Urinary levels of RANTES and M-CSF are predictors of lupus nephritis flare

Macrophage colony-stimulating factor receptor/CD115+ non-classical monocytes are expanded in systemic lupus erythematosus and associated with lupus nephritis

OBJECTIVE

In systemic lupus erythematosus (SLE), the non-classical monocyte compartment is expanded, but its phenotype and association with clinical disease manifestations have not been explored.

METHOD

Monocyte subsets from 39 SLE patients, 32 healthy age-matched controls, and 16 patients from a disease control (autoimmune connective tissue disease other than SLE) were determined based on CD14 and CD16 surface expression. Cell surface expression of the receptors for macrophage colony-stimulating factor (M-CSF) (CD115) and granulocyte-macrophage colony-stimulating factor (GM-CSF) (CD116), as well as 6-Sulpho LacNAc (slan), were analysed by flow cytometry. The association of monocyte populations with disease manifestations, disease activity markers, and current medication of each patient was analysed by chart review.

RESULTS

Non-classical monocytes displayed a cell-type specific signature of high M-CSF receptor CD115 and low GM-CSF receptor CD116 expression that separated them from the other two monocyte subsets. In healthy individuals, the M-CSF receptor on non-classical monocytes was an age-dependent surface marker, with lower expression in young adults. However, SLE monocytes were characterized by a marked expansion of M-CSF receptor/CD115+ non-classical monocytes in patients of all ages. The expanded population of M-CSF receptor/CD115+ non-classical monocytes was associated with lupus nephritis but not with disease activity, and coexpressed slan.

CONCLUSION

The non-classical monocyte subset in SLE is characterized by an expansion of M-CSF receptor/CD115+ cells that are associated with lupus nephritis and coexpress slan.

Targeting CSF-1R represents an effective strategy in modulating inflammatory diseases

Colony-stimulating factor-1 receptor (CSF-1R), also known as FMS kinase, is a type I single transmembrane protein mainly expressed in myeloid cells, such as monocytes, macrophages, glial cells, and osteoclasts. The endogenous ligands, colony-stimulating factor-1 (CSF-1) and Interleukin-34 (IL-34), activate CSF-1R and downstream signaling pathways including PI3K-AKT, JAK-STATs, and MAPKs, and modulate the proliferation, differentiation, migration, and activation of target immune cells. Over the past decades, the promising therapeutic potential of CSF-1R signaling inhibition has been widely studied for decreasing immune suppression and escape in tumors, owing to depletion and reprogramming of tumor-associated macrophages. In addition, the excessive activation of CSF-1R in inflammatory diseases is consecutively uncovered in recent years, which may result in inflammation in bone, kidney, lung, liver and central nervous system. Agents against CSF-1R signaling have been increasingly investigated in preclinical or clinical studies for inflammatory diseases treatment. However, the pathological mechanism of CSF-1R in inflammation is indistinct and whether CSF-1R signaling can be identified as biomarkers remains controversial. With the background information aforementioned, this review focus on the dialectical roles of CSF-1R and its ligands in regulating innate immune cells and highlights various therapeutic implications of blocking CSF-1R signaling in inflammatory diseases.

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.

CD52 Is Elevated on B cells of SLE Patients and Regulates B Cell Function

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by B cell dysregulation and breaks in tolerance that lead to the production of pathogenic autoantibodies. We performed single-cell RNA sequencing of B cells from healthy donors and individuals with SLE which revealed upregulated CD52 expression in SLE patients. We further demonstrate that SLE patients exhibit significantly increased levels of B cell surface CD52 expression and plasma soluble CD52, and levels of soluble CD52 positively correlate with measures of lupus disease activity. Using CD52-deficient JeKo-1 cells, we show that cells lacking surface CD52 expression are hyperresponsive to B cell receptor (BCR) signaling, suggesting an inhibitory role for the surface-bound protein. In healthy donor B cells, antigen-specific BCR-activation initiated CD52 cleavage in a phospholipase C dependent manner, significantly reducing cell surface levels. Experiments with recombinant CD52-Fc showed that soluble CD52 inhibits BCR signaling in a manner partially-dependent on Siglec-10. Moreover, incubation of unstimulated B cells with CD52-Fc resulted in the reduction of surface immunoglobulin and CXCR5. Prolonged incubation of B cells with CD52 resulted in the expansion of IgD+IgMlo anergic B cells. In summary, our findings suggest that CD52 functions as a homeostatic protein on B cells, by inhibiting responses to BCR signaling. Further, our data demonstrate that CD52 is cleaved from the B cell surface upon antigen engagement, and can suppress B cell function in an autocrine and paracrine manner. We propose that increased expression of CD52 by B cells in SLE represents a homeostatic mechanism to suppress B cell hyperactivity.

Tumor Necrosis Factor-Like Weak Inducer of Apoptosis and Selected Cytokines-Potential Biomarkers in Children with Solitary Functioning Kidney

This study was performed to explore serum tumor necrosis factor-like weak inducer of apoptosis (TWEAK) and its dependent cytokines urinary excretion: monocyte chemoattractant protein-1 (MCP-1) and regulated on activation, normal T cell expressed and secreted chemokine (RANTES) with their relation to the kidney function parameters in children with solitary functioning kidney (SFK). The study included 80 children and adolescents (median age 9.75 year) with congenital and acquired (after surgical removal) SFK. Serum TWEAK and urinary MCP-1 and RANTES levels were significantly higher in SFK patients (p < 0.05). The serum TWEAK was positively related to serum creatinine (r = 0.356; p < 0.001). Moreover, in SFK the receiver operating characteristic analyses revealed good diagnostic profile for serum TWEAK with AUC (Area Under The Curve)—0.853, uRANTES—0.757, and for RANTES/cr.: AUC—0.816. Analysis carried out to identify children with impaired renal function (albuminuria and/or decreased estimated glomerular filtration rate < 90 mL/min/1.73 m² and/or hypertension) showed good profile for TWEAK (AUC—0.79) and quite good profile for uRANTES and RANTES/cr. (AUC 0.66 and 0.631, respectively). This is the first study investigating serum TWEAK and urinary excretion of MCP-1 and RANTES together in children with SFK. Obtained results indicate that TWEAK and RANTES may serve as potential markers of renal impairment.

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.

