Machine learning models predicts risk of proliferative lupus nephritis

Objective

This study aims to develop and validate machine learning models to predict proliferative lupus nephritis (PLN) occurrence, offering a reliable diagnostic alternative when renal biopsy is not feasible or safe.

Methods

This study retrospectively analyzed clinical and laboratory data from patients diagnosed with SLE and renal involvement who underwent renal biopsy at West China Hospital of Sichuan University between 2011 and 2021. We randomly assigned 70% of the patients to a training cohort and the remaining 30% to a test cohort. Various machine learning models were constructed on the training cohort, including generalized linear models (e.g., logistic regression, least absolute shrinkage and selection operator, ridge regression, and elastic net), support vector machines (linear and radial basis kernel functions), and decision tree models (e.g., classical decision tree, conditional inference tree, and random forest). Diagnostic performance was evaluated using ROC curves, calibration curves, and DCA for both cohorts. Furthermore, different machine learning models were compared to identify key and shared features, aiming to screen for potential PLN diagnostic markers.

Results

Involving 1312 LN patients, with 780 PLN/NPLN cases analyzed. They were randomly divided into a training group (547 cases) and a testing group (233 cases). we developed nine machine learning models in the training group. Seven models demonstrated excellent discriminatory abilities in the testing cohort, random forest model showed the highest discriminatory ability (AUC: 0.880, 95% confidence interval(CI): 0.835-0.926). Logistic regression had the best calibration, while random forest exhibited the greatest clinical net benefit. By comparing features across various models, we confirmed the efficacy of traditional indicators like anti-dsDNA antibodies, complement levels, serum creatinine, and urinary red and white blood cells in predicting and distinguishing PLN. Additionally, we uncovered the potential value of previously controversial or underutilized indicators such as serum chloride, neutrophil percentage, serum cystatin C, hematocrit, urinary pH, blood routine red blood cells, and immunoglobulin M in predicting PLN.

Conclusion

This study provides a comprehensive perspective on incorporating a broader range of biomarkers for diagnosing and predicting PLN. Additionally, it offers an ideal non-invasive diagnostic tool for SLE patients unable to undergo renal biopsy.

Noninvasive biomarkers for lupus nephritis

Lupus nephritis (LN) is one of the most severe clinical manifestations of systemic lupus erythematosus (SLE). Notably, the clinical manifestations of LN are not always consistent with the histopathological findings. Therefore, the diagnosis and activity monitoring of this disease are challenging and largely depend on invasive renal biopsy. Renal biopsy has side effects and is associated with the risk of bleeding and infection. There is a growing interest in the development of novel noninvasive biomarkers for LN. In this review, we summarize most of the LN biomarkers discovered so far by correlating current knowledge with future perspectives. These biomarkers fundamentally reflect the biological processes of kidney damage and repair during disease. Furthermore, this review highlights the role of urinary cell phenotype detection in the diagnosis, monitoring, and treatment of LN and summarizes the limitations and countermeasures of this test.

Biomarkers Associated with Drugs for the Treatment of Lupus Nephritis

The constant updating of lupus drug treatment guidelines has led to a question. How can the efficacy of treatment be more effectively monitored? Systemic lupus erythematosus (SLE) is a complex autoimmune disease that often presents clinically with multi-organ involvement, and approximately 30% of patients with SLE develop lupus nephritis (LN). Therefore, it is important to better track disease progression and drug efficacy. Now, kidney biopsy is still the gold standard for diagnosing and guiding the treatment of LN, but it is invasive and expensive. If simple, non-invasive and effective biomarkers can be found, drug intervention and prognosis can be better monitored and targeted. In this review, we focus on LN and explore biomarkers related to LN therapeutics, providing clinicians with more possibilities to track the therapeutic effect of drugs, improve treatment options and assess patient outcomes.

MCP-1/CCR2 axis is involved in the regulation of γδT cells in lupus nephritis

γδT cells are important innate immune cells that are involved in the occurrence and development of autoimmune diseases such as systemic lupus erythematosus (SLE). Lupus nephritis (LN) is a serious complication of SLE, characterized by the accumulation of immune cells (including γδT cells) in the target organs to participate in the disease process. Therefore, clarifying how γδT cells chemotactically migrate to target organs may be a key to developing therapeutic methods against LN. Enzyme-linked immunosorbent assay (ELISA) was used to detect serum levels of chemokines in LN patients and healthy controls. Real-time polymerase chain reaction (RT-PCR) and flow cytometry were used to measure the expression of chemokine receptors on the surface of γδT cells. The chemotactic migration ability of γδT cells was detected by Transwell assay. Signalling pathway activation of γδT cells was detected by Automated Capillary Electrophoresis Immunoassay and flow cytometry. The serum levels of chemokines, including monocyte chemoattractant protein-1 (MCP-1) in LN patients, were significantly increased. CCR2, the receptor of MCP-1, was also highly expressed on the surface of peripheral γδT cells in LN patients. In addition, the exogenous addition of MCP-1 can enhance chemotactic migration of γδT cells in LN patients. MCP-1 could activate STAT3 signalling in LN patients' peripheral γδT cells. γδT cells might participate in the pathogenesis of LN through MCP-1/CCR2 axis. This finding provides new opportunities for developing treatment methods against LN by targeting MCP-1/CCR2 axis.

Diagnostic test accuracy of novel biomarkers for lupus nephritis-An overview of systematic reviews

INTRODUCTION

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with multiorgan inflammatory involvement and a mortality rate that is 2.6-fold higher than individuals of the same age and sex in the general population. Approximately 50% of patients with SLE develop renal impairment (lupus nephritis). Delayed diagnosis of lupus nephritis is associated with a higher risk of progression to end-stage renal disease, the need for replacement therapy, and mortality. The initial clinical manifestations of lupus nephritis are often discrete or absent and are usually detected through complementary tests. Although widely used in clinical practice, their accuracy is limited. A great scientific effort has been exerted towards searching for new, more sensitive, and specific biomarkers in recent years. Some systematic reviews have individually evaluated new serum and urinary biomarkers tested in patients with lupus nephritis. This overview aimed to summarize systematic reviews on the accuracy of novel serum and urinary biomarkers for diagnosing lupus nephritis in patients with SLE, discussing how our results can guide the clinical management of the disease and the direction of research in this area.

METHODS

The research question is "What is the accuracy of the new serum and urinary biomarkers studied for the diagnosis of LN in patients with SLE?". We searched for systematic reviews of observational studies evaluating the diagnostic accuracy of new serum or urinary biomarkers of lupus nephritis. The following databases were included: PubMed, EMBASE, BIREME/LILACS, Scopus, Web of Science, and Cochrane, including gray literature found via Google Scholar and PROQUEST. Two authors assessed the reviews for inclusion, data extraction, and assessment of the risk of bias (ROBIS tool).

RESULTS

Ten SRs on the diagnostic accuracy of new serum and urinary BMs in LN were selected. The SRs evaluated 7 distinct BMs: (a) antibodies (anti-Sm, anti-RNP, and anti-C1q), (b) cytokines (TWEAK and MCP-1), (c) a chemokine (IP-10), and (d) an acute phase glycoprotein (NGAL), in a total of 20 review arms (9 that analyzed serum BMs, and 12 that analyzed BMs in urine). The population evaluated in the primary studies was predominantly adults. Two SRs included strictly adults, 5 reviews also included studies in the paediatric population, and 4 did not report the age groups. The results of the evaluation with the ROBIS tool showed that most of the reviews had a low overall risk of bias.

CONCLUSIONS

There are 10 SRs of evidence relating to the diagnostic accuracy of serum and urinary biomarkers for lupus nephritis. Among the BMs evaluated, anti-C1q, urinary MCP-1, TWEAK, and NGAL stood out, highlighting the need for additional research, especially on LN diagnostic panels, and attempting to address methodological issues within diagnostic accuracy research. This would allow for a better understanding of their usefulness and possibly validate their clinical use in the future.

REGISTRATION

This project is registered on the International Prospective Registry of Systematic Reviews (PROSPERO) database (CRD42020196693).

