Inflammatory cytokine gene expression in the urinary sediment of patients with lupus nephritis

Decipher the Immunopathological Mechanisms and Set Up Potential Therapeutic Strategies for Patients with Lupus Nephritis

Lupus nephritis (LN) is one of the most severe complications in patients with systemic lupus erythematosus (SLE). Traditionally, LN is regarded as an immune complex (IC) deposition disease led by dsDNA-anti-dsDNA-complement interactions in the subendothelial and/or subepithelial basement membrane of glomeruli to cause inflammation. The activated complements in the IC act as chemoattractants to chemically attract both innate and adaptive immune cells to the kidney tissues, causing inflammatory reactions. However, recent investigations have unveiled that not only the infiltrating immune-related cells, but resident kidney cells, including glomerular mesangial cells, podocytes, macrophage-like cells, tubular epithelial cells and endothelial cells, may also actively participate in the inflammatory and immunological reactions in the kidney. Furthermore, the adaptive immune cells that are infiltrated are genetically restricted to autoimmune predilection. The autoantibodies commonly found in SLE, including anti-dsDNA, are cross-reacting with not only a broad spectrum of chromatin substances, but also extracellular matrix components, including α-actinin, annexin II, laminin, collagen III and IV, and heparan sulfate proteoglycan. Besides, the glycosylation on the Fab portion of IgG anti-dsDNA antibodies can also affect the pathogenic properties of the autoantibodies in that α-2,6-sialylation alleviates, whereas fucosylation aggravates their nephritogenic activity. Some of the coexisting autoantibodies, including anti-cardiolipin, anti-C1q, anti-ribosomal P autoantibodies, may also enhance the pathogenic role of anti-dsDNA antibodies. In clinical practice, the identification of useful biomarkers for diagnosing, monitoring, and following up on LN is quite important for its treatments. The development of a more specific therapeutic strategy to target the pathogenic factors of LN is also critical. We will discuss these issues in detail in the present article.

Down-regulated miR-146a expression with increased neutrophil extracellular traps and apoptosis formation in autoimmune-mediated diffuse alveolar hemorrhage

BACKGROUND

Increasing evidences have suggested an important role of microRNAs (miRNAs) in regulating cell death processes including NETosis and apoptosis. Dysregulated expression of miRNAs and increased formation of neutrophil extracellular traps (NETs) and apoptosis participate in autoimmune-mediated diffuse alveolar hemorrhage (DAH), mostly associated with pulmonary capillaritis in systemic lupus erythematosus (SLE) patients. In particular, besides the inhibition of apoptosis, miR-146a can control innate and acquired immune responses, and regulate the toll-like receptor pathway through targeting TRAF6 to reduce the expression of pro-inflammatory cytokines/chemokines like IL-8, a NETosis inducer.

METHODS

Expression of miR-146a, TRAF6 and NETs were examined in peripheral blood neutrophils (PBNs) and lung tissues from SLE-associated DAH patients, and in neutrophils and pristane-induced DAH lung tissues from C57BL/6 mice. To assess NETs formation, we examined NETosis-related DNAs morphology and crucial mediators including protein arginine deiminase 4 and citrullinated Histone 3. Expression of miR-146a and its endogenous RNA SNHG16 were studied in HL-60 promyelocytic cells and MLE-12 alveolar cells during NETosis and apoptosis processes, respectively. MiR-146a-overexpressed and CRISPR-Cas13d-mediated SNHG16-silenced HL-60 cells were investigated for NETosis. MiR-146a-overexpressed MLE-12 cells were analyzed for apoptosis. Pristane-injected mice received intra-pulmonary miR-146a delivery to evaluate therapeutic efficacy in DAH.

RESULTS

In DAH patients, there were down-regulated miR-146a levels with increased TRAF6 expression and PMA/LPS-induced NETosis in PBNs, and down-regulated miR-146a levels with increased TRAF6, high-mobility group box 1 (HMGB1), IL-8, NETs and apoptosis expression in lung tissues. HMGB1-stimulated mouse neutrophils had down-regulated miR-146a levels with increased TRAF6, IL-8 and NETs expression. PMA-stimulated HL-60 cells had down-regulated miR-146a levels with enhanced NETosis. MiR-146a-overexpressed or SNHG16-silenced HL-60 cells showed reduced NETosis. Apoptotic MLE-12 cells had down-regulated miR-146a expression and increased HMGB1 release, while miR-146a-overexpressed MLE-12 cells showed reduced apoptosis and HMGB1 production. There were down-regulated miR-146a levels with increased TRAF6, HMGB1, IL-8, NETs and apoptosis expression in mouse DAH lung tissues. Intra-pulmonary miR-146a delivery could suppress DAH by reducing TRAF6, IL-8, NETs and apoptosis expression.

CONCLUSIONS

Our results demonstrate firstly down-regulated pulmonary miR-146a levels with increased TRAF6 and IL-8 expression and NETs and apoptosis formation in autoimmune-mediated DAH, and implicate a therapeutic potential of intra-pulmonary miR-146a delivery.

Chemokine isoforms and processing in inflammation and immunity

The first dimension of chemokine heterogeneity is reflected by their discovery and purification as natural proteins. Each of those chemokines attracted a specific inflammatory leukocyte type. With the introduction of genomic technologies, a second wave of chemokine heterogeneity was established by the discovery of putative chemokine-like sequences and by demonstrating chemotactic activity of the gene products in physiological leukocyte homing. In the postgenomic era, the third dimension of chemokine heterogeneity is the description of posttranslational modifications on most chemokines. Proteolysis of chemokines, for instance by dipeptidyl peptidase IV (DPP IV/CD26) and by matrix metalloproteinases (MMPs) is already well established as a biological control mechanism to activate, potentiate, dampen or abrogate chemokine activities. Other posttranslational modifications are less known. Theoretical N-linked and O-linked attachment sites for chemokine glycosylation were searched with bio-informatic tools and it was found that most chemokines are not glycosylated. These findings are corroborated with a low number of experimental studies demonstrating N- or O-glycosylation of natural chemokine ligands. Because attached oligosaccharides protect proteins against proteolytic degradation, their absence may explain the fast turnover of chemokines in the protease-rich environments of infection and inflammation. All chemokines interact with G protein-coupled receptors (GPCRs) and glycosaminoglycans (GAGs). Whether lectin-like GAG-binding induces cellular signaling is not clear, but these interactions are important for leukocyte migration and have already been exploited to reduce inflammation. In addition to selective proteolysis, citrullination and nitration/nitrosylation are being added as biologically relevant modifications contributing to functional chemokine heterogeneity. Resulting chemokine isoforms with reduced affinity for GPCRs reduce leukocyte migration in various models of inflammation. Here, these third dimension modifications are compared, with reflections on the biological and pathological contexts in which these posttranslational modifications take place and contribute to the repertoire of chemokine functions and with an emphasis on autoimmune diseases.

Potential serum and urine biomarkers in patients with lupus nephritis and the unsolved problems

Lupus nephritis (LN) is one of the most frequent and serious complications in the patients with systemic lupus erythematosus. Autoimmune-mediated inflammation in both renal glomerular and tubulointerstitial tissues is the major pathological finding of LN. In clinical practice, the elevated anti-dsDNA antibody titer concomitant with reduced complement C3 and C4 levels has become the predictive and disease-activity surrogate biomarkers in LN. However, more and more evidences suggest that autoantibodies other than anti-dsDNA antibodies, such as anti-nucleosome, anti-C1q, anti-C3b, anti-cardiolipin, anti-endothelial cell, anti-ribonuclear proteins, and anti-glomerular matrix (anti-actinin) antibodies, may also involve in LN. Researchers have demonstrated that the circulating preformed and in situ-formed immune complexes as well as the direct cytotoxic effects by those cross-reactive autoantibodies mediated kidney damage. On the other hand, many efforts had been made to find useful urine biomarkers for LN activity via measurement of immune-related mediators, surface-enhanced laser desorption/ionization time-of-flight mass spectrometry proteomic signature, and assessment of mRNA and exosomal-derived microRNA from urine sediment cell. Our group had also devoted to this field with some novel findings. In this review, we briefly discuss the possible mechanisms of LN and try to figure out the potential serum and urine biomarkers in LN. Finally, some of the unsolved problems in this field are discussed.

Autoantigen microarrays reveal autoantibodies associated with proliferative nephritis and active disease in pediatric systemic lupus erythematosus

Introduction

Pediatric systemic lupus erythematosus (pSLE) patients often initially present with more active and severe disease than adults, including a higher frequency of lupus nephritis. Specific autoantibodies, including anti-C1q, anti-DNA and anti-alpha-actinin, have been associated with kidney involvement in SLE, and DNA antibodies are capable of initiating early-stage lupus nephritis in severe combined immunodeficiency (SCID) mice. Over 100 different autoantibodies have been described in SLE patients, highlighting the need for comprehensive autoantibody profiling. Knowledge of the antibodies associated with pSLE and proliferative nephritis will increase the understanding of SLE pathogenesis, and may aid in monitoring patients for renal flare.

Methods

We used autoantigen microarrays composed of 140 recombinant or purified antigens to compare the serum autoantibody profiles of new-onset pSLE patients (n = 45) to healthy controls (n = 17). We also compared pSLE patients with biopsy-confirmed class III or IV proliferative nephritis (n = 23) and without significant renal involvement (n = 18). We performed ELISA with selected autoantigens to validate the microarray findings. We created a multiple logistic regression model, based on the ELISA and clinical information, to predict whether a patient had proliferative nephritis, and used a validation cohort (n = 23) and longitudinal samples (88 patient visits) to test its accuracy.

Results

Fifty autoantibodies were at significantly higher levels in the sera of pSLE patients compared to healthy controls, including anti-B cell-activating factor (BAFF). High levels of anti-BAFF were associated with active disease. Thirteen serum autoantibodies were present at significantly higher levels in pSLE patients with proliferative nephritis than those without, and we confirmed five autoantigens (dsDNA, C1q, collagens IV and X and aggrecan) by ELISA. Our model, based on ELISA measurements and clinical variables, correctly identified patients with proliferative nephritis with 91 % accuracy.

Conclusions

Autoantigen microarrays are an ideal platform for identifying autoantibodies associated with both pSLE and specific clinical manifestations of pSLE. Using multiple regression analysis to integrate autoantibody and clinical data permits accurate prediction of clinical manifestations with complex etiologies in pSLE.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0682-6) contains supplementary material, which is available to authorized users.

Differential efficacy of human mesenchymal stem cells based on source of origin

Mesenchymal stem cells (MSCs) are useful in tissue repair but also possess immunomodulatory properties. Murine and uncontrolled human trials suggest efficacy of MSCs in treating lupus. Autologous cells are preferable; however, recent studies suggest that lupus-derived MSCs lack efficacy in treating disease. Thus, the optimum derivation of MSCs for use in lupus is unknown. It is also unknown which in vitro assays of MSC function predict in vivo efficacy. The objectives for this study were to provide insight into the optimum source of MSCs and to identify in vitro assays that predict in vivo efficacy. We derived MSCs from four umbilical cords, four healthy bone marrows (BMs), and four lupus BMs. In diseased MRL/lpr mice, MSCs from healthy BM and umbilical cords significantly decreased renal disease, whereas lupus BM MSCs only delayed disease. Current in vitro assays did not differentiate efficacy of the different MSCs. However, differences in MSC efficacy were observed in B cell proliferation assays. Our results suggest that autologous MSCs from lupus patients are not effective in treating disease. Furthermore, standard in vitro assays for MSC licensing are not predictive of in vivo efficacy, whereas inhibiting B cell proliferation appears to differentiate effective MSCs from ineffective MSCs.

Urinary mRNA in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a relapsing autoimmune disease with clinical manifestations that affect multiple organ systems. Lupus nephritis is recognized as one of the most severe organ involvements in SLE and affects half of the lupus patients. Notably, lupus nephritis is characterized by intrarenal lymphocyte activation and inflammation. Since most of the cytokines exert their effects in a paracrine fashion, measuring their expression at the site of pathology should be of biological relevance. Although kidney biopsy is widely used to determine the histology and severity of lupus nephritis, this invasive procedure has its own risk and is not practical for serial monitoring. In the past decade, extraction and quantification of messenger RNA (mRNA) from urinary sediment has emerged as a robust laboratory technique. Quantification of mRNA expression in urinary sediment has been tested as a noninvasive means to assess the disease activity of SLE patients. Available published evidence, however, is limited to small-scale studies. Based on the result of these studies, a number of cytokine and transcript factor genes have been found to have potential for the differentiation between active and inactive SLE, between proliferative and membranous types of lupus nephritis, assessment of the systemic lupus activity or histological activity of kidney biopsy specimen, monitoring of treatment response in active lupus nephritis, or detection of lupus disease flare in clinically quiescent patients. Being a simple and noninvasive method, urinary mRNA level deserves further studies to validate its role in risk stratification and monitoring of therapeutic response in patients with lupus nephritis.

Urine biomarkers in juvenile-onset SLE nephritis

Over 80 % of patients with juvenile-onset systemic lupus erythematosus will have renal involvement compared to 40 % with adult-onset disease. Up to 44 % of children who do have lupus nephritis (LN) progress to renal failure in early adulthood. Improved methods of detecting onset of LN would allow earlier treatment, which may prevent irreversible renal scarring and a decline in renal function. Current conventional markers of disease activity fail to adequately predict renal lupus flares and include proteinuria, complement levels, anti-double-stranded DNA antibodies and serum creatinine concentrations. Standardized histological classification is currently the gold standard for diagnosing and classifying LN, but its invasive nature limits routine use for monitoring, especially in a childhood population. Novel biomarkers need to be sensitive and specific-and preferably non-invasive and cost-effective. The most promising biomarkers in juvenile-onset LN include urinary neutrophil gelatinase associated lipocalin, monocyte chemoattractant protein 1 and transforming growth factor-beta, although many others have been identified and are under investigation. No one biomarker yet discovered is unique to LN, indicating an overlap in disease pathophysiology. It is likely that a combination of biomarkers will be required for assessing disease flare detection, response to treatment and prognostic information. Potential biomarkers require longitudinal validation in large paediatric, prospective cohorts to assess their ability to act as clinically useful adjuncts.

Urinary sediment miRNA levels in adult nephrotic syndrome

BACKGROUND

MicroRNAs are a group of non-coding RNA molecules that play important roles in the pathogenesis of various kidney diseases. We investigate the urinary sediment miRNA levels of adult patients with nephrotic syndrome.

METHODS

We study 20 patients with diabetic glomerulosclerosis (DGS), 21 with minimal change nephropathy (MCN) or focal glomerulosclerosis (FGS), 23 with membranous nephropathy (MGN), and 10 healthy controls. Urinary sediment miRNA levels are quantified.

RESULTS

Urinary sediment miR-29a, miR-192, and miR-200c levels were significantly different between diagnosis groups. Post hoc analysis showed that urinary miR-638 level was significantly lower in all causes of nephrotic syndrome than healthy controls, while the DGS group had lower urinary miR-192 level than other diagnosis groups. In contrast, the MCN/FGS group had higher urinary miR-200c level than other diagnosis groups. For each specific pathology group, urinary level of several miRNA targets significantly correlated with kidney function and histological scarring.

CONCLUSIONS

Urinary miR-29a, miR-192 and miR-200c levels have characteristic alterations among patients with different causes of nephrotic syndrome. Our results suggest that urinary miRNA levels have the potential of being developed as the diagnosis tool and marker of disease severity in adult nephrotic syndrome.

Urinary neutrophil gelatinase-associated lipocalin is a potential biomarker for renal damage in patients with systemic lupus erythematosus

Neutrophil gelatinase-associated lipocalin (NGAL) has been demonstrated to be a novel biomarker in acute and chronic kidney disease. We hypothesized that 24-hour urinary NGAL excretion may be a predictor for renal damage in patients with systemic lupus erythematosus (SLE). Thirty-four SLE patients with renal involvement (SLE-renal group), 8 SLE patients without renal involvement (SLE-nonrenal group), 14 patients with non-SLE autoimmune diseases (disease control or DC group), and 12 healthy volunteers (normal control or NC group) were compared for 24-hour urinary excretion of NGAL and different cytokines. We found that the 24-hour urinary NGAL excretion in the SLE-renal group was higher than that in the SLE-non-renal, DC, and NC groups. However, the excretion of interleukin-10, transforming growth factor-β1, and tumor necrosis factor-α was not different between the SLE-renal and SLE-non-renal groups. Furthermore, NGAL excretion in the SLE-renal group was correlated with serum creatinine levels and creatinine clearance, but not with the SLE Disease Activity Index score. Multivariate logistic regression analysis and receiver operating characteristic curve analysis revealed that 24-hour urinary NGAL excretion is a potential biomarker for renal damage in SLE patients, with higher sensitivity and specificity than anti-dsDNA antibody titers.

Immunopathological roles of cytokines, chemokines, signaling molecules, and pattern-recognition receptors in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease with unknown etiology affecting more than one million individuals each year. It is characterized by B- and T-cell hyperactivity and by defects in the clearance of apoptotic cells and immune complexes. Understanding the complex process involved and the interaction between various cytokines, chemokines, signaling molecules, and pattern-recognition receptors (PRRs) in the immune pathways will provide valuable information on the development of novel therapeutic targets for treating SLE. In this paper, we review the immunopathological roles of novel cytokines, chemokines, signaling molecules, PRRs, and their interactions in immunoregulatory networks and suggest how their disturbances may implicate pathological conditions in SLE.

Monitoring of urinary messenger RNA levels for the prediction of flare in systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is characterized by disease flares and remission. We hypothesize that in clinically quiescent SLE patients, the mRNA level of target genes in the urinary sediment is an early indicator of disease flare.

METHODS

From a cohort of 134 adult SLE patients prospectively followed for 56 weeks, we identified 19 patients with a single disease flare. The mRNA level of eight pre-defined target genes in their urinary sediment before disease flare was compared to 19 matched controls with no disease flare during the same period.

RESULTS

Urinary mRNA level remained static in the control group during the study period. Before disease flare, there was a significant increase in the mRNA level of monocyte chemotactic protein (MCP)-1 and forkhead box P3 (FOXP3), and decrease in interleukin (IL)-17 and GATA-3, in the urinary sediment. The mRNA level of FOXP3 in urinary sediment increases 8 weeks prior to a flare, which precedes the corresponding change in serum complement and anti-DNA antibody titer, while that of MCP-1, IL-17, and GATA3 began to change 4 weeks prior to a flare. The same pattern of change in urinary mRNA level was observed in patients with mild-to-moderate or severe flare, and those with renal or non-renal flare. The SLE Disease Activity Index (SLEDAI) score at the time of flare significantly correlated with the change in urinary level of IL-17 (r=-0.462, p=0.046) and GATA-3 (r=-0.455, p=0.05), but not MCP-1 or FOXP3, prior to the flare.

CONCLUSION

Monitoring of MCP-1, IL-17, GATA-3 and FOXP3 mRNA level in urinary sediment may provide an early clue for detecting disease flare in SLE patients.

Autoimmune disease and gender: plausible mechanisms for the female predominance of autoimmunity

A large number of autoimmune diseases (ADs) are more prevalent in women. The more frequent the AD and the later it appears, the more women are affected. Many ideas mainly based on hormonal and genetic factors that influence the autoimmune systems of females and males differently, have been proposed to explain this predominance. These hypotheses have gained credence mostly because many of these diseases appear or fluctuate when there are hormonal changes such as in late adolescence and pregnancy. Differences in X chromosome characteristics between men and women with an AD have led researchers to think that the genetic background of this group of diseases also relates to the genetic determinants of gender. These hormonal changes as well as the genetic factors that could explain why women are more prone to develop ADs are herein reviewed.

Lupus nephritis: current update

Lupus nephritis is a major cause of morbidity and mortality in patients with systemic lupus erythematosus. The general consensus is that 60% of lupus patients will develop clinically relevant nephritis at some time in the course of their illness. Prompt recognition and treatment of renal disease is important, as early response to therapy is correlated with better outcome. The present review summarizes our current understanding of the pathogenic mechanisms underlying lupus nephritis and how the disease is currently diagnosed and treated.

Anti-IL-2 receptor antibody decreases cytokine-induced apoptosis of human renal tubular epithelial cells (TEC)

BACKGROUND

Transplant rejection is mediated by T-cell activation which is modulated by interleukin-2 (IL-2) binding to IL-2R (CD25). Monoclonal anti-IL-2 receptor antibody is used in renal transplantation to reduce rejection. Interestingly, proximal tubular epithelial cells (TEC) express CD25, similar to T cells. We have demonstrated that IL-2 induces murine TEC apoptosis through down-regulation of the caspase-8 inhibitor protein c-FLIP. Anti-CD25 antibody may be useful clinically to limit renal injury, but this has not been tested in human TEC.

METHODS

Human PT-2 TEC were isolated and cloned from the urine of transplant patients. Apoptosis was determined by FACS with Annexin-V FITC. Protein expression was studied using western blot, and mRNA levels by quantitative real-time (PR-PCR).

RESULTS

We demonstrated that the morphology of a human kidney cell line (PT-2) cloned from urine was consistent with proximal TEC and expresses alkaline phosphatase, cytokeratin, vimentin, CD13, CD26, and low levels of E-cadherin. Basal IL-2 receptor (CD25) was up-regulated by IL-2/IFN-γ stimulation, and cytokine exposure induced apoptosis in a dose-dependent manner. Apoptosis with IL-2/IFN-γ was associated with increased caspase-8 activity and decreased endogenous caspase-8 inhibitor c-FLIP mRNA and protein expression. IL-2/IFN-γ-induced apoptosis could be blocked by pre-treatment of PT-2 with anti IL-2R antibody (basiliximab) but not control IgG antibody.

CONCLUSIONS

These data demonstrate for the first time in human TEC that IL-2 and IFN-γ can induce TEC apoptosis which can be blocked by CD25 blockade antibody. These data suggest that anti-CD25 mAb might similarly attenuate inflammation-induced TEC injury in vivo. Kidney-expressed CD25 may represent a clinically important new target for attenuating early inflammatory injury in donor kidneys and preserving renal function during anti-rejection therapy.

Interferon-lambda1 induces peripheral blood mononuclear cell-derived chemokines secretion in patients with systemic lupus erythematosus: its correlation with disease activity

INTRODUCTION

Systemic lupus erythematosus (SLE) is an autoimmune disease involving multiple organ systems. Previous studies have suggested that interferon-lambda 1 (IFN-λ1), a type III interferon, plays an immunomodulatory role. In this study we investigated its role in SLE, including its correlation with disease activity, organ disorder and production of chemokines.

METHODS

We determined levels of IFN-λ1 mRNA in peripheral blood mononuclear cells (PBMC) and serum protein levels in patients with SLE using real-time polymerase chain reaction (real-time PCR) and enzyme-linked immunoassay (ELISA). Further, we detected the concentration of IFN-inducible protein-10 (IP-10), monokine induced by IFN-γ (MIG) and interleukin-8 (IL-8) secreted by PBMC under the stimulation of IFN-λ1 using ELISA.

RESULTS

IFN-λ1 mRNA and serum protein levels were higher in patients with SLE compared with healthy controls. Patients with active disease showed higher IFN-λ1 mRNA and serum protein levels compared with those with inactive disease as well. Serum IFN-λ1 levels were positively correlated with Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), anti-dsDNA antibody, C-reactive protein (CRP) and negatively correlated with complement 3. Serum IFN-λ1 levels were higher in SLE patients with renal involvement and arthritis compared with patients without the above-mentioned manifestations. IFN-λ1 with different concentrations displayed different effects on the secretion of the chemokines IP-10, MIG and IL-8.

CONCLUSIONS

These findings indicate that IFN-λ1 is probably involved in the renal disorder and arthritis progression of SLE and associated with disease activity. Moreover, it probably plays an important role in the pathogenesis of SLE by stimulating secretion of the chemokines IP-10, MIG and IL-8. Thus, IFN-λ1 may provide a novel research target for the pathogenesis and therapy of SLE.

Major lupus organ involvement: severe lupus nephritis

Lupus nephritis is a common and severe complication of systemic lupus erythematosus. A number of patients have nephritis as a presenting feature that, in its severe form, can shortly lead to end-stage renal disease and/or death. Renal flare usually occurs a few years after the first episode and is remarkably predominant in the Asian population. Frequent monitoring for renal flare enhances early recognition and timely treatment. The mainstay therapy continues to be the prolonged use of cytotoxic/immunosuppressive drugs that have a number of undesirable effects, particularly ovarian failure and development of opportunistic infections. This review will focus on the pathogenesis and the unique genetic factors found in Asian patients with lupus nephritis. Here, we propose an appropriate management scheme for the treatment of lupus nephritis in Asian patients.

Treatment of proliferative lupus nephritis: a slowly changing landscape

Proliferative lupus nephritis is the most severe form of lupus nephritis. Outcomes of this disease are affected by ethnicity, clinical characteristics, irreversible damage on renal biopsy, initial response to treatment and future disease course (for example, the occurrence of renal flares). Initial intensive (induction) treatment of proliferative lupus nephritis is aimed at achieving remission, but optimal duration and intensity are not well defined. A combination of intravenous cyclophosphamide and corticosteroids have been shown to decrease the risk of end-stage renal disease, but are associated with substantial acute toxic effects (such as infections) and chronic toxic effects (such as ovarian failure). In white populations, low-dose cyclophosphamide is a reasonable alternative to high-dose cyclophosphamide as it is similarly effective and associated with less toxicity. Mycophenolate mofetil is as effective as high-dose intravenous cyclophosphamide in terms of inducing remission and similar in terms of safety. Although most patients respond to induction treatment, remission is often only achieved after patients are switched to maintenance treatment. As maintenance treatment, mycophenolate mofetil is superior to azathioprine and azathioprine is similarly effective to ciclosporin in terms of prevention or reducing the risk of relapse. Rituximab should be reserved for patients with refractory disease. Treatment of lupus nephritis should be individually tailored to patients, with more aggressive therapy reserved for patients at high risk of renal dysfunction and progression of renal disease.

