Anti-DNA autoantibodies initiate experimental lupus nephritis by binding directly to the glomerular basement membrane in mice

The additional role of anti-nucleosome antibodies in the prediction of renal damage in systemic lupus erythematosus based on CSTAR (XXV)

OBJECTIVES

The predominant determinant of an unfavorable prognosis among Systemic Lupus Erythematosus (SLE) patients resides in the irreversible organ damage. This prospective cohort study aimed to identify the additional value of anti-nucleosome antibodies on organ damage accumulation in SLE patients.

METHODS

Based on the Chinese SLE Treatment and Research group (CSTAR) registry, demographic characteristics, autoantibodies profiles, and clinical manifestations were collected at baseline. Follow-up data were collected by reviewing clinical records.

RESULTS

Of 2481 SLE patients with full follow-up data, 663 (26.7%) were anti-nucleosome antibodies positive and 1668 (68.0%) were anti-dsDNA antibodies positive. 764 (30.8%) patients developed new organ damage during a mean follow-up of 4.31 ± 2.60 years. At baseline, patients with positive anti-nucleosome antibodies have a higher rate of lupus nephritis (50.7% vs 36.2%, p < .001). According to the multivariable Cox regression analysis, both anti-nucleosome (HR = 1.30, 95% CI, 1.09-1.54, p < .001) and anti-dsDNA antibodies (HR=1.68, 95% CI, 1.38-2.05, p < .001) were associated with organ damage accumulation. Anti-nucleosome (HR = 2.51, 95% CI, 1.81-3.46, p < .001) and anti-dsDNA antibodies (HR = 1.69, 95% CI, 1.39-2.06, p < .001) were independent predictors for renal damage. Furthermore, the combination of the two antibodies can provide more accurate information about renal damage in overall SLE patients (HR = 3.19, 95% CI, 2.49-4.10, p < .001) and patients with lupus nephritis at baseline (HR = 2.86, 95% CI, 2.29-3.57, p < .001).

CONCLUSION

Besides anti-dsDNA antibodies, anti-nucleosome antibodies can also provide information about organ damage accrual during follow-up. The ability of co-positivity of anti-nucleosome and anti-dsDNA antibodies in predicting renal damage may lead to additional benefits in the follow-up of these patients.

SLE: a cognitive step forward-a synthesis of rethinking theories, causality, and ignored DNA structures

Systemic lupus erythematosus (SLE) is classified by instinctual classification criteria. A valid proclamation is that these formally accepted SLE classification criteria legitimate the syndrome as being difficult to explain and therefore enigmatic. SLE involves scientific problems linked to etiological factors and criteria. Our insufficient understanding of the clinical condition uniformly denoted SLE depends on the still open question of whether SLE is, according to classification criteria, a well-defined one disease entity or represents a variety of overlapping indistinct syndromes. Without rational hypotheses, these problems harm clear definition(s) of the syndrome. Why SLE is not anchored in logic, consequent, downstream interdependent and interactive inflammatory networks may rely on ignored predictive causality principles. Authoritative classification criteria do not reflect consequent causality criteria and do not unify characterization principles such as diagnostic criteria. We need now to reconcile legendary scientific achievements to concretize the delimitation of what SLE really is. Not all classified SLE syndromes are "genuine SLE"; many are theoretically "SLE-like non-SLE" syndromes. In this study, progressive theories imply imperative challenges to reconsider the fundamental impact of "the causality principle". This may offer us logic classification and diagnostic criteria aimed at identifying concise SLE syndromes as research objects. Can a systems science approach solve this problem?

A critical view on autoantibodies in lupus nephritis: Concrete knowledge based on evidence

Deposition of autoantibodies in glomeruli is a key factor in the development of lupus nephritis (LN). For a long time, anti-dsDNA and anti-C1q antibodies were thought to be the main cause of the kidney damage. However, recent studies have shown that the list of autoantibidies that have renal tropism and deposit in the kidney in LN is increasing and the link between anti-dsDNA and renal pathology is weak due to potential confounders. Aspecific bindings of dsDNA with cationic antibodies and of anti-dsDNA with several renal antigens such as actinin, laminin, entactin, and annexinA2 raised doubts about the specific target of these antibodies in the kidney. Moreover, the isotype of anti-dsDNA in SLE and LN has never received adequate interest until the recent observation that IgG2 are preponderant over IgG1, IgG3 and IgG4. Based on the above background, recent studies investigated the involvement of anti-dsDNA IgG2 and of other antibodies in LN. It was concluded that circulating anti-dsDNA IgG2 levels do not distinguish between LN versus non-renal SLE, and, in patients with LN, their levels do not change over time. Circulating levels of other antibodies such as anti-ENO1 and anti-H2 IgG2 were, instead, higher in LN vs non-renal SLE at the time of diagnosis and decreased following therapies. Finally, new classes of renal antibodies that potentially modify the anti-inflammatory response in the kidney are emerging as new co-actors in the pathogenetic scenario. They have been defined as 'second wave antibodies' for the link with detoxifying mechanisms limiting the oxidative stress in glomeruli that are classically stimulated in a second phase of inflammation. These findings have important clinical implications that may modify the laboratory approach to LN. Serum levels of anti-ENO1 and anti-H2 IgG2 should be measured in the follow up of patients for designing the length of therapies and identify those patients who respond to treatments. Anti-SOD2 could help to monitor and potentiate the anti-inflammatory response in the kidney.

Anti-DNA antibody-targeted D-peptide nanoparticles ameliorate lupus nephritis in MRL/lpr mice

Peptide ALW (ALWPPNLHAWVP) targeting anti-dsDNA antibodies has shown promising therapeutic effects in alleviating lupus nephritis, but is potentially limited by poor stability and non-kidney targeting. We recently developed a D-form modified ALW, called D-ALW, which has the capacity to widely inhibit pathogenic polyclonal anti-dsDNA antibody reactions. Further modification of D-ALW using PEG-PLGA nanoparticles to enhance good kidney-targeting ability and extend half-life. Here, we demonstrate that the D-form modified ALW maintains higher binding and inhibition efficiencies and achieves higher stability. Most importantly, D-ALW nanoparticles exhibit excellent kidney-targeting ability and prolong the half-life of the peptides in BALB/c mice. Additionally, compared to D-ALW, D-ALW nanoparticles significantly reduce the glomerular deposition of IgG and C3, improve renal histopathologies, such as glomerular proliferation and inflammatory cells infiltration, and markedly prolong lifespan in MRL/lpr lupus-prone mice. Overall, these results establish that the D-ALW nanoparticles offer synergistic benefits in both safety and efficacy, providing long-term renal preservation and treatment advantages in lupus nephritis.

Precise Targeting of Autoantigen-Specific B Cells in Lupus Nephritis with Chimeric Autoantibody Receptor T Cells

Despite conventional therapy, lupus nephritis (LN) remains a significant contributor to short- and long-term morbidity and mortality. B cell abnormalities and the production of autoantibodies against nuclear complexes like anti-dsDNA are recognised as key players in the pathogenesis of LN. To address the challenges of chronic immunosuppression associated with current therapies, we have engineered T cells to express chimeric autoantibody receptors (DNA-CAART) for the precise targeting of B cells expressing anti-dsDNA autoantibodies. T cells from LN patients were transduced using six different CAAR vectors based on their antigen specificity, including alpha-actinin, histone-1, heparan sulphate, or C1q. The cytotoxicity, cytokine production, and cell-cell contact of DNA-CAART were thoroughly investigated in co-culture experiments with B cells isolated from patients, both with and without anti-dsDNA positivity. The therapeutic effects were further evaluated using an in vitro immune kidney LN organoid. Among the six proposed DNA-CAART, DNA4 and DNA6 demonstrated superior selectively cytotoxic activity against anti-dsDNA+ B cells. Notably, DNA4-CAART exhibited improvements in organoid morphology, apoptosis, and the inflammatory process in the presence of IFNα-stimulated anti-dsDNA+ B cells. Based on these findings, DNA4-CAART emerge as promising candidates for modulating autoimmunity and represent a novel approach for the treatment of LN.

Characterization of glomerular basement membrane components within pediatric glomerular diseases

Background

Disruptions in gene expression associated with the glomerular basement membrane (GBM) could precipitate glomerular dysfunction. Nevertheless, a comprehensive understanding of the characterization of GBM components within pediatric glomerular diseases and their potential association with glomerular function necessitates further systematic investigation.

Methods

We conducted a systematic analysis focusing on the pathological transformations and molecular attributes of key constituents within the GBM, specifically Collagen IV α3α4α5, Laminin α5β2γ1, and Integrin α3β1, across prevalent pediatric glomerular diseases.

Results

We observed upregulation of linear expression levels of COL4A3/4/5 and Laminin 5α proteins, along with a partial reduction in the linear structural expression of Podocin in idiopathic nephrotic syndrome (INS), encompassing minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS), but showing a reduction in IgA nephropathy (IgAN), IgA vasculitis nephritis (IgAVN) and lupus nephritis (LN). Furthermore, our study revealed reductions in Laminin β2γ1 and Integrin α3β1 in both primary and secondary childhood glomerular diseases.

