response. Key Points • We evaluate the renal response rates in Chinese patients with lupus nephritis in the real world for 2 years. • A total of 48.2% and 75.0% of patients achieved a complete response after standard treatment for 6 months and 2 years. • Female, disease duration, partial response within 6 months, and UPCR are predictors of complete renal response.

Revisited Cyclophosphamide in the Treatment of Lupus Nephritis

Lupus nephritis (LN) is the most common serious complication of systemic lupus erythematosus (SLE). The pathogenesis of LN is complex, and the majority causes of LN are the renal deposition of circulating or/and in situ-formed immune complexes. These immune complexes trigger glomerular and tubulointerstitial inflammation, which finally leads to proteinuria and loss of renal function. Despite the emergence of new biological agents, cyclophosphamide (CY), an alkylating agent, is still the first-line drug widely used to treat patients with severe LN. In this review, we outline the application history, molecular structure, and pharmacokinetics of CY in the treatment of LN. We also detail its latest known immunopharmacological mechanisms, with a focus on supplemental regulation and inhibition of CD4 and CD8 positive T cells, differences in the use of various guidelines, and the combination with other drugs. The side effects of CY are also mentioned in this review.

Dickkopf Homolog 3 (DKK3) as a Prognostic Marker in Lupus Nephritis: A Prospective Monocentric Experience

Background: The gold standard for diagnosis of lupus nephritis (LN) is still represented by renal biopsy, and serological prognostic biomarkers are still lacking. Dickkopf homolog-3 (DKK3) has been suggested as a marker of tissue fibrosis in different conditions; however, its role in autoimmune diseases needs to be elucidated. Here, we investigated the prognostic role of DKK3 in systemic lupus erythematosus (SLE) patients with and without LN, assessing its changes in relation to kidney function, flares, and interstitial fibrosis. Methods: Overall, 132 SLE patients (57 with LN) were included and prospectively followed up for at least 36 months. DKK3 was measured in serum at baseline. Biopsies were evaluated for glomerular involvement, interstitial fibrosis, and tubular atrophy. Results: Patients with biopsy-proven LN had significantly higher levels of DKK3 than those without (median [min−max]: 215 ng/mL [81−341] vs. 21.1 ng/mL [1−69], p < 0.01). DKK3 levels were associated with prevalent chronic kidney diseases (OR: 4.31 [C.I. 2.01−6.61] per DKK3 doubling, p < 0.01), higher chronicity index at biopsy (1.75 [1.51−2.77] per DKK3 doubling, p < 0.01), and flares rate (OR: 1.45 [C.I. 1.1−5.71] per DKK3 doubling, p < 0.044). Conclusions: While kidney biopsy still represents the gold standard for diagnostic and prognostic assessment in LN, DKK3 could represent an additional prognostic tool to monitor SLE patients and guide therapeutic choices.

The Role of Advanced Glycation End Products and Its Soluble Receptor in Kidney Diseases

Patients with chronic kidney disease (CKD) are more prone to oxidative stress and chronic inflammation, which may lead to an increase in the synthesis of advanced glycation end products (AGEs). Because AGEs are mostly removed by healthy kidneys, AGE accumulation is a result of both increased production and decreased kidney clearance. On the other hand, AGEs may potentially hasten decreasing kidney function in CKD patients, and are independently related to all-cause mortality. They are one of the non-traditional risk factors that play a significant role in the underlying processes that lead to excessive cardiovascular disease in CKD patients. When AGEs interact with their cell-bound receptor (RAGE), cell dysfunction is initiated by activating nuclear factor kappa-B (NF-κB), increasing the production and release of inflammatory cytokines. Alterations in the AGE-RAGE system have been related to the development of several chronic kidney diseases. Soluble RAGE (sRAGE) is a decoy receptor that suppresses membrane-bound RAGE activation and AGE-RAGE-related toxicity. sRAGE, and more specifically, the AGE/sRAGE ratio, may be promising tools for predicting the prognosis of kidney diseases. In the present review, we discuss the potential role of AGEs and sRAGE as biomarkers in different kidney pathologies.