Current and emerging strategies for the treatment and management of systemic lupus erythematosus based on molecular signatures of acute and chronic inflammation

Lupus is a chronic, systemic inflammatory condition in which eicosanoids, cytokines, nitric oxide (NO), a deranged immune system, and genetics play a significant role. Our studies revealed that an imbalance in the pro- and antioxidants and NO and an alteration in the metabolism of essential fatty acids exist in lupus. The current strategy of management includes administration of nonsteroidal anti-inflammatory drugs such as hydroxychloroquine and immunosuppressive drugs such as corticosteroids. Investigational drugs include the following: 1) belimumab, a fully human monoclonal antibody that specifically recognizes and inhibits the biological activity of B-lymphocyte stimulator, also known as B-cell-activation factor of the TNF family; 2) stem cell transplantation; 3) rituximab, a chimeric monoclonal antibody against CD20, which is primarily found on the surface of B-cells and can therefore destroy B-cells; and 4) IL-27, which has potent anti-inflammatory actions. Our studies showed that a regimen of corticosteroids and cyclophosphamide, and methods designed to enhance endothelial NO synthesis and augment antioxidant defenses, led to induction of long-lasting remission of the disease. These results suggest that methods designed to modulate molecular signatures of the disease process and suppress inflammation could be of significant benefit in lupus. Some of these strategies could be vagal nerve stimulation, glucose-insulin infusion, and administration of lipoxins, resolvins, protectins, and nitrolipids by themselves or their stable synthetic analogs that are known to suppress inflammation and help in the resolution and healing of the inflammation-induced damage. These strategies are likely to be useful not only in lupus but also in other conditions, such as rheumatoid arthritis, scleroderma, ischemia-reperfusion injury to the myocardium, ischemic heart disease, and sepsis.

Retinoic acid-inducible gene-I (RIG-I) is induced by IFN-{gamma} in human mesangial cells in culture: possible involvement of RIG-I in the inflammation in lupus nephritis

Interferon-gamma is a potent Th1-type cytokine and a key molecule in the pathogenesis of autoimmune diseases including lupus nephritis. Retinoic acid-inducible gene-I is a putative RNA helicase that plays an important role in immune and inflammatory reactions. We previously demonstrated the increased expression of the retinoic acid-inducible gene-I protein in the kidney tissue of patients with lupus nephritis, and the presence of a significant amount of retinoic acid-inducible gene-I mRNA in the urinary sediment of patients with this inflammatory renal disease. In the present study, interferon-gamma was found to induce the expression of retinoic acid-inducible gene-I in human mesangial cells in culture. Knockdown of retinoic acid-inducible gene-I inhibited the interferon-gamma-induced upregulation of interferon regulatory factor 7, a transcriptional factor involved in immune and inflammatory reactions. These findings suggest that retinoic acid-inducible gene-I produced by mesangial cells may be involved in the pathogenesis of lupus nephritis.

Atorvastatin therapy reduces interferon-regulated chemokine CXCL9 plasma levels in patients with systemic lupus erythematosus

A recent study showed transcriptional levels of interferon-inducible chemokines in peripheral blood cells were associated with disease activity and organ damage in systemic lupus erythematosus, and may be useful in monitoring disease activity and prognosis. Our objective was to evaluate the capacity of atorvastatin to reduce plasma levels of interferon-regulated chemokines (CCL2, CCL3 and CXCL9) and to study the correlation between these chemokines and disease activity in patients with systemic lupus erythematosus. Eighty-eight female patients with systemic lupus erythematosus were divided into two groups: 64 receiving 20 mg/day of atorvastatin (intervention group) and 24 without atorvastatin (control group). All patients were followed for 8 weeks. At baseline and after 8 weeks laboratory tests were performed for all patients. Plasma levels of chemokines were measured by ELISA using commercial kits (DuoSet, R&D Systems, Minneapolis, USA). In a univariate analysis we found correlation between CCL2, CCL3 and CXCL9 plasma levels and SLEDAI score. In the intervention group we observed a significant decrease in CXCL9 plasma levels comparing baseline and levels at the end of the study (p = 0.04); however, no differences were observed regarding CCL2 or CCL3 plasma levels in this study. No significant difference was observed in the plasma levels of these chemokines in the control group. We conclude that treatment with atorvastatin was associated with a significant decrease in the plasma levels of CXCL9 in patients with systemic lupus erythematosus. As the plasma levels of CXCL9 correlated with the SLEDAI score, we ask whether reducing levels of this chemokine could help to control systemic lupus erythematosus activity.

Urine proteome scans uncover total urinary protease, prostaglandin D synthase, serum amyloid P, and superoxide dismutase as potential markers of lupus nephritis

To identify potential biomarkers in immune-mediated nephritis, urine from mice subjected to an augmented passive model of anti-glomerular basement membrane (GBM)-induced experimental nephritis was resolved using two-dimensional gels. The urinary proteome in these diseased mice was comprised of at least 71 different proteins. Using orthogonal assays, several of these molecules, including serum amyloid P (SAP), PG D synthase, superoxide dismutase, renin, and total protease were validated to be elevated in the urine and kidneys of mice during anti-GBM disease, as well as in mice with spontaneously arising lupus nephritis. Among these, urinary protease was the only marker that appeared to be exclusively renal in origin, whereas the others were partly serum-derived. Longitudinal studies in murine lupus demonstrated that total urinary protease had better predictive value for histologically active nephritis (r = 0.78) compared with proteinuria (r = -0.04), azotemia (r = 0.28), or the other markers examined, whereas urine SAP emerged as the single most predictive marker of histological glomerulonephritis. Collectively, these studies uncover total urinary protease, PG D synthase, SAP, and superoxide dismutase as novel biomarkers of anti-GBM disease and lupus nephritis, with stronger correlation to renal disease compared with currently employed biomarkers. These findings could have important diagnostic and prognostic ramifications in the management of these renal diatheses.

Activation profile of Toll-like receptors of peripheral blood lymphocytes in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease associated with aberrant activation of T and B lymphocytes for the production of inflammatory cytokines and autoreactive antibodies. Animal studies of SLE have indicated that Toll-like receptors (TLR) are important in the pathogenesis of murine lupus. In the present clinical study, differential protein expressions of TLR-1-9 of monocytes and different lymphocyte subsets from patients with SLE and normal control subjects were determined by flow cytometry. Results showed that the expression of intracellular TLRs (TLR-3, -8, -9) and extracellular TLRs (TLR-1, -2, -4, -5, -6) were elevated in monocytes, CD4(+) T lymphocytes, CD8(+) T lymphocytes and B lymphocytes of SLE patients compared to control subjects (all P < 0.001). Moreover, cell surface expression of TLR-4 on CD4(+) T lymphocytes and CD8(+) T lymphocytes, and TLR-6 on B lymphocytes, were correlated positively with SLE disease activity index (SLEDAI) (TLR-4 on CD4(+) T lymphocytes and CD8(+) T lymphocytes: r = 0.536, P = 0.04; r = 0.713, P = 0.003; TLR-6 in B lymphocytes: r = 0.572, P = 0.026). In concordance with the above results, there is an observable increased relative induction (%) of inflammatory cytokine interleukin (IL)-1beta, IL-6, IL-10 and IL-12, chemokines CCL2, CXCL8, CCL5 and CXCL10 from peripheral blood mononuclear cells (PBMC) upon differential stimulation by PolyIC (TLR-3 ligand), lipopolysaccharide (TLR-4 ligand), peptidoglycan (TLR-2 ligand), flagellin (TLR-5 ligand), R837 (TLR-7 ligand) and CpG DNA (TLR-9 ligand) in SLE patients compared to controls. These results suggest that the innate immune response for extracellular pathogens and self-originated DNA plays immunopathological roles via TLR activation in SLE.

Biomarkers for lupus nephritis: the quest continues

Current treatment of severe lupus nephritis is unsatisfactory in terms of both outcome and toxicity. To improve the efficacy and decrease the adverse effects of immunosuppression, it would be ideal to be able to predict the course and pathology of lupus nephritis and adjust therapy appropriately. This will require biomarkers that reflect disease activity. Recently, significant effort has been put into identifying biomarkers that can anticipate impending lupus renal flare, forecast development of chronic kidney disease, or reflect kidney histology at the time of flare. Although these biomarkers are potentially useful, to date none has been clinically validated in a large, prospective cohort of patients with SLE. This article reviews the current status of lupus nephritis biomarker investigation and articulates a perspective of how future efforts should be focused.