Conclusion

In INS, notably MCD and FSGS, there is a notable increase in the linear expression levels of COL4A3/4/5 and Laminin 5α proteins. In contrast, in IgAN, IgAVN, and LN, there is a consistent reduction in the expression of these markers. Furthermore, the persistent reduction of Laminin β2γ1 and Integrin α3β1 in both primary and secondary childhood glomerular diseases suggests a shared characteristic of structural alterations within the GBM across these conditions.

The greatest contribution to medical science is the transformation from studying symptoms to studying their causes-the unrelenting legacy of Robert Koch and Louis Pasteur-and a causality perspective to approach a definition of SLE

The basic initiative related to this study is derived from the fact that systemic lupus erythematosus (SLE) is a unique and fertile system science subject. We are, however, still far from understanding its nature. It may be fair to indicate that we are spending more time and resources on studying the complexity of classified SLE than studying the validity of classification criteria. This study represents a theoretical analysis of current instinctual SLE classification criteria based on "the causality principle." The discussion has its basis on the radical scientific traditions introduced by Robert Koch and Louis Pasteur. They announced significant changes in our thinking of disease etiology through the implementation of the modern version of "the causality principle." They influenced all aspects of today's medical concepts and research: the transformation of medical science from studies of symptoms to study their causes, relevant for monosymptomatic diseases as for syndromes. Their studies focused on bacteria as causes of infectious diseases and on how the immune system adapts to control and prevent contagious spreading. This is the most significant paradigm shift in the modern history of medicine and resulted in radical changes in our view of the immune system. They described acquired post-infection immunity and active immunization by antigen-specific vaccines. The paradigm "transformation" has a great theoretical impact also on current studies of autoimmune diseases like SLE: symptoms and their cause(s). In this study, the evolution of SLE classification and diagnostic criteria is discussed from "the causality principle" perspective, and if contemporary SLE classification criteria are as useful as believed today for SLE research. This skepticism is based on the fact that classification criteria are not selected based on cogent causal strategies. The SLE classification criteria do not harmonize with Koch's and Pasteur's causality principle paradigms and not with Witebsky's Koch-derived postulates for autoimmune and infectious diseases. It is not established whether the classification criteria can separate SLE as a "one disease entity" from "SLE-like non-SLE disorders"-the latter in terms of SLE imitations. This is discussed here in terms of weight, rank, and impact of the classification criteria: Do they all originate from "one basic causal etiology"? Probably not.

Significance of co-positivity for anti-dsDNA, -nucleosome, and -histone antibodies in patients with lupus nephritis

OBJECTIVE

The aim of this study was to define the clinical, histopathologic, and prognostic features associated with simultaneous positivity for anti-dsDNA, -nucleosome, and -histone antibodies (3-pos) in Korean patients with biopsy-proven lupus nephritis (LN).

METHODS

The 102 patients included in the study had undergone kidney biopsy prior to the start of induction treatment, were treated with immunosuppressives, and followed-up for >12 months.

RESULTS

In total, 44 (43.1%) of the 102 LN patients were 3-pos. Patients with 3-pos had a higher SLEDAI-2K score (p = .002), lower lymphocyte count (p = .004), and higher rates of proteinuria > 3.5 g/24 h (p = .039) and positivity for urinary sediments (p = .005) at the time of renal biopsy than non-3-pos patients. 3-pos patients had a more proliferative form of LN (p = .045) in the renal histopathologic findings, and as co-positivity gradually increased from 0 to 3, the total activity score in the renal biopsy findings increased significantly (p = .033). In addition, 3-pos patients had a more rapid eGFR decline than non-3-pos patients after a follow-up of 83.2 months (p = .016).

CONCLUSIONS

Our findings suggest that 3-pos is related to severe LN and that 3-pos patients are more likely to experience a rapid decline of renal function than non-3-pos patients.KEY MESSAGEPatients with co-positivity for anti-dsDNA, -nucleosome, and -histone antibodies (3-pos) had higher disease activity and a worse renal histopathology than those without co-positivity.3-pos patients had a more rapid decline of renal function than non-3-pos patients.

Recommendations for the use of anti-dsDNA autoantibodies in the diagnosis and follow-up of systemic lupus erythematosus - A proposal from an expert panel

Anti-dsDNA autoantibodies are listed as one of the classification criteria for systemic lupus erythematosus (SLE) and are relatively effective indicators for monitoring disease activity and treatment response. Therefore, clinicians rely on them to diagnose and adjust medication and treatment strategies for SLE patients. However, the use of anti-dsDNA antibodies is not free from controversy. Part of this controversy stems from the fact that anti-dsDNA antibodies are found in several disorders, besides SLE. In addition to this, anti-dsDNA antibodies are a heterogeneous group of antibodies, and their determination still lacks proper standardization. Moreover, anti-dsDNA testing specificity and diagnostic performance change depending on the population under study. These and other issues result in inconsistency and encumber the clinical use of anti-dsDNA antibodies. A panel of medical laboratory and clinical experts on SLE discussed such issues based on their clinical experience in a first meeting, establishing a series of recommendations. The proceedings of this first meeting, plus an exhaustive review of the literature, were used to compose a paper draft. The panel subsequently discussed and refined this draft in a second meeting, the result of which is this paper. This document is relevant to clinical laboratories as it guides to improving diagnosis and monitoring of SLE. Simultaneously, it will help laboratories compile more informative reports, not limited to a mere number. It is also relevant to clinical doctors who wish to better understand laboratory methods so that they can do a more efficient, better-aimed laboratory test ordering.

Assessment of anti-nucleosome antibody (ANuA) isotypes for the diagnosis and prediction of systemic lupus erythematosus and lupus nephritis activity

Our study aims to investigate the serum levels of anti-nucleosome antibody (ANuA) isotypes in patients with systemic lupus erythematosus (SLE) and clarify ANuA isotypes that may diagnose and predict SLE. We detected anti-nucleosome antibodies (ANuA) in the serum from 120 patients with SLE, 99 patients suffering from other autoimmune diseases (OAD), and 50 healthy controls by performing IgG-, IgA-, and IgM-specific ELISAs. The serum levels of total anti-nuclear antibodies (ANA IgG), ANuA IgG subclasses (IgG1, IgG2, IgG3, and IgG4), anti-dsDNA antibodies, and the avidities of ANA IgG were also analysed using ELISAs. The levels of three ANuA isotypes (IgG, IgA, and IgM) were significantly higher in patients with SLE than in patients with OAD and healthy controls (p < 0.05). Moreover, the concentrations of ANuA isotypes increased in the active SLE and lupus nephritis (LN) groups and in patients with SLE presenting high-avidity IgG ANA (p < 0.05). Furthermore, ANuA isotype levels decreased significantly with drug therapy, while anti-dsDNA IgG levels decreased with the same trend. Additionally, ANuA isotypes were positively related to the SLEDAI (SLE Disease Activity Index) score, RAI (relative avidity index) of high-avidity IgG ANAs, and serum anti-dsDNA IgG levels. Last, the sensitivity and specificity values for SLE were 83.33 and 96.67% for ANuA IgG, 85.83 and 93.33% for ANuA IgA, and83.33 and 86.67% for ANuA IgM, respectively. The sensitivity and specificity values for LN were 61.67 and 96.67% for ANuA IgG, 49.17 and 96.67% for ANuA IgA, and 52.50 and 96.67% for ANuA IgM, respectively. In conclusion, we evaluated whether ANuA isotypes represent a diagnostic tool to predict SLE activity and define subsets of patients with LN.

Nucleic acid-triggered tumoral immunity propagates pH-selective therapeutic antibodies through tumor-driven epitope spreading

Important roles of humoral tumor immunity are often pointed out; however, precise profiles of dominant antigens and developmental mechanisms remain elusive. We systematically investigated the humoral antigens of dominant intratumor immunoglobulin clones found in human cancers. We found that approximately half of the corresponding antigens were restricted to strongly and densely negatively charged polymers, resulting in simultaneous reactivities of the antibodies to both densely sulfated glycosaminoglycans (dsGAGs) and nucleic acids (NAs). These anti-dsGAG/NA antibodies matured and expanded via intratumoral immunological driving force of innate immunity via NAs. These human cancer-derived antibodies exhibited acidic pH-selective affinity across both antigens and showed specific reactivity to diverse spectrums of human tumor cells. The antibody-drug conjugate exerted therapeutic effects against multiple cancers in vivo by targeting cell surface dsGAG antigens. This study reveals that intratumoral immunological reactions propagate tumor-oriented immunoglobulin clones and demonstrates a new therapeutic modality for the universal treatment of human malignancies.