The Bladder Microbiome, Metabolome, Cytokines, and Phenotypes in Patients with Systemic Lupus Erythematosus

Emerging studies reveal unique bacterial communities in the human bladder, with alteration of composition associated to disease states. Systemic lupus erythematosus (SLE) is a complex autoimmune disease that is characterized by frequent impairment of the kidney. Here, we explored the bladder microbiome, metabolome, and cytokine profiles in SLE patients, as well as correlations between microbiome and metabolome, cytokines, and disease profiles. We recruited a group of 50 SLE patients and 50 individually matched asymptomatic controls. We used transurethral catheterization to collect urine samples, 16S rRNA gene sequencing to profile bladder microbiomes, and liquid chromatography-tandem mass spectrometry to perform untargeted metabolomic profiling. Compared to controls, SLE patients possessed unique bladder microbial communities and increased alpha diversity. These differences were accompanied by differences in urinary metabolomes, cytokines, and patients’ disease profiles. The SLE-enriched genera, including Bacteroides, were positively correlated with several SLE-enriched metabolites, including olopatadine. The SLE-depleted genera, such as Pseudomonas, were negatively correlated to SLE-depleted cytokines, including interleukin-8. Alteration of the bladder microbiome was associated with disease profile. For example, the genera Megamonas and Phocaeicola were negatively correlated with serum complement component 3, and Streptococcus was positively correlated with IgG. Our present study reveals associations between the bladder microbiome and the urinary metabolome, cytokines, and disease phenotypes. Our results could help identify biomarkers for SLE.

IMPORTANCE Contrary to dogma, the human urinary bladder possesses its own unique bacterial community with alteration of composition associated with disease states. Systemic lupus erythematosus (SLE) is a complex autoimmune disease often characterized by kidney impairment. Here, we explored the bladder microbiome, metabolome, and cytokine profiles in SLE patients, as well as correlations between the microbiome and metabolome, cytokines, and disease profiles. Compared to controls, SLE patients possessed a unique bladder microbial community and elevated alpha diversity. These differences were accompanied by differences in bladder metabolomes, cytokines, and patients’ disease profiles. SLE-enriched genera were positively correlated with several SLE-enriched metabolites. SLE-depleted genera were negatively correlated to SLE-depleted cytokines. Alteration of the bladder microbiome was associated with disease profile. Thus, our study reveals associations between the bladder microbiome and the bladder metabolome, cytokines, and disease phenotypes. These results could help identify biomarkers for SLE.

Serum and Urine Interferon Gamma-Induced Protein 10 (IP-10) Levels in Lupus Nephritis

Background: Lupus nephritis (LN) is a prevalent and severe complication of systemic lupus erythematosus (SLE). Non-invasive diagnostics are limited, and current therapies have inadequate response rates. Expression of the chemokine Interferon-γ-induced protein 10 (IP-10) is regulated by Interferon-γ signaling and NF-κB, and its molecular activity and enhanced urine concentrations are implicated in LN, but its utility as a diagnostic marker and association with demographic, clinical, or pathologic features is not defined. Methods: 38 LN patients and 11 patients with non-LN glomerular diseases (GD) with active disease were included. Eighteen of the LN patients had achieved remission at one follow-up during the study time. Serum and urine were obtained from these samples, and the IP-10 levels were measured. Results: Serum and urine IP-10 levels are significantly enhanced in LN patients with active disease as compared with normal individuals (serum average 179.7 pg/mL vs. 7.2 pg/mL, p < 0.0001; urine average 28.7 pg/mg vs. 1.6 pg/mg, p = 0.0019) and patients with other forms of glomerular disease (serum average 179.7 pg/mL vs. 84.9 pg/mL, p = 0.0176; urine average 28.7 pg/mg vs. 0.18 pg/mg, p = 0.0011). Urine IP-10 levels are significantly higher in patients with proliferative LN (PLN) than those with membranous LN (MLN) (average 32.8 pg/mg vs. 7.6 pg/mg, p = 0.0155). Urine IP-10 levels are also higher in MLN versus primary membranous nephropathy (MN) (average 7.6 pg/mg vs. 0.2 pg/mg, p = 0.0193). Importantly, serum IP-10 levels remain elevated during active LN and LN remission, but urine IP-10 levels are decreased from active LN to remission in 72% of our patients. Lastly, serum, but not urine IP-10 levels are significantly higher in African American than White American LN patients in active LN (average 227.8 pg/mL vs. 103.4 pg/mL, p = 0.0309) and during LN remission (average 254.6 pg/mL vs. 89.2 pg/mL, p = 0.0399). Conclusions: Our findings suggest that serum and urine IP-10 measurements provide promising tests for monitoring LN activity, differentiation between classifications of LN, and differentiation between LN and other forms of glomerular disease. We also conclude that further assessment of elevated IP-10 levels in the serum and urine of high-risk populations (i.e., African American) could be beneficial in determining why many of these patients have worse outcomes and are non-responsive to standard therapeutics.

Serum and urinary galectin-9 and C-X-C motif chemokine ligand 10

BACKGROUND

Systemic lupus erythematosus (SLE) is characterized by a type I interferon (IFN) signature, and traditional methods for its measurement like gene expression analysis are cumbersome for routine use. Thus, we aimed to study galectin-9 as a biomarker and compared it with a validated marker, C-X-C motifchemokine ligand 10(CXCL-10).

METHODS

Ninety-seven patients with SLE (26 years; 89 females) were included and stratified based on renal involvement and activity into - active (SLEDAI > 4) renal (35), active non-renal (32) and inactive renal subgroups (30) along with 20 healthy controls (HC, 25 years; 15 females). The median disease duration was 24 months (6-48), and SLEDAI 2K was 9 (2-15). Serum and urine galectin-9 and CXCL-10 levels were measured by ELISA. Urine levels were normalized with spot urine creatinine values. Follow-up serum and urine galectin-9 levels were measured for those in the active renal group at 6 months.

RESULTS

Patients with SLE had higher serum galectin-9 (5.6 vs 1.7 μg/mL, p = .0001) but not urine galectin-9 (0.52 vs 0.32 μg, p = .7) levels as compared to HC. Serum galectin-9 but not urine galectin-9 was higher in patients with active as compared to inactive lupus (12.9 - active renal, 16.7 - active non-renal vs 3.57 μg/mL, p = .04 and .005). Serum CXCL-10 (0.16 vs 0.05, p = .01) and urine CXCL-10 (0 vs 0, p = .01) were both significantly higher in the SLE group as compared with HC. Serum but not urine CXCL-10 was higher in the active as compared to inactive lupus (0.2 - active renal, 0.3 - active non-renal vs 0.08 μg/mL, p = .9 and .02). Serum galectin-9 showed a modest correlation with CXCL-10 0.4 (0.2-0.6), whereas none was found between their urine levels.Serum galectin-9 and CXCL-10 showed a moderate positive correlation with SLEDAI 2K. Serum galectin-9 showed a greater AUC than CXCL-10 (0.77 vs 0.67) in differentiating active from inactive SLE, and both tested together had the best AUC of 0.82. However, urinary levels had no association with SLEDAI 2K or renal SLEDAI. In a subset of patients with active renal disease, serum galectin-9 but not urine levels declined significantly after 6 months.

CONCLUSION

Serum galectin-9 is a good marker of lupus activity; however, it does not differentiate between active renal and active non-renal disease. It performs slightly better than CXCL-10. Urinary galectin-9 does not reflect renal activity.

Inflammatory markers in saliva and urine reflect disease activity in patients with systemic lupus erythematosus

BACKGROUND

Laboratory tests of blood and sometimes urine are used to diagnose and to monitor disease activity (DA) in SLE. Clinical practice would be simplified if non-invasive urine and salivary tests could be introduced as alternatives to blood samples. We therefore explored the levels of innate immunity-related biomarkers in matched serum, urine and saliva samples from patients with SLE.

METHODS

A total of 84 patients with SLE selected to represent high and low general DA, and 21 controls were included. All participants underwent a thorough clinical examination. General DA and renal DA were measured. The levels of colony-stimulating factor (CSF)-1, interleukin (IL)-34, tumour necrosis factor (TNF)-α, interferon-γ-induced protein (IP)-10, monocyte chemoattractant protein (MCP)-1, calprotectin, macrophage inflammatory protein (MIP)-1α and MIP-1β were analysed by immunoassays and related to DA.