Abnormal cortical thickness and structural covariance networks in systemic lupus erythematosus patients without major neuropsychiatric manifestations

BACKGROUND

Non-neuropsychiatric systemic lupus erythematosus (non-NPSLE) has been confirmed to have subtle changes in brain structure before the appearance of obvious neuropsychiatric symptoms. Previous literature mainly focuses on brain structure loss in non-NPSLE; however, the results are heterogeneous, and the impact of structural changes on the topological structure of patients' brain networks remains to be determined. In this study, we combined neuroimaging and network analysis methods to evaluate the changes in cortical thickness and its structural covariance networks (SCNs) in patients with non-NPSLE.

METHODS

We compare the cortical thickness of non-NPSLE patients (N=108) and healthy controls (HCs, N=88) using both surface-based morphometry (SBM) and regions of interest (ROI) methods, respectively. After that, we analyzed the correlation between the abnormal cortical thickness results found in the ROI method and a series of clinical features. Finally, we constructed the SCNs of two groups using the regional cortical thickness and analyzed the abnormal SCNs of non-NPSLE.

RESULTS

By SBM method, we found that cortical thickness of 34 clusters in the non-NPSLE group was thinner than that in the HC group. ROI method based on Destrieux atlas showed that cortical thickness of 57 regions in the non-NPSLE group was thinner than that in the HC group and related to the course of disease, autoantibodies, the cumulative amount of immunosuppressive agents, and cognitive psychological scale. In the SCN analysis, the cortical thickness SCNs of the non-NPSLE group did not follow the small-world attribute at a few densities, and the global clustering coefficient appeared to increase. The area under the curve analysis showed that there were significant differences between the two groups in clustering coefficient, degree, betweenness, and local efficiency. There are a total of seven hubs for non-NPSLE, and five hubs in HCs, the two groups do not share a common hub distribution.

CONCLUSION

Extensive and obvious reduction in cortical thickness and abnormal topological organization of SCNs are observed in non-NPSLE patients. The observed abnormalities may not only be the realization of brain damage caused by the disease, but also the contribution of the compensatory changes within the nervous system.

Prioritization of Diagnostic and Prognostic Biomarkers for Lupus Nephritis Based on Integrated Bioinformatics Analyses

Lupus nephritis (LN) is an important driver of end-stage renal disease (ESRD). However, few biomarkers are available for evaluating the diagnosis and prognosis of LN. For this study, we downloaded microarray data of multiple LN expression profiles from the GEO database. We used the WGCNA and R limma packages to identify LN hub genes and differentially-expressed genes (DEGs). We identified nine co-DEGs in the intersection with LN-related genes from the Genecards database. We found DEGs that are primarily associated with immune-related functions and pathways (including with the complement pathway, primary immunodeficiency markers, and MHC-like protein complexes) through our comprehensive GSEA, GO, and KEGG enrichment analyses. We used other LN and SLE validation datasets and discovered six explicitly expressed co-DEGs: HLA-DMA, HLA-DPA1, HLA-DPB1, HLA-DRA, IL10RA, and IRF8 in the LN set; ROC and Precision-Recall curve analyses revealed that these six genes have a good diagnostic efficacy. The correlation analysis with prognostic data from the Nephroseq database indicates that the differential expression of these co-DEGs is associated with a low glomerular filtration rate in that cohort. Additionally, we used a single-cell LN database of immune cells (for the first time) and discovered these co-DEGs to be predominantly distributed in different types of macrophages and B cells. In conclusion, by integrating multiple approaches for DEGs discovery, we identified six valuable biomarkers that are strongly correlated with the diagnosis and prognosis of LN. These markers can help clarify the pathogenesis and improve the clinical management of LN.

Prognostic and Diagnostic Values of Novel Serum and Urine Biomarkers in Lupus Nephritis: A Systematic Review

INTRODUCTION

While renal biopsy remains the gold standard for diagnosing lupus nephritis (LN), the prognostic and diagnostic role of non-invasive biomarkers for LN is currently debated.

METHODS

Available studies published in last 5 years (2015-2020) assessing the diagnostic and prognostic value of urinary and/or serological biomarkers in subjects with LN were analyzed in this systematic review.

RESULTS

Eighty-five studies were included (comprehending 13,496 patients with systemic lupus erythematosus [SLE], 8,872 LN, 487 pediatric LN, 3,977 SLE but no LN, 160 pediatric SLE but no LN and 7,679 controls). Most of the studies were cross-sectional (62; 73%), while 14 (17%) were prospective. In sixty studies (71%), the diagnosis of LN was biopsy-confirmed. Forty-four out of 85 (52%) investigated only serological biomarkers, 29 studies (34%) tested their population only with urinary biomarkers, and 12 (14%) investigated the presence of both. Outcome measures to assess the clinical utility of the analyzed biomarkers were heterogeneous, including up to 21 different activity scores, with the SLEDAI (in 60%) being the most used. Despite some heterogeneity, promising results have been shown for biomarkers such as urinary monocyte chemoattractant protein, urinary adiponectin, and urinary vascular cell adhesion protein 1.