Urinary biomarkers in lupus nephritis

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

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.

The human glomerular endothelial cells are potent pro-inflammatory contributors in an in vitro model of lupus nephritis

Juvenile-onset lupus nephritis (LN) affects up to 80% of juvenile-onset systemic lupus erythematosus patients (JSLE). As the exact role of human renal glomerular endothelial cells (GEnCs) in LN has not been fully elucidated, the aim of this study was to investigate their involvement in LN. Conditionally immortalised human GEnCs (ciGEnCs) were treated with pro-inflammatory cytokines known to be involved in LN pathogenesis and also with LPS. Secretion and surface expression of pro-inflammatory proteins was quantified via ELISA and flow cytometry. NF-κΒ and STAT-1 activation was investigated via immunofluorescence. Serum samples from JSLE patients and from healthy controls were used to treat ciGEnCs to determine via qRT-PCR potential changes in the mRNA levels of pro-inflammatory genes. Our results identified TNF-α, IL-1β, IL-13, IFN-γ and LPS as robust in vitro stimuli of ciGEnCs. Each of them led to significantly increased production of different pro-inflammatory proteins, including; IL-6, IL-10, MCP-1, sVCAM-1, MIP-1α, IP-10, GM-CSF, M-CSF, TNF-α, IFN-γ, VCAM-1, ICAM-1, PD-L1 and ICOS-L. TNF-α and IL-1β were shown to activate NF-κB, whilst IFN-γ activated STAT-1. JSLE patient serum promoted IL-6 and IL-1β mRNA expression. In conclusion, our in vitro model provides evidence that human GEnCs play a pivotal role in LN-associated inflammatory process.

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.

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.

Predictive biological markers of systemic lupus erythematosus flares: a systematic literature review

BACKGROUND

The aim of this study was to identify the most reliable biomarkers in the literature that could be used as flare predictors in systemic lupus erythematosus (SLE).

METHODS

A systematic review of the literature was performed using two databases (MEDLINE and EMBASE) through April 2015 and congress abstracts from the American College of Rheumatology and the European League Against Rheumatism were reviewed from 2010 to 2014. Two independent reviewers screened titles and abstracts and analysed selected papers in detail, using a specific questionnaire. Reports addressing the relationships between one or more defined biological test(s) and the occurrence of disease exacerbation were included in the systematic review.

RESULTS

From all of the databases, 4668 records were retrieved, of which 69 studies or congress abstracts were selected for the systematic review. The performance of seven types of biomarkers performed routinely in clinical practice and nine types of novel biological markers was evaluated. Despite some encouraging results for anti-double-stranded DNA antibodies, anti-C1q antibodies, B-lymphocyte stimulator and tumour necrosis factor-like weak inducer of apoptosis, none of the biomarkers stood out from the others as a potential gold standard for flare prediction. The results were heterogeneous, and a lack of standardized data prevented us from identifying a powerful biomarker.

CONCLUSIONS

No powerful conclusions could be drawn from this systematic review due to a lack of standardized data. Efforts should be undertaken to optimize future research on potential SLE biomarkers to develop validated candidates. Thus, we propose a standardized pattern for future studies.

A systems approach to renal inflammation in SLE

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

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.

Biomarkers for kidney involvement in pediatric lupus

Lupus nephritis (LN), the renal involvement in systemic lupus erythematosus, is currently diagnosed by histopathology obtained by percutaneous renal biopsy and is associated with increased morbidity and mortality in both adults and children. LN is more prevalent and severe in children, requiring aggressive and prolonged immunosuppression. The consequences of the diagnosis and its treatment have devastating long-term effects on the growth, well-being and quality of life of affected children. The paucity of reliable clinical indicators of the presence and severity of renal involvement have contributed to a halt in the reduction of progression to end-stage renal disease in recent years. Here, we discuss the recent development of biomarkers in the management of LN and their role as therapeutic targets.

Monoclonal antibody against macrophage colony-stimulating factor suppresses circulating monocytes and tissue macrophage function but does not alter cell infiltration/activation in cutaneous lesions or clinical outcomes in patients with cutaneous lupus erythematosus

This study's objective was to assess the effects of PD-0360324, a fully human immunoglobulin G2 monoclonal antibody against macrophage colony-stimulating factor in cutaneous lupus erythematosus (CLE). Patients with active subacute CLE or discoid lupus erythematosus were randomized to receive 100 or 150 mg PD-0360324 or placebo via intravenous infusion every 2 weeks for 3 months. Blood and urine samples were obtained pre- and post-treatment to analyse pharmacokinetics and pharmacodynamic changes in CD14(+) CD16(+) monocytes, urinary N-terminal telopeptide (uNTX), alanine/aspartate aminotransferases (ALT/AST) and creatine kinase (CK); tissue biopsy samples were taken to evaluate macrophage populations and T cells using immunohistochemistry. Clinical efficacy assessments included the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI). Among 28 randomized/analysed patients, peak/trough plasma concentrations increased in a greater-than-dose-proportional manner with dose increases from 100 to 150 mg. Statistically significant differences were observed between active treatment and placebo groups in changes from baseline in CD14(+) CD16(+) cells, uNTX, ALT, AST and CK levels at most time-points. The numbers, density and activation states of tissue macrophages and T cells did not change from baseline to treatment end. No between-group differences were seen in CLASI. Patients receiving PD-0360324 reported significantly more adverse events than those receiving placebo, but no serious adverse events. In patients with CLE, 100 and 150 mg PD-0360324 every 2 weeks for 3 months suppressed a subset of circulating monocytes and altered activity of some tissue macrophages without affecting cell populations in CLE skin lesions or improving clinical end-points.

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.

Lack of Interferon and Proinflammatory Cyto/chemokines in Serologically Active Clinically Quiescent Systemic Lupus Erythematosus

OBJECTIVE

Serologically active clinically quiescent (SACQ) patients with systemic lupus erythematosus (SLE) remain clinically quiescent for prolonged periods despite anti-dsDNA antibodies and/or low complements, indicating the presence of immune complexes. The immune mechanisms leading to this quiescence are unknown. However, in addition to activating complement, immune complex uptake by various cells leads to the production of interferon (IFN)-α and other proinflammatory factors that are also involved in tissue damage. Here we investigate whether production of these factors is reduced in SACQ patients.

METHODS

The levels of 5 IFN-induced genes and 19 cyto/chemokines were measured in SACQ patients and were compared with those in serologically and clinically active (SACA) and serologically and clinically quiescent (SQCQ) patients. SACQ and SQCQ were defined as ≥ 2 years without clinical activity, with/without persistent serologic activity, respectively, and off corticosteroids/immunosuppressives. SACA was defined as disease activity compelling immunosuppression. Levels of OAS1, IFIT1, MX1, LY6E, and ISG15 were measured by quantitative real-time polymerase chain reaction (PCR) and a composite score (IFN-5) derived from this. Plasma cyto/chemokines were measured by Luminex assay. Nonparametric univariate and logistic regression analyses were conducted.

RESULTS

There were no differences in gene expression or cyto/chemokine levels between SACQ and SQCQ patients. The SACQ IFN-5 score was significantly lower than that of SACA (p = 0.003) and was driven by SACQ status, not by autoantibody profile or disease duration. Levels of granulocyte-macrophage colony-stimulating factor, interleukin (IL) 6, IL-10, IFN-γ-inducible protein 10, monocyte chemoattractant protein 1, and tumor necrosis factor-α were significantly lower in SACQ than SACA.

CONCLUSION

The levels of proinflammatory factors in SACQ mirror those of SQCQ patients, indicating reduced production of these factors despite the presence of immune complexes.

Pathogenic Inflammation and Its Therapeutic Targeting in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE, lupus) is a highly complex and heterogeneous autoimmune disease that most often afflicts women in their child-bearing years. It is characterized by circulating self-reactive antibodies that deposit in tissues, including skin, kidneys, and brain, and the ensuing inflammatory response can lead to irreparable tissue damage. Over many years, clinical trials in SLE have focused on agents that control B- and T-lymphocyte activation, and, with the single exception of an agent known as belimumab which targets the B-cell survival factor BAFF, they have been disappointing. At present, standard therapy for SLE with mild disease is the agent hydroxychloroquine. During disease flares, steroids are often used, while the more severe manifestations with major organ involvement warrant potent, broad-spectrum immunosuppression with cyclophosphamide or mycophenolate. Current treatments have severe and dose-limiting toxicities and thus a more specific therapy targeting a causative factor or signaling pathway would be greatly beneficial in SLE treatment. Moreover, the ability to control inflammation alongside B-cell activation may be a superior approach for disease control. There has been a recent focus on the innate immune system and associated inflammation, which has uncovered key players in driving the pathogenesis of SLE. Delineating some of these intricate inflammatory mechanisms has been possible with studies using spontaneous mouse mutants and genetically engineered mice. These strains, to varying degrees, exhibit hallmarks of the human disease and therefore have been utilized to model human SLE and to test new drugs. Developing a better understanding of the initiation and perpetuation of disease in SLE may uncover suitable novel targets for therapeutic intervention. Here, we discuss the involvement of inflammation in SLE disease pathogenesis, with a focus on several key proinflammatory cytokines and myeloid growth factors, and review the known outcomes or the potential for targeting these factors in SLE.

Urine Monocyte Chemoattractant Protein-1 and Lupus Nephritis Disease Activity: Preliminary Report of a Prospective Longitudinal Study

Objective. This longitudinal study aimed to determine the urine monocyte chemoattractant protein-1 (uMCP-1) levels in patients with biopsy-proven lupus nephritis (LN) at various stages of renal disease activity and to compare them to current standard markers. Methods. Patients with LN—active or inactive—had their uMCP-1 levels and standard disease activity markers measured at baseline and 2 and 4 months. Urinary parameters, renal function test, serological markers, and renal SLE disease activity index-2K (renal SLEDAI-2K) were analyzed to determine their associations with uMCP-1. Results. A hundred patients completed the study. At each visit, uMCP-1 levels (pg/mg creatinine) were significantly higher in the active group especially with relapses and were significantly associated with proteinuria and renal SLEDAI-2K. Receiver operating characteristic (ROC) curves showed that uMCP-1 was a potential biomarker for LN. Whereas multiple logistic regression analysis showed that only proteinuria and serum albumin and not uMCP-1 were independent predictors of LN activity. Conclusion. uMCP-1 was increased in active LN. Although uMCP-1 was not an independent predictor for LN activity, it could serve as an adjunctive marker when the clinical diagnosis of LN especially early relapse remains uncertain. Larger and longer studies are indicated.

Advances in biomarkers for paediatric rheumatic diseases

The search for biomarkers in paediatric rheumatic diseases, particularly juvenile idiopathic arthritis (JIA), childhood lupus nephritis (LN), and juvenile idiopathic inflammatory myopathies (JIIMs) is attracting increased interest. In JIA, a number of biomarkers have shown potential for predicting clinical phenotype, disease activity and severity, clinical remission and relapse, response to treatment, and disease course over time. In systemic JIA, measurement of biomarkers that reflect the degree of activation and expansion of T cells and macrophages might be helpful for detecting subclinical macrophage activation syndrome. Urine biomarkers for childhood LN hold promise for facilitating early diagnosis and improving disease monitoring and assessment of response to therapy. Myositis-specific autoantibodies define distinct serological subgroups of JIIMs, albeit with similar clinical features, responses to therapy, and prognoses. Use of biomarkers may potentially help to avoid invasive procedures, such as renal biopsy in systemic lupus erythematosus and muscle biopsy in juvenile dermatomyositis. Incorporation of effective and reliable biomarkers into routine practice might facilitate adoption of a stratified approach to investigation and management, foster the implementation of research into the design of personalized and targeted therapies, and ultimately lead to more rational and effective clinical care.

Identification of stage-specific genes associated with lupus nephritis and response to remission induction in (NZB × NZW)F1 and NZM2410 mice

OBJECTIVE

To elucidate the molecular mechanisms involved in renal inflammation during the progression, remission, and relapse of nephritis in murine lupus models using transcriptome analysis.

METHODS

Kidneys from (NZB × NZW)F1 (NZB/NZW) and NZM2410 mice were harvested at intervals during the disease course or after remission induction. Genome-wide expression profiles were obtained from microarray analysis of perfused kidneys. Real-time polymerase chain reaction (PCR) analysis for selected genes was used to validate the microarray data. Comparisons between groups using SAM, and unbiased analysis of the entire data set using singular value decomposition and self-organizing maps were performed.

RESULTS

Few changes in the renal molecular profile were detected in prenephritic kidneys, but a significant shift in gene expression, reflecting inflammatory cell infiltration and complement activation, occurred at proteinuria onset. Subsequent changes in gene expression predominantly affected mitochondrial dysfunction and metabolic stress pathways. Endothelial cell activation, tissue remodeling, and tubular damage were the major pathways associated with loss of renal function. Remission induction reversed most, but not all, of the inflammatory changes, and progression toward relapse was associated with recurrence of inflammation, mitochondrial dysfunction, and metabolic stress signatures.

CONCLUSION

Immune cell infiltration and activation is associated with proteinuria onset and is reversed by immunosuppressive therapy, but disease progression is associated with renal hypoxia and metabolic stress. Optimal therapy for lupus nephritis may therefore need to target both immune and nonimmune disease mechanisms. In addition, the overlap of a substantial subset of molecular markers with those expressed in the kidneys of lupus patients suggests potential new biomarkers and therapeutic targets.

Colony-stimulating factor-1: a potential biomarker for lupus nephritis

A noninvasive means to predict the onset and recurrence of lupus nephritis (LN) before overt renal injury is needed to optimize and individualize treatment. Colony-stimulating factor-1 (CSF-1) is expressed by kidney tubules at the onset of LN, increases with disease progression, and spills into the circulation in lupus-prone mice. We tested the hypothesis that amplified expression of CSF-1 detected in the serum or urine correlates with intrarenal CSF-1 expression and histopathology (increased macrophage accumulation, activity indices) and clinical kidney disease activity and predicts the onset and recurrence of nephritis in patients with systemic lupus erythematosus (SLE). We found increased serum or urine CSF-1 levels in patients with cutaneous, serositis, and musculoskeletal disease; however, the increase in CSF-1 levels was far greater in LN. Moreover, an elevation in serum or urine CSF-1 levels correlated with increasing intrarenal CSF-1 expression and histopathology. By longitudinally tracking patients, we found that elevated serum CSF-1 heralded the initial onset of disease, and a rise in serum or urine CSF-1 predicted recurrences of LN before clinical evidence of glomerular dysfunction and conventional serologic measures, even in patients with other manifestations of SLE. These findings indicate that serial monitoring for a rise in serum or urine CSF-1 levels in patients with SLE reflects kidney histopathology and may predict renal disease activity and the onset and recurrence of LN more accurately than conventional laboratory measures.

Role of chemokines in proteinuric kidney disorders

Experimental and human studies have shown that proteinuria contributes to the progression of renal disease. Overexposure to filtered proteins promotes the expression and release of chemokines by tubular epithelial cells, thus leading to inflammatory cell recruitment and renal impairment. This review focuses on recent progress in cellular and molecular understanding of the role of chemokines in the pathogenesis of proteinuria-induced renal injury, as well as their clinical implications and therapeutic potential.

Biomarkers in systemic lupus erythematosus: challenges and prospects for the future

The search for lupus biomarkers to diagnose, monitor, stratify, and predict individual response to therapy is currently more intense than ever before. This effort is essential for several reasons. First, epidemic overdiagnosis and underdiagnosis of lupus, even by certified rheumatologists, leads to errors in therapy with concomitant side effects which may be more serious than the disease itself. Second, identification of lupus flares remains as much an art as it is a science. Third, the capacity to stratify patients so as to predict those who will develop specific patterns of organ involvement is not currently possible but would potentially lead to preventive therapeutic strategies. Fourth, only one new drug for the treatment of lupus has been approved by the US Food and Drug Administration in over 50 years. A major obstacle in this pipeline is the dearth of biomarkers available to prove a patient has responded to an experimental therapeutic intervention. This review will summarize the challenges faced in the discovery and validation of lupus biomarkers, the most promising lupus biomarkers identified to date, and the promise of future directions.

Biomarkers and updates on pediatrics lupus nephritis

Lupus nephritis is a common complication of systemic lupus erythematosus in children and adolescents. This article reviews the clinical relevance of lupus nephritis and its current treatment. The reader is introduced to novel biomarkers that are expected to improve the management of lupus nephritis in the future, and support the testing of novel medication regimens.

A study on the association of autoantibodies, chemokine, and its receptor with disease activity in systemic lupus erythematosus in North Indian population

Systemic lupus erythematosus (SLE) is a chronic and complex autoimmune disease characterized by the production of autoantibodies against a spectrum of nuclear antigens. RANTES and its receptor CCR5 have been associated with the pathogenesis of SLE. The objective of this study is to analyze autoantibodies (DNA/RNA), allelic distribution of RANTES and the association of levels of RANTES and its receptor CCR5 in SLE patients in North Indian region. The RANTES-403 and RANTES-28 polymorphism in the promoter region of RANTES gene was studied in 80 patients and 80 healthy controls. The levels of chemokine RANTES, its receptor CCR5, anti-dsDNA, and anti-SSA antibodies levels were determined. Disease activity was assessed with the systemic lupus erythematosus disease activity index (SLEDAI) score. All the parameters were studied for statistical analysis by using t test (graph pad prism) and correlation by SPSS data. PCR-RFLP performed showed 28C/C and the 403G/G genotypes in both patients and controls, but no other genotypes such as 28C/G, 28G/G and 403A/G, 403A/A were found. Patients had higher levels of RANTES (1840.48 ± 739.42 vs. 835.44 ± 70.48 pg/ml; P < 0.0001) and its receptor CCR5 expression (26.49 ± 0.16 vs. 24.72 ± 3.02 %; P < 0.05) compared to controls. The levels of autoantibodies anti-dsDNA and anti-SSA were also higher in patients than controls. The patients showing elevated anti-dsDNA had negative correlation with SLEDAI score (P < 0.05) while borderline patients were not found to be correlated. In case of anti-Ro/anti-SSA antibody levels, the borderline patients showed a moderately significant negative correlation as compared to controls than patients with elevated autoantibody (P < 0.01). The levels of RANTES and CCR5 were also higher in case of patients than controls. But there was no significant correlation of RANTES and CCR5 with disease activity. We were unable to find an association of RANTES polymorphism with SLE in North Indian population in our sample. No significant difference in allele distribution of RANTES-28 and RANTES-403 in the sample of 160 individuals was detected. Of the two autoantibodies studied, anti-Ro/anti-SSA levels in borderline lupus patients appeared as an important parameter for monitoring/diagnosis of lupus patients.

Urinary CXCL-10/IP-10 and MCP-1 as markers to assess activity of lupus nephritis

Objective

IP-10 and MCP-1 are pro-inflammatory chemokines which are involved in the immunopathogenesis of lupus nephritis and may thus be useful biomarkers.

Methods

SLE patients fulfilling ACR 1997 criteria were included. SLEDAI was calculated and blood and urine samples collected. Active lupus was defined as SLEDAI ≥4. Active patients were divided into active renal (proteinuria ≥ 500 mg/day or active sediment in urine) and active non-renal lupus. Patients with active renal lupus were followed until the nephritis became inactive, when a second sample was collected. Serum and urinary levels of MCP-1 and IP-10 (pg/ml) were measured by ELISA. Urinary values were normalized for urinary spot creatinine (in mg/dL. Thus the values were expressed as pg/mg creatinine × 100 creatinine).

Results

A total of 136 patients with SLE including 78 active (46 active renal and 32 active non-renal) were included. Median age was 25 (10–55) years and SLE duration was 23 (six to 48) months. Both serum (data not shown) and urinary levels of MCP-1 (35.2 (12.7–71.7), 9.4 (4.4–17), p < 0.001) and IP-10 (9.5 (4.4–17.9), 3.9 (1.9–9.3), p < 0.001) were higher in active compared to inactive SLE. However, in active renal compared to active non-renal SLE, there was no difference in serum levels; only urinary levels of MCP-1 (46.2 (19.9–125), 12.7 (5.8–43.9), p < 0.001) and IP-10 (12.5 (5.6–22.7), 5.2 (2.3–12.2), p < 0.05) were higher. On longitudinal follow-up of active renal patients ( n = 24), there was a decrease in urinary levels of MCP-1 and IP-10 ( p = 0.005). On ROC analysis, urinary MCP-1 outperformed C4 and urinary IP-10, but was similar to dsDNA and C3 in differentiating active renal from non-renal SLE.

Conclusions

Urinary and serum IP-10 and MCP-1 are potentially useful markers of lupus activity; however, only the urinary levels are indicative of renal activity. However, on ROC analysis, they are not better than conventional markers.

Plasma levels of osteopontin identify patients at risk for organ damage in systemic lupus erythematosus

Introduction

Osteopontin (OPN) has been implicated as a mediator of Th17 regulation via type I interferon (IFN) receptor signaling and in macrophage activity at sites of tissue repair. This study assessed whether increased circulating plasma OPN (cOPN) precedes development of organ damage in pediatric systemic lupus erythematosus (pSLE) and compared it to circulating plasma neutrophil gelatinase-associated lipocalin (cNGAL), a predictor of increased SLE disease activity.

Methods

cOPN and cNGAL were measured in prospectively followed pSLE (n = 42) and adult SLE (aSLE; n = 23) patients and age-matched controls. Time-adjusted cumulative disease activity and disease damage were respectively assessed using adjusted-mean SLE disease activity index (SLEDAI) (AMS) and SLICC/ACR damage index (SDI).

Results

Compared to controls, elevated cOPN and cNGAL were observed in pSLE and aSLE. cNGAL preceded worsening SLEDAI by 3-6 months (P = 0.04), but was not associated with increased 6-month AMS. High baseline cOPN, which was associated with high IFNalpha activity and expression of autoantibodies to nucleic acids, positively correlated with 6-month AMS (r = 0.51 and 0.52, P = 0.001 and 0.01 in pSLE and aSLE, respectively) and was associated with SDI increase at 12 months in pSLE (P = 0.001). Risk factors for change in SDI in pSLE were cOPN (OR 7.5, 95% CI [2.9-20], P = 0.03), but not cNGAL, cumulative prednisone, disease duration, immunosuppression use, gender or ancestry using univariate and multivariate logistic regression. The area under the curve (AUC) when generating the receiver-operating characteristic (ROC) of baseline cOPN sensitivity and specificity for the indication of SLE patients with an increase of SDI over a 12 month period is 0.543 (95% CI 0.347-0.738; positive predictive value 95% and negative predictive value 38%).

Conclusion

High circulating OPN levels preceded increased cumulative disease activity and organ damage in SLE patients, especially in pSLE, and its value as a predictor of poor outcome should be further validated in large longitudinal cohorts.

Targeting chemokines in proteinuria-induced renal disease

INTRODUCTION

Proteinuria is a common finding in glomerular diseases that contributes to the progression of chronic kidney injury. Tubular cells reabsorb the excess of albumin and other plasma proteins from the tubular lumen, triggering several pathophysiologic responses, such as overexpression of fibrogenic mediators and inflammatory chemokines. Chemokines are implicated both in the recruitment of inflammatory infiltrate and in a number of physiological and pathological processes related to protein overload.

AREAS COVERED

In recent years, the specific chemokines and their receptors and the intracellular signaling pathways involved in proteinuria-induced renal damage have been identified. This review provides an overview of the role of chemokines and their receptors in proteinuria-related renal disease and summarizes novel therapeutic approaches to restrain the progression of renal damage.

EXPERT OPINION

Inhibition of chemokine-induced biological activities is a promising therapeutic strategy in proteinuric disorders. Neutralizing antibodies and small organic molecules targeting chemokines and chemokine receptors have been proven to prevent inflammation and renal damage in experimental models of protein overload. Some of these compounds are currently being tested in human clinical trials.

Association of RANTES and MBL gene polymorphisms with systemic lupus erythematosus: a meta-analysis

The RANTES (regulated on activation normal T cell expressed and secreted) and MBL (mannose binding lectin) single-nucleotide polymorphisms have been repeatedly associated with systemic lupus erythematosus (SLE), but the findings are not consistent across studies. The aim of this study was to determine whether the functional RANTES-28, -403 and MBL2 A/O polymorphisms confer susceptibility to SLE in multiple ethnic populations. A meta-analysis was conducted (allelic contrast, the additive model, the dominant model and the recessive model) on RANTES with seven studies (four studies for RANTES-28: three Asian and one American studies; three studies for RANTES-403: two Asian and one European studies), MBL with eight studies (five European and three American studies). OR is used as a measure of the effect of the association in a fixed/random effects model. The meta-analysis indicated that none of the two polymorphisms in gene of the RANTES showed any significant association with SLE risk, respectively, except for the recessive model (OR = 1.24, 95 % CI: 1.01-1.52, P = 0.04) in all study subjects combined with the two polymorphisms. According to the MBL2 A/O polymorphism, the results indicated a significant association between the polymorphism and SLE in allelic contrast (OR = 0.83, 95 % CI: 0.73-0.93, P = 0.002). While stratified by ethnicity in European, no significant association was found. In summary, the present study suggests that the RANTES-28, -403 polymorphisms do not associate with SLE, but the MBL2 A/O polymorphism might associate with SLE.

Inhibition of the TWEAK/Fn14 pathway attenuates renal disease in nephrotoxic serum nephritis

Previously it was shown that the TNF superfamily member TWEAK (TNFSF12) acts through its receptor, Fn14, to promote proinflammatory responses in kidney cells, including the production of MCP-1, RANTES, IP-10 and KC. In addition, the TWEAK/Fn14 pathway promotes mesangial cell proliferation, vascular cell activation, and renal cell death. To study the relevance of the TWEAK/Fn14 pathway in the pathogenesis of antibody-induced nephritis using the mouse model of nephrotoxic serum nephritis (NTN), we induced NTN by passive transfer of rabbit anti-glomerular antibodies into Fn14 knockout (KO) and wild type (WT) mice. Severe proteinuria as well as renal histopathology were induced in WT but not in Fn14 KO mice. Similarly, a pharmacologic approach of anti-TWEAK mAb administration into WT mice in the NTN model significantly ameliorated proteinuria and improved kidney histology. Anti-TWEAK treatment did not affect the generation of mouse anti-rabbit antibodies; however, within the kidney there was a significant decrease in glomerular immunoglobulin deposition, as well as macrophage infiltrates and tubulointerstitial fibrosis. The mechanism of action is most likely due to reductions in downstream targets of TWEAK/Fn14 signaling, including reduced renal expression of MCP-1, VCAM-1, IP-10, RANTES as well as Fn14 itself, and other molecular pathways associated with fibrosis in anti-TWEAK treated mice. Thus, TWEAK/Fn14 interactions are instrumental in the pathogenesis of nephritis in the NTN model, apparently mediating a cascade of pathologic events locally in the kidney rather than by impacting the systemic immune response. Disrupting TWEAK/Fn14 interactions may be an innovative kidney-protective approach for the treatment of lupus nephritis and other antibody-induced renal diseases.

Biomarkers for systemic lupus erythematosus

In recent years, biomarkers have shown significant promise in helping decision-making in drug development. Systemic lupus erythematosus (SLE) is a complicated and highly heterogeneous disease that involves all organs. Only one drug, belimumab, has been approved by the US Food and Drug Administration to treat SLE during the last 50 years and there remains a high unmet medical need to develop new and effective therapies to benefit different patient populations in SLE. Due to the extreme heterogeneity of the disease and the complex and rigorous process to validate individual biomarkers, there is currently a very limited number of consensus biomarkers to aid the treatment decision-making in SLE. This review provides a snapshot of some biomarkers in the field that have the potential to make a big impact on drug development and/or treatment decisions by physicians. These include: type I interferon (IFN) gene signature as a pharmacodynamic marker and potential predictive marker for anti-type I IFN therapy; anti-double stranded DNA as a disease marker and potential predictive marker for flares; the complements and neutrophil signatures as disease marker of SLE; and TWEAK (a tumor necrosis factor family member produced by macrophages) and MCP-1 as potential markers to predict renal flares. Most of these markers need carefully planned and prospective studies with high statistical power to confirm their respective utilities. With the development and application of powerful new technologies, more successful biomarkers will emerge in SLE. This could improve the management of patients in the clinic and facilitate the development of novel and more effective therapeutics for this difficult-to-treat disease.

Role of TWEAK in lupus nephritis: a bench-to-bedside review

There is significant unmet need in the treatment of lupus nephritis (LN) patients. In this review, we highlight the role of the TWEAK/Fn14 pathway in mediating key pathologic processes underlying LN involving both glomerular and tubular injury, and thus the potential for renal protection via blockade of this pathway. The specific pathological mechanisms of TWEAK - namely promoting inflammation, renal cell proliferation and apoptosis, vascular activation and fibrosis - are described, with supporting data from animal models and in vitro systems. Furthermore, we detail the translational relevance of these mechanisms to clinical readouts in human LN. We present the opportunity for an anti-TWEAK therapeutic as a renal protective agent to improve efficacy relative to current standard of care treatments hopefully without increased safety risk, and highlight a phase II trial with BIIB023, an anti-TWEAK neutralizing antibody, designed to assess efficacy in LN patients. Taken together, targeting the TWEAK/Fn14 axis represents a potential new therapeutic paradigm for achieving renal protection in LN patients.

Biomarkers for systemic lupus erythematosus

The urgent need for lupus biomarkers was demonstrated in September 2011 during a Workshop sponsored by the Food and Drug Administration: Potential Biomarkers Predictive of Disease Flare. After 2 days of discussion and more than 2 dozen presentations from thought leaders in both industry and academia, it became apparent that highly sought biomarkers to predict lupus flare have not yet been identified. Even short of the elusive biomarker of flare, few biomarkers for systemic lupus erythematosus (SLE) diagnosis, monitoring, and stratification have been validated and employed for making clinical decisions. This lack of reliable, specific biomarkers for SLE hampers proper clinical management of patients with SLE and impedes development of new lupus therapeutics. As such, the intensity of investigation to identify lupus biomarkers is climbing a steep trajectory, lending cautious optimism that a validated panel of biomarkers for lupus diagnosis, monitoring, stratification, and prediction of flare may soon be in hand.

FMS Kinase Inhibitors: Current Status and Future Prospects

FMS, first discovered as the oncogene responsible for Feline McDonough Sarcoma, is a type III receptor tyrosine kinase that binds to the macrophage or monocyte colony-stimulating factor (M-CSF or CSF-1). Signal transduction through that binding results in survival, proliferation, and differentiation of monocyte/macrophage lineage. Overexpression of CSF-1 and/or FMS has been implicated in a number of disease states such as the growth of metastasis of certain types of cancer, in promoting osteoclast proliferation in bone osteolysis, and many inflammatory disorders. Inhibition of CSF-1 and/or FMS may help treat these pathological conditions. This article reviews FMS gene, FMS kinase, CSF-1, IL-34, and their roles in bone osteolysis, cancer biology, and inflammation. Monoclonal antibodies, FMS crystal structure, and small molecule FMS kinase inhibitors of different chemical scaffolds are also reviewed.

Importance of the CCR5-CCL5 axis for mucosal Trypanosoma cruzi protection and B cell activation

Trypanosoma cruzi is an intracellular parasite and the causative agent of Chagas disease. Previous work has shown that the chemokine receptor CCR5 plays a role in systemic T. cruzi protection. We evaluated the importance of CCR5 and CCL5 for mucosal protection against natural oral and conjunctival T. cruzi challenges. T. cruzi-immune CCR5(-/-) and wild-type C57BL/6 mice were generated by repeated infectious challenges with T. cruzi. CCR5(-/-) and wild-type mice developed equivalent levels of cellular, humoral, and protective mucosal responses. However, CCR5(-/-)-immune mice produced increased levels of CCL5 in protected gastric tissues, suggesting compensatory signaling through additional receptors. Neutralization of CCL5 in CCR5(-/-)-immune mice resulted in decreased mucosal inflammatory responses, reduced T. cruzi-specific Ab-secreting cells, and significantly less mucosal T. cruzi protection, confirming an important role for CCL5 in optimal immune control of T. cruzi replication at the point of initial mucosal invasion. To investigate further the mechanism responsible for mucosal protection mediated by CCL5-CCR5 signaling, we evaluated the effects of CCL5 on B cells. CCL5 enhanced proliferation and IgM secretion in highly purified B cells triggered by suboptimal doses of LPS. In addition, neutralization of endogenous CCL5 inhibited B cell proliferation and IgM secretion during stimulation of highly purified B cells, indicating that B cell production of CCL5 has important autocrine effects. These findings demonstrate direct effects of CCL5 on B cells, with significant implications for the development of mucosal adjuvants, and further suggest that CCL5 may be important as a general B cell coactivator.

Correlations of urinary biomarkers, TNF-like weak inducer of apoptosis (TWEAK), osteoprotegerin (OPG), monocyte chemoattractant protein-1 (MCP-1), and IL-8 with lupus nephritis

OBJECTIVE

This case-controlled study was designed to correlate urinary biomarkers, TNF-like weak inducer of apoptosis (TWEAK), osteoprotegerin (OPG), monocyte chemoattractant protein-1 (MCP-1), and interleukin-8 (IL-8) levels, with renal involvement in a cohort of systemic lupus erythematosus (SLE) patients to examine their diagnostic performance.

PATIENTS AND METHODS

In 73 SLE patients, and in 23 healthy volunteers, urinary levels of TWEAK, OPG, MCP-1, and IL-8 levels were measured. Disease activity was assessed by total SLE disease activity index, and renal activity by renal activity index (rSLEDAI), and both were correlated with urinary biomarkers. Sensitivity, specificity, and predictive values of individual biomarkers to predict lupus nephritis were also calculated.

RESULTS

Significantly higher levels of urinary biomarkers were observed in SLE patients with lupus nephritis (LN) compared with those without LN (TWEAK, p < 0.001; MCP-1, p < 0.001; OPG, p < 0.001; IL-8, p < 0.032). Other significantly higher levels were observed in SLE patients with LN compared with control subjects (TWEAK, MCP-1, OPG, and IL-8 p < 0.001). Positive correlations were observed between rSLEDAI and TWEAK (r = 0.612 and p < 0.001), MCP-1 (r = 0.635 and p < 0.001), and OPG (r = 0.505 and p < 0.001).

CONCLUSIONS

Urinary levels of TWEAK, OPG, and MCP-1 positively correlate with renal involvement as assessed by rSLEDAI with reasonable sensitivity, specificity, and predictive values to detect lupus nephritis while IL-8 was not significantly associated with global or rSLEDAI.

MicroRNA-125a contributes to elevated inflammatory chemokine RANTES levels via targeting KLF13 in systemic lupus erythematosus

OBJECTIVE

MicroRNA (miRNA) have received increasing attention as posttranscriptional regulators that fine-tune the homeostasis of the inflammatory response. This study aimed to clarify whether miR-125a, which was identified in a pilot expression profiling step, is involved in the inflammatory chemokine pathway in systemic lupus erythematosus (SLE).

METHODS

Independent verification of miR-125a expression in amplified samples from SLE patients and normal controls was performed by TaqMan quantitative polymerase chain reaction (PCR) analysis. A combination of 3 bioinformatic prediction techniques and reporter gene assays was used to identify miR-125a targets. In vitro systems of overexpression by transfection and inducible expression by stimulation were performed to investigate the function of miR-125a, which was followed by real-time quantitative PCR and enzyme-linked immunosorbent assay.

RESULTS

In SLE patients, the expression of miR-125a was reduced and the expression of its predicted target gene, KLF13, was increased. Bioinformatics predicted that miR-125a base-paired with sequences in the 3'-untranslated region of KLF13. Overexpression of miR-125a led to a significant reduction in the expression of RANTES and KLF13. MicroRNA-125a inhibited endogenous KLF13 expression in a dose-dependent manner, as determined using gain- and loss-of-function methods. A luciferase reporter system confirmed the miR-125a binding sites. Notably, miR-125a expression was induced in T cells in a dose- and time-dependent manner. Finally, the introduction of miR-125a into T cells from SLE patients alleviated the elevated RANTES expression.

CONCLUSION

MicroRNA-125a negatively regulates RANTES expression by targeting KLF13 in activated T cells. The underexpression of miR-125a contributes to the elevated expression of RANTES in SLE. Our findings extend the role of miRNA in the pathogenesis of lupus and provide potential strategies for therapeutic intervention.

[MCP-1 in urine as biomarker of renal lupus in absence of cytokines, interferon-γ and growth factors]

OBJECTIVE

To characterize 17 immunological markers in the Urine of patients with SLE.

INTRODUCTION

Lupus nephritis is an inflammatory disease affecting the renal parenchyma. Cytokines and chemokines are key immune mediators that have been related with the pathogenesis of the disease. Obtaining non invasive prognosis markers is a highly desirable objective in order to improve the clinical management of these patients.

PATIENTS AND METHODS

In this study we profiled 17 immune mediators (Th1, Th2, Th17 cytokines, chemokines and growth factors) in the urine of 25 patients with systemic lupus erythematosus with active renal disease by using a Biorad© 17-plex kit on a Luminex© platform. A group of healthy volunteers of similar age and comparable sex distribution was recruited as control (n=10).

RESULTS

Results evidenced that the only detectable mediators in urine were IL-8, MCP-1 and MIP-1 β. When levels of these mediators were compared between patients and controls, significantly higher levels of MCP-1 were observed in the urine of the patients. MCP-1 levels in urine correlated positively with the SLEDAI score in a significant way and negatively with plasma levels of complement C4.

CONCLUSIONS

Our results reinforce the role of MCP-1 in urine as biomarker of disease activity in renal lupus, excluding the detection of other soluble immune mediators such as Th1, Th2 ,Th17 cytokines and growth factors as suitable markers in this non invasive sample.

Anti-macrophage-derived chemokine antibody relieves murine lupus nephritis

We observed the distribution of monocyte's changes in damage to renal tissue and the expression of macrophage-derived chemokine (MDC) in MRL/lpr mice. The 8-week-old MRL/lpr mice were randomly assigned to receive either MDC antibodies (n = 6) or placebo (n = 6) at a once-every-other-day dose of 300 μl from week 4. We then quantified the differences in 24-h urine protein and serum creatinine concentrations, performed a histological evaluation of renal tissue and assessed the expression of MDC protein and mRNA between the two groups 4 weeks after treatment was initiated. Antibody-treated mice demonstrated significantly lower urine protein and serum creatinine concentrations and had fewer renal lesions compared with control mice. The expression of MDC protein and mRNA in renal tissues was significantly lower in the antibody-treated mice than in control mice, suggesting that the elevated expression of MDC, which led to monocyte infiltration in the kidney, may play an important role in the development of lupus nephritis. Furthermore, the anti-MDC antibodies may act to alleviate the renal lesions of murine lupus nephritis by inhibiting the infiltration of monocytes in the renal tissue of the lupus mice.

Biomarkers for lupus nephritis: a critical appraisal

Kidney disease is one of the most serious manifestations of systemic lupus erythematosus (SLE). Despite the improvement in the medical care of SLE in the past two decades, the prognosis of lupus nephritis remains unsatisfactory. Besides exploring more effective but less toxic treatment modalities that will further improve the remission rate, early detection and treatment of renal activity may spare patients from intensive immunosuppressive therapies and reduce renal damage. Conventional clinical parameters such as creatinine clearance, proteinuria, urine sediments, anti-dsDNA, and complement levels are not sensitive or specific enough for detecting ongoing disease activity in the lupus kidneys and early relapse of nephritis. Thus, novel biomarkers are necessary to enhance the diagnostic accuracy and sensitivity of lupus renal disease, prognostic stratification, monitoring of treatment response, and detection of early renal flares. This paper reviews promising biomarkers that have recently been evaluated in longitudinal studies of lupus nephritis.

Vitamin D and cardiovascular risk

Vitamin D deficiency results in abnormal mineralization of bones and has resulted in prevention programs for children with supplementation when they are breast fed. Further activities of vitamin D relate to defence of microbial infections, e.g. tuberculosis, prevention of cancer, contractility of muscle cells and counteraction of congestive heart failure. Given early reports in the 1960s on deleterious effects of vitamin D supplementation in rodents, that is ectopic media ossification of arterial vessels, a pro-atherogenic function had been anticipated for humans as well. However, cross-sectional studies reveal that vitamin D deficiency in humans is associated with elevated blood pressure and propagation of atherogenesis. These contradictory findings on the progression of atherosclerosis may be reconciled by dissecting the activation mechanism(s) of vitamin D in rodents versus humans. Notably, novel findings convincingly indicate that vitamin D exerts anti-inflammatory effects. In conclusion, vitamin D supplementation in adults may be regarded as simple means with few potential side effects to prevent atherogenesis or halt its progression and combat arterial hypertension. Adjustment of vitamin D dosing regimens is required in patients with chronic kidney disease; however, prospective clinical trials are urgently needed to guide these recommendations with evidence.

Circulating CSF-1 promotes monocyte and macrophage phenotypes that enhance lupus nephritis

Macrophages mediate kidney disease and are prominent in a mouse model (MRL-Fas(lpr)) of lupus nephritis. Colony stimulating factor-1 (CSF-1) is the primary growth factor for macrophages, and CSF-1 deficiency protects MRL-Fas(lpr) mice from kidney disease and systemic illness. Whether this renoprotection derives from a reduction of macrophages and whether systemic CSF-1, as opposed to intrarenal CSF-1, promotes macrophage-dependent lupus nephritis remain unclear. Here, we found that increasing systemic CSF-1 hastened the onset of lupus nephritis in MRL-Fas(lpr) mice. Using mutant MRL-Fas(lpr) strains that express high, moderate, or no systemic CSF-1, we detected a much higher tempo of kidney disease in mice with the highest level of CSF-1. Furthermore, we uncovered a multistep CSF-1-dependent systemic mechanism central to lupus nephritis. CSF-1 heightened monocyte proliferation in the bone marrow (SSC(low)CD11b(+)), and these monocytes subsequently seeded the circulation. Systemic CSF-1 skewed the frequency of monocytes toward "inflammatory" (SSC(low)CD11b(+)Ly6C(high)) and activated populations that homed to sites of inflammation, resulting in a more rapid accumulation of intrarenal macrophages (CD11b(+)CSF-1R(+) or CD68(+)) that induced apoptosis of tubular epithelial cells, damaging the kidney. In humans, we found increased levels of CSF-1 in the serum, urine, and kidneys of patients with lupus compared with healthy controls. Furthermore, serum and urine CSF-1 levels correlated with lupus activity, and intrarenal CSF-1 expression correlated with the histopathology activity index of lupus nephritis. Taken together, circulating CSF-1 is a potential therapeutic target for lupus nephritis.