RESULTS

CSF-1, TNF-α, IP-10 and MCP-1 in saliva, serum and urine, as well as calprotectin in saliva and urine were increased in patients with SLE as compared with controls (p<0.05). TNF-α, IP-10 and MCP-1 in saliva, serum and urine, and CSF-1 in saliva and serum distinguished patients with SLE from controls (area under the curve >0.659; p<0.05 for all). CSF-1 in serum and urine, and calprotectin in saliva and urine, as well as TNF- α, IP-10 and MCP-1 in urine correlated positively with measures of general DA (p<0.05). Patients with SLE with active renal disease presented elevated levels of TNF-α, IP-10 and MCP-1 in urine and CSF-1 and IP-10 in serum as compared with patients with SLE with non-active renal disease.

CONCLUSIONS

Our investigation demonstrates that saliva is a novel alternative body fluid, with potential for surveillance of general DA in patients with SLE, but urine is more informative in patients with SLE with predominantly renal DA.

Emerging Molecular Markers Towards Potential Diagnostic Panels for Lupus

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease which can affect various tissues and organs, posing significant challenges for clinical diagnosis and treatment. The etiology of SLE is highly complex with contributions from environmental factors, stochastic factors as well as genetic susceptibility. The current criteria for diagnosing SLE is based primarily on a combination of clinical presentations and traditional lab testing. However, these tests have suboptimal sensitivity and specificity. They are unable to indicate disease cause or guide physicians in decision-making for treatment. Therefore, there is an urgent need to develop a more accurate and robust tool for effective clinical management and drug development in lupus patients. It is fortunate that the emerging Omics have empowered scientists in the discovery and identification of potential novel biomarkers of SLE, especially the markers from blood, urine, cerebrospinal fluids (CSF), and other bodily fluids. However, many of these markers have not been carefully validated for clinical use. In addition, it is apparent that individual biomarkers lack sensitivity or specificity. This review summarizes the sensitivity, specificity and diagnostic value of emerging biomarkers from recent studies, and discusses the potential of these markers in the development of biomarker panel based diagnostics or disease monitoring system in SLE.

CX3CR1 might be a promising predictor of systemic lupus erythematosus patients with pulmonary fibrosis

The inflammatory process in systemic lupus erythematosus (SLE) affects many organs including the lungs. Chemokines are suggested to play important roles in the pathogenesis of SLE with pulmonary fibrosis (PF). In the present study, our objective is to evaluate the correlation between chemokines and PF in SLE patients. Transcriptome sequencing analysis was used to find the different expressed genes between SLE patients with PF and without PF. Enzyme-linked immunosorbent assay (ELISA) was used to detect serum levels of chemokines in SLE patients and healthy controls. Expression of CX3CR1 was measured by real-time polymerase chain reaction (PCR) and flow cytometer. Sixteen differentially chemokine genes were found to be associated to SLE with PF. Meanwhile, the upregulation of C-X3-C motif chemokine receptor 1 (CX3CR1) and its ligand, CX3C chemokine ligand 1 (CX3CL1) were observed in SLE patients with PF than that of SLE patients without PF and healthy control. Phenotypic analysis also showed that the surface expression of CX3CR1 increased in PBMCs from SLE patients with PF. Our observations indicated that CX3CL1/CX3CR1 axis is associated with PF in SLE. CX3CR1 might be a promising predictor of SLE with PF and the interactions between CX3CL1 and CX3CR1 might provide potential candidate target for the treatment of SLE with PF.

Review on Inflammation Markers in Chronic Kidney Disease

Chronic kidney disease (CKD) is one of the major health problems of the modern age. It represents an important public health challenge with an ever-lasting rising prevalence, which reached almost 700 million by the year 2017. Therefore, it is very important to identify patients at risk for CKD development and discover risk factors that cause the progression of the disease. Several studies have tackled this conundrum in recent years, novel markers have been identified, and new insights into the pathogenesis of CKD have been gained. This review summarizes the evidence on markers of inflammation and their role in the development and progression of CKD. It will focus primarily on cytokines, chemokines, and cell adhesion molecules. Nevertheless, further large, multicenter studies are needed to establish the role of these markers and confirm possible treatment options in everyday clinical practice.

Systemic lupus erythematosus: The search for the ideal biomarker

During the last decades, there has been an increased interest in the discovery and validation of biomarkers that reliably reflect specific aspects of lupus. Although many biomarkers have been developed, few of them have been validated and used in clinical practice, but with unsatisfactory performances. Thus, there is still a need to rigorously validate many of these novel promising biomarkers in large-scale longitudinal studies and also identify better biomarkers not only for lupus diagnosis but also for monitoring and predicting upcoming flares and response to treatment. Besides serological biomarkers, urinary and cerebrospinal fluid biomarkers have emerged for assessing both renal and central nervous system involvement in systemic lupus erythematosus, respectively. Also, novel omics techniques help us to understand the molecular basis of the disease and also allow the identification of novel biomarkers which may be potentially useful for guiding new therapeutic targets.

Diagnostic value of urinary monocyte chemoattractant protein-1 in evaluating the activity of lupus nephritis: a meta-analysis

Objective

This study aimed to assess systematically the overall diagnostic value of urinary monocyte chemoattractant protein-1 (uMCP-1) in systemic lupus erythematosus (SLE) patients with active lupus nephritis (LN).

Methods

Articles from PubMed, Web of Science, EMBASE and Cochrane Library were retrieved up to 5 November 2019. Study quality was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool, and statistical analyses were performed.

Results

A total of seven original studies with 521 participants were included in this meta-analysis. The summary estimates were: sensitivity 0.89 (95% confidence interval (CI) 0.86–0.93), specificity 0.63 (95% CI 0.55–0.69), positive likelihood ratio 2.16 (95% CI 1.66–2.80), negative likelihood ratio 0.15 (95% CI 0.08–0.30), diagnostic odds ratio 19.40 (95% CI 7.24–51.96) and area under the curve 0.9042.

Conclusion

As a non-invasive biomarker, uMCP-1 has high diagnostic accuracy for active LN.

Serum and urine TNF-like weak inducer of apoptosis, monocyte chemoattractant protein-1 and neutrophil gelatinase-associated lipocalin as biomarkers of disease activity in patients with systemic lupus erythematosus

OBJECTIVES

TNF-like weak inducer of apoptosis (TWEAK), monocyte chemoattractant protein-1 (MCP-1) and neutrophil gelatinase-associated lipocalin (NGAL) are proinflammatory cytokines/chemokines that are considered as potential biomarkers reflecting disease activity in systemic lupus erythematosus (SLE). In this study, we aimed to investigate the association of serum (s) and urine (u) levels of TWEAK, MCP-1 and NGAL with disease activity in both renal and extra-renal SLE.

METHODS

Thirty active patients with SLE (15 renal and 15 extra-renal) were recruited. Thirty-one inactive patients with SLE (16 renal and 15 extra-renal), 14 patients with ANCA-associated vasculitis (AAV) all of whom had active renal involvement and 20 healthy volunteers were selected as control groups. Serum and urine levels of TWEAK, MCP-1 and NGAL were tested using ELISA.

RESULTS

Serum and urine levels of TWEAK and NGAL were significantly higher in the active SLE group compared to the inactive SLE group (sTWEAK p = 0.005; uTWEAK p = 0.026; sNGAL p < 0.001; uNGAL p = 0.002), whilst no significant differences regarding serum and urine MCP-1 levels were observed (p = 0.189 and p = 0.106, respectively). uTWEAK (p = 0.237), sMCP-1 (p = 0.141), uMCP-1 (p = 0.206), sNGAL (p = 0.419) and uNGAL (p = 0.443) levels did not differ between patients with active renal and extra-renal SLE. Serum TWEAK was higher in patients with active renal SLE (p = 0.006). There were no differences between active renal SLE and active renal AAV. Levels of all biomarkers were correlated with the SLE Disease Activity Index.

CONCLUSION

sTWEAK, uTWEAK, sNGAL and uNGAL are biomarkers showing disease activity in SLE. However, our results implicate that these biomarkers may not be specific for SLE, and can be elevated in patients with active renal involvement of AAV.

