Biomarker For Lupus Nephritis Research Articles

Elevated Urinary Neutrophil Gelatinase-Associated Lipocalin Is a Biomarker for Lupus Nephritis: A Systematic Review and Meta-Analysis.

Objective Lupus nephritis (LN) is a major and severe complication of systemic lupus erythematosus (SLE). Neutrophil gelatinase-associated lipocalin (NGAL), as a promising next-generation biomarker in clinical nephrology, has received extensive attention. However, its diagnostic performance in LN has high variability. Therefore, we performed an updated meta-analysis to further evaluate the diagnostic accuracy of urinary NGAL (uNGAL). Materials and Methods PubMed, Embase, and Cochrane Library were searched from inception to October 27, 2019. Meta-analysis was performed with a bivariate random effects model. Additionally, the summary receiver operating characteristic (SROC) curves were established. The sources of heterogeneity were explored by meta-regression, subgroup analysis, and sensitivity analysis. Publication bias was assessed using the Deeks test. Results 19 articles consisting of 21 eligible studies were included. In diagnosing LN, the estimates (95% confidence interval (CI)) were as follows: sensitivity, 0.84 (0.71-0.91); specificity, 0.91 (0.70-0.98); and the SROC-AUC value, 0.92 (0.90-0.94). In identifying active LN, the estimates were as follows: sensitivity, 0.72 (0.56-0.84); specificity, 0.71 (0.51-0.84); and the AUC value, 0.77 (0.74-0.81). With respect to predicting renal flare, the estimates were as follows: sensitivity, 0.80 (0.57-0.92); specificity, 0.67 (0.58-0.75); and the AUC value, 0.74 (0.70-0.78). For the studies to distinguish proliferative LN, the estimates were as follows: sensitivity, 0.87 (0.66-0.97), and specificity, 0.69 (0.39-0.91). Deeks' funnel plot suggested that there was no significant publication bias. Conclusions Our meta-analysis indicates that uNGAL was a useful biomarker for diagnosis, estimation of activity, and prediction of renal flare of LN. In addition, the usefulness of uNGAL to distinguish pathological types of LN needs to be further investigated.

Proteomic analysis in lupus mice identifies Coronin-1A as a potential biomarker for lupus nephritis

BackgroundApproximately 50% of systemic lupus erythematosus (SLE) patients develop nephritis, which is among the most severe and frequent complications of the disease and a leading cause of morbidity and mortality. Despite intensive research, there are still no reliable lupus nephritis (LN) markers in clinical use that can assess renal damage and activity with a high sensitivity and specificity. To this end, the aim of this study was to identify new clinically relevant tissue-specific protein biomarkers and possible underlying molecular mechanisms associated with renal involvement in SLE, using mass spectrometry (MS)-based proteomics.MethodsKidneys were harvested from female triple congenic B6.NZMsle1/sle2/sle3 lupus mice model, and the respective sex- and age-matched C57BL/6 control mice at 12, 24 and 36 weeks of age, representing pre-symptomatic, established and end-stage LN, respectively. Proteins were extracted from kidneys, purified, reduced, alkylated and digested by trypsin. Purified peptides were separated by liquid chromatography and analysed by high-resolution MS. Data were processed by the Progenesis QIp software, and functional annotation analysis was performed using DAVID bioinformatics resources. Immunofluorescence and multiple reaction monitoring (MRM) MS methods were used to confirm prospective biomarkers in SLE mouse strains as well as human serum samples.ResultsProteomic profiling of kidney tissues from SLE and control mice resulted in the identification of more than 3800 unique proteins. Pathway analysis revealed a number of dysregulated molecular pathways that may be mechanistically involved in renal pathology, including phagosome and proximal tubule bicarbonate reclamation pathways. Proteomic analysis supported by human transcriptomic data and pathway analysis revealed Coronin-1A, Ubiquitin-like protein ISG15, and Rho GDP-dissociation inhibitor 2, as potential LN biomarkers. These results were further validated in other SLE mouse strains using MRM-MS. Most importantly, experiments in humans showed that measurement of Coronin-1A in human sera using MRM-MS can segregate LN patients from SLE patients without nephritis with a high sensitivity (100%) and specificity (100%).ConclusionsThese preliminary findings suggest that serum Coronin-1A may serve as a promising non-invasive biomarker for LN and, upon validation in larger cohorts, may be employed in the future as a screening test for renal disease in SLE patients.