DISCUSSION/CONCLUSION

While serum and urine biomarkers have the potential to improve diagnostic and prognostic pathways in patients with LN, the vast heterogeneity across studies severely limits their applicability in current clinical practice. With the kidney biopsy still representing the gold standard, future efforts should focus on harmonizing study inclusion criteria and outcomes, particularly in clinical trials, in order to improve comparability and facilitate the implementations of available biomarkers into the daily practice.

Interleukin-12 exacerbates symptoms in an MRL/MpJ-Faslpr mouse model of systemic lupus erythematosus

Interleukin (IL)-12 modulates the generation and function of a variety of immune cells and serves an important role in the pathogenesis of autoimmune diseases. However, the precise role of IL-12 in the pathogenesis of systemic lupus erythematosus (SLE) remains to be elucidated. In the present study, the serum levels of IL-12 in patients with SLE were determined using an ELISA. The association between serum levels of IL-12 and clinical and laboratory indices, specifically, disease activity and complement 3, were analyzed. Recombinant IL-12 or an anti-IL-12 antibody was used to treat the MRL/MpJ-Fas^lpr mouse model of systemic lupus erythematosus. The glomerulonephritis and inflammatory cell infiltration was examined to evaluate histological changes using hematoxylin and eosin and Periodic acid-Schiff staining. Serum creatinine and proteinuria were used to determine renal function. The levels of anti-double stranded DNA and anti-nuclear autoantibodies were assessed. The results demonstrated that serum levels of IL-12 were markedly increased in patients with SLE compared with controls and in lupus model mice in comparison with control mice. The serum levels of IL-12 increased with disease severity in patients with SLE. SLE-like symptoms were exacerbated in lupus model mice treated with exogenous IL-12. However, SLE-like symptoms were ameliorated in lupus model mice treated with an anti-IL-12 antibody. The present results demonstrated that IL-12 aggravated SLE and anti-IL12 antibodies ameliorated SLE. The present data suggest that blocking IL-12 may be a beneficial therapeutic strategy to halt the progression of lupus nephritis.

Risikostratifizierung ausgewählter schwerer Organbeteiligungen bei Systemischer Sklerose und bei Lupus-Nephritis

Interstitielle Lungenerkrankung (ILD), pulmonal-arterielle Hypertonie (PAH), kardiale Beteiligung und renale Krise sind schwere Prognose-bestimmende Manifestationen der Systemischen Sklerose (SSc). Digitale Ulcerationen führen zu erheblicher Beeinträchtigung von Erwerbsfähigkeit und Lebensqualität. Im Rahmen der Betreuung von SSc-Patienten ist daher eine Risikostratifizierung in Hinblick auf Entwicklung und Progression dieser schweren Manifestationen von wesentlicher Bedeutung. Risikofaktoren für die Entwicklung einer SSc-ILD sind diffuse cutane Sklerodermie (dcSSc), männliches Geschlecht und der Nachweis von Topoisomerase-I-Antikörpern. Ausmaß und Verlauf der SSc-ILD sind variabel. Klinik, Ausgangsbefund und Dynamik der Lungenfunktion und hochauflösendes CT (HR-CT) des Thorax werden genutzt, um frühzeitig Patienten zu identifizieren, welche einer Immunsuppression bedürfen und von jenen zu unterscheiden, bei denen zunächst engmaschige Verlaufskontrollen vertretbar sind. Zu den Risikofaktoren einer SSc-PAH zählen langer Krankheitsverlauf, hohes Lebensalter bei Beginn der SSc, schwere Raynaud-Symptomatik, schwere digitale Ischämien sowie Teleangiektasien, der Nachweis von Centromer-Antikörpern sowie Antikörpern gegen Endothelin-A-Rezeptor und Angiotensin-1-Rezeptor und Hyperurikämie. Bei etablierter PAH erfolgt die Risikostratifizierung auf Basis der kalkulierten 1-Jahres-Mortaliät. Zur Kalkulation der 1-Jahresmortalität werden anamnestische und klinische Parameter wie Symptomprogression, Auftreten von Synkopen, Vorhandensein klinischer Zeichen einer Rechtsherzinsuffizienz, funktionelle WHO-Klasse, funktionsdiagnostische, laborchemische, echokardiografische sowie hämodynamische Parameter herangezogen. Nach den aktuellen Empfehlungen zur Therapie der PAH ist eine primäre Kombinationstherapie zumindest ab WHO-Funktionsklasse III und einem intermediären Risiko (1-Jahres-Mortalität≥5%) indiziert. Wesentliche Risikofaktoren einer kardialen Beteiligung bei SSc sind höheres Lebensalter, dcSSc und der Nachweis von Topoisomerase I-Antikörpern. Zu den Risikofaktoren der renalen Krise bei SSc zählen dcSSc, männliches Geschlecht, der Nachweis von RNA-Polymerase III-Antikörpern, vorbestehende Proteinurie, aber auch eine Vortherapie mit Glukokortikoiden, ACE-Hemmern und Cyclosporin. Digitale Ulcera (DU) treten bei ca. 50% der Patienten auf. Risikofaktoren von DU sind dcSSc, Nachweis von Topoisomerase I-Antikörpern, früher Beginn der Raynaud-Symptomatik, hoher Rodnan Skin Score und männliches Geschlecht. Entscheidendes Therapieziel bei der Lupus-Nephritis (LN) ist der Erhalt einer normalen Nierenfunktion und die Vermeidung einer terminalen Niereninsuffizienz, welche mit einer erhöhten Letalität assoziiert ist. Zu den Risikofaktoren eines ungünstigen Langzeitverlaufs der LN zählen v. a. eine initiale irreversible Nierenfunktionseinschränkung im Zusammenhang mit irreversiblen chronischen Läsionen in der Nierenbiopsie, unzureichend kontrollierte arterielle Hypertonie, ausgeprägte initiale Proteinurie und männliches Geschlecht. Eine effektive Reduktion der Proteinurie auf<0,5–0,8 g/d innerhalb von 12 Monaten nach Beginn der Remissionsinduktion signalisiert dagegen eine günstige Prognose. Frühestmögliche Diagnose der LN und umgehende auf dem Befund der Nierenbiopsie basierende Therapie sowie Reinduktion bei ausbleibender Remission sind entscheidend für eine Minimierung der Risikos.

[Clinicopathological features of children with lupus nephritis with positive antineutrophil cytoplasmic antibody]

OBJECTIVE

To study the clinicopathological features of children with lupus nephritis (LN) with positive anti-neutrophil cytoplasmic antibody (ANCA).

METHODS

A retrospective analysis was performed for the children who were diagnosed with LN in the First Affiliated Hospital of Sun Yat-sen University from January 2003 to December 2019. According to the results of serum ANCA, they were divided into two groups: ANCA-positive group (n=59) and ANCAnegative group (n=454). The two groups were compared in terms of clinical manifestations, histopathological features, remission rate, and prognosis.

RESULTS

Compared with the ANCA-negative group, the ANCA-positive group had a significant reduction in leukocytes and a significant increase in erythrocyte sedimentation rate (P < 0.05). There were no significant differences between the two groups in serum creatinine, urine protein, and urine red blood cell count (P > 0.05). A total of 308 children underwent kidney biopsy. The results on light microscopy showed that compared with the ANCAnegative group, the ANCA-positive group had a significantly higher proportion of children with cellular fibrous crescents (P < 0.05) and a significantly lower proportion of children with immune complex deposition (P < 0.05). There were no significant differences between the two groups in the remission rate and survival rate (P > 0.05).

CONCLUSIONS

Children with ANCA-positive LN tend to have more severe renal pathological injury, which is not exactly parallel with clinical manifestations, suggesting that timely renal biopsy is of great importance.

Autoimmunity and organ damage in systemic lupus erythematosus

Impressive progress has been made over the last several years toward understanding how almost every aspect of the immune system contributes to the expression of systemic autoimmunity. In parallel, studies have shed light on the mechanisms that contribute to organ inflammation and damage. New approaches that address the complicated interaction between genetic variants, epigenetic processes, sex and the environment promise to enlighten the multitude of pathways that lead to what is clinically defined as systemic lupus erythematosus. It is expected that each patient owns a unique 'interactome', which will dictate specific treatment.