Role of Chemokine (C-X-C Motif) Ligand 10 (CXCL10) in Renal Diseases

Chemokine C-X-C ligand 10 (CXCL10), also known as interferon-γ-inducible protein 10 (IP-10), exerts biological function mainly through binding to its specific receptor, CXCR3. Studies have shown that renal resident mesangial cells, renal tubular epithelial cells, podocytes, endothelial cells, and infiltrating inflammatory cells express CXCL10 and CXCR3 under inflammatory conditions. In the last few years, strong experimental and clinical evidence has indicated that CXCL10 is involved in the development of renal diseases through the chemoattraction of inflammatory cells and facilitation of cell growth and angiostatic effects. In addition, CXCL10 has been shown to be a significant biomarker of disease severity, and it can be used as a prognostic indicator for a variety of renal diseases, such as renal allograft dysfunction and lupus nephritis. In this review, we summarize the structures and biological functions of CXCL10 and CXCR3, focusing on the important role of CXCL10 in the pathogenesis of kidney disease, and provide a theoretical basis for CXCL10 as a potential biomarker and therapeutic target in human kidney disease.

Interferon-Inducible Protein 10 and Disease Activity in Systemic Lupus Erythematosus and Lupus Nephritis: A Systematic Review and Meta-Analysis

There is increasing evidence of a correlation between interferon-inducible protein 10 (IP-10) and disease activity of systemic lupus erythematosus (SLE) and lupus nephritis (LN). We conducted a comprehensive search on IP-10 using MEDLINE, Scopus, and Cochrane electronic databases from the beginning to the end of December 2017. All studies that compared serum and/or urine IP-10 between active SLE/LN patients and any control groups were identified and included in this systematic review and meta-analysis. The mean difference (MD) of IP-10 level among active SLE and LN patients, as well as the correlation of IP-10 with disease activity, were meta-analyzed using a random-effects model. From 23 eligible studies, 15 provided adequate data for meta-analysis. Serum IP-10 was significantly elevated in patients with active SLE compared to non-active SLE patients (MD 356.5 pg/mL, 95% CI 59.6 to 653.4, p = 0.019). On the other hand, the levels of serum IP-10 was not different between active LN and non-active LN. However, serum IP-10 was positively correlated with disease activity like SLE disease activity index (SLEDAI) (pooled r = 0.29, 95% CI 0.22 to 0.35, p < 0.001). Furthermore, urine IP-10 tended to be higher in patients with active LN compared to non-active LN patients but this did not reach statistical significance (MD 3.47 pg/mgCr × 100, 95% CI -0.18 to 7.12, p = 0.06). Nevertheless, urine IP-10 was positively correlated with renal SLEDAI (pooled r = 0.29, 95% CI 0.05 to 0.50, p = 0.019). In conclusion, serum and urine IP-10 levels may be useful in monitoring the disease activity of SLE and LN. Serum IP-10 was correlated with systemic disease whereas urine IP-10 was a useful biomarker for detecting active LN.

Lupus: the new epidemic

Is systemic lupus erythematosus (SLE) is occurring more frequently now than in decades past? Despite improvements in the identification of patients with SLE, the development of new classification criteria, and the recognition of several biomarkers used alone or in combination, the diagnosis of SLE is still a challenge for clinicians, in particular early in the course of the disease, which makes the recognition of secular trends difficult to ascertain. Lacking a uniform definition of preclinical lupus or incomplete lupus, it is difficult to predict accurately which patients would go on to develop SLE. We will briefly review the classification criteria, early or preclinical SLE, the epidemiology of SLE, antinuclear antibodies-negative SLE, and biomarkers of the disease.

Soluble TNF-R1, VEGF and other cytokines as markers of disease activity in systemic lupus erythematosus and lupus nephritis

Background

Current non-invasive methods of assessing disease activity in systemic lupus erythematosus (SLE) are of limited sensitivity and specificity. Testing includes acute phase markers, autoantibodies and complement levels. Although measurements of dsDNA antibodies and complement C3/C4 levels are routine, they remain of limited value. Improved blood and urine markers may help in early detection of flare, distinction between flare and chronic damage, and monitoring response to therapy.

Methods

A total of 87 patients with SLE were tested for the following cytokines in serum and urine: monocyte chemoattractant protein 1 (MCP-1), regulated upon activation, normal T cell expressed and secreted (RANTES), soluble tumour necrosis factor receptor 1 (sTNF-R1), interferon-inducible protein 10 (IP-10), monocyte inhibitory protein 1α (MIP-1α) and vascular endothelial growth factor (VEGF). Patients attending the Lupus Unit at St Thomas’ Hospital, London, UK were divided into active lupus nephritis (LN), inactive LN and non-renal SLE groups based on their renal pathology and SLE disease activity index (SLEDAI). Cytokine testing was performed using the FIDIS multiplex bead assay.

Results

The mean level of serum sTNF-R1 was higher in the active LN group compared with both inactive LN and non-renal SLE groups ( p < 0.001). For urine measurements there were significant differences between active LN and non-renal SLE for VEGF ( p = 0.016), after statistical correction for multiple testing. Both urinary and serum sTNF-R1 and IP-10 levels correlated with SLEDAI scores ( p < 0.001), while serum VEGF correlated weakly with SLEDAI ( p = 0.025). The optimum combination for differentiating active from inactive LN patients was serum VEGF, sTNF-R1, MCP-1 and glomerular filtration rate plus urinary sTNF-R1 and protein-creatinine ratio.

Conclusion

These results indicate that for active LN, sTNF-R1 could be a useful serum cytokine marker, with potential for VEGF in the urine. This study has confirmed the ability of the multiplex bead technique to detect cytokines in a good analytical range, including very low and high levels, in both serum and urine. Combining serum and urine markers provided additional sensitivity in distinguishing active from inactive LN.

Proteomic profiling of urine: implications for lupus nephritis

INTRODUCTION

Lupus nephritis (LN) is a common and significant manifestation, affecting 60% of adults and 80% of children with systemic lupus erythematosus, with up to 30% of patients progressing to end stage renal disease. There remains an unmet need for non-invasive markers of disease activity, damage, and response to therapy. In addition, non-invasive biomarkers that predict therapeutic efficacy are needed to enable cost-effective clinical trials of novel agents. Areas covered: This review examines the methodological aspects of urinary proteomics, the role of proteome profiling in identifying promising urinary biomarkers in LN, and the translation of research findings into clinically useful tools in the management of LN. Expert opinion: Targeted and unbiased proteomics have identified several promising urinary biomarkers that predict LN activity, damage (chronicity), and response to therapy. In particular, a combination of biologically plausible urinary biomarkers termed as RAIL (Renal Activity Index for Lupus) has emerged as an excellent predictor of LN activity as well as response to therapy, being able to predict efficacy within 3 months of therapy. If validated in additional large prospective studies, the RAIL biomarkers will transform the care of patients with LN, allowing for a personalized and predictive approach and improved outcomes.

A Markov Multi-State model of lupus nephritis urine biomarker panel dynamics in children: Predicting changes in disease activity

BACKGROUND

A urine 'biomarker panel' comprising alpha-1-acid-glycoprotein, ceruloplasmin, transferrin and lipocalin-like-prostaglandin-D synthase performs to an 'excellent' level for lupus nephritis identification in children cross-sectionally. The aim of this study was to assess if this biomarker panel predicts lupus nephritis flare/remission longitudinally.

METHODS

The novel urinary biomarker panel was quantified by enzyme linked immunoabsorbant assay in participants of the United Kingdom Juvenile Systemic Lupus Erythematosus (UK JSLE) Cohort Study, the Einstein Lupus Cohort, and the South African Paediatric Lupus Cohort. Monocyte chemoattractant protein-1 and vascular cell adhesion molecule-1 were also quantified in view of evidence from other longitudinal studies. Serial urine samples were collected during routine care with detailed clinical and demographic data. A Markov Multi-State model of state transitions was fitted, with predictive clinical/biomarker factors assessed by a corrected Akaike Information Criterion (AICc) score (the better the model, the lower the AICc score).

RESULTS

The study included 184 longitudinal observations from 80 patients. The homogeneous multi-state Markov model of lupus nephritis activity AICc score was 147.85. Alpha-1-acid-glycoprotein and ceruloplasmin were identified to be the best predictive factors, reducing the AICc score to 139.81 and 141.40 respectively. Ceruloplasmin was associated with the active-to-inactive transition (hazard ratio 0.60 (95% confidence interval [0.39, 0.93])), and alpha-1-acid-glycoprotein with the inactive-to-active transition (hazard ratio 1.49 (95% confidence interval [1.10, 2.02])). Inputting individual alpha-1-acid-glycoprotein/ceruloplasmin values provides 3, 6 and 12 months probabilities of state transition.

CONCLUSIONS

Alpha-1-acid-glycoprotein was predictive of active lupus nephritis flare, whereas ceruloplasmin was predictive of remission. The Markov state-space model warrants testing in a prospective clinical trial of lupus nephritis biomarker led monitoring.

Growing international evidence for urinary biomarker panels identifying lupus nephritis in children - verification within the South African Paediatric Lupus Cohort

BACKGROUND

A urinary biomarker panel including alpha-1-acid-glycoprotein (AGP), lipocalin-like-prostaglandin-D-synthase (LPGDS), transferrin and ceruloplasmin demonstrates an 'excellent' ability for identifying active lupus nephritis in UK/US children. This study aimed to assess whether this panel identifies active lupus nephritis within the South African Paediatric Lupus Cohort.

METHODS

Juvenile-onset-systemic lupus erythematosus (JSLE) patients aged < 19 years at diagnosis and healthy controls were recruited. Patients were categorized as having active lupus nephritis (renal BILAG score; A/B and previous histological confirmation) or inactive lupus nephritis (renal BILAG score: D/E). Urinary biomarkers were quantified by ELISA. Mann-Whitney U-test compared biomarker levels between groups. Binary logistic regression and receiver operating curve analysis assessed biomarker combinations.

RESULTS

Twenty-three juvenile-onset-systemic lupus erythematosus patients were recruited with a median age of 13.5 years (interquartile range (IQR) 12.7-14.9) and disease duration of 2.6 years (IQR 1.8-4.0). Eighteen healthy controls had a median age of 11.0 years (IQR 10.0-12.0). AGP, LPGDS, transferrin, ceruloplasmin and VCAM-1 were significantly higher in active than in inactive lupus nephritis patients (corrected p-values, all p_c < 0.05), with no difference between inactive lupus nephritis patients and healthy controls (all p_c = 1.0). The optimal biomarker combination included AGP, ceruloplasmin, LPGDS and transferrin (area under the curve = 1.0).

CONCLUSIONS

A urinary biomarker panel comprising AGP, ceruloplasmin, LPGDS and transferrin previously validated within UK/US cohorts also performed excellently within a racially distinct South African cohort which displayed more severe lupus nephritis.

Urinary B-cell-activating factor of the tumour necrosis factor family (BAFF) in systemic lupus erythematosus

INTRODUCTION

We examined the clinical relevance of urinary concentrations of B-cell-activating factor of the tumour necrosis factor family (BAFF) and a proliferation-inducing ligand (APRIL) in systemic lupus erythematosus (SLE).

METHODS

We quantified urinary BAFF (uBAFF) by enzyme-linked immunosorbent assay in 85 SLE, 28 primary Sjögren syndrome (pSS), 40 immunoglobulin A nephropathy (IgAN) patients and 36 healthy controls (HCs). Urinary APRIL (uAPRIL) and monocyte chemoattractant protein 1 (uMCP-1) were also quantified. Overall and renal SLE disease activity were assessed using the Systemic Lupus Erythematosus Disease Activity Index 2000.

RESULTS

uBAFF was detected in 12% (10/85) of SLE patients, but was undetectable in HCs, IgAN and pSS patients. uBAFF was detectable in 28% (5/18) of SLE patients with active nephritis vs 5/67 (7%) of those without ( p = 0.03), and uBAFF was significantly higher in active renal patients ( p = 0.02) and more likely to be detected in patients with persistently active renal disease. In comparison, uAPRIL and uMCP-1 were detected in 32% (25/77) and 46% (22/48) of SLE patients, respectively. While no difference in proportion of samples with detectable uAPRIL was observed between SLE, HCs and IgAN patients, both uAPRIL and uMCP-1 were significantly detectable in higher proportions of patients with active renal disease.

CONCLUSIONS

uBAFF was detectable in a small but a significant proportion of SLE patients but not in other groups tested, and was higher in SLE patients with active renal disease.

Urinary epidermal growth factor, monocyte chemoattractant protein-1 or their ratio as predictors for rapid loss of renal function in type 2 diabetic patients with diabetic kidney disease

BACKGROUND

Increased monocyte chemoattractant protein-1 (MCP-1) and decreased epidermal growth factor (EGF) are promising biomarkers to predict progressive decline in kidney function in non-diabetic kidney diseases. We aimed to evaluate the performance of urinary EGF, MCP-1 or their ratio in predicting rapid decline of GFR in a cohort of Type 2 diabetic patients (T2DM) with diabetic kidney disease (DKD).

METHODS

T2DM patients (n = 83) with DKD at high risk for renal progression were followed up prospectively. The baseline urine values of MCP-1 to creatinine ratio (UMCP-1), EGF to creatinine ratio (UEGF), EGF to MCP-1 ratio (UEGF/MCP-1) and albumin to creatinine ratio (UACR) were measured. The primary outcome was a decline in estimated glomerular filtration rate (GFR) of ≥25% yearly from baseline.

RESULTS

During follow-up time of 23 months, patients with rapid decline in estimated GFR of ≥25% yearly from baseline had significantly higher baseline levels of UMCP-1, and UACR and lower UEGF and UEGF/MCP-1 ratio. All renal biomarkers predicted primary outcomes with ROC (95%CI) for UMCP-1=0.73 (0.62-0.84), UEGF=0.68 (0.57-0.80), UEGF/MCP-1=0.74 (0.63-0.85), and UACR =0.84 (0.75-0.93). By univariate analysis, blood pressure, GFR, UACR, UMCP-1, UEGF, and UEGF/MCP-1 were associated with rapid decline GFR. By multivariate analysis, UACR, systolic blood pressure, and UMCP-1 or UEGF/MCP-1 were independently associated with rapid GFR decline.

CONCLUSIONS

UMCP-1 or UEGF/MCP-1 ratio were associated with rapid renal progression independent from conventional risk factors in DKD.

Podocytes contribute, and respond, to the inflammatory environment in lupus nephritis

Lupus nephritis (LN) affects up to 80% of juvenile onset systemic lupus erythematosus patients, leading to end stage renal failure requiring dialysis or transplantation in 10-15%. Podocytes are specialized epithelial cells of the glomerulus known to be a key site of damage in glomerular diseases. However, their roles in LN have yet to be fully identified. This project aims to identify structural and functional roles of podocytes in an in vitro model of LN. Conditionally immortalized podocytes were treated with proinflammatory cytokines (IL-1β, TNF-α, IFN-α, and IFN-γ) alone and in combination in an in vitro model of LN and were assessed for their structural and functional characteristics. Podocytes produce TNF-α, IL-6, IL-8, VEGF, granulocyte-monocyte colony stimulating factor (GM-CSF), and macrophage colony stimulating factor (M-CSF) at relatively low levels under basal conditions; stimulation with IL-1β led to increased secretion of IL-6 ( P = 0.011), IL-8 ( P = 0.05), VEGF ( P = 0.02), and M-CSF ( P = 0.03). Stimulation with TNF-α led to increased secretion of M-CSF ( P = 0.049) and stimulation with IFN-γ led to novel production of IL-10 ( P = 0.036) and interferon-γ-inducible protein-10 ( P = 0.036). Podocytes demonstrate a reduction in the area covered by filamentous-actin in response to IL-1β treatment within 1 h ( P = 0.011), which is restored by 24 h, associated with an increase in the level of intracellular calcium but not with increased cell death. Podocytes contribute to the inflammatory milieu in LN through cytokine/chemokine secretion and respond to the inflammatory milieu via rearrangement of the actin cytoskeleton leading to effacement, a well-known method of protection against apoptosis in these cells. This demonstrates that podocytes are involved in the pathogenesis of LN.