Evidence for charge-based mimicry in anti dsDNA antibody generation

Mechanisms for the generation of anti-dsDNA autoantibodies are still not completely elucidated. One theory states that dsDNA interacts for mimicry with antibodies raised versus other antigens but molecular features for mimicry are unknown. Here we show that, at physiological acid-base balance, anti-Annexin A1 binds IgG2 dsDNA in a competitive and dose-dependent way with Annexin A1 and that the competition between the two molecules is null at pH 9. On the other hand, these findings also show that dsDNA and Annexin A1 interact with their respective antibodies on a strictly pH-dependent basis: in both cases, the binding was minimal at pH 4 and maximal at pH9-10. The anionic charge of dsDNA is mainly conferred by the numerous phosphatidic residues. The epitope binding site of Annexin A1 for anti-Annexin A1 IgG2 was here characterized as a string of 34 amino acids at the NH2 terminus, 10 of which are anionic. Circulating levels of anti-dsDNA and anti-Annexin A1 IgG2 antibodies were strongly correlated in patients with systemic lupus erythematosus (n 496) and lupus nephritis (n 425) stratified for age, sex, etc. These results show that dsDNA competes with Annexin A1 for the binding with anti-Annexin A1 IgG2 on a dose and charged mediated base, being able to display an inhibition up to 75%. This study provides the first demonstration that dsDNA may interact with antibodies raised versus other anionic molecules (anti-Annexin A1 IgG2) because of charge mimicry and this interaction may contribute to anti-dsDNA antibodies generation.

The role of anticomplement therapy in lupus nephritis

The complement system plays crucial roles in homeostasis and host defense against microbes. Deficiency of early complement cascade components has been associated with increased susceptibility to systemic lupus erythematosus (SLE), whereas excessive complement consumption is a hallmark of this disease. Although enhanced classical pathway activation by immune complexes was initially thought to be the main contributor to lupus nephritis (LN) pathogenesis, an increasing body of evidence has suggested the alternative and the lectin pathways are also involved. Therapeutic agents targeting complement activation have been used in LN patients and clinical trials are ongoing. We review the mechanisms by which complement system dysregulation contributes to renal injury in SLE and summarize the latest evidence on the use of anticomplement agents to manage this condition.

Anti-double stranded DNA antibodies: A rational diagnostic approach in limited resource settings

Context

Anti-double-stranded deoxyribonucleic acid antibodies (dsDNA Abs) are highly specific markers of systemic lupus erythematosus (SLE). Multiple methods are employed for their detection in routine diagnostics.

Objectives

The aim of this study was to evaluate a diagnostic approach for anti-dsDNA Abs using DNA-ELISA and Crithidia luciliae fluorescence test (CLIFT), in combination with antinuclear antibody (ANA) screening.

Methods

We enrolled 113 patients—53 with SLE, 50 with other systemic autoimmune rheumatic diseases (OSARD), and 10 with non-autoimmune clinical conditions (NAICC).

Patients’ samples were tested for anti-dsDNA Abs using an enzyme-linked immunosorbent assay (ELISA) and CLIFT, combined to ANA screening by indirect immunofluorescence assay (ANA-IIFA).

Results

The mean age of patients was 39.94 ± 15 years (ranges: 11–85 years). Overall, specimens from 77.3%, 11.7%, and 20% of patients with SLE, OSARD and NAICC respectively were ELISA-positive; and those from 54.7% to 4% of patients with SLE and OSARD, respectively, were CLIFT-positive. CLIFT positivity was significantly associated with high ELISA titers (p = 0.002) and homogeneous ANA-IIF pattern (p = 0.0002).

Conclusion

For better clinical relevance of anti-dsDNA antibodies, we suggest a combined detection strategy based on ELISA, CLIFT and ANA-IIFA, considering the clinical criteria of SLE.

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Anti-dsDNA Abs represent an excellent indicator of systemic lupus erythematosus (SLE) activity and valuable diagnostic biomarker.

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We tested 103 autoimmune disease cases and 10 non-autoimmune condition cases for anti-dsDNA Abs using DNA and CLIFT, in combination with ANA-IIF screening.

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CLIFT positivity was significantly associated with high DNA-ELISA titers (p = 0.002) and homogeneous ANA-IIF pattern (p = 0.0002).

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High DNA-ELISA titers with a positive CLIFT are clinically relevant for the diagnosis of SLE, especially in the presence of a homogeneous ANA-IIF pattern.

Induction of broadly reactive influenza antibodies increases susceptibility to autoimmunity

Infection and vaccination repeatedly expose individuals to antigens that are conserved between influenza virus subtypes. Nevertheless, antibodies recognizing variable influenza epitopes greatly outnumber antibodies reactive against conserved epitopes. Elucidating factors contributing to the paucity of broadly reactive influenza antibodies remains a major obstacle for developing a universal influenza vaccine. Here, we report that inducing broadly reactive influenza antibodies increases autoreactive antibodies in humans and mice and exacerbates disease in four distinct models of autoimmune disease. Importantly, transferring broadly reactive influenza antibodies augments disease in the presence of inflammation or autoimmune susceptibility. Further, broadly reactive influenza antibodies spontaneously arise in mice with defects in B cell tolerance. Together, these data suggest that self-tolerance mechanisms limit the prevalence of broadly reactive influenza antibodies, which can exacerbate disease in the context of additional risk factors.

The Anti-DNA Antibodies: Their Specificities for Unique DNA Structures and Their Unresolved Clinical Impact-A System Criticism and a Hypothesis

Systemic lupus erythematosus (SLE) is diagnosed and classified by criteria, or by experience, intuition and traditions, and not by scientifically well-defined etiology(ies) or pathogenicity(ies). One central criterion and diagnostic factor is founded on theoretical and analytical approaches based on our imperfect definition of the term “The anti-dsDNA antibody”. “The anti-dsDNA antibody” holds an archaic position in SLE as a unique classification criterium and pathogenic factor. In a wider sense, antibodies to unique transcriptionally active or silent DNA structures and chromatin components may have individual and profound nephritogenic impact although not considered yet – not in theoretical nor in descriptive or experimental contexts. This hypothesis is contemplated here. In this analysis, our state-of-the-art conception of these antibodies is probed and found too deficient with respect to their origin, structural DNA specificities and clinical/pathogenic impact. Discoveries of DNA structures and functions started with Miescher’s Nuclein (1871), via Chargaff, Franklin, Watson and Crick, and continues today. The discoveries have left us with a DNA helix that presents distinct structures expressing unique operations of DNA. All structures are proven immunogenic! Unique autoimmune antibodies are described against e.g. ssDNA, elongated B DNA, bent B DNA, Z DNA, cruciform DNA, or individual components of chromatin. In light of the massive scientific interest in anti-DNA antibodies over decades, it is an unexpected observation that the spectrum of DNA structures has been known for decades without being implemented in clinical immunology. This leads consequently to a critical analysis of historical and contemporary evidence-based data and of ignored and one-dimensional contexts and hypotheses: i.e. “one antibody - one disease”. In this study radical viewpoints on the impact of DNA and chromatin immunity/autoimmunity are considered and discussed in context of the pathogenesis of lupus nephritis.

The role of organ-deposited IgG in the pathogenesis of multi-organ and tissue damage in systemic lupus erythematosus

Systemic lupus erythematosus (SLE), often known simply as lupus, is a severe chronic autoimmune disease that is characterized by multi-organ and tissue damage and high levels of autoantibodies in serum. We have recently investigated, using animal models, the role of organ-deposited IgG autoantibodies in the pathogenesis of organ and tissue damage in SLE. We found that intra-organ injection of serum from mice with lupus (i.e., lupus mice) into healthy mice triggered inflammation in tissue and organs but that serum from other healthy mice did not, and that the severity of inflammation was related to the dose of serum injected. Immunohistochemistry showed that a large number of IgG molecules are deposited at the site of organ and tissue damage in lupus mice, and that IgG is a major contributor to the development of tissue inflammation triggered by serum from lupus mice or patients. The development of tissue inflammation induced by IgG in serum from lupus mice requires the presence of monocytes/macrophages, but not of lymphocytes or neutrophils; tumor necrosis factor (TNF)/tumor necrosis factor receptor 1 (TNFR1) and interleukin 1 (IL-1) also play essential roles in the development of tissue inflammation triggered by IgG. In addition, it has been found that TNFR1 inhibitors can suppress skin injury in lupus mice and that spleen tyrosine kinase (Syk) inhibitors, which can block the signaling transduction of IgG/Fc gamma receptors (FcγRs), can prevent and treat skin injury and kidney damage in lupus mice. We have also observed that lupus IgG might protect against bone erosion. Based on these results, we conclude that IgG plays a crucial role in the development of organ and tissue damage in SLE and in protecting bone erosion and arthritis, and we suggest that the IgG/FcγR signaling pathway is an important therapeutic target in SLE.

The interaction of anti-DNA antibodies with DNA antigen: Evidence for hysteresis for high avidity binding

Antibodies to DNA (anti-DNA) are the serological hallmark of systemic lupus erythematosus. Previous studies have indicated that the phosphodiester backbone is the main antigenic target, with electrostatic interactions important for high avidity. To define further these interactions, the effects of ionic strength on anti-DNA binding of SLE plasmas were assessed in association and dissociation assays by ELISA. As these studies demonstrated, increasing ionic strength to a concentration of 1000 mM NaCl reduced antibody binding although the extent of the reduction varied among samples. In dissociation assays, differences among plasmas were also observed. For one of the plasmas, binding to DNA displayed resistance to dissociation by increasing ionic strength even though these concentrations limited binding in association assays. Time course studies showed a gradual change in binding interactions. These studies indicate that anti-DNA binding can involve both electrostatic and non-electrostatic interactions, with binding in some plasmas showing evidence of hysteresis.

Sex Bias and Autoimmune Diseases

Sex bias in immune function has been well-described, and women have been shown to counter immunologically stimulating phenomena such as infection, malignancy, and trauma with more protective responses than men. Heightened immunity in women may also result in a predisposition for loss of self-tolerance and development of autoimmunity, reflected by the overwhelming female sex bias of patients with autoimmune diseases. In this review, we discuss the postulated evolutionary etiologies for sexual dimorphism in immunity. We also review the molecular mechanisms underlying divergent immune responses in men and women, including sex hormone effects, X chromosome dosage, and autosomal sex-biased genes. With increasing evidence that autoimmune disease susceptibility is influenced by numerous hormonal and genetic factors, a comprehensive understanding of these topics may facilitate the development of much-needed targeted therapeutics.

Serum IgG2 antibody multi-composition in systemic lupus erythematosus and in lupus nephritis (Part 2): prospective study

OBJECTIVES

Circulating anti-ENO1 and anti-H2A IgG2 have been identified as specific signatures of LN in a cross-over approach. We sought to show whether the same antibodies identify selected population of patients with LN with potentially different clinical outcomes.

METHODS

Here we report the prospective analysis over 36 months of circulating IgG2 levels in patients with newly diagnosed LN (n=91) and SLE (n=31) and in other patients with SLE recruited within 2 years from diagnosis (n=99). Anti-podocyte (ENO1), anti-nucleosome (DNA, histone 2 A, histone 3) and anti-circulating proteins (C1q, AnnexinA1-ANXA1) IgG2 antibodies were determined by home-made techniques.

RESULTS

LN patients were the main focus of the study. Anti-ENO1, anti-H2A and anti-ANXA1 IgG2 decreased in parallel to proteinuria and normalized within 12 months in the majority of patients while anti-dsDNA IgG2 remained high over the 36 months. Anti-ENO1 and anti-H2A had the highest association with proteinuria (Heat Map) and identified the highest number of patients with high proteinuria (68% and 71% respectively) and/or with reduced estimated glomerula filtration rate (eGFR) (58% for both antibodies) compared with 23% and 17% of anti-dsDNA (agreement analysis). Anti-ENO1 positive LN patients had higher proteinuria than negative patients at T0 and presented the maximal decrement within 12 months.

CONCLUSIONS

Anti-ENO1, anti-H2A and anti-ANXA1 antibodies were associated with high proteinuria in LN patients and Anti-ENO1 also presented the maximal reduction within 12 months that paralleled the decrease of proteinuria. Anti-dsDNA were not associated with renal outcome parameters. New IgG2 antibody signatures should be utilized as tracers of personalized therapies in LN.

TRIAL REGISTRATION

The Zeus study was registered at https://clinicaltrials.gov (study number: NCT02403115).

The occurrence of lupus nephritis is regulated by USP7-mediated JMJD3 stabilization

Ubiquitin-specific peptidases7 (USP7) participates in the regulation of various metabolic and immune disorders. However, the role of USP7 in lupus nephritis (LN) remains unknown. The current study set out to elucidate the regulatory role of USP7 in LN together with JMJD3 and NF-κB. SLE MRL/LPR mice and mouse glomerular mesangial cells SV40 MES 13 cells were employed for in vivo or vitro experiments. USP7, JMJD3 and NF-κB expression in MRL/LPR mice were detected, followed by investigation of their functions in the proliferation of mesangial cells and mesangial matrix. Subsequently, the interaction among USP7, JMJD3 and NF-κB was determined by means of ChIP and co-immunoprecipitation assay. The results indicated that USP7, JMJD3, p-NF-κB p65 were all highly-expressed in MRL/LPR mice. USP7 promoted the proliferation of mesangial cells and mesangial matrix, and stabilized the JMJD3 protein via deubiquitination in SV40 MES 13 cells. Meanwhile, silencing of JMJD3 inhibited the promotive effect of USP7 on the proliferation of mesangial cells and mesangial matrix. Furthermore, JMJD3 increased the expression of NF-κB p65 through demethylation, whereas silencing JMJD3 alleviated the proliferation of mesangial cells and mesangial matrix. Lastly, NF-κB p65 was proved to aggravate LN pathogenesis. Altogether, our findings highlighted that USP7 promoted the occurrence of LN by regulating the NF-κB p65 signaling pathway via stabilization of JMJD3.

High frequency of concurrent anti-C1q and anti-dsDNA but not anti-C3b antibodies in patients with Lupus Nephritis

Lupus Nephritis (LN) in patients with Systemic Lupus Erythematosus (SLE) is one of the most serious and prevalent manifestations. The procedure of renal biopsy is harmful and accompanied by potential hazards. Therefore, introducing reliable biomarkers to predict LN is exceedingly worthwhile. In the present study, we compared the diagnostic values of circulating autoantibodies against dsDNA, C1q, C3b, SSA, SSB, and Sm alone or in combination to predict LN. This study evaluated the abovementioned autoantibodies in 40 healthy controls (HCs) and 95 SLE patients with different kidney involvements, including absent (n = 40), inactive (n = 20), and active (n = 35) LN using EIA method. The frequency and odds ratio of anti-dsDNA (71.4%, OR = 4.2), anti-C1q (62.9%, OR = 5.1), and the simultaneous existence of anti-C1q and anti-dsDNA (51.4%, OR = 6) antibodies were significantly higher in the active LN group compared with both inactive and absent LN groups. Moreover, the levels of anti-C1q and anti-dsDNA antibodies positively correlated with disease activity in patients with SLE. The prevalence of these autoantibodies was associated with the severity of LN biopsies. These data suggest that anti-C1q and anti-dsDNA antibodies and also their simultaneous presence may be valuable diagnostic biomarkers for LN prediction in patients with SLE.

Bioactive potential of natural biomaterials: identification, retention and assessment of biological properties

Biomaterials have had an increasingly important role in recent decades, in biomedical device design and the development of tissue engineering solutions for cell delivery, drug delivery, device integration, tissue replacement, and more. There is an increasing trend in tissue engineering to use natural substrates, such as macromolecules native to plants and animals to improve the biocompatibility and biodegradability of delivered materials. At the same time, these materials have favourable mechanical properties and often considered to be biologically inert. More importantly, these macromolecules possess innate functions and properties due to their unique chemical composition and structure, which increase their bioactivity and therapeutic potential in a wide range of applications. While much focus has been on integrating these materials into these devices via a spectrum of cross-linking mechanisms, little attention is drawn to residual bioactivity that is often hampered during isolation, purification, and production processes. Herein, we discuss methods of initial material characterisation to determine innate bioactivity, means of material processing including cross-linking, decellularisation, and purification techniques and finally, a biological assessment of retained bioactivity of a final product. This review aims to address considerations for biomaterials design from natural polymers, through the optimisation and preservation of bioactive components that maximise the inherent bioactive potency of the substrate to promote tissue regeneration.

Cellular aspects of the pathogenesis of lupus nephritis

PURPOSE OF REVIEW

Lupus nephritis is a common severe manifestation of systemic lupus erythematosus. Despite recent advances in therapeutics and understanding of its pathogenesis, there are still substantial unmet needs. This review discusses recent discoveries in these areas, especially the role of tubulointerstitial inflammation (TII) in lupus nephritis.

RECENT FINDINGS

Non-white ethnicity is still a major risk and poor prognostic factor in lupus nephritis. TII and fibrosis have been found to be associated with worse renal outcome but the current lupus nephritis treatment guidelines and trials are based on the degree of glomerular inflammation. In combination with mycophenolate mofetil, a B-cell-targeted therapy (belimumab) and a calcineurin inhibitor (voclosporin) have shown efficacy in recent lupus nephritis trials. However, response rates have been modest. While lupus glomerulonephritis results from immune complex deposition derived from systemic autoantibodies, TII arises from complex processes associated with in situ adaptive cell networks. These include local antibody production, and cognate or antigen-induced interactions between T follicular helper cells, and likely other T-cell populations, with antigen presenting cells including B cells, myeloid dendritic cells and plasmacytoid dendritic cells.

SUMMARY

Better understanding of the pathogenesis of TII will identify novel therapeutic targets predicted to improve outcomes in our patients with lupus nephritis.

Patients with Proliferative Lupus Nephritis Have Autoantibodies That React to Moesin and Demonstrate Increased Glomerular Moesin Expression

Kidney involvement in systemic lupus erythematosus (SLE)—termed lupus nephritis (LN)—is a severe manifestation of SLE that can lead to end-stage kidney disease (ESKD). LN is characterized by immune complex deposition and inflammation in the glomerulus. We tested the hypothesis that autoantibodies targeting podocyte and glomerular cell proteins contribute to the development of immune complex formation in LN. We used Western blotting with SLE sera from patients with and without LN to identify target antigens in human glomerular and cultured human-derived podocyte membrane proteins. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), we identified the proteins in the gel regions corresponding to reactive bands observed with sera from LN patients. We identified 102 proteins that were present in both the podocyte and glomerular samples. We identified 10 high-probability candidates, including moesin, using bioinformatic analysis. Confirmation of moesin as a target antigen was conducted using immunohistochemical analysis (IHC) of kidney biopsy tissue and enzyme-linked immunosorbent assay (ELISA) to detect circulating antibodies. By IHC, biopsies from patients with proliferative lupus nephritis (PLN, class III/IV) demonstrated significantly increased glomerular expression of moesin (p < 0.01). By ELISA, patients with proliferative LN demonstrated significantly increased antibodies against moesin (p < 0.01). This suggests that moesin is a target glomerular antigen in lupus nephritis.

Antibodies to an Epstein Barr Virus protein that cross-react with dsDNA have pathogenic potential

Pathogens such as the Epstein Barr virus (EBV) have long been implicated in the etiology of systemic lupus erythematosus (SLE). The Epstein Barr virus nuclear antigen I (EBNA-1) has been shown to play a role in the development of anti-nuclear antibodies characteristic of SLE. One mechanism by which EBV may play a role in SLE is molecular mimicry. We previously generated two monoclonal antibodies (mAbs) to EBNA-1 and demonstrated that they cross-react with double-stranded DNA (dsDNA). In the present study, we demonstrate that these mAbs have pathogenic potential. We show that they can bind to isolated rat glomeruli and that binding can be greatly diminished by pretreatment of glomeruli with DNase I, suggesting that these mAbs bind dsDNA in the kidney. We also demonstrate that these antibodies can deposit in the kidney when injected into mice and can induce proteinuria and elicit histopathological alterations consistent with glomerulonephritis. Finally, we show that these antibodies can cross-react with laminin and collagen IV in the extracellular matrix suggesting that direct binding to the glomerular basement membrane or mesangial matrix may also contribute to the antibody deposition in the kidney. In summary, our results indicate that EBNA-1 can elicit antibodies that cross-react with dsDNA, that can deposit in the kidney, and induce kidney damage. These results are significant because they support the role of a viral protein in SLE and lupus nephritis.

Autoimmunity and SLE: Factual and Semantic Evidence-Based Critical Analyses of Definitions, Etiology, and Pathogenesis

One cannot discuss anti-dsDNA antibodies and lupus nephritis without discussing the nature of Systemic lupus erythematosus (SLE). SLE is insistently described as a prototype autoimmune syndrome, with anti-dsDNA antibodies as a central biomarker and a pathogenic factor. The two entities, “SLE” and “The Anti-dsDNA Antibody,” have been linked in previous and contemporary studies although serious criticism to this mutual linkage have been raised: Anti-dsDNA antibodies were first described in bacterial infections and not in SLE; later in SLE, viral and parasitic infections and in malignancies. An increasing number of studies on classification criteria for SLE have been published in the aftermath of the canonical 1982 American College of Rheumatology SLE classification sets of criteria. Considering these studies, it is surprising to observe a nearby complete absence of fundamental critical/theoretical discussions aimed to explain how and why the classification criteria are linked in context of etiology, pathogenicity, or biology. This study is an attempt to prioritize critical comments on the contemporary definition and classification of SLE and of anti-dsDNA antibodies in context of lupus nephritis. Epidemiology, etiology, pathogenesis, and measures of therapy efficacy are implemented as problems in the present discussion. In order to understand whether or not disparate clinical SLE phenotypes are useful to determine its basic biological processes accounting for the syndrome is problematic. A central problem is discussed on whether the clinical role of anti-dsDNA antibodies from principal reasons can be accepted as a biomarker for SLE without clarifying what we define as an anti-dsDNA antibody, and in which biologic contexts the antibodies appear. In sum, this study is an attempt to bring to the forum critical comments on the contemporary definition and classification of SLE, lupus nephritis and anti-dsDNA antibodies. Four concise hypotheses are suggested for future science at the end of this analytical study.

Comparative efficacy and safety of mycophenolate mofetil and cyclophosphamide in the induction treatment of lupus nephritis: A systematic review and meta-analysis

BACKGROUND

Lupus nephritis (LN) remains a predominant cause of morbidity and mortality in SLE. Here we performed a meta-analysis to evaluate the efficacy and safety of the induction treatment with mycophenolate mofetil (MMF) and cyclophosphamide (CYC) for LN.

METHODS

Relevant literature was searched by computer from the establishment of the database to November 2019. A meta-analysis was conducted to analysis the efficacy and safety between mycophenolate mofetil and cyclophosphamide as induction therapy in LN patients. The primary end-point was response to urine protein, serum creatinine (Scr) and serum complement C3, and the secondary end-points were complete remission and adverse reactions.

RESULTS

Eighteen articles were selected for the final meta-analysis, involving 1989 patients with LN, of which the renal biopsy result could be classified into class III-V according to the standards of WHO/ISN. The results revealed that MMF was superior to CYC in increasing the level of serum complement C3 [SMD = 0.475, 95%CI (0.230-0.719)] and complete remission [RR = 1.231, 95%CI (1.055-1.437)]. Furthermore, the subgroup analysis showed that it was in Asian patients, rather than in Caucasian patients, that CYC exerted a better effect on lowering the level of urine protein (UPRO) than MMF [SMD = 0.405, 95%CI (0.081-0.730)]. Besides, when the initial UPRO level was less than 4 g/day, the effect of CYC was better than MMF [SMD = 0.303, 95%CI (0.014-0.591)]. There was no significant difference between MMF and CYC in improving Scr [SMD = 0.090, 95%CI (-0.060-0.239)]. When it came to the comparison of safety between MMF and CYC, the meta-analysis showed that MMF was superior to CYC in decreasing infection in Caucasian patients [RR = 0.727, 95%CI (0.532-0.993)], reducing the risk of leukopenia and menstrual abnormalities in Asian patients and lowering the frequency of gastrointestinal symptoms [RR = 0.639, 95%CI (0.564-0.724)], independent of race.

CONCLUSIONS

MMF precedes CYC in improving serum complement C3 and complete remission regardless of race, as well as shows fewer adverse drug reactions in the induction treatment of LN belonging to type III-V. But for Asian patients or those initial UPRO levels are less than 4 g/day, CYC may be superior to MMF.

Autoantibody-dependent amplification of inflammation in SLE

Anti-double stranded DNA antibodies (anti-dsDNA) are a hallmark of SLE but their role in disease pathogenesis is not fully resolved. Anti-dsDNA in serum are highly heterogeneous therefore in this study, we aimed to dissect the functional specificities of anti-dsDNA using a panel of human monoclonal antibodies (humAbs) generated from patients with active lupus nephritis. A total of 46 ANA reactive humAbs were isolated and divided into four broad classes based on their reactivity to histones, DNA and Crithidia. Functional analysis indicated that one subclass of antibodies bound strongly to decondensed DNA areas in neutrophil extracellular traps (NETs) and protected NETs from nuclease digestion, similar to the sera from active SLE patients. In addition, these anti-dsDNA antibodies could stimulate type I interferon responses in mononuclear phagocytic cells, or NF-kB activity in endothelial cells, by uptake of NETs-anti-NETs immune complexes and subsequently trigging inflammatory responses in an Fc-gamma receptor (Fcg-R)-dependant manner. Together our data suggest that only a subset of anti-dsDNA antibodies is capable to amplify inflammatory responses by deposit in the nephritic kidney in vivo, protecting NETs digestion as well as uptake of NETs immune complexes into Fcg-R-expressing cells in vitro.

Harnessing SLE Autoantibodies for Intracellular Delivery of Biologic Therapeutics

Intracellular delivery of therapeutic antibodies is highly desirable but remains a challenge for biomedical research and the pharmaceutical industry. Approximately two-thirds of disease-associated targets are found inside the cell. Difficulty blocking these targets with available drugs creates a need for technology to deliver highly specific therapeutic antibodies intracellularly. Historically, antibodies have not been believed to traverse the cell membrane and neutralize intracellular targets. Emerging evidence has revealed that anti-DNA autoantibodies found in systemic lupus erythematosus (SLE) patients can penetrate inside the cell. Harnessing this technology has the potential to accelerate the development of drugs against intracellular targets. Here, we dissect the mechanisms of the intracellular localization of SLE antibodies and discuss how to apply these insights to engineer successful cell-penetrating antibody drugs.

Consequences of Vitamin A Deficiency: Immunoglobulin Dysregulation, Squamous Cell Metaplasia, Infectious Disease, and Death

Vitamin A is an important regulator of immune protection, but it is often overlooked in studies of infectious disease. Vitamin A binds an array of nuclear receptors (e.g., retinoic acid receptor, peroxisome proliferator-activated receptor, retinoid X receptor) and influences the barrier and immune cells responsible for pathogen control. Children and adults in developed and developing countries are often vitamin A-deficient or insufficient, characteristics associated with poor health outcomes. To gain a better understanding of the protective mechanisms influenced by vitamin A, we examined immune factors and epithelial barriers in vitamin A deficient (VAD) mice, vitamin D deficient (VDD) mice, double deficient (VAD+VDD) mice, and mice on a vitamin-replete diet (controls). Some mice received insults, including intraperitoneal injections with complete and incomplete Freund’s adjuvant (emulsified with PBS alone or with DNA + Fus-1 peptide) or intranasal inoculations with Sendai virus (SeV). Both before and after insults, the VAD and VAD+VDD mice exhibited abnormal serum immunoglobulin isotypes (e.g., elevated IgG2b levels, particularly in males) and cytokine/chemokine patterns (e.g., elevated eotaxin). Even without insult, when the VAD and VAD+VDD mice reached 3–6 months of age, they frequently exhibited opportunistic ascending bacterial urinary tract infections. There were high frequencies of nephropathy (squamous cell hyperplasia of the renal urothelium, renal scarring, and ascending pyelonephritis) and death in the VAD and VAD+VDD mice. When younger VAD mice were infected with SeV, the predominant lesion was squamous cell metaplasia of respiratory epithelium in lungs and bronchioles. Results highlight a critical role for vitamin A in the maintenance of healthy immune responses, epithelial cell integrity, and pathogen control.

Human cytomegalovirus pp65 peptide-induced autoantibodies cross-reacts with TAF9 protein and induces lupus-like autoimmunity in BALB/c mice

Human cytomegalovirus (HCMV) has been linked to the triggering of systemic lupus erythematosus (SLE). We proposed that B cell epitope region of HCMV phosphoprotein 65 (HCMVpp65)_422-439 mimics an endogenous antigen and initiates lupus-like autoimmunity. Amino acid homology between HCMVpp65_422-439 and TAF9_134-144 (TATA-box binding protein associated factor 9, TAF9) was investigated using a similarity search in NCBI protein BLAST program (BLASTP). A murine model was used to confirm their antigenicity and ability to induce lupus-like symptoms. HCMVpp65_422-439 induced immune responses with the presence of specific antibodies against HCMVpp65_422-439 and TAF9_134-144, as well as anti-nuclear and anti-double-stranded (ds)DNA antibodies that are characteristic of SLE. In addition, the majority of HCMVpp65_422-439 and TAF9_134-144 immunized mice developed proteinuria, and their renal pathology revealed glomerulonephritis with typical abnormalities, such as mesangial hypercellularity and immune complex deposition. Immunoglobulin eluted from the glomeruli of HCMVpp65_422-439 immunized mice showed cross-reactivity with TAF9_134-144 and dsDNA. Increased anti-TAF9 antibody activity was also observed in the sera from SLE patients compared with healthy people and disease controls. Molecular mimicry between HCMVpp65 peptide and host protein has the potential to drive lupus-like autoimmunity. This proof-of-concept study highlights the mechanisms underlying the link between HCMV infection and the induction of SLE.

Sustained B cell depletion by CD19-targeted CAR T cells is a highly effective treatment for murine lupus

The failure of anti-CD20 antibody (Rituximab) as therapy for lupus may be attributed to the transient and incomplete B cell depletion achieved in clinical trials. Here, using an alternative approach, we report that complete and sustained CD19⁺ B cell depletion is a highly effective therapy in lupus models. CD8⁺ T cells expressing CD19-targeted chimeric antigen receptors (CARs) persistently depleted CD19⁺ B cells, eliminated autoantibody production, reversed disease manifestations in target organs, and extended life spans well beyond normal in the (NZB × NZW) F₁ and MRL ^fas/fas mouse models of lupus. CAR T cells were active for 1 year in vivo and were enriched in the CD44⁺CD62L⁺ T cell subset. Adoptively transferred splenic T cells from CAR T cell-treated mice depleted CD19⁺ B cells and reduced disease in naive autoimmune mice, indicating that disease control was cell-mediated. Sustained B cell depletion with CD19-targeted CAR T cell immunotherapy is a stable and effective strategy to treat murine lupus, and its effectiveness should be explored in clinical trials for lupus.

Wire-loop lesion is associated with serological immune abnormality, but not renal prognosis, in lupus nephritis

BACKGROUND

Wire-loop lesion (WL) is one of the active lesions of lupus nephritis (LN). However, few reports have focused on the clinicopathological relationships of WL to serological immune abnormality and renal prognosis.

METHODS

We enrolled 126 Japanese LN patients subjected to renal biopsy in 11 hospitals from 2000 to 2018. In patients with class III or IV of the International Society of Nephrology/Renal Pathology Society classification, we retrospectively compared clinicopathological findings between those with WL (WL+ group) and without WL (WL- group) to detect factors associated with WL. Chronic kidney disease (CKD) was defined as an estimated glomerular filtration rate of <60 mL/min/1.73m² for more than three months. We also compared these findings between those with CKD (CKD+ group) and without CKD (CKD- group) at the last visit to investigate factors associated with renal prognosis.

RESULTS

Of 126 patients, 100 (79.4%) were classified as class III or IV. WL was found in 36 (36.0%) of them. Although the renal function did not differ, the WL+ group had a higher titre of serum anti-dsDNA antibodies and lower serum complement 3 levels than the WL- group. Linear regression analysis revealed a significant association only between anti-dsDNA antibodies and WL (β = 0.27, 95% confidence interval (CI) 0.001-0.100, p = 0.01). Of these patients, 69 were tracked for 59.6 ± 55.1 months. Kaplan-Meier analysis showed no difference in renal prognosis between these groups. Next, the CKD+ group included 15 (22.1%) patients. They were older and had higher frequencies of hypertension and hyperuricaemia, serum creatinine (Cr) level, glomerulosclerosis, interstitial inflammation, interstitial fibrosis and tubular atrophy than the CKD- group at the time of renal biopsy. The frequency of WL was not significantly different. Cox regression analysis revealed significant associations of CKD with hypertension, hyperuricaemia, serum Cr level at the time of renal biopsy clinically and with tubular atrophy histologically.

CONCLUSIONS

WL was associated with serum anti-dsDNA antibodies but not with renal prognosis, suggesting that WL reflects immune abnormality but is not an independent factor predictive of renal prognosis in LN.

Clinicopathological factors for tubulointerstitial injury in lupus nephritis

OBJECTIVE

To investigate the incidence of tubulointerstitial injury in lupus nephritis (LN) and to examine clinicopathological factors that could indicate the presence of tubulointerstitial injury.

METHODS

This study included 98 patients with LN. Clinical data and the pathological results of the initial renal biopsy were collected.

RESULTS

The frequency of each tubulointerstitial injury parameter was over 50%, except for the interstitial edema, in the 98 patients investigated in this study. The most frequently detected tubulointerstitial injury parameter was tubular atrophy in this study. Neutrophil infiltration/karyorrhexis, wire loop lesion, and arteriosclerosis were observed frequently in patients with tubulointerstitial injuries. High serum creatinine and blood urea nitrogen (BUN) were observed more frequently in patients with tubulointerstitial injuries except tubular degeneration. The multivariable regression analysis showed a relationship between neutrophil infiltration/karyorrhexis and interstitial fibrosis/tubular degeneration, a relationship between wire loop lesion and tubulointerstitial inflammation/edema, and a relationship between arteriosclerosis and tubulointerstitial injuries (except interstitial edema). Patients with tubular degeneration had lower D-Dimer levels compared with those without. Patients with interstitial fibrosis had higher blood leukocyte counts than those without. The rate of low response to therapy was 13% among those without tubulointerstitial inflammation, but 35% in those with interstitial inflammation (P = 0.03).

CONCLUSION

Acute and chronic renal tubulointerstitial lesions are often found along with glomerular and vascular lesions. Immune and vascular factors are probably involved in tubulointerstitial injuries. Tubulointerstitial inflammation may be the initiator of chronic renal injury and may predict response to therapy.Key Points•To provide a theoretical basis for tubulointerstitial injury in LN.

ALW peptide ameliorates lupus nephritis in MRL/lpr mice

Background

Lupus nephritis (LN) is a common and serious complication of systemic lupus erythematosus. Anti-double-stranded (ds) DNA immunoglobulin G (IgG) plays a pivotal role in the pathogenesis of LN. Currently, there are various therapies for patients with LN; however, most of them are associated with considerable side effects. We confirmed previously that ALW (ALWPPNLHAWVP), a 12-amino acid peptide, inhibited the binding of polyclonal anti-dsDNA antibodies to mesangial cells and isolated glomeruli in vitro. In this study, we further investigate whether the administration of ALW peptide decreases renal IgG deposition and relevant damage in MRL/lpr lupus-prone mice.

Methods

Forty female MRL/lpr mice were randomly divided into four groups. The mice were intravenously injected with D-form ALW peptide (ALW group), scrambled peptide (PLP group), and normal saline (NaCl group) or were not treated (blank group). The IgG deposition, the histopathologic changes, and the expressions of profibrotic factors were analyzed in the kidney of MRL/lpr mice.

Results

Compared with the other groups, glomerular deposition of IgG, IgG2a, IgG2b, and IgG3 was decreased in the ALW group. Moreover, ALW administration attenuated renal histopathologic changes in MRL/lpr mice, including mesangial proliferation and infiltration of inflammatory cells. Furthermore, the expressions of profibrotic cytokines, such as transforming growth factor-beta1 (TGF-β1) and platelet-derived growth factor B (PDGF-B), decreased in the serum and kidney tissue of ALW-treated mice.

Conclusions

Our study demonstrated that ALW peptide ameliorates the murine model of LN, possibly through inhibiting renal IgG deposition and relevant tissue inflammation and fibrosis.

An Update on Antibodies to Necleosome Components as Biomarkers of Sistemic Lupus Erythematosus and of Lupus Flares

Systemic lupus erythematosus (SLE) is an autoimmune disease with variable clinical expression. It is a potentially devastating condition affecting mostly women and leading to clinically unpredictable outcomes. Remission and flares may, in fact, alternate over time and a mild involvement limited to few articular sites may be followed by severe and widespread organ damage. SLE is the prototype of any autoimmune condition and has, for this reason, attracted the interest of basic immunologists. Therapies have evolved over time and clinical prognosis has, in parallel, been improved. What clinicians still lack is the possibility to use biomarkers of the disease as predictors of outcome and, in this area, several studies are trying to find solutions. Circulating autoantibodies are clearly a milestone of clinical research and the concrete possibility is to integrate, in the future, classical markers of activation (like C3) with target organ autoantibodies. Anti-dsDNA antibodies represent a basic point in any predictive attempt in SLE and should be considered the benchmark for any innovative proposal in the wide field of target organ pathologies related to SLE. DNA is part of the nucleosome that is the basic unit of chromatin. It consists of DNA wrapped around a histone octamer made of 2 copies each of Histone 2A, 2B, 3, and 4. The nucleosome has a plastic organization that varies over time and has the potential to stimulate the formation of antibodies directed to the whole structure (anti-nucleosome) or its parts (anti-dsDNA and anti-Histones). Here, we present an updated review of the literature on antibodies directed to the nucleosome and the nucleosome constituents, i.e., DNA and Histones. Wetriedto merge the data first published more than twenty years ago with more recent results to create a balanced bridge between old dogma and more recent research that could serve as a stimulus to reconsider mechanisms for SLE. The formation of large networks would provide the chance of studying large cohorts of patients and confirm what already presented in small sample size during the last years.

Utilization of Biomarkers in Lupus Nephritis

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

Podocyte Injury in Lupus Nephritis

Systemic lupus erythematosus (SLE) is characterized by a broad spectrum of renal lesions. In lupus glomerulonephritis, histological classifications are based on immune-complex (IC) deposits and hypercellularity lesions (mesangial and/or endocapillary) in the glomeruli. However, there is compelling evidence to suggest that glomerular epithelial cells, and podocytes in particular, are also involved in glomerular injury in patients with SLE. Podocytes now appear to be not only subject to collateral damage due to glomerular capillary lesions secondary to IC and inflammatory processes, but they are also a potential direct target in lupus nephritis. Improvements in our understanding of podocyte injury could improve the classification of lupus glomerulonephritis. Indeed, podocyte injury may be prominent in two major presentations: lupus podocytopathy and glomerular crescent formation, in which glomerular parietal epithelial cells play also a key role. We review here the contribution of podocyte impairment to different presentations of lupus nephritis, focusing on the podocyte signaling pathways involved in these lesions.

Anti-double Stranded DNA Antibodies: Origin, Pathogenicity, and Targeted Therapies

Systemic lupus erythematosus (SLE) is characterized by high-titer serological autoantibodies, including antibodies that bind to double-stranded DNA (dsDNA). The origin, specificity, and pathogenicity of anti-dsDNA antibodies have been studied from a wider perspective. These autoantibodies have been suggested to contribute to multiple end-organ injuries, especially to lupus nephritis, in patients with SLE. Moreover, serum levels of anti-DNA antibodies fluctuate with disease activity in patients with SLE. By directly binding to self-antigens or indirectly forming immune complexes, anti-dsDNA antibodies can accumulate in the glomerular and tubular basement membrane. These autoantibodies can also trigger the complement cascade, penetrate into living cells, modulate gene expression, and even induce profibrotic phenotypes of renal cells. In addition, the expression of suppressor of cytokine signaling 1 is reduced by anti-DNA antibodies simultaneously with upregulation of profibrotic genes. Anti-dsDNA antibodies may even participate in the pathogenesis of SLE by catalyzing hydrolysis of certain DNA molecules or peptides in cells. Recently, anti-dsDNA antibodies have been explored in greater depth as a therapeutic target in the management of SLE. A substantial amount of data indicates that blockade of pathogenic anti-dsDNA antibodies can prevent or even reverse organ damage in murine models of SLE. This review focuses on the recent research advances regarding the origin, specificity, classification, and pathogenicity of anti-dsDNA antibodies and highlights the emerging therapies associated with them.

[Lupus nephritis]

Systemic lupus erythematosus is the most characteristic of auto-immune disorders that can lead to tissue damage in many organs, including kidney. Lupus nephritis occurs in 10 to 40% of lupus patients. Its clinical hallmark is the appearance of a proteinuria as soon as a 0.5 g/g or 0.5 g/d threshold, which calls for a renal histological evaluation in order to determine the lupus nephritis severity and the need for specific therapy. More than half of renal biopsies lead to the diagnosis of active lupus nephritis-class III or class IV A according to the ISN/RPS classification-that are the most severe in regards to renal prognosis and mortality. Their treatment aims to their clinical remission and to the prevention of relapse with minimal adverse effects for eventually the preservation of renal function, the prevention of other irreversible damage, and the reduction of risk of death. The remission is obtained through induction therapies of which the association of high dose steroids and cyclophosphamide is the most experienced. When this association must be challenged by the prevention of side-effect, in particular infertility, mycophenolate can be given instead of cyclophosphamide. Maintenance therapy, for the prevention of relapse, consists in mycophenolate or in azathioprine, mycophenolate being the most efficient however associated with a high risk of teratogenicity. Withdrawal of maintenance therapy is possible after two to three years in absence of high risk factors of relapse of lupus nephritis, however a reliable assessment of the risk of relapse is still lacking. Only pure membranous lupus nephritis (pure class V) associated with high level proteinuria requires specific therapies that usually associates steroids and an immunosuppressive drug. However, their choice hierarchy and even the use of less immunosuppressive strategies remain to be determined in terms of benefice over risk ratios. In spite of its trigger effect on lupus activity, pregnancy can be safe and successful if scheduled in the lowest risk periods with close multidisciplinary monitoring before, during and after. When necessary, renal replacement therapy does not require specific adaptation, renal transplantation is the best option when possible, as early as possible.

The dsDNA, Anti-dsDNA Antibody, and Lupus Nephritis: What We Agree on, What Must Be Done, and What the Best Strategy Forward Could Be

This study aims to understand what lupus nephritis is, its origin, clinical context, and its pathogenesis. Truly, we encounter many conceptual and immanent tribulations in our attempts to search for the pathogenesis of this disease—and how to explain its assumed link to SLE. Central in the present landscape stay a short history of the early studies that substantiated the structures of isolated or chromatin-assembled mammalian dsDNA, and its assumed, highly controversial role in induction of anti-dsDNA antibodies. Arguments discussed here may provoke the view that anti-dsDNA antibodies are not what we think they are, as they may be antibodies operational in quite different biological contexts, although they bind dsDNA by chance. This may not mean that these antibodies are not pathogenic but they do not inform how they are so. This theoretical study centers the content around the origin and impact of extra-cellular DNA, and if dsDNA has an effect on the adaptive immune system. The pathogenic potential of chromatin-anti-dsDNA antibody interactions is limited to incite lupus nephritis and dermatitis which may be linked in a common pathogenic process. These are major criteria in SLE classification systems but are not shared with other defined manifestations in SLE, which may mean that they are their own disease entities, and not integrated in SLE. Today, the models thought to explain lupus nephritis are divergent and inconsistent. We miss a comprehensive perspective to try the different models against each other. To do this, we need to take all elements of the syndrome SLE into account. This can only be achieved by concentrating on the interactions between autoimmunity, immunopathology, deviant cell death and necrotic chromatin in context of elements of system science. System science provides a framework where data generated by experts can be compared, and tested against each other. This approach open for consensus on central elements making up “lupus nephritis” to separate what we agree on and how to understand the basis for conflicting models. This has not been done yet in a systematic context.

RNAi Silencing of HIF-1α Ameliorates Lupus Development in MRL/lpr Mice

Th17 cell and IL-17-mediated autoimmunity and inflammatory responses have been implicated in the development of organ damage in systemic lupus erythematosus (SLE), and new evidence suggests that hypoxia-inducible factor 1α (HIF-1α) enhances Th17 differentiation and promotes IL-17 production. However, the role of HIF-1α in the pathogenesis of lupus has not been examined. In this study, we silenced HIF-1α in vivo in a murine model of SLE to investigate whether lupus progression and the associated inflammatory pathways were affected by downregulating HIF-1α. Treatment with HIF1α-shRNA suppressed serum IL-17 level in MRL/lpr mice. Decreased anti-nucleosome antibody level, reduced urinary protein concentrations, ameliorated pathological damage, and remarkably reduced renal IgG and C3 depositions were observed in HIF1α-shRNA-treated group compared to those in the controls. Our results provide the first evidence for a role of HIF-1α in the pathogenesis of lupus and suggest a potential new therapeutic avenue for the treatment of lupus patients through reducing the HIF-1α level.