THU0250 URINE AND SERUM S100 PROTEINS ASSOCIATE WITH LUPUS NEPHRITIS AND RESPONSE TO TREATMENT

Background:Systemic lupus erythematosus (SLE) is a systemic autoimmune/inflammatory disease. Approximately 30% of SLE patients develop lupus nephritis (LN) that affects treatment and prognosis. Easily accessible biomarkers do not exist to reliably predict renal disease1. Recently, calcium-binding S100 proteins have been suggested as biomarkers in systemic inflammatory conditions, including SLE2,3.Objectives:The MASTERPLANS Consortium aims to identify indicators of treatment responses in SLE. This study tested the applicability of S100 proteins in serum and urine as biomarkers for disease activity and response to treatment with rituximab in LN.Methods:S100A8/A9 and S100A12 proteins were quantified in the serum and urine of 243 SLE patients from the BILAG-BR study and 48 matched controls using MSD technology to determine whether they perform as biomarkers for active LN (n=85 SLE patients) and/or may be used to predict response to treatment with rituximab. Renal disease activity and response to treatment was based on BILAG-BR scores and changes in response to treatment4,5.Results:Serum S100A12 (p<0.001), and serum and urine S100A8/A9 (p<0.001) are elevated in SLE patients. While serum and urine S100 levels do not correlate with global SLE disease activity (SLEDAI), levels in urine and urine/serum ratios are elevated in SLE patients with active LN (S100A8/A9: urine p>0.005, urine/serum p<0.05; S100A12: urine p<0.05, serum/urine p<0.005). S100 proteins perform better as biomarkers for active LN involvement in SLE patients positive for anti-dsDNA antibodies. Lastly, binary logistic regression and AUC analysis suggests the combination of serum S100A8/A9 and S100A12 to predict response to RTX treatment in LN after 6 months.Conclusion:Findings from this study show promise for clinical application of S100 proteins to predict active renal disease in SLE and response to treatment with rituximab. Significantly overlapping values between groups currently prohibit the definition of cut-off values and prospective studies are required to validate findings.

AB0412 URINARY SOLUBLE VCAM-1 IS A USEFUL BIOMARKER OF DISEASE ACTIVITY AND TREATMENT RESPONSE IN LUPUS NEPHRITIS

Background:The traditional lupus nephritis (LN) biomarkers are not sensitive nor specific enough for detecting ongoing disease activity and early relapse of nephritis and they do not reflect kidney damage nor have prognostic value1. Urinary biomarkers are directly excreted by the kidney and are easily obtained. They can also differentiate the renal activity of the disease from other organic manifestations more accurately than the serum biomarkers2. Vascular cell adhesion molecule-1 (VCAM-1) is involved in the progression of glomerular and tubulointerstitial injury in LN and its soluble form can be easily assessed in urine (uVCAM-1)3. Several studies correlated the uVCAM-1 levels with urine protein-creatinine ratio (UPC), with general disease activity and with active LN3.Objectives:To assess uVCAM-1 as a biomarker of disease activity and treatment response in LN.Methods:This prospective study enrolled patients with class III, IV or V LN diagnosed within the last three years and divided them in two groups: with and without active nephritis at the inclusion. The patients with active nephritis were included before they started a new immunosuppressive treatment. Active LN was defined as proteinuria (UPC≥0.5) plus active urinary sediment (hematuria, leukocyturia or cellular hematic/granular casts). At each visit, a urine sample was collected for uVCAM-1 evaluation and the nephritis status was accessed.Results:Median uVCAM-1 level was elevated in patients with active compared to inactive LN (p<0.001). The ROC curve of uVCAM-1 demonstrated an AUC of 0.84 and a cutoff of 47.2 ng/mgCr yielded a good sensitivity (74.2%) and specificity (74.2%) for the diagnosis of active LN. A significant correlation was found between uVCAM-1 level and renal activity scores and traditional biomarkers of LN (table 1). The level of uVCAM-1 dropped in patients with active LN who went into remission (p<0.001), increased in patients who went into activity (p=0.002) and did not change in patients who remained inactive (p=0.797) (figure 1). The level of uVCAM-1 peaked during the flare of LN (p<0.05) (figure 2).Table 1.Correlations between urinary soluble VCAM-1 and other LN biomarkers/disease scoresLN biomarkers/disease scoresVCAM-1SLEDAI-2k0.597***Renal SLEDAI0.569***Renal SLAM-R0.470***Renal SLICC0.620***Anti-dsDNA0.342**C3-0.344**C4-0.382**UPC0.654***Spearman’s correlation coefficients*pvalue <0.05; **pvalue <0.01; ***pvalue <0.001C, complement; LN, lupus nephritis; SLEDAI, Systemic Lupus Erythematosus Disease Activity Index; renal SLAM-R, The renal Systemic Lupus Activity Measure revised; renal SLICC, The Systemic Lupus International Collaborating Clinics renal activity/response exercise; UPC, urine protein-creatinine ratio.Conclusion:The uVCAM-1 is a reliable biomarker that reflects renal disease activity and is useful for monitoring individual patients with lupus nephritis over time.

Association of Urine sCD163 With Proliferative Lupus Nephritis, Fibrinoid Necrosis, Cellular Crescents and Intrarenal M2 Macrophages.

CD163 is a marker for alternatively activated macrophages, which have been implicated in the pathogenesis of lupus nephritis (LN). In our preliminary screening of urine proteins in LN, urine soluble CD163 (sCD163) was significantly elevated in patients with active LN. To evaluate the potential of sCD163 as a biomarker in LN, urine sCD163 was assayed in patients with active LN, active non-renal lupus patients (ANR), inactive SLE and healthy controls (HC), using ELISA and normalized to urine creatinine. The correlation of urine sCD163 with clinical parameters and renal pathological attributes was further investigated in LN patients with concurrent renal biopsies. A total of 228 SLE patients and 56 HC were included from three cohorts. Results demonstrated that urine sCD163 was significantly elevated in active LN when compared with HC, inactive SLE, or ANR in African-American, Caucasian and Asian subjects (all P < 0.001). In LN patients with concurrent renal biopsies, urine sCD163 was significantly increased in patients with proliferative LN when compared with non-proliferative LN (P < 0.001). Urine sCD163 strongly correlated with SLEDAI, rSLEDAI, activity index (AI) of renal pathology, fibrinoid necrosis, cellular crescents, and interstitial inflammation on biopsies (all P < 0.01). Macrophages, particularly M2 macrophages, the predominant cells expressing CD163 within LN kidneys, represented a potential source of elevated urine sCD163, based on single-cell RNA sequencing analysis. To conclude, urine sCD163 discriminated patients with active LN from other SLE patients and was significantly elevated in proliferative LN. It strongly correlated with concurrent AI and several specific pathological attributes, demonstrating its potential in predicting renal pathology.

Neutrophil Extracellular Traps (NETs): An unexplored territory in renal pathobiology, a pilot computational study.

In the age of modern medicine and artificial intelligence, image analysis and machine learning have revolutionized diagnostic pathology, facilitating the development of computer aided diagnostics (CADs) which circumvent prevalent diagnostic challenges. Although CADs will expedite and improve the precision of clinical workflow, their prognostic potential, when paired with clinical outcome data, remains indeterminate. In high impact renal diseases, such as diabetic nephropathy and lupus nephritis (LN), progression often occurs rapidly and without immediate detection, due to the subtlety of structural changes in transient disease states. In such states, exploration of quantifiable image biomarkers, such as Neutrophil Extracellular Traps (NETs), may reveal alternative progression measures which correlate with clinical data. NETs have been implicated in LN as immunogenic cellular structures, whose occurrence and dysregulation results in excessive tissue damage and lesion manifestation. We propose that renal biopsy NET distribution will function as a discriminate, predictive biomarker in LN, and will supplement existing classification schemes. We have developed a computational pipeline for segmenting NET-like structures in LN biopsies. NET-like structures segmented from our biopsies warrant further study as they appear pathologically distinct, and resemble non-lytic, vital NETs. Examination of corresponding H&E regions predominantly placed NET-like structures in glomeruli, including globally and segmentally sclerosed glomeruli, and tubule lumina. Our work continues to explore NET-like structures in LN biopsies by: 1.) revising detection and analytical methods based on evolving NETs definitions, and 2.) cataloguing NET morphology in order to implement supervised classification of NET-like structures in histopathology images.

Differential analysis of serum and urine S100 proteins in juvenile-onset systemic lupus erythematosus (jSLE)

Up to 80% of juvenile-onset systemic lupus erythematosus (jSLE) patients develop lupus nephritis (LN) that affects treatment and prognosis. Easily accessible biomarkers do not exist to reliably diagnose LN, leaving kidney biopsies as the gold-standard. Calcium-binding S100 proteins are expressed by innate immune cells and epithelia and may act as biomarkers in systemic inflammatory conditions.We quantified S100 proteins in the serum and urine of jSLE patients, matched healthy and inflammatory (IgA vasculitis) controls. Serum S100A8/A9, and serum and urine S100A12 are increased in jSLE patients when compared to controls. Furthermore, serum S100A8/A9, and serum and urine S100A12 are increased in jSLE patients with active as compared to patients with inactive/no LN. No differences in S100A4 levels were seen between groups.This study demonstrates potential promise for S100A8/A9 and S100A12 as biomarkers for jSLE and active LN. Findings require to be confirmed and tested prospectively in independent and larger multi-ethnic cohorts.

Dysregulation of cell-free long non-coding RNAs (NEAT2, CTC-471J1.2 and lnc-DC) in Egyptian systemic lupus and lupus nephritis patients

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disorder; lupus nephritis (LN) is the main cause of disability and death in SLE patients. Although long noncoding RNAs (lncRNAs) lack a protein-coding ability, they have a significant role in the regulation of gene expression. We aimed to evaluate cell-free lncRNAs (NEAT2, CTC-471 J1.2 and lnc-DC) as biomarkers for SLE and LN. Quantification of the expression level of cell-free lncRNAs (NEAT2, CTC-471J1.2 and lnc-DC) was performed by real-time PCR in 90 controls and 139 patients with SLE, who were further subdivided into 70 patients with LN and 69 patients without LN. The expression levels of the NEAT2 and lnc-DC genes were significantly up-regulated and that of the CTC-471J1.2 gene was down-regulated in patients with SLE versus controls. Additionally, NEAT2 showed the best performance to differentiate SLE patients from controls, with a sensitivity of 92% and a specificity of 89%. To predict the future development of LN, CTC-471J1.2 showed the highest sensitivity (87%) and specificity (90%). A significantly positive correlation was found between lnc-DC expression and the activity of SLE (as assessed by the SLEDAI score) in LN patients, and a negative correlation was found between CTC471J1.1 expression and the SLEDAI score in both SLE subgroups. We concluded that cell-free NEAT2 is the most sensitive biomarker for SLE diagnosis and that circulating CTC-471J1.2 is the most specific and sensitive diagnostic biomarker for LN. Both lnc-DC and CTC-471J1.2 could be considered predictive biomarkers for SLE activity and LN development.

Urinary Tumor Necrosis Factor-Like Weak Inducer of Apoptosis as a Biomarker for Diagnosis and Evaluating Activity in Lupus Nephritis: A Meta-analysis.

Urinary tumor necrosis factor-like weak inducer of apoptosis (uTWEAK) has been identified as a candidate biomarker for lupus nephritis (LN). However, its diagnostic value remains unclear. This meta-analysis was conducted to comprehensively evaluate the value of uTWEAK for diagnosis and evaluating activity in LN. Medline, Web of Science, Chinese Biomedical Medical, and Chinese National Knowledge Infrastructure databases were searched to acquire eligible studies published before September 30, 2019. The quality of the studies was evaluated by Quality Assessment of Diagnostic Accuracy Studies-2. Summary receiver operating characteristic curve and area under the curve were applied to summarize the overall diagnostic performances. The pooled sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated with the fixed-effects model. RevMan 5.3, Stata 12.0, and Meta-disc 1.4 software were used. A total of 7 studies were included. Of these, 4 studies were available for comparison between SLE with and without LN, and 3 studies were for active and inactive LN. The total area under the curve was 0.8640, and DOR was 14.89 (95% confidence interval [CI], 7.95-27.86). For LN diagnosis, the pooled sensitivity, specificity, and DOR were 0.55 (95% CI, 0.47-0.63), 0.92 (95% CI, 0.86-0.96), and 16.54 (95% CI, 7.57-36.15), respectively. For assessing LN activity, the pooled sensitivity, specificity, and DOR were 0.91 (95% CI, 0.82-0.96), 0.70 (95% CI, 0.58-0.81), and 18.45 (95% CI, 7.45-45.87), respectively. This meta-analysis indicated that uTWEAK has relatively moderate sensitivity and specificity for diagnosis and evaluating activity in LN, suggesting that uTWEAK can serve as a helpful biomarker for LN.

Utility of urinary transferrin and ceruloplasmin in patients with systemic lupus erythematosus for differentiating patients with lupus nephritis.

Diagnosis of lupus nephritis (LN) is usually based on renal biopsy, which is an invasive technique that involves multiple risks. Therefore, different biomarkers have emerged as alternatives for the diagnosis of LN. Nonetheless, studies regarding urinary biomarkers in Latin American patients are limited. The objective of this study was to assess the diagnostic value of urinary transferrin and ceruloplasmin to differentiate patients who have renal involvement from those who do not. Systemic lupus erythematosus (SLE) patients that met the revised American College of Rheumatology (ACR) classification criteria were recruited. Patients with another autoimmune disease, active infection (urinary tract or systemic infection), renal replacement therapy, human immunodeficiency virus infection or pregnancy were excluded. A urine sample was collected from each patient. LN was diagnosed according to ACR criteria. The activity and chronicity of LN were measured using the Austin indices. Urinary transferrin and ceruloplasmin levels were measured using commercial enzyme-linked immunosorbent assay (ELISA) kits. Mann-Whitney U test and Student's t-test were used to compare data. Spearman's rank correlation was used to determine associations. Lastly, receiver operating characteristic (ROC) curves were created. The study involved 120 SLE patients. In all, 85% were female, 76% mestizo, the mean age was 32.8±12.1years and mean systemic lupus erythematosus disease activity index (SLEDAI) was 8.4±8.9; 64% had renal involvement. Urinary levels of the two biomarkers were significantly higher in patients with LN compared to those without LN. Similarly, urinary levels of both biomarkers were significantly higher in patients with active LN compared to those with inactive LN. Furthermore, urinary transferrin levels were significantly higher in Afro-Latin American patients. On the other hand, urinary transferrin levels correlated with SLEDAI and proteinuria, and transferrin and ceruloplasmin levels correlated with each other. The diagnostic value of ROC curves for these urinary biomarkers for LN were good. In our cohort of SLE patients, we found that transferrin and ceruloplasmin were potential biomarkers for LN, and can even differentiate active LN.

Expression of BAFF, APRIL, and cognate receptor genes in lupus nephritis and potential use as urinary biomarkers

BackgroundB-cell activating factor (BAFF), a proliferation-inducing ligand (APRIL), and their receptors BAFF-R, BCMA, and TACI are crucial factors for the survival of B lymphocytes. Recent evidence has also demonstrated the importance of BAFF/APRIL signaling in lupus nephritis (LN). This study evaluated the relationships between LN clinical characteristics and the urinary expression levels of BAFF, APRIL, and cognate receptors to assess their potential value as disease biomarkers. MethodsExpression levels of these genes were assessed in urine samples collected from systemic lupus erythematosus (SLE) patients before renal biopsy using reverse transcription real-time PCR. ResultsThirty-five patients with LN were included. Most of the patients were female (82.86%) with median Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) of 15. BAFF mRNA was detectable in 28.57%, APRIL mRNA in 42.85%, BR3 mRNA in 48.57%, and TACI mRNA in 42.85% of urine samples. On the other hand, urinary (u)BCMA mRNA was not found in any sample. Urinary expression of most biomarkers was detected with greater frequency in class III and IV LN compared to class V LN. The expression level of uBR3 mRNA was correlated with SLEDAI-2K and histological activity index. ConclusionUrinary expression of BAFF/APRIL signaling factors, especially TACI, APRIL, and BR3 mRNAs, may be useful biomarkers for LN.

CD36 identified by weighted gene co-expression network analysis as a hub candidate gene in lupus nephritis.

Lupus nephritis (LN) is a severe manifestation of systemic lupus erythematosus (SLE), which often progresses to end-stage renal disease (ESRD) and ultimately leads to death. At present, there are no definitive therapies towards LN, so that illuminating the molecular mechanism behind the disease has become an urgent task for researchers. Bioinformatics has become a widely utilized method for exploring genes related to disease. This study set out to conduct weighted gene co-expression network analysis (WGCNA) and screen the hub gene of LN. We performed WGCNA on the microarray expression profile dataset of GSE104948 from the Gene Expression Omnibus (GEO) database with 18 normal and 21 LN samples of glomerulus. A total of 5,942 genes were divided into 5 co-expression modules, one of which was significantly correlated to LN. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were conducted on the LN-related module, and the module was proved to be associated mainly with the activation of inflammation, immune response, cytokines, and immune cells. Genes in the most significant GO terms were extracted for sub-networks of WGNCA. We evaluated the centrality of genes in the sub-networks by Maximal Clique Centrality (MCC) method and CD36 was ultimately screened out as a hub candidate gene of the pathogenesis of LN. The result was verified by its differentially expressed level between normal and LN in GSE104948 and the other three multi-microarray datasets of GEO. Moreover, we further demonstrated that the expression level of CD36 is related to the WHO Lupus Nephritis Class of LN patients with the help of Nephroseq database. The current study proposed CD36 as a vital candidate gene in LN for the first time and CD36 may perform as a brand-new biomarker or therapeutic target of LN in the future.

Urinary Neuropilin-1: A Predictive Biomarker for Renal Outcome in Lupus Nephritis.

At present, Lupus Nephritis (LN) is still awaiting a biomarker to better monitor disease activity, guide clinical treatment, and predict a patient’s long-term outcome. In the last decade, novel biomarkers have been identified to monitor the disease, but none have been incorporated into clinical practice. The transmembrane receptor neuropilin-1 (NRP-1) is highly expressed by mesangial cells and its genetic deletion results in proteinuric disease and glomerulosclerosis. NRP-1 is increased in kidney biopsies of LN. In this work we were interested in determining whether urinary NRP-1 levels could be a biomarker of clinical response in LN. Our results show that patients with active LN have increased levels of urinary NRP-1. When patients were divided according to clinical response, responders displayed higher urinary and tissue NRP-1 levels at the time of renal biopsy. Areas under the receiver operating characteristic curve, comparing baseline creatinine, proteinuria, urinary NRP-1, and VEGFA protein levels, showed NRP-1 to be an independent predictor for clinical response. In addition, in vitro studies suggest that NRP-1could promote renal recovery through endothelial proliferation and migration, mesangial migration and local T cell cytotoxicity. Based on these results, NRP-1 may be used as an early prognostic biomarker in LN.

Utilization of Biomarkers in Lupus Nephritis.

Lupus nephritis (LN) occurs in up to 60% of SLE patients, and is a leading cause of disability and death. Current treatment of LN consists of a combination of high dose corticosteroids that non-specifically decrease inflammation and cytotoxic medications that reduce auto-antibody production. That combination of therapy is associated with significant side effects while remission rates remain inadequate. Since the introduction of biologics into the pharmacological armamentarium, there has been hope for less toxic and more effective therapies for LN. Unfortunately, after multiple clinical trials, no biologic has improved efficacy over standard of care therapies for LN. This is likely, in part, due to disease heterogeneity. The utilization of biomarkers in LN may provide a way to stratify patients and guide therapeutic options. In this review, we summarize traditional and novel LN biomarkers and discuss how they may be used to diagnose, stratify, and guide therapy in patients with LN, bringing precision medicine to the forefront of LN therapy.

Urinary Interleukin 6: A Prognostic Bio Marker in Lupus Nephritis

Urinary Interleukin 6: A Prognostic Bio Marker in Lupus Nephritis

Urinary pro-thrombotic, anti-thrombotic, and fibrinolytic molecules as biomarkers of lupus nephritis

ObjectiveThis study evaluates the utility of urinary pro-thrombotic molecules such as tissue factor (TF), anti-thrombotic molecules such as tissue factor pathway inhibitor (TFPI), and fibrinolytic molecules such as plasmin and d-dimer as biomarkers of lupus nephritis (LN).MethodsUrine samples from 113 biopsy-proven LN patients (89 active LN and 24 inactive LN), 45 chronic kidney disease patients, and 41 healthy controls were examined for d-dimer, plasmin, TF, and TFPI levels by ELISA. The area under the receiver operating characteristic curve (AUC) analysis, multivariate regression analysis, and Bayesian network analysis were performed to assess the diagnostic value of the assayed molecules in LN.ResultsAlthough urinary d-dimer, plasmin, TF, and TFPI were all elevated in active LN compared to all control groups, and correlated with rSLEDAI and SLICC RAS disease activity indices, urine plasmin emerged as the strongest independent predictor of eGFR and renal disease status, by multivariate regression analysis and Bayesian network analysis. Whereas urine plasmin discriminated active LN from inactive disease with an AUC of 0.84, the combination of urine plasmin and TFPI discriminated ALN from ILN with an AUC of 0.86, with both surpassing the specificity and positive predictive value of traditional markers such as anti-dsDNA and complement C3.ConclusionBoth thrombogenic and thrombolytic cascades appear to be upregulated in lupus nephritis, with proteins from both cascades appearing in the urine. Of the coagulation cascade proteins surveyed, urine plasmin emerges as the strongest predictor of eGFR and clinical renal disease in patients with LN.

Utility of urinary transferrin and ceruloplasmin in patients with systemic lupus erythematosus for differentiating patients with lupus nephritis

Background and objectiveDiagnosis of lupus nephritis (LN) is usually based on renal biopsy, which is an invasive technique that involves multiple risks. Therefore, different biomarkers have emerged as alternatives for the diagnosis of LN. Nonetheless, studies regarding urinary biomarkers in Latin American patients are limited. The objective of this study was to assess the diagnostic value of urinary transferrin and ceruloplasmin to differentiate patients who have renal involvement from those who do not. Materials and methodsSystemic lupus erythematosus (SLE) patients that met the revised American College of Rheumatology (ACR) classification criteria were recruited. Patients with another autoimmune disease, active infection (urinary tract or systemic infection), renal replacement therapy, human immunodeficiency virus infection or pregnancy were excluded. A urine sample was collected from each patient. LN was diagnosed according to ACR criteria. The activity and chronicity of LN were measured using the Austin indices. Urinary transferrin and ceruloplasmin levels were measured using commercial enzyme-linked immunosorbent assay (ELISA) kits. Mann–Whitney U test and Student's t-test were used to compare data. Spearman's rank correlation was used to determine associations. Lastly, receiver operating characteristic (ROC) curves were created. ResultsThe study involved 120 SLE patients. In all, 85% were female, 76% mestizo, the mean age was 32.8±12.1years and mean systemic lupus erythematosus disease activity index (SLEDAI) was 8.4±8.9; 64% had renal involvement. Urinary levels of the two biomarkers were significantly higher in patients with LN compared to those without LN. Similarly, urinary levels of both biomarkers were significantly higher in patients with active LN compared to those with inactive LN. Furthermore, urinary transferrin levels were significantly higher in Afro-Latin American patients. On the other hand, urinary transferrin levels correlated with SLEDAI and proteinuria, and transferrin and ceruloplasmin levels correlated with each other. The diagnostic value of ROC curves for these urinary biomarkers for LN were good. ConclusionsIn our cohort of SLE patients, we found that transferrin and ceruloplasmin were potential biomarkers for LN, and can even differentiate active LN.

Immunoglobulin Binding Protein 1 as a Potential Urine Biomarker in Patients with Lupus Nephritis.

We evaluated the role of immunoglobulin binding protein 1 (IGBP1), a phosphoprotein associated with the B cell receptor (BCR) complex, as a urine biomarker in lupus nephritis (LN). The IGBP1 concentrations in plasma and urine of patients with LN, systemic lupus erythematosus (SLE) without nephritis and healthy controls were estimated by ELISA. IGBP1 expression in the kidneys of LN patients and transplantation donors was detected by immunohistochemistry. Microarray-based global gene expression profile of HK-2 cells with IGBP1 knock-down and fluorescence-activated cell sorting (FACS) for intracellular IGBP1 expression in human peripheral blood mononuclear cells (PBMCs) was performed. Urine IGBP1 levels were elevated significantly in LN patients, and it correlated with the clinical activity indices (complement 3 (C3) level, anti-dsDNA antibodies titer, SLE Disease Activity Index-2000 (SLEDAI-2K) and histological activity index. IGBP1 expression was increased in LN patients as compared to the donors and was detected mainly in the tubules by histopathology. In microarray analysis, several genes related to SLE pathogenesis (PPME1, ROCK2, VTCN1, IL-17R, NEU1, HLA-DM, and PTX3) responded to siRNA-mediated IGBP1 silencing. In FACS, IGBP1 was expressed mainly in the CD14+ cells. The overall expression of IGBP1 in PBMCs was higher in LN patients as compared with that in SLE patients without nephritis. Conclusively, urinary IGBP1 may be a novel biomarker reflecting the clinical and histological activities in LN.

Urinary VCAM-1, KIM-1, and ET-1 as Biomarkers of Lupus Nephritis: Correlation with Immunological Parameters in Hospital USM

Urinary VCAM-1, KIM-1, and ET-1 as Biomarkers of Lupus Nephritis: Correlation with Immunological Parameters in Hospital USM

Identification of Low-Abundance Urinary Biomarkers in Lupus Nephritis Using Electrochemiluminescence Immunoassays.

To investigate the utility of a sensitive platform using electrochemiluminescence (ECL) for the identification of low-abundance urinary protein biomarkers in lupus nephritis (LN). Forty-eight urine samples were obtained from subjects in 2 independent cohorts, each consisting of 3 groups (matched for age, sex, and race) of 8 patients with active LN (renal Systemic Lupus Erythematosus Disease Activity Index [SLEDAI] >0), 8 patients with inactive SLE (renal SLEDAI 0), and 8 healthy controls. Samples were tested using a preexisting 40-plex ECL panel. A custom 5-plex ECL panel was then developed for further validation studies and used to test 140 urine samples (from 44 patients with active LN, 41 patients with inactive SLE, 28 healthy controls, and 27 patients with other kidney diseases). Levels of 17 urinary proteins were elevated (P < 0.05 by 2-tailed Mann-Whitney U test) in samples from patients with active LN compared to samples from patients with inactive SLE and healthy controls in cohort 1, while 9 were similarly elevated in cohort 2. Of these, interleukin-7 (IL-7), IL-12p40, IL-15, interferon-γ-inducible protein 10 (IP-10), and thymus and activation-regulated chemokine (TARC) were chosen for further validation. These 5 proteins were undetectable by enzyme-linked immunosorbent assay (ELISA). Hence, a custom 5-plex ECL panel was developed and used to validate the results from the initial 40-plex screening panel. Urinary IL-7, IL-12p40, IL-15, IP-10, and TARC levels were again significantly elevated in patients with active LN compared to those with inactive SLE and healthy controls, and correlated well with the renal SLEDAI and physician's global assessment of disease activity (R > 0.67, P < 0.05). All 5 urinary proteins were more frequently elevated in LN compared to controls with other chronic kidney diseases, although overall group differences attained significance only for urinary IL-7 and IL-15. Urinary levels of IL-7, IL-12p40, IL-15, IP-10, and TARC are potentially useful diagnostic tools in LN. The use of ECL assays may allow detection of urinary biomarkers that are below ELISA detection limits.