CXCR3-deficient mesenchymal stem cells fail to infiltrate into the nephritic kidney and do not ameliorate lupus symptoms in MRL. Faslpr mice

Mesenchymal stem cell therapy is a promising candidate for the treatment of systemic lupus erythematosus (SLE). To exert their efficacy fully, mesenchymal stem cells must infiltrate efficiently into the lesion sites. Here, we examined the role of CXCR3 in mesenchymal stem cell infiltration into the kidney of MRL. Fas^lpr mice, which highly expressed CXCL10. The phenotypes, production of immunosuppressive mediators, and capacity to inhibit T and B cells of CXCR3-deficient mesenchymal stem cells were similar to those of wild-type mesenchymal stem cells. However, they showed less infiltration into the nephritic kidney, less conjugation with endothelial cells and weaker MMP-9 expression than did wild-type mesenchymal stem cells. Consequently, CXCR3-deficient mesenchymal stem cells did not ameliorate lupus symptoms in MRL. Fas^lpr mice in comparison with wild-type mesenchymal stem cells. In summary, our data suggest that upregulation of CXCR3 in mesenchymal stem cells will be a good strategy to increase their infiltration into the kidney, which will improve therapeutic outcomes in SLE.

Rapid detection of urinary soluble intercellular adhesion molecule-1 for determination of lupus nephritis activity

The current methods of monitoring the activity of lupus nephritis (LN) may cause unnecessary hospital visits or delayed immunosuppressive therapy. We aimed to find a urinary biomarker that could be developed as a home-based test for monitoring the activity of LN.Urine samples were collected immediately before a renal biopsy from patients of suspected active LN, and also from patients with inactive LN, systemic lupus erythematous without LN or healthy controls. Biomarker search was conducted on a cytokine antibody array and confirmation was done by quantitative evaluation with enzyme-linked immunosorbent assay. The Mann-Whiney test or Student t test was used to compare the levels of 9 cytokines between different groups. The sensitivity and specificity of each cytokine for diagnosis of LN was evaluated by receiver operating characteristic curve. A rapid test based on colloidal gold immunochromatography was then developed for bedside or home use. Furthermore, an experimental e-healthcare system was constructed for recording and sharing the results of the rapid test a cloud-assisted internet of things (IoT) consisting of a sensing device, an IoT device and a cloud server.Adiponectin (Acrp30), soluble intercellular cell adhesion molecule-1 (sICAM-1), neural cell adhesion molecule 1 (NCAM-1), and CD26 were significantly higher in urine samples of active LN patients. sICAM-1 appeared more sensitive and specific among these candidates. When the cut-off value of sICAM-1 was set at 1.44 ng/mL, the sensitivity reached 98.33% with a specificity at 85.71%. The sICAM-1 strip test showed comparable sensitivity of 95% and a specificity of 83.3% for assessing the LN activity. Meanwhile, the e-healthcare system was able to conveniently digitize and share the sICAM-1 rapid test results.sICAM-1 appeared to be an excellent biomarker for monitoring LN activity. The e-healthcare system with cloud-assisted IoT could assist the digitalization and sharing of the bedside or home-based sICAM-1 test results.

Serum IP-10 is useful for identifying renal and overall disease activity in pediatric systemic lupus erythematosus

BACKGROUND

Traditional serological biomarkers often fail to assess systemic lupus erythematosus (SLE) disease activity and discriminate lupus nephritis (LN). The aim of this study was to identify novel markers for evaluating renal and overall disease activity in Chinese patients with pediatric systemic lupus erythematosus (pSLE).

METHODS

The study included 46 patients with pSLE (35 girls, 11 boys; average age 13.3 ± 2.6 years) and 31 matched healthy controls (22 girls, 9 boys; average age 12.3 ± 2.4 years). The SLE Disease Activity Index (SLEDAI) and renal SLEDAI were used to assess disease activity. Nine different soluble mediators in plasma, including tumor necrosis factor alpha (TNF-α), platelet-derived growth factor-BB (PDGF-BB), interferon (IFN) gamma inducible protein 10 (IP-10), interleukin (IL)-1β, IFN-γ, IL-17A, IL-2, Fas and Fas ligand, were measured by Luminex assay and compared between patients with active and inactive pSLE as well as between patients with pSLE with active and inactive renal disease. Receiver operating characteristic curve analysis was used to measure the discrimination accuracy.

RESULTS

Of the 46 patients with pSLE, 30 (65.2%) had LN. These patients had significantly elevated levels of serum TNF-α, PDGF-BB, IP-10 and Fas. The serum levels of IP-10 were also significantly higher in patients with active pSLE. We found that IP-10 was also more sensitive and specific than conventional laboratory parameters, including anti-double-stranded DNA and complement components C3 and C4, for distinguishing active lupus from quiescent lupus. The serum level of IP-10 was also significantly increased in children with pSLE with active renal disease relative to those with inactive renal disease. There was also a positive correlation between serum IP-10 levels and renal SLEDAI scores as well as with 24 h urine protein.

CONCLUSIONS

Serum IP-10 is useful for identifying renal and overall disease activity in children with pSLE.

Urinary cytokines and mRNA expression as biomarkers of disease activity in lupus nephritis

Introduction

Renal involvement is one of the most serious manifestations of systemic lupus erythematosus, but non-invasive assessment of inflammatory response in kidneys is challenging. In this study we aimed to validate markers of active lupus nephritis (LN) using urine immune profiling.

Methods

Urine and serum cytokines (17-plex array) and urine mRNA expression (∼40 immune and glomerular injury genes) were measured in LN patients with active disease ( n = 17) during remission ( n = 16) and in healthy subjects ( n = 18).

Results

Urine and serum levels of CCL2, CCL5 and CXCL10 were elevated in active LN as compared with disease remission (best discrimination for urine CXCL10 and CCL2) and correlated with LN activity. In the active disease, urinary cell transcriptome showed marked upregulation of proinflammatory cytokines (e.g. TNF, CCL2, CCL5, CXCL10), and type-1 immunity-related genes (e.g. CD3G, CD4, TBX21, IFNG). An active pattern of gene expression was also observed in four patients in remission, who had moderately increased urinary leucocyte count. Two patients from this group developed renal exacerbation during the following 3 months. Markers of type-17 immune axis (e.g. IL-17A) were not significantly increased in active LN.

Conclusions

Active LN patients were characterized by marked increase of proinflammatory mediators in the urine. Urine cytokines (CCL2 and CXCL10) and type-1 T-cell-related gene markers in the urine sediment had similar diagnostic performance in detection of active LN.

ABIN1 Determines Severity of Glomerulonephritis via Activation of Intrinsic Glomerular Inflammation

Transcription factor NF-κB regulates expression of numerous genes that control inflammation and is activated in glomerular cells in glomerulonephritis (GN). We previously identified genetic variants for a NF-κB regulatory, ubiquitin-binding protein ABIN1 as risk factors for GN in systemic autoimmunity. The goal was to define glomerular inflammatory events controlled by ABIN1 function in GN. Nephrotoxic serum nephritis was induced in wild-type (WT) and ubiquitin-binding deficient ABIN1[D485N] mice, and renal pathophysiology and glomerular inflammatory phenotypes were assessed. Proteinuria was also measured in ABIN1[D485N] mice transplanted with WT mouse bone marrow. Inflammatory activation of ABIN1[D472N] (D485N homolog) cultured human-derived podocytes, and interaction with primary human neutrophils were also assessed. Disruption of ABIN1 function exacerbated proteinuria, podocyte injury, glomerular NF-κB activity, glomerular expression of inflammatory mediators, and glomerular recruitment and retention of neutrophils in antibody-mediated nephritis. Transplantation of WT bone marrow did not prevent the increased proteinuria in ABIN1[D845N] mice. Tumor necrosis factor-stimulated enhanced expression and secretion of NF-κB-targeted proinflammatory mediators in ABIN1[D472N] cultured podocytes compared with WT cells. Supernatants from ABIN1[D472N] podocytes accelerated chemotaxis of human neutrophils, and ABIN1[D472N] podocytes displayed a greater susceptibility to injurious morphologic findings induced by neutrophil granule contents. These studies define a novel role for ABIN1 dysfunction and NF-κB in mediating GN through proinflammatory activation of podocytes.