Fn14 Deficiency Ameliorates Anti-dsDNA IgG-Induced Glomerular Damage in SCID Mice

Many studies have demonstrated that anti-dsDNA IgG is closely associated with lupus nephritis. Recently, it was found that activation of the fibroblast growth factor-inducible 14 (Fn14) signaling pathway damages glomerular filtration barrier in MRL/lpr lupus-prone mice. However, MRL/lpr mice have high titers of serum autoantibodies other than anti-dsDNA IgG. The aim of this study was to further explore the effect of Fn14 deficiency on anti-dsDNA IgG-induced glomerular damage in severe combined immunodeficiency (SCID) mice that have no endogenous IgG. Fn14 deficiency was generated in SCID mice. The murine hybridoma cells producing control IgG or anti-dsDNA IgG were intraperitoneally injected into mice. In two weeks, the urine, serum, and kidney tissue samples were harvested from mice at sacrifice. It showed that the injection of anti-dsDNA IgG, but not control IgG hybridoma cells, induced proteinuria and glomerular damage in SCID mice. Between the wild-type (WT) and knockout (KO) mice injected with anti-dsDNA IgG hybridoma cells, the latter showed a decrease in both proteinuria and glomerular IgG deposition. The histopathological changes, inflammatory cell infiltration, and proinflammatory cytokine production were also attenuated in the kidneys of the Fn14-KO mice upon anti-dsDNA IgG injection. Therefore, Fn14 deficiency effectively protects SCID mice from anti-dsDNA IgG-induced glomerular damage.

Precision medicine in lupus nephritis: can biomarkers get us there?

Patients with systemic lupus erythematosus frequently develop lupus nephritis (LN), a condition that can lead to end-stage kidney disease. Multiple serum and urine biomarkers for LN have been proposed in recent years, yet none have become incorporated into clinical use. The majority of studies have been single center with significant variability in cohorts, assays, and sample storage, leading to inconclusive results. It has become clear that no single biomarker is likely to be sufficient to diagnose LN, identify flares, and define the response to therapy and prognosis. A more likely scenario is a panel of urine, serum, tissue, and genetic biomarkers. In this review, we summarize traditional and novel biomarkers and discuss how they may be utilized in order to bring precision medicine to clinical practice in LN.

Intrarenal activation of adaptive immune effectors is associated with tubular damage and impaired renal function in lupus nephritis

Objectives

Chronic renal impairment remains a feared complication of lupus nephritis (LN). The present work aimed at identifying mechanisms and markers of disease severity in renal tissue samples from patients with LN.

Methods

We performed high-throughput transcriptomic studies (Illumina HumanHT-12 v4 Expression BeadChip) on archived kidney biopsies from 32 patients with LN and eight controls (pretransplant donors). Histological staging (glomerular and tubular scores) and immunohistochemistry experiments were performed on the same and on a replication set of 37 LN kidney biopsy samples.

Results

A group of LN samples was identified by unsupervised clustering studies based on their gene expression features, that is, the overexpression of transcripts involved in antigen presentation, T and B cell activation. These samples were characterised by a significantly lower estimated glomerular filtration rate (eGFR) at the time of biopsy (T0) compared with the other systemic lupus erythematosus samples. Yet, apparent disease duration at T0, double-stranded DNA antibody titres at T0 and other relevant characteristics (serum C3, proteinuria, histological scores, numbers of previous flares) were not different between groups.

Immunohistochemistry studies confirmed the association between interstitial infiltration by adaptive immune effectors and decreased renal function in the same and in a replication group of LN kidney biopsies. This was associated with transcriptomic, histological and immunohistochemical evidence of renal tubular cell involvement.

Conclusion

Interstitial infiltration of LN kidney biopsies by adaptive immune effectors is associated with impaired renal tubular cell function and decreased eGFR. These results open new perspectives in evaluating and treating patients with LN, focusing on intrarenal mechanisms of immune cell activation.

Urinary levels of sirtuin-1 associated with disease activity in lupus nephritis

Identifying new markers of disease flares in lupus nephritis (LN) that facilitate patient stratification and prognosis is important. Therefore, the aim of the present study was to analyze whether urinary SIRT1 expression was altered in LN and whether SIRT1 values in urine could be valuable biomarker of disease activity. In a cohort study, urinary pellets from 40 patients diagnosed with systemic lupus erythematosus (SLE) were analyzed. Clinical measures of lupus activity were assessed. The expression of SIRT1 was quantified by quantitative PCR (qRT-PCR) and immunoblot, then compared between patients with active lupus nephritis, in remission and healthy controls. Association with lupus activity and renal histological features was also analyzed. A significant increase in SIRT1 mRNA levels in patients with active LN was observed compared with those in remission (P=0.02) or healthy controls (P=0.009). In addition, SIRT-1 protein levels were also augmented in LN group than remission (P=0.029) and controls (P=0.001). A strong association was found between SIRT1 expression with anti-dsDNA in SLE and in patients with LN. In addition, histological features in LN biopsies were related with SIRT1, increasing its expression in proliferative forms. Finally, SIRT1 expression values showed a strong discriminatory power of renal injury in SLE. Our study demonstrated an altered urinary expression of SIRT1 and a strong association with disease activity in LN patients, being a valuable marker of renal injury. These results showed the role of the SIRT1 pathway in the SLE pathogenesis.

Systemic Lupus Erythematosus: Definitions, Contexts, Conflicts, Enigmas

Systemic lupus erythematosus (SLE) is an inadequately defined syndrome. Etiology and pathogenesis remain largely unknown. SLE is on the other hand a seminal syndrome that has challenged immunologists, biologists, genetics, and clinicians to solve its nature. The syndrome is characterized by multiple, etiologically unlinked manifestations. Unexpectedly, they seem to occur in different stochastically linked clusters, although single gene defects may promote a smaller spectrum of symptoms/criteria typical for SLE. There is no known inner coherence of parameters (criteria) making up the disease. These parameters are, nevertheless, implemented in The American College of Rheumatology (ACR) and The Systemic Lupus Collaborating Clinics (SLICC) criteria to classify SLE. Still, SLE is an abstraction since the ACR or SLICC criteria allow us to define hundreds of different clinical SLE phenotypes. This is a major point of the present discussion and uses "The anti-dsDNA antibody" as an example related to the problematic search for biomarkers for SLE. The following discussion will show how problematic this is: the disease is defined through non-coherent classification criteria, its complexity is recognized and accepted, its pathogenesis is plural and poorly understood. Therapy is focused on dominant symptoms or organ manifestations, and not on the syndrome itself. From basic scientific evidences, we can add substantial amount of data that are not sufficiently considered in clinical medicine, which may change the paradigms linked to what "The Anti-DNA antibody" is-and is not-in context of the imperfectly defined syndrome SLE.

Plasma Cell Depletion Attenuates Hypertension in an Experimental Model of Autoimmune Disease

Numerous studies show a direct relation between circulating autoantibodies, characteristic of systemic autoimmune disorders, and primary hypertension in humans. Whether these autoantibodies mechanistically contribute to the development of hypertension remains unclear. Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder characterized by aberrant immunoglobulin production, notably pathogenic autoantibodies, and is associated with prevalent hypertension, renal injury, and cardiovascular disease. Because plasma cells produce the majority of serum immunoglobulins and are the primary source of autoantibodies in SLE, we hypothesized that plasma cell depletion using the proteasome inhibitor bortezomib would lower autoantibody production and attenuate hypertension. Thirty-week-old female SLE (NZBWF1) and control (NZW [New Zealand White]) mice were injected IV with vehicle (0.9% saline) or bortezomib (0.75 mg/kg) twice weekly for 4 weeks. Bortezomib treatment significantly lowered the percentage of bone marrow plasma cells in SLE mice. Total plasma IgG and anti-dsDNA IgG levels were higher in SLE mice compared with control mice but were lowered by bortezomib treatment. Mean arterial pressure (mm Hg) measured in conscious mice by carotid artery catheter was higher in SLE mice than in control mice, but mean arterial pressure was significantly lower in bortezomib-treated SLE mice. Bortezomib also attenuated renal injury, as assessed by albuminuria and glomerulosclerosis, and reduced glomerular immunoglobulin deposition and B and T lymphocytes infiltration into the kidneys. Taken together, these data show that the production of autoantibodies by plasma cells mechanistically contributes to autoimmune-associated hypertension and suggests a potential role for patients with primary hypertension who have increased circulating immunoglobulins.

Transcriptomic profiling in human mesangial cells using patient-derived lupus autoantibodies identified miR-10a as a potential regulator of IL8

Autoantibody-mediated inflammation directed at resident kidney cells mediates lupus nephritis (LN) pathogenesis. This study investigated the role of miRNA in human mesangial cells (HMCs) stimulated with auto anti-dsDNA immunoglobulin (Ig)G antibodies. HMCs were treated with antibodies purified from active LN patients or non-specific IgG controls in the presence of normal serum. Aberrant miRNA was screened using high throughput sequencing. Anti-dsDNA IgG up-regulated 103 miRNAs and down-regulated 30 miRNAs. The miRNAs regulated genes in the cell cycle, catabolic processes, regulation of transcription and apoptosis signalling. miR-10a was highly abundant in HMCs but was specifically downregulated upon anti-dsDNA IgG induction. Interestingly, the expression of miR-10a in kidney biopsies from class III and IV LN patients (n = 26) was downregulated compared with cadaveric donor kidneys (n = 6). Functional studies highlighted the downstream regulator of miR-10a in the chemokine signalling and cell proliferation or apoptosis pathways. Luciferase assay confirmed for the first time that IL8 was a direct target of miR-10a in HMCs. In conclusion, anti-dsDNA IgG Ab down-regulated miR-10a expression in HMCs resulting in the induction of various target genes involved in HMC proliferation and chemokine expression.