Urinary FOXP3 mRNA in patients with lupus nephritis--relation with disease activity and treatment response

OBJECTIVE

Regulatory T lymphocytes (Tregs) probably play an important role in the pathogenesis of SLE.

METHODS

We quantified messenger RNA (mRNA) expression of FOXP3, a critical regulator for the development and function of Tregs, in the urinary sediment of 25 subjects with active lupus nephritis (LN), 17 with inactive lupus and 7 healthy subjects.

RESULTS

We found that the expression level of FOXP3 was significantly higher in urine from patients with active LN than from subjects with inactive lupus and healthy controls (24.5 +/- 45.8 vs 0.8 +/- 1.0 vs 0.6 +/- 0.8 copy; P < 0.001). In the active group, urinary FOXP3 mRNA expression level was higher in patients with proliferative LN than non-proliferative nephritis (34.6 +/- 56.3 vs 2.7 +/- 2.1 copy; P = 0.019). Urinary FOXP3 mRNA level significantly correlated with SLEDAI (r = 0.668; P < 0.001) and proteinuria (r = 0.414; P = 0.006). In the active group, urinary FOXP3 mRNA level also significantly correlated with histological activity index (r = 0.541; P = 0.009) and marginally with intra-renal FOXP3 mRNA level (r = 0.360; P = 0.08). Urinary FOXP3 mRNA in patients with no response to therapy was higher than those with partial response or complete response (57.6 +/- 69.8 vs 2.4 +/- 1.9 copies; P = 0.02).

CONCLUSION

We concluded that urinary FOXP3 mRNA is markedly up-regulated in patients with active LN, and the level of expression is closely correlated with the clinical and histological disease activity. A high urinary FOXP3 mRNA in LN predicts a poor therapeutic response. Measurement of FOXP3 mRNA in urine sediment may be a non-invasive biomarker for assessing the severity and risk stratification in LN.

Podocyte loss in human hypertensive nephrosclerosis

BACKGROUND

Podocyte injury probably plays important roles in the pathogenesis of hypertensive nephropathy, but human data are limited. We studied glomerular podocyte count and intrarenal expression of podocyte-associated molecules in patients with hypertensive nephrosclerosis.

METHODS

We studied 41 consecutive patients with biopsy-proven hypertensive nephropathy, 10 cadaveric kidney donors, and 9 healthy subjects. Intrarenal and urinary mRNA expression of podocyte-associated molecules was quantified and podocyte number was determined by stereological method.

RESULTS

Intrarenal mRNA expression levels of nephrin, podocin, and synaptopodin were lower, and urinary mRNA expression levels were higher in patients with hypertensive nephropathy than controls. Glomerular podocyte number was significantly lower in patients with hypertensive nephrosclerosis than kidney donors (545 +/- 237 vs. 773 +/- 296 per glomeruli, P < 0.02). Podocyte density and intrarenal gene expression of podocyte-associated molecules significantly correlated with estimated glomerular filtration rate (GFR) and inversely correlated with blood pressure and the degree of renal fibrosis. Intrarenal gene expression of nephrin significantly correlated with change in renal function decline.

CONCLUSION

This study demonstrates a decrease in podocyte number and intrarenal gene expression of podocyte-associated molecules in patients with hypertensive nephrosclerosis. We observed correlations between glomerular podocyte density and intrarenal expression of podocyte-associated molecules with renal function and the degree of renal fibrosis, suggesting podocyte loss may play an important role in the pathogenesis of hypertensive nephrosclerosis.

Overexpression of interleukin-12 and T helper 1 predominance in lupus nephritis

Imbalance of cytokine homeostasis is a prominent feature of both experimental and human systemic lupus erythematosus (SLE). Because interleukin (IL)-12 promotes interferon (IFN)-gamma production leading to polarization of peripheral cells toward a T helper (Th) 1 phenotype, we investigated its role in lupus nephritis (LN). Soluble Th1 and Th2 cytokines were measured by enzyme-linked immunosorbent assay (ELISA) in sera and urines of SLE patients and controls. Th1/Th2 peripheral lymphocyte polarization was determined by flow cytometry. Glomerular accumulation of IL-12 was evaluated by immunohistochemistry, whereas urinary IL-12 was evaluated by ELISA. Higher serum IL-12 levels in SLE were associated with LN, whereas IL-4 was unrelated to the renal damage. Peripheral cells from LN patients showed a Th1 phenotype with a high IFN-gamma expression that paralleled the severity of renal damage. IL-12 was present within glomerular mononuclear cells in classes IV and V LN, and its accumulation was correlated strongly with urinary levels. IL-12 overexpression in SLE may contribute to the development of LN. Both serum and urinary IL-12 elevation reflect its glomerular production and parallel Th1 polarization of peripheral T cells and high IFN-gamma production. In SLE patients, IL-12 measurement may thus be predictive of the development of LN.

Interferon-induced protein IFIT4 is associated with systemic lupus erythematosus and promotes differentiation of monocytes into dendritic cell-like cells

INTRODUCTION

Using oligonucleotide microarray, many IFN-inducible genes have been found to be highly expressed in peripheral blood mononuclear cells (PBMCs) from most patients with systemic lupus erythematosus (SLE). Among these IFN-inducible genes, IFN-induced protein with tetratricopeptide repeats 4 (IFIT4) is a novel gene whose function is unknown.

METHODS

In this study we examined the role played by IFIT4 in monocyte differentiation and the correlation between IFIT4 expression and the clinical manifestation of SLE. To this end, we used plasmid transfection, flow cytometry, mixed leucocyte responses, ELISA, quantitative RT-PCR and Western blotting.

RESULTS

We found that both IFIT4 mRNA and protein expression levels were significantly higher in PBMCs and monocytes from SLE patients than in those from healthy control individuals. IFIT4 expression was positively correlated with antinuclear antibodies, anti-double-stranded DNA, and anti-Sm auto-immune antibodies in SLE. Patients with SLE exhibiting higher expression of IFIT4 had a higher prevalence of leucopenia, thrombocytopenia and C3/C4 decrease. IFIT4 protein was localized exclusively to the cytoplasm, and it was significantly upregulated by IFN-alpha in normal PBMCs. To determine the role played by IFIT4 in monocyte differentiation, the monocytic cell line THP-1 was transfected with pEGFP-IFIT4 expression plasmid and stimulated with granulocyte-macrophage colony-stimulating factor/IL-4 to generate IFIT4-primed dendritic cell-like cells (DCLCs). IFIT4-primed DCLCs acquired morphological characteristics of dendritic cells more quickly, with greater resemblance to dendritic cells, as compared with DCLCs primed with pEGFP-C1 control plasmid trasfection. Furthermore, they exhibited higher expressions of CD40, CD86, CD80, HLA-DR and CD83, along with lower expression of CD14; increased IL-12 secretion; and an increased ability to stimulate T-cell proliferation. In addition, IFIT4-primed DCLCs enhanced IFN-gamma secretion (about 2.4-fold) by T cells compared with controls.

CONCLUSION

Our findings suggest that IFIT4 might play roles in promoting monocyte differentiation into DCLCs and in directing DCLCs to modulate T-helper-1 cell differentiation; these actions might contribute to the autoimmunity and pathogenesis of SLE.

Expression of mRNA for functional molecules in urinary sediment in glomerulonephritis

Recent studies have suggested that gene expression studies using urinary sediment might be a non-invasive approach to assessing activity and pathogenesis in glomerulonephritis. However, little information is available regarding the mRNA expression patterns of functional molecules, such as T-bet, GATA-3, FOXP3, and retinoic acid-inducible gene-I (RIG-I), in urinary sediment, from patients with immunocomplex-mediated glomerulonephritis. Fourteen lupus nephritis (LN) patients, 13 IgA nephropathy (IgAN) patients, and 12 healthy controls were enrolled in the study. The mRNA expressions of T-bet, GATA-3, FOXP3 and RIG-I in urinary sediment were measured using real time quantitative polymerase chain reaction. We also studied the expression of RIG-I in kidney tissue specimens obtained from LN and IgAN patients. Significant differences in the expression patterns of GATA-3, FOXP3 and RIG-I, and marginal differences in T-bet expression, were observed between the three study groups. Immunofluorescent staining for RIG-I was observed in the tissue specimens from the LN patients, but not in those from the IgAN patients. The mRNA expression patterns of T-bet, GATA-3, FOXP3 and RIG-I in urinary sediment differ according to diagnostic category. These results suggest that the measurement of these target gene expressions might be a useful, non-invasive method for clinical monitoring and studying of pathogenesis in glomerulonephritis.

Quantification of gene expression in urinary sediment for the study of renal diseases

Urinalysis has been used extensively in clinical practice to aid in the diagnosis of various renal diseases. With the advances in technology of molecular biology, gene expression and proteomic studies are now possible for urinary sediment. In this review article, we focus on the quantification of messenger RNA expression in urinary sediment by reverse-transcription and real-time quantitative polymerase chain reaction. Recently, this technique has been explored for three potential applications: (i) distinguishing the different causes of kidney disease; (ii) assessment of kidney disease activity, progression and response to therapy; and (iii) as a tool to study the pathogenesis. Although the method is simple and non-invasive, it requires further research to define the role in routine clinical practice. At this moment, the technique should only be considered experimental albeit promising.

Intrarenal cytokine gene expression in lupus nephritis

BACKGROUND

Lupus nephritis is characterised by intrarenal inflammation and lymphocyte activation.

AIM

To examine the profile of cytokine gene expression in glomerulus and tubulointerstitium in patients with lupus nephritis.

METHODS

36 consecutive patients with systemic lupus erythematosus having active renal disease were recruited, and they were required to undergo kidney biopsy. Glomerular and tubulointestitial cytokine expression of interleukin (IL)2, 4, 10, 12, 18, interferon gamma (IFN)gamma, T-bet (the Th1 transcription factor), GATA-3 (the Th2 transcription factor), transforming growth factor beta and monocyte chemoattractant protein (MCP)1 were studied by laser microdissection of the renal biopsy specimen, followed by real-time quantitative PCR.

RESULTS

There were 13 patients with World Health Organization class III nephritis, 14 patients with class IV nephritis and 9 patients with class V nephritis. There was a significant correlation between serum C3, C4 and anti-double strand DNA antibody level with glomerular expression of T-bet, IFNgamma and IL2. There was a significant correlation between histological activity index and glomerular expression of IL12, IL18, IL10 and MCP1. In addition, the degree of glomerular leucocyte infiltration significantly correlated with glomerular expression of IFNgamma, IL10, IL12 and IL18. By contrast, histological chronicity index correlated with the tubulointerstitial expression of IL2, MCP1 and GATA-3.

CONCLUSIONS

Intraglomerular expression of certain target genes correlate with the severity of systemic as well as histological activity, whereas the tubulointerstitial expression of other target genes correlate with the degree of chronic kidney scarring. This result may shed light on the immunopathogenesis of lupus nephritis.

Messenger RNA expression of podocyte-associated molecules in the urinary sediment of patients with diabetic nephropathy

BACKGROUND

Podocyte loss plays an important role in the pathogenesis of diabetic nephropathy. We hypothesize that messenger RNA expression of podocyte-associated molecules in urinary sediment may provide important clinical information in patients with diabetic nephropathy.

METHOD

We studied 21 patients with biopsy-proven diabetic nephropathy and 9 healthy controls. The mRNA expression of nephrin, podocin, synaptopodin, Wilms' tumor-1 (WT-1) and alpha-actinin-4 in urinary sediment were measured by real-time quantitative polymerase chain reaction. The degree of histological damage was quantified by morphometric analysis. Patients were then followed for an average of 25.63 +/- 10.76 months. The rate of glomerular filtration rate (GFR) decline was calculated by the least-square regression.

RESULTS

There were significant differences in nephrin, podocin, synaptopodin, alpha-actinin-4 (p < 0.01 for all comparisons) and WT-1 (p = 0.028) expression between patients and normal controls. Urinary nephrin expression was significantly correlated with proteinuria (r = 0.502, p = 0.020); urinary synaptopodin was significantly correlated with proteinuria (r = 0.585, p = 0.005), serum creatinine (r = 0.516, p = 0.017) and estimated GFR (r = -0.560, p = 0.008), and urinary WT-1 expression was significantly correlated with the degree of tubulointerstitial fibrosis (r = 0.558, p = 0.009). There was no significant correlation between GFR decline and urinary expression of target genes.

CONCLUSION

Urinary mRNA expressions of nephrin, podocin, synaptopodin, WT-1 and alpha-actinin-4 are higher in patients with diabetic nephropathy than in normal controls. Urinary nephrin and synaptopodin expressions are correlated with baseline clinical parameters such as proteinuria or renal function, while WT-1 expression is related to the degree of histological damage. Our results suggest that urinary mRNA expression of podocyte-associated molecules may be used for risk stratification of diabetic nephropathy.

Gender and autoimmunity

The enhanced immunoreactivity in females is a double-edged sword that provides better protection against infections, but may lead to enhanced autoreactivity and thereby contribute to the induction of autoimmunity. Autoimmune diseases demonstrate a gender bias and represent the fifth leading cause of death by disease among females of reproductive age. Clinical and murine experimental studies indicate that the gender bias in autoimmunity may be influenced by sex hormones, predominantly displayed in the development and exacerbations of the prototypical autoimmune disease lupus. The associations between sex hormones and other autoimmune diseases are less clear. Our review on the impact of gender via sex hormones and sex related genes in the pathogenesis of several autoimmune diseases suggests that a better understanding of the underlying mechanisms behind the sexual dimorphism of the immune system may lead to the development of novel therapeutic approaches to autoimmunity.

Predominance of CD8+ T lymphocytes among periglomerular infiltrating cells and link to the prognosis of class III and class IV lupus nephritis

OBJECTIVE

Recent studies have revealed a potential implication of CD8+ T lymphocytes in the pathogenesis of systemic lupus erythematosus (SLE) through their ability to induce tissue damage. The aim of the present study was to analyze the localization of CD8+ cells in the kidneys of patients with class III and class IV lupus nephritis and to establish correlations with histologic, biologic, and clinical features of SLE.

METHODS

Twenty-five consecutive SLE patients with class III or class IV lupus nephritis were enrolled. Phenotype analyses of blood lymphocytes and renal immunohistochemistry studies were performed.

RESULTS

CD8+ T cells were the predominant kidney-infiltrating subset of cells. The mean +/- SD numbers of CD8+ T cells and CD4+ T cells were 66.2 +/- 65.2/mm(2) and 19.3 +/- 29.4/mm(2), respectively. There was a significant correlation between the percentage of blood CD3+,CD8+,DR+ cells and the total number of renal CD8+ T cells (r = 0.42, P = 0.039). Renal CD8+ T cell infiltration correlated well with the renal activity index (r = 0.63, P = 0.0007) and with high serum creatinine levels (r = 0.75, P = 0.0001). This CD8+ T cell infiltrate, which was predominantly in the periglomerular area, was correlated with cellular crescents and Bowman's capsule rupture and was associated with a poor response after conventional induction therapy.

CONCLUSION

CD8+ T lymphocytes infiltrate the periglomerular area in patients with severe (class III and class IV) lupus nephritis and are linked to a poor outcome after induction therapy. These results reveal a new potential effector pathway operant in lupus nephritis.

Predictive value of mucosal TNF-alpha transcripts in steroid-refractory Crohn's disease patients receiving intensive immunosuppressive therapy

BACKGROUND

Concentrations of proinflammatory cytokines are increased in the intestinal mucosa of patients with active Crohn's disease (CD). In a prospective study we investigated whether cytokines can predict long-term remission (>6 months) in patients with steroid-refractory CD receiving treatment with infliximab or cyclophosphamide, followed by azathioprine or methotrexate.

METHODS

Cytokine transcripts were quantified using real-time polymerase chain reaction (PCR) in mucosal biopsies from 19 patients with active, steroid-refractory CD before and 8 weeks after initiation of therapy. Patients were treated with cyclophosphamide (monthly treatment of 750 mg cyclophosphamide intravenously) or infliximab (5 mg/kg body weight) and were followed until relapse of the disease. Statistical analysis was performed to identify predictive factors to discriminate between patients with or without long-term remission.

RESULTS

Seventeen out of 19 patients achieved remission of the disease, two patients were nonresponders, while six out of 17 patients exhibited an early recurrence. Pretreatment TNF-alpha, IL-18, MRP-14, and IL-8 transcripts were significantly correlated with long-term remission. While several cytokines, most importantly MMP-1, determined after 8 weeks were able to predict patients achieving long-term remission, only a decrease of TNF-alpha levels after 8 weeks was predictive. Overall, statistical analysis identified lower pretreatment TNF-alpha levels as the strongest predictor of long-term remission among baseline variables.

CONCLUSIONS

Quantification of mucosal TNF-alpha transcripts prior to therapy allows identification of patients achieving long-term remission upon immunosuppression with infliximab or cyclophosphamide. Real-time PCR might have considerable potential in the analysis of disease activity and subsequent clinical management of patients with immunosuppressive therapies.

Pathogenesis and treatment of systemic lupus erythematosus nephritis

PURPOSE OF REVIEW

Glomerulonephritis is a challenging complication of systemic lupus erythematosus that still results in kidney loss in up to 30% of patients. In this review we highlight the development of integrated efforts to link pathogenesis with disease definition and new therapeutics.

RECENT FINDINGS

Immune complex deposition in the kidney initiates an inflammatory cascade that causes glomerular disease but there are many modulating factors including genetic predisposition, products of the innate immune system, cytokines, complement and activated cells (both renal and immune). Animal models can help dissect potential disease mechanisms but the study of multiple models will be required since there are multiple subsets of human disease. Recent therapeutic studies in humans address the distinction between therapies for remission induction and remission maintenance. Multiple studies confirm the therapeutic equivalence of mycophenolate mofetil and cyclophosphamide in induction of remission but results are still far from ideal. The next few years should see the testing of new biologic reagents in humans. Another area of interest is the search for noninvasive measures of disease and disease response.

SUMMARY

Although there has been remarkable progress in our understanding of the immunology and phenotype of lupus nephritis current therapies have insufficient efficacy. As new therapies emerge, improved clinical design coupled with mechanistic studies will be needed to identify agents that may be effective only in some patient subpopulations.

Messenger RNA expression of RANTES in the urinary sediment of patients with lupus nephritis

BACKGROUND

Lupus nephritis is characterized by intra-renal inflammation. Patients with systemic lupus erythematosus (SLE) showed abnormal T-cell expression of RANTES (regulated upon activation, normal T cell expressed) and its level in their serum. The authors studied the mRNA expression of RANTES in the urinary sediment of lupus patients.

METHODS

The authors studied 88 lupus patients, who were classified into active, remission and non-renal SLE groups according to the disease activity, 29 non-SLE and 10 healthy controls. Lupus activity was assessed by the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Urinary mRNA expression of RANTES was studied by real-time quantitative polymerase chain reaction.

RESULTS

The expression of RANTES in urinary sediment was significantly elevated in active group (P < 0.001). Expression level of RANTES correlated with the SLEDAI score (r = 0.57; P < 0.001) and renal score in SLEDAI (r = 0.60; P < 0.001). In addition, urinary expression of RANTES had significant correlation with degree of proteinuria, serum creatinine, albumin and estimated glomerular filtration rate.

CONCLUSION

The authors conclude that the mRNA expression of RANTES was elevated in the urinary sediment of patients with active lupus nephritis. Measurement of urinary mRNA expression may be a novel non-invasive method for the assessment of lupus disease activity and the severity of renal involvement.

Simvastatin treatment ameliorates autoimmune disease associated with accelerated atherosclerosis in a murine lupus model

Patients with systemic lupus erythematosus develop accelerated atherosclerosis independent of traditional risk factors. The 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase inhibitors are widely prescribed for hyperlipidemia, but they also exhibit anti-inflammatory actions that appear to be independent of their suppressive actions on plasma cholesterol levels. In this study, we analyzed the effect of the HMG-CoA reductase inhibitor simvastatin on disease manifestations in gld.apoE-/- mice that lack functional Fas ligand and apolipoprotein E and exhibit accelerated atherosclerosis and aggravated lupus-like features. Wild-type, gld, apoE-/-, and gld.apoE-/- mice were maintained on a high cholesterol Western diet and received daily simvastatin (0.125 mg/kg) or saline for 12 wk. Serum cholesterol levels were unaffected by simvastatin treatment, but atherosclerotic lesion area was reduced in both apoE-/- and gld.apoE-/- mice treated with simvastatin. Simvastatin also reduced the lymphadenopathy, renal disease, and proinflammatory cytokine production seen in gld.apoE-/-, but not gld, mice. The immunomodulatory effects in gld.apoE-/- mice were associated with enhanced STAT6 and decreased STAT4 induction in submandibular lymph node cells. Along with reductions in serum TNF-alpha and IFN-gamma levels, there was also an increase in IL-4 and IL-10 transcript levels in lymph nodes. These data indicate that HMG-CoA reductase inhibitors ameliorate atherosclerosis and lupus-like autoimmunity independent of their cholesterol-lowering effects via a shift from a Th1 to a Th2 phenotype in the gld.apoE-/- model. Thus, the anti-inflammatory activities of statins may have utility for the treatment of both autoimmunity and atherosclerosis in patients with systemic lupus erythematosus.

Molecular approaches to chronic kidney disease

PURPOSE OF REVIEW

The progression of chronic kidney disease to terminal renal failure remains a major challenge in nephrology. Definition of the dynamic differences in gene regulation, protein interaction and protein function in this process might allow the development of rationally designed management strategies for the individual patient. Current approaches to identifying the molecular markers required to implement this 'personalized medicine' concept in progressive renal failure will be presented in this review.

RECENT FINDINGS

In small populations, molecular fingerprints derived from renal biopsies have allowed the definition of distinct patient subgroups. These parameters could be shown to correlate with the response to available therapies and, in chronic transplant failure, with the therapeutic toxicity of cyclosporine. Urine analysis for mRNA and protein markers is rapidly evolving as a non-invasive approach for molecular patient monitoring. As only a small fraction of these fingerprints have been evaluated in independent populations, studies to test marker sets in diverse cohorts for their clinical applicability are warranted.

SUMMARY

The genome-wide tools discussed in this review might define the molecular mechanism active in each single patient with progressive kidney disease. Reflecting the individuality of the disease process could result in a tailored therapy for the unique human being, contrasting with the 'one-size-fits-all' therapies currently employed in nephrology.

mRNA expression of target genes in the urinary sediment as a noninvasive prognostic indicator of CKD

BACKGROUND

Study of messenger RNA (mRNA) expression of target genes in urinary sediment was suggested as a noninvasive marker of renal damage in patients with chronic kidney diseases (CKDs). We studied the relationship between urinary mRNA expression of target genes and risk for renal function deterioration in patients with CKD.

METHODS

We studied 131 patients with CKD with kidney biopsy. mRNA expression of 11 target genes in urinary sediment was measured by means of quantitative polymerase chain reaction. Patients then were followed up for 27.4 +/- 10.1 months. The primary end point is doubling of serum creatinine concentration or end-stage renal disease.

RESULTS

Thirty-six patients (27.5%) reached the primary end point during follow-up. Univariate analysis showed that sex, age, proteinuria, estimated glomerular filtration rate, histological diagnosis, degree of tubulointerstitial scarring, percentage of glomerulosclerosis, and urinary mRNA expression of hepatocyte growth factor (HGF) were predictors of the primary end point. At 24 months, event-free survival rates were 90.9% and 64.3% for patients with low and high urinary HGF expression, respectively (log rank test, P = 0.002). After adjusting for other confounding factors by using a Cox proportional hazard model, urinary HGF expression remained an independent predictor of the primary end point, and a 1-fold increase in expression was associated with a 4.0% (95% confidence interval, 0.5 to 7.5; P = 0.024) increase in risk.

CONCLUSION

In the target genes examined, urinary HGF expression is an independent prognostic indicator of CKD after adjusting for confounding clinical and histological factors. Measurement of urinary HGF mRNA expression may be a useful noninvasive tool for risk stratification of patients with CKD.

Daily urinary interleukin-11 excretion correlated with proteinuria in IgA nephropathy and lupus nephritis

Interleukin-11 (IL-11) is a multifunctional cytokine with both thrombopoietic and anti-inflammatory effects. In an animal study IL-11 was shown to reduce proteinuria in mice with necrotizing glomerulonephritis. The purpose of this current study is to explore the role of IL-11 in human glomerulonephritis. Subjects of this study were patients with proteinuria (daily urine protein excretion >40 mg/m2 per hour) and underlying pathology of IgA nephropathy (IgAN) (n=20), lupus nephritis (LN) (n=40), and idiopathic nephrotic syndrome (INS) (n=68). Daily urinary IL-11 level was measured by enzyme-linked immunosorbent assay (ELISA). Correlation between urinary IL-11 and urinary protein was determined by Pearson's correlation coefficient. Another five patients with serial data of urinary protein, IL-11 and IL-11 messenger RNA (mRNA) expression in urine sediment are presented. The correlation between urinary IL-11 and daily urinary protein was significant for patients with IgAN (r=0.596, P=0.006) and LN (r=0.630, P<0.001), but not for patients with INS (r=0.030, P=0.812). Serial data revealed the same correlation. Furthermore, the peak of urinary IL-11 mRNA preceded that of urinary IL-11. We conclude that daily urinary IL-11 excretion is correlated with urinary protein loss in nephritis having local T helper (Th)1 predominant immune response, such as IgAN and LN. Local IL-11 production may serve as a counter cytokine against Th1-mediated inflammation.

Genomic view of systemic autoimmunity in MRLlpr mice

MRLlpr mice develop spontaneous systemic autoimmunity with many hallmarks of the human disease systemic lupus erythematosus. Although a variety of genes have been implicated in this model, disease pathogenesis is still poorly understood. In an effort to identify novel genes and pathways, we performed genome-wide mRNA expression analysis in the spleens and kidneys of MRLlpr mice throughout the disease course. Samples were collected from cohorts of C57BL/6, MRL+/+ and MRLlpr mice, and profiled by flow cytometry and gene expression microarrays. Serum autoantibodies and renal pathology were studied in parallel. We identified 236 genes in MRLlpr spleen that showed significant threefold or greater changes in expression between 6 and 20 weeks. Of interest, a number of interferon-responsive genes were expressed early, and remained dysregulated throughout the disease course. Many chemokines, cell surface proteins, transcription factors and cytokines, including IFN-gamma, also showed altered expression as disease progressed. Analysis of kidneys indicated the presence of severe inflammation that coincided with evidence for changes in kidney function and elevated expression of IFN-inducible genes, complement components and antigen presentation genes. These data provide a unique genomic view of the progression to fatal autoimmunity in MRLlpr mice, and provide new candidate genes and pathways to explore.

Imbalance of Th1/Th2 transcription factors in patients with lupus nephritis

OBJECTIVE

Systemic lupus erythematosus (SLE) is characterized by the aberrant activation of T lymphocytes. Since T-bet and GATA-3 are the principal transcription factors for the differentiation of type-1 and type-2 helper T lymphocytes, respectively, we studied their mRNA expression in the urinary sediment of SLE patients and compared this with their urinary and intra-renal protein expression.

METHODS

We studied 100 SLE patients and 10 healthy subjects. Urinary mRNA expression of T-bet and GATA-3 were studied by the real-time quantitative polymerase chain reaction. Intra-renal and urinary expressions of T-bet and GATA-3 were studied by immunohistochemistry and western blotting, respectively.

RESULTS

The urinary mRNA and protein expressions of T-bet were significantly higher in SLE patients with active nephritis than those with inactive disease (mRNA: P < 0.001; protein: P = 0.004). The urinary mRNA expression of T-bet correlated with the SLE disease activity index (SLEDAI) score (r = 0.55, P < 0.001) and the histological activity index (r = 0.48, P = 0.03). On the other hand, the urinary mRNA and protein expressions of GATA-3 were significantly lower in SLE patients with active nephritis (mRNA: P < 0.001; protein: P = 0.006), and GATA-3 mRNA expression inversely correlated with the SLEDAI score (r = 0.38, P < 0.001). For the 22 SLE patients with kidney biopsy, tubular expressions of T-bet and GATA-3 significantly correlated with the histological activity index (T-bet: r = 0.57, P = 0.006; GATA-3: r = -0.79, P < 0.001).

CONCLUSIONS

Patients with active lupus nephritis have increased T-bet and depressed GATA-3 expression in the urinary sediment and kidney tissue, indicating a predominant Th1 type of T-lymphocyte activation.

Raised plasma concentration and ex vivo production of inflammatory chemokines in patients with systemic lupus erythematosus

BACKGROUND

Chemokines are involved in leucocyte chemotaxis. Infiltrating leucocytes play an important role of tissue injury in systemic lupus erythematosus (SLE).

OBJECTIVE

To investigate the role of inflammatory chemokines and their association with interleukin 18 (IL18) in SLE pathogenesis and disease activity.

METHODS

Plasma concentrations and ex vivo peripheral blood mononuclear cell production of inflammatory chemokines IP-10, RANTES, MIG, MCP-1, TARC, IL8, and GROalpha, and proinflammatory cytokines IL18, IFNgamma, IL2, IL4, and IL10 were assayed in 80 SLE patients with or without renal disease and 40 healthy controls by immunofluorescence flow cytometry and enzyme linked immunosorbent assay.

RESULTS

Plasma IP10, RANTES, MIG, MCP-1, GROalpha, and IL18 concentrations in all SLE patients were higher than in controls, and correlated significantly with SLEDAI score (all p<0.05). In SLE patients without renal disease, IP10, RANTES, MIG, MCP-1, IL8, and IL18 correlated positively with SLEDAI score, while in those with renal derangement, IP10, IL8, IL10, and IL18 correlated with disease activity (all p<0.05). Plasma IL18 concentration correlated positively with IP10, MIG, GROalpha, and IL8 in all SLE patients (all p<0.005). Mitogen induced increases in ex vivo production of IP10, MCP-1, TARC, IFNgamma, IL4, and IL10 were higher in all SLE patients regardless of their difference in disease activity (all p<0.05). Patients with renal disease had an augmented ex vivo release of RANTES.

CONCLUSIONS

The correlation of raised plasma concentration and ex vivo production of inflammatory chemokines with disease activity, and their association with IL18, supports the view that chemotaxis of Th1/Th2 lymphocytes and neutrophils is important in SLE pathogenesis.

Measurement of urinary chemokine and growth factor messenger RNAs: A noninvasive monitoring in lupus nephritis

Noninvasive molecular tests of urine cells have been developed to monitor the activity of kidney diseases. We evaluate whether measurement of urinary messenger RNA (mRNA) levels of chemokine and growth factor genes could distinguish between diffuse proliferative lupus nephritis (class IV LN) and others and whether it is able to predict the response to therapy. Prebiopsy urine samples were collected from 26 LN patients. Urine specimens were serially collected over a period of 6 months from class IV LN patients who were receiving standard immunosuppressive treatments. Urinary interferon-producing protein 10 and its CXC chemokine receptor (CXCR)3, transforming growth factor-beta (TGF-beta), and vascular endothelial growth factor (VEGF) mRNA levels were analyzed by quantitative real-time polymerase chain reactions. Levels of chemokine or growth factor mRNAs in urine could distinguish class IV LN from others, with a sensitivity of 85% and a specificity of 94%. The receiver-operative characteristic curve demonstrated that urine mRNA levels of these genes could identify active class IV LN with an accuracy greater than the current available clinical markers, namely systemic lupus erythematosus (SLE) disease activity index, proteinuria, renal function, or urinalysis. A significant reduction of interferon-producing protein 10 (IP-10), CXCR3, TGF-beta, and VEGF mRNA levels from baselines was observed in patients who responded to therapy, whereas the levels tended to increase in those who resisted to treatment. Measurement of urinary chemokine and growth factor mRNAs can precisely distinguish class IV LN from others. Temporal association between these markers and therapeutic response is demonstrated. This noninvasive approach serves as a practical tool in diagnosis and management of LN.

The effect of immunosuppressive therapy on the messenger RNA expression of target genes in the urinary sediment of patients with active lupus nephritis

BACKGROUND

Previous studies have shown that messenger RNA (mRNA) expression of target genes is increased in the urinary sediment of patients with active lupus. We study the effect of immunosuppressive therapy on the urinary gene expression profile in patients with active lupus nephritis. Method. We recruited nine patients with active systemic lupus erythematosus (SLE) and renal disease, and required corticosteroid, with or without cytotoxic treatment. They were followed for 6 months, urine samples were collected at 0, 4, 12 and 24 weeks and gene expression profile was determined by polymerase chain reactions. The pattern of gene expression was compared to clinical parameters of therapeutic response.

RESULTS

Amongst the target genes studied, there was a progressive decline in the urinary expression of T-bet, interleukin (IL)-10, transforming growth factor-beta (TGF-beta), monocyte chemoattractant protein-1 (MCP-1), and interferon-gamma (IFN-gamma) after immunosuppressive treatment, although the change of IFN-gamma was not statistically significant. The time course of their urinary expression was parallel to the systemic activity as reflected by the systemic lupus erythematosus disease activity index (SLEDAI). Throughout the study period, the SLEDAI score correlated significantly with the expressions of IFN-gamma (r = 0.43, P = 0.009), T-bet (r = 0.40, P = 0.016), TGF-beta (r = 0.51, P = 0.002) and MCP-1 (r = 0.38, P = 0.022). The anti-double strand(anti-ds)DNA antibody titer correlated significantly with the expressions of IFN-gamma (r = 0.45, P = 0.009), T-bet (r = 0.37, P = 0.034), IL-10 (r = 0.59, P<0.001), TGF-beta (r = 0.44, P = 0.010) and MCP-1 (r = 0.49, P = 0.004). On the other hand, the expression level of IL-2, IL-4, IL-12, IL-18 and GATA-3 remained static throughout the study period.

CONCLUSIONS

The mRNA expression of T-bet, IL-10, TGF-beta, MCP-1, and probably IFN-gamma in the urinary sediment of patients with active lupus nephritis improves with successful immunosuppressive therapy, and the change in gene expression profile is in phase with the clinical disease activity. Measurement of urinary mRNA expression of target genes may be a potential non-invasive tool for the monitoring of lupus disease activity.