Plasma Interferon-Gamma-Inducible Protein 10 Level Associates With Abnormal Memory B Cells Phenotypes in Perinatal HIV Infection

We demonstrate for perinatally HIV-infected children and adolescents receiving combined antiretroviral therapy and in good clinical status with respect to HIV disease that high concentrations of interferon-gamma-inducible protein 10 associate with increased exhausted memory B cells.

Re-Examining Neutrophil Participation in GN

Significant advances in understanding the pathogenesis of GN have occurred in recent decades. Among those advances is the finding that both innate and adaptive immune cells contribute to the development of GN. Neutrophils were recognized as key contributors in early animal models of GN, at a time when the prevailing view considered neutrophils to function as nonspecific effector cells that die quickly after performing antimicrobial functions. However, advances over the past two decades have shown that neutrophil functions are more complex and sophisticated. Specifically, research has revealed that neutrophil survival is regulated by the inflammatory milieu and that neutrophils demonstrate plasticity, mediate microbial killing through previously unrecognized mechanisms, demonstrate transcriptional activity leading to the release of cytokines and chemokines, interact with and regulate cells of the innate and adaptive immune systems, and contribute to the resolution of inflammation. Therefore, neutrophil participation in glomerular diseases deserves re-evaluation. In this review, we describe advances in understanding classic neutrophil functions, review the expanded roles of neutrophils in innate and adaptive immune responses, and summarize current knowledge of neutrophil contributions to GN.

A functional SNP MCP-1 (-2518A/G) predispose to renal disorder in Indian Systemic Lupus Erythematosus patients

Systemic Lupus Erythematosus (SLE) is a clinically heterogeneous chronic, inflammatory autoimmune disorder that affects multiple organs where exact etiology of the disease is not yet clearly understood. Various evidences suggest that genetic polymorphisms in inflammatory mediators like cytokines and chemokines may influence development of the disease. Here, we investigated whether functional polymorphism at the Monocyte Chemoattractant Protein-1 (MCP-1) regulatory region associates with disease phenotype in Indian SLE patients. This case control study included 200 SLE patients and 201 ethnically matched healthy controls. Genotyping of MCP-1 (-2518 A/G) polymorphism was performed using PCR-RFLP method. Serum MCP-1 levels were detected by bead-based multiplex immunoassay. Serum MCP-1 levels were found to be higher in patients compared with healthy individuals (p<0.0001). A significant difference for MCP-1G allele frequency (OR=1.9, 95%CI=1.4-2.6, p<0.0001) was observed among SLE patients against healthy individuals. A significant difference in the distribution of MCP-1 -2518GG (OR=3.0, 95%CI=1.4-6.7, p=0.0041) and AG+GG genotypes (OR=2.0, 95%CI=1.4-3.0, p=0.0005) was also noted among SLE patients when compared with healthy individuals. A significant association was observed between A/G and G/G versus A/A genotypes with renal manifestations (p<0.0001, Pc<0.001). Serum MCP-1 levels in active LN patients were found to be significantly higher than inactive LN (p=0.0059), mild LN (p=0.0061) as well as non-LN patients (p=0.0001). These findings suggest that -2518G allele of MCP-1 -2518 A/G polymorphism is associated with renal disorders and may influence MCP-1 gene expression among Indian SLE patients.

The innate immune system in human systemic lupus erythematosus

Although the role of adaptive immune mechanisms, e.g. autoantibody formation and abnormal T-cell activation, has been long noted in the pathogenesis of human systemic lupus erythematosus (SLE), the role of innate immunity has been less well characterized. An intricate interplay between both innate and adaptive immune elements exists in protective anti-infective immunity as well as in detrimental autoimmunity. More recently, it has become clear that the innate immune system in this regard not only starts inflammation cascades in SLE leading to disease flares, but also continues to fuel adaptive immune responses throughout the course of the disease. This is why targeting the innate immune system offers an additional means of treating SLE. First trials assessing the efficacy of anti-type I interferon (IFN) therapy or modulators of pattern recognition receptor (PRR) signalling have been attempted. In this review, we summarize the available evidence on the role of several distinct innate immune elements, especially neutrophils and dendritic cells as well as the IFN system, as well as specific innate PRRs along with their signalling pathways. Finally, we highlight recent clinical trials in SLE addressing one or more of the aforementioned components of the innate immune system.

Organ-specific biomarkers in lupus

Systemic lupus erythematosus (SLE) is a complex and highly heterogeneous disease, which affects multiple organs, including joints, skin, kidneys, heart, hematopoietic system, and nerve system. While the etiopathogenesis of SLE still remains unclear, genetic susceptibilities and aberrant epigenetic modifications are believed to be involved. For precision therapy, it is necessary to assess accurately and objectively organ involvements and disease activity, which is difficult by current clinical laboratory tests. Biomarkers, which are a biologic, genetic, epigenetic or a chemical characteristic and conveniently detectable, serve as measures of disease diagnosis, activity, prognosis, and manifestation prediction, thereby providing instruction for individualized therapy. In addition, biomarkers differ according to different manifestations, since the disease activity index and treatments vary significantly. For example, unlike other non-renal SLE, lupus nephritis requires significant immunosuppressive drugs. Over the past decades, the research on biomarkers in lupus has been strengthened and numerous promising biomarkers have been identified at levels of genomics, transcriptomics and proteomics. In this review, we summarize the conventional and novel biomarkers in the tissue-specific manner, and discuss their roles in specific organ diagnosis, future manifestation prediction, disease activity assessment and their correlation with histology results. By doing so, it aims to shed a light on individualized treatment.

International validation of a urinary biomarker panel for identification of active lupus nephritis in children

BACKGROUND

Conventional markers of juvenile-onset systemic lupus erythematosus (JSLE) disease activity fail to adequately identify lupus nephritis (LN). While individual novel urine biomarkers are good at detecting LN flares, biomarker panels may improve diagnostic accuracy. The aim of this study was to assess the performance of a biomarker panel to identify active LN in two international JSLE cohorts.

METHODS

Novel urinary biomarkers, namely vascular cell adhesion molecule-1 (VCAM-1), monocyte chemoattractant protein 1 (MCP-1), lipocalin-like prostaglandin D synthase (LPGDS), transferrin (TF), ceruloplasmin, alpha-1-acid glycoprotein (AGP) and neutrophil gelatinase-associated lipocalin (NGAL), were quantified in a cross-sectional study that included participants of the UK JSLE Cohort Study (Cohort 1) and validated within the Einstein Lupus Cohort (Cohort 2). Binary logistic regression modelling and receiver operating characteristic curve analysis [area under the curve (AUC)] were used to identify and assess combinations of biomarkers for diagnostic accuracy.

RESULTS

A total of 91 JSLE patients were recruited across both cohorts, of whom 31 (34 %) had active LN and 60 (66 %) had no LN. Urinary AGP, ceruloplasmin, VCAM-1, MCP-1 and LPGDS levels were significantly higher in those patients with active LN than in non-LN patients [all corrected p values (p _c) < 0.05] across both cohorts. Urinary TF also differed between patient groups in Cohort 2 (p _c = 0.001). Within Cohort 1, the optimal biomarker panel included AGP, ceruloplasmin, LPGDS and TF (AUC 0.920 for active LN identification). These results were validated in Cohort 2, with the same markers resulting in the optimal urine biomarker panel (AUC 0.991).

CONCLUSION

In two international JSLE cohorts, urinary AGP, ceruloplasmin, LPGDS and TF demonstrate an 'excellent' ability for accurately identifying active LN in children.

A discrete cluster of urinary biomarkers discriminates between active systemic lupus erythematosus patients with and without glomerulonephritis

Background

Management of lupus nephritis (LN) would be greatly aided by the discovery of biomarkers that accurately reflect changes in disease activity. Here, we used a proteomics approach to identify potential urinary biomarkers associated with LN.

Methods

Urine was obtained from 60 LN patients with paired renal biopsies, 25 active non-LN SLE patients, and 24 healthy controls. Using Luminex, 128 analytes were quantified and normalized to urinary creatinine levels. Data were analyzed by linear modeling and non-parametric statistics, with corrections for multiple comparisons. A second cohort of 33 active LN, 16 active non-LN, and 30 remission LN SLE patients was used to validate the results.

Results

Forty-four analytes were identified that were significantly increased in active LN as compared to active non-LN. This included a number of unique proteins (e.g., TIMP-1, PAI-1, PF4, vWF, and IL-15) as well as known candidate LN biomarkers (e.g., adiponectin, sVCAM-1, and IL-6), that differed markedly (>4-fold) between active LN and non-LN, all of which were confirmed in the validation cohort and normalized in remission LN patients. These proteins demonstrated an enhanced ability to discriminate between active LN and non-LN patients over several previously reported biomarkers. Ten proteins were found to significantly correlate with the activity score on renal biopsy, eight of which strongly discriminated between active proliferative and non-proliferative/chronic renal lesions.

Conclusions

A number of promising urinary biomarkers that correlate with the presence of active renal disease and/or renal biopsy changes were identified and appear to outperform many of the existing proposed biomarkers.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1120-0) contains supplementary material, which is available to authorized users.

CCL21 and IP-10 as blood biomarkers for pulmonary involvement in systemic lupus erythematosus patients

Biomarkers for pulmonary manifestations in systemic lupus erythematosus (SLE) are missing. Plasma samples of nine SLE patients with known pulmonary involvement (SLEpulm) and nine SLE patients without pulmonary involvement (SLE) were tested by multiplex microarray analysis for various cyto- and chemokines. Significantly decreased lung function paramters for forced vital capacity (FVC), total lung capacity (TLC), diffusion capacity for carbon monoxide (DLCO) and diffusion of CO corrected on lung volume (KLCO) were observed in SLEpulm as compared to SLE patients. CC chemokine ligand 21 (CCL21) and interferon gamma-induced protein 10 (IP-10) levels were significantly higher in SLEpulm, than in patients without pulmonary manifestations. CCL21 correlated negatively with DLCO ( r = −0.73; p < 0.01) and KLCO ( r = −0.62; p < 0.01), while IP-10 with FVC and forced expiratory volume one second. Receiver Operating Characteristics (ROC) analysis confirmed high sensitivity and specificity for the separation of SLE patients with and without pulmonary involvement for the chemokines CCL21 (Area Under Curve (AUC): 0.85; sensitivity%: 88.90; specificity%: 75.00; p < 0.01) and IP-10 (AUC: 0.82; sensitivity%: 66.67, specificity%: 100; p < 0.01). Pleuropulmonary manifestations in SLE patients associated with lung functional and DLCO/KLCO changes and were associated with significant increase in CCL21 and IP-10. These chemokines might serve as potential biomarkers of lung involvement in SLE patients.

Lupus nephritis biomarkers

Lupus nephritis (LN), a potentially destructive outcome of SLE, is a real challenge in the management of SLE because of the difficulty in diagnosing its subclinical onset and identifying relapses before serious complications set in. Conventional clinical parameters such as proteinuria, GFR, urine sediments, anti-dsDNA and complement levels are not sensitive or specific enough for detecting ongoing disease activity in lupus kidneys and early relapse of nephritis. There has long been a need for biomarkers of disease activity in LN. Such markers ideally should be capable of predicting early sub-clinical flares and could be used to gauge response to therapy, thus obviating the need for serial renal biopsies with their possible hazardous complications. Since urine can be readily obtained, it lends itself as an obvious biological substrate. In this review, the use of urine and serum as sources of lupus nephritis biomarkers is described, and the results of biomarker discovery studies using candidate and proteomic approaches are summarized.

Urinary biomarkers in childhood lupus nephritis

Juvenile-onset systemic lupus erythematosus (JSLE) is a rare, severe multisystem autoimmune disease affecting the kidney (Lupus Nephritis, LN) in up to 80% of children. LN is more severe in children than adults, with potential for irreversible kidney damage requiring dialysis or transplant. Renal biopsy is currently the gold standard for diagnosing and monitoring LN, however, it is invasive and associated with complications. Urine biomarkers have been shown to be better than serum biomarkers in differentiating renal disease from other organ manifestations. Over the past decade, there have been an increasing number of studies investigating specific candidate biomarkers implicated in the pathogenesis of LN or screening for urinary biomarkers using hypothesis free methods. In this review, developments in urine biomarkers for LN will be reviewed, highlighting those that are of relevance to children and have gone through validation in independent international patient cohorts, bringing them close to clinical translation.

Chemokines and Chemokine Receptors in the Development of Lupus Nephritis

Lupus nephritis (LN) is a major cause of morbidity and mortality in the patients with systemic lupus erythematosus (SLE), an autoimmune disease with damage to multiple organs. Leukocyte recruitment into the inflamed kidney is a critical step to promote LN progression, and the chemokine/chemokine receptor system is necessary for leukocyte recruitment. In this review, we summarize recent studies on the roles of chemokines and chemokine receptors in the development of LN and discuss the potential and hurdles of developing novel, chemokine-based drugs to treat LN.

Serum and Urinary Interferon-Gamma-Inducible Protein 10 in Lupus Nephritis

BACKGROUND

Lupus nephritis is a serious manifestation of systemic lupus erythematosus (SLE). The objective of this study was to identify the sensitivity, specificity, and cut-off values of IP-10 in the serum and urine of patients with lupus nephritis compared to renal biopsy, albumin/creatinine ratio, and serum anti-dsDNA.

METHODS

Thirty female SLE patients were included. SLEDAI was calculated and blood and urine samples were collected. Patients were divided into 10 SLE patients with renal involvement (six active and four inactive), 10 active SLE, and 10 inactive SLE patients. Ten age-matched healthy (control) were included. Serum and urinary levels of IP-10 were measured by ELISA. Anti-dsDNA, urine albumin/creatinine ratio were performed.

RESULTS

Serum and urinary IP-10 in active SLE patients had significantly increased levels as compared to inactive SLE patients (P = 0.015, P = 0.033, respectively). However, there was no difference in serum and urinary levels between active renal and active non-renal patients. Albumin/creatinine ratio is a better marker in differentiating between lupus nephritis and SLE with no renal involvement. Any of serum and urinary IP-10, albumin/creatinine ratio, and anti-dsDNA did not correlate with the class of lupus nephritis in renal biopsy.

CONCLUSION

Urinary and serum IP-10 are useful markers of lupus activity, but not indicative of renal activity. Albumin/creatinine ratio is superior in identifying lupus nephritis and renal activity.

The Changing Landscape of Renal Inflammation

Kidney inflammation is a major contributor to progressive renal injury, leading to glomerulonephritis (GN) and chronic kidney disease. We review recent advances in our understanding of leukocyte accumulation in the kidney, emphasizing key chemokines involved in GN. We discuss features of renal inflammation such as the evolving concept of immune cell plasticity. We also describe certain aspects of organ-specific tissue microenvironments in shaping immune cell responses, as well as the current knowledge of how regulatory T lymphocytes impact on other immune effector cell populations to control inflammation. It is clear that present and future research in these areas may contribute to the development of novel targeted therapeutics, with the hope of alleviating the burden of end-stage renal disease (ESRD).

Biomarkers in lupus nephritis

Lupus nephritis (LN) has significant impact on the outcome of patients with systemic lupus erythematosus (SLE). In the absence of any new breakthrough for management of LN over the last few years, using existing treatment modalities in a more effective manner is the mainstay of improving outcomes. For effectively using the drugs, disease activity needs to be assessed accurately and more objectively, which is not possible with present clinical assessment tools. Biomarkers help in accurate assessment of disease activity and enable the physician to individualize the therapy. Conventional disease activity markers have limitations which need to be addressed and research in the area of biomarker discovery in LN has immensely expanded over the last two decades as evident by the literature. Moreover, biomarkers for LN should be different from the markers of overall disease activity as LN requires significant immunosuppression, unlike other non-renal manifestations of SLE. Newly discovered biomarkers exhibit qualities pertaining to different aspects of disease activity and damage. In this review, we discuss the established as well as new biomarkers of SLE in the light of their role in LN diagnosis, follow-up, prediction of renal flare and correlation with renal histology findings.