Disturbances of apoptotic cell clearance in systemic lupus erythematosus

Canonical and noncanonical functions of complement in systemic lupus erythematosus

For many years complement activation in systemic lupus erythematosus (SLE) was viewed as a major cause of tissue injury. However, human and murine studies showed that complement plays a protective as well as a proinflammatory role in tissue damage. A hierarchy is apparent with early classical pathway components, particularly C1q, exerting the greatest influence. Understanding the mechanisms underlying the protective function(s) of complement remains an important challenge for the future and has implications for the use of complement therapy in SLE. We review recent advances in the field and give a new perspective on the complement conundrum in SLE.

Double-negative B cells and DNASE1L3 colocalise with microbiota in gut-associated lymphoid tissue

Intestinal homeostasis is maintained by the response of gut-associated lymphoid tissue to bacteria transported across the follicle associated epithelium into the subepithelial dome. The initial response to antigens and how bacteria are handled is incompletely understood. By iterative application of spatial transcriptomics and multiplexed single-cell technologies, we identify that the double negative 2 subset of B cells, previously associated with autoimmune diseases, is present in the subepithelial dome in health. We show that in this location double negative 2 B cells interact with dendritic cells co-expressing the lupus autoantigens DNASE1L3 and C1q and microbicides. We observe that in humans, but not in mice, dendritic cells expressing DNASE1L3 are associated with sampled bacteria but not DNA derived from apoptotic cells. We propose that fundamental features of autoimmune diseases are microbiota-associated, interacting components of normal intestinal immunity.

Ex Vivo-Generated Tolerogenic Dendritic Cells: Hope for a Definitive Therapy of Autoimmune Diseases

Current therapies for autoimmune diseases are immunosuppressant agents, which have many debilitating side effects. However, dendritic cells (DCs) can induce antigen-specific tolerance. Tolerance restoration mediated by ex vivo-generated DCs can be a therapeutic approach. Therefore, in this review, we summarize the conceptual framework for developing ex vivo-generated DC strategies for autoimmune diseases. First, we will discuss the role of DCs in developing immune tolerance as a foundation for developing dendritic cell-based immunotherapy for autoimmune diseases. Then, we also discuss relevant findings from pre-clinical and clinical studies of ex vivo-generated DCs for therapy of autoimmune diseases. Finally, we discuss problems and challenges in dendritic cell therapy in autoimmune diseases. Throughout the article, we discuss autoimmune diseases, emphasizing SLE.

A glance on the role of IL-35 in systemic lupus erythematosus (SLE)

It is well known that systemic lupus erythematosus (SLE) is an auto-inflammatory disease that is characterized by chronic and widespread inflammation. The exact pathogenesis of SLE is still a matter of debate. However, it has been suggested that the binding of autoantibodies to autoantigens forms immune complexes (ICs), activators of the immune response, in SLE patients. Ultimately, all of these responses lead to an imbalance between anti-inflammatory and pro-inflammatory cytokines, resulting in cumulative inflammation. IL-35, the newest member of the IL-12 family, is an immunosuppressive and anti-inflammatory cytokine secreted mainly by regulatory cells. Structurally, IL-35 is a heterodimeric cytokine, composed of Epstein-Barr virus-induced gene 3 (EBI3) and p35. IL-35 appears to hold therapeutic and diagnostic potential in cancer and autoimmune diseases. In this review, we summarized the most recent associations between IL and 35 and SLE. Unfortunately, the comparative review of IL-35 in SLE indicates many differences and contradictions, which make it difficult to generalize the use of IL-35 in the treatment of SLE. With the available information, it is not possible to talk about targeting this cytokine for the lupus treatment. So, further studies would be needed to establish the clear and exact levels of this cytokine and its related receptors in people with lupus to provide IL-35 as a preferential therapeutic or diagnostic candidate in SLE management.

CCR5 promoter region polymorphisms in systemic lupus erythematosus

This study investigated the impacts of CCR5 promoter region polymorphisms on the development of systemic lupus erythematosus (SLE) by comparing CCR5 genotypes and haplotypes from SLE patients with ethnically matched controls. A total of 382 SLE patients (289 European-derived and 93 African-derived) and 375 controls (243 European-derived and 132 African-derived) were genotyped for the CCR2-64I G > A (rs1799864), CCR5-59353 C > T (rs1799988), CCR5-59356 C > T (rs41469351), CCR5-59402 A > G (rs1800023) and CCR5-59653 C > T (rs1800024) polymorphisms through polymerase chain reaction-restriction fragment length polymorphism and direct sequencing. Previous data from CCR5Δ32 analysis was included in the study to infer the CCR5 haplotypes and as a possible confounding factor in the binary logistic regression. European-derived patients showed a higher frequency of CCR5 wild-type genotype (conversely, a reduced frequency of Δ32 allele) and a reduced frequency of the HHG*2 haplotype compared to controls; both factors significantly affecting disease risk [p = .003 (OR 3.5, 95%CI 1.6-7.5) and 2.0% vs. 7.2% (residual p = 2.9E - 5), respectively]. Additionally, the HHA/HHB, HHC and HHG*2 haplotype frequencies differed between African-derived patients and controls [10% vs. 20.5% (residual p = .003), 29.4% vs. 17.4% (residual p = .003) and 3.9% vs. 0.8% (residual p = .023), respectively]. Considering the clinical manifestations of the disease, the CCR5Δ32 presence was confirmed as a susceptibility factor to class IV nephritis in the African-derived group and when all patients were grouped for comparison [pcorrected  = .012 (OR 3.0; 95%CI 3.0-333.3) and pcorrected  = .0006 (OR 6.8; 95%CI 1.9-24.8), respectively]. In conclusion, this study indicates that CCR5 promoter polymorphisms are important disease modifiers in SLE. Present data reinforces the CCR5Δ32 polymorphism as a protective factor for the development of the disease in European-derived patients and as a susceptibility factor for class IV nephritis in African-derived patients. Furthermore, we also described a reduced frequency of HHA/HHB and an increased frequency of HHC and HHG*2 haplotypes in African-derived patients, which could modify the CCR5 protein expression in specific cell subsets.

Regulatory B Cells Evaluation in Systemic Lupus Erythematosus Patients with Subclinical Atherosclerosis and Secondary Antiphospholipid Syndrome

Objectives

The current knowledge of human studies that address B cells in Systemic Lupus Erythematosus (SLE) patients with subclinical atherosclerosis remains insufficient. We aimed to evaluate the contribution of Breg cells in SLE and secondary antiphospholipid syndrome (APS) patients taking into consideration its relation to subclinical atherosclerosis and the disease activity.

Methods

Thirty SLE patients and 23 controls were included. Systemic Lupus Erythematosus Disease Activity Index-2000 was estimated. Evaluation of Breg cells percentage using flow cytometry was done. All participants underwent carotid doppler ultrasound examination for measurements of the intima-media thickness of the common carotid artery (cIMT). The coronary artery calcium scoring was calculated using the Agatston method.

Results

The mean± SD of age was 32.60±8.34 years, while of the age of onset was 28.27±7.60 years. Twenty-three patients (76.7%) had subclinical atherosclerosis. There was a highly significant difference in Breg cells between SLE and APS patients with subclinical atherosclerosis and controls (P= 0.001, 0.005). SLE and APS patients had significantly higher mean cIMT than control (P=0.01, 0.050). Breg cells had 70% sensitivity and 87% specificity for diagnosing of SLE (P=0.01). Multivariate regression analysis indicated that low Breg cells were predictive for the disease activity (OR=1.76, 95% CI=1.21- 2.85; P= 0.01).

Conclusion

SLE patients had a high frequency of subclinical atherosclerosis, those and patients with secondary APS had a high risk of plaque formation. We found a contribution of Breg cells in SLE patients with subclinical atherosclerosis. Breg cells are considered a good predictor of diagnosis of SLE.

A Coxsackievirus B1-mediated nonlytic Extracellular Vesicle-to-cell mechanism of virus transmission and its possible control through modulation of EV release

Like most non-enveloped viruses, CVB1 mainly uses cell lysis to spread. Details of a nonlytic virus transmission remain unclear. Extracellular Vesicles (EVs) transfer biomolecules between cells. We show that CVB1 entry into HeLa cells results in apoptosis and release of CVB1-induced 'medium-sized' EVs (CVB1i-mEVs). These mEVs (100-300 nm) harbour CVB1 as shown by immunoblotting with anti-CVB1-antibody; viral capsids were detected by transmission electron microscopy and RT-PCR revealed CVB1 RNA. The percentage of mEVs released from CVB1-infected HeLa cells harbouring virus was estimated from TEM at 34 %. Inhibition of CVB1i-mEV production, with calpeptin or siRNA knockdown of CAPNS1 in HeLa cells limited spread of CVB1 suggesting these vesicles disseminate CVB1 virions to new host cells by a nonlytic EV-to-cell mechanism. This was confirmed by detecting CVB1 virions inside HeLa cells after co-culture with CVB1i-mEVs; EV release may also prevent apoptosis of infected cells whilst spreading apoptosis to secondary sites of infection.

Anti-Phosphatidylserine, Anti-Prothrombin, and Anti-Annexin V Autoantibodies in Antiphospholipid Syndrome: A Real-Life Study

The antiphospholipid antibodies (aPL) increase the risk of developing thrombotic events and may coexist with a variety of autoimmune diseases. They can be detected chronically or temporarily in patients with infectious diseases, during drug therapy, or in cases of cancer. A thrombotic event with aPL detection is known as antiphospholipid syndrome (APS) and the diagnostic criteria include the presence of lupus anticoagulant (LA), anticardiolipin (aCL) and β2-glycoprotein-1(aβ2GPI) antibodies. Other autoantigens recognized in APS are phosphatidylserine (aPS), prothrombin (aPT) and Annexin-5 (aA5). This real life study aimed to explore the connections between laboratory criteria and the prevalence of "non-criteria aPL" in APS. This study followed 300 patients with thrombosis and employed two phospholipid sensitivity assays for LA detection, chemiluminescence assays for aCL and aβ2GPI and enzyme-linked immunoassays for aPS, aPT and aA5. A significant association was found between aPS and aCL (r = 0.76) as well as aβ2GPI (r = 0.77), while the association with LA was less significant (r = 0.33). The results of the aPT and aA5 test did not correlate with criteria-antiphospholipid antibodies (r < 0.30). Since the risk of thrombotic complications increases with the intensity and the number of positive autoantibodies, measuring aPT and aA5 autoantibodies may be useful, particularly in aCL/aβ2GPI-negative patients or in cases of isolated LA positivity.

The genomic landscape of ANCA-associated vasculitis: Distinct transcriptional signatures, molecular endotypes and comparison with systemic lupus erythematosus

Introduction

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs) present with a complex phenotype and are associated with high mortality and multi-organ involvement. We sought to define the transcriptional landscape and molecular endotypes of AAVs and compare it to systemic lupus erythematosus (SLE).

Methods

We performed whole blood mRNA sequencing from 30 patients with AAV (granulomatosis with polyangiitis/GPA and microscopic polyangiitis/MPA) combined with functional enrichment and network analysis for aberrant pathways. Key genes and pathways were validated in an independent cohort of 18 AAV patients. Co-expression network and hierarchical clustering analysis, identified molecular endotypes. Multi-level transcriptional overlap analysis to SLE was based on our published data from 142 patients.

Results

We report here that “Pan-vasculitis” signature contained 1,982 differentially expressed genes, enriched in leukocyte differentiation, cytokine signaling, type I and type II IFN signaling and aberrant B-T cell immunity. Active disease was characterized by signatures linked to cell cycle checkpoints and metabolism pathways, whereas ANCA-positive patients exhibited a humoral immunity transcriptional fingerprint. Differential expression analysis of GPA and MPA yielded an IFN-g pathway (in addition to a type I IFN) in the former and aberrant expression of genes related to autophagy and mRNA splicing in the latter. Unsupervised molecular taxonomy analysis revealed four endotypes with neutrophil degranulation, aberrant metabolism and B-cell responses as potential mechanistic drivers. Transcriptional perturbations and molecular heterogeneity were more pronounced in SLE. Molecular analysis and data-driven clustering of AAV uncovered distinct transcriptional pathways that could be exploited for targeted therapy.

Discussion

We conclude that transcriptomic analysis of AAV reveals distinct endotypes and molecular pathways that could be targeted for therapy. The AAV transcriptome is more homogenous and less fragmented compared to the SLE which may account for its superior rates of response to therapy.

From waste to wealth: Repurposing slaughterhouse waste for xenotransplantation

Slaughterhouses produce large quantities of biological waste, and most of these materials are underutilized. In many published reports, the possibility of repurposing this form of waste to create biomaterials, fertilizers, biogas, and feeds has been discussed. However, the employment of particular offal wastes in xenotransplantation has yet to be extensively uncovered. Overall, viable transplantable tissues and organs are scarce, and developing bioartificial components using such discarded materials may help increase their supply. This perspective manuscript explores the viability and sustainability of readily available and easily sourced slaughterhouse waste, such as blood vessels, eyes, kidneys, and tracheas, as starting materials in xenotransplantation derived from decellularization technologies. The manuscript also examines the innovative use of animal stem cells derived from the excreta to create a bioartificial tissue/organ platform that can be translated to humans. Institutional and governmental regulatory approaches will also be outlined to support this endeavor.

Targeting epigenetic regulators for inflammation: Mechanisms and intervention therapy

Emerging evidence indicates that resolution of inflammation is a critical and dynamic endogenous process for host tissues defending against external invasive pathogens or internal tissue injury. It has long been known that autoimmune diseases and chronic inflammatory disorders are characterized by dysregulated immune responses, leading to excessive and uncontrol tissue inflammation. The dysregulation of epigenetic alterations including DNA methylation, posttranslational modifications to histone proteins, and noncoding RNA expression has been implicated in a host of inflammatory disorders and the immune system. The inflammatory response is considered as a critical trigger of epigenetic alterations that in turn intercede inflammatory actions. Thus, understanding the molecular mechanism that dictates the outcome of targeting epigenetic regulators for inflammatory disease is required for inflammation resolution. In this article, we elucidate the critical role of the nuclear factor-κB signaling pathway, JAK/STAT signaling pathway, and the NLRP3 inflammasome in chronic inflammatory diseases. And we formulate the relationship between inflammation, coronavirus disease 2019, and human cancers. Additionally, we review the mechanism of epigenetic modifications involved in inflammation and innate immune cells. All that matters is that we propose and discuss the rejuvenation potential of interventions that target epigenetic regulators and regulatory mechanisms for chronic inflammation-associated diseases to improve therapeutic outcomes.

A pregnancy hormone-cell death link promotes enhanced lupus-specific immunological effects

Women of reproductive age demonstrate an increased incidence of systemic lupus erythematosus, and reproductive hormones have been implicated in disease progression. Additionally, pregnancy can be associated with disease "flares", the reasons for which remain obscure. While apoptotic bodies are believed to provide an autoantigenic trigger in lupus, whether autoantigenic constituents vary with varying cellular insults, and whether such variations can be immunologically consequential in the context of pregnancy, remains unknown. As assessed by antigenicity and mass spectrometry, apoptotic bodies elicited by different drugs demonstrated the differential presence of lupus-associated autoantigens, and varied in the ability to elicit lupus-associated cytokines from lupus splenocytes and alter the phenotype of lupus B cells. Immunization of tamoxifen-induced apoptotic bodies in lupus-prone mice generated higher humoral autoreactive responses than did immunization with cisplatin-induced apoptotic bodies, and both apoptotic bodies were poorly immunogenic in healthy mice. Incubation of lupus splenocytes (but not healthy splenocytes) with the pregnancy hormone human chorionic gonadotropin (hCG) along with tamoxifen-induced apoptotic bodies (but not cisplatin-induced apoptotic bodies) induced increases in the secretion of lupus-associated cytokines and in the up-modulation of B cell phenotypic markers. In addition, levels of secreted autoantibodies (including of specificities linked to lupus pathogenesis) were enhanced. These events were associated with the heightened phosphorylation of several signaling intermediates. Observations suggest that hCG is a potential disease-promoting co-stimulant in a lupus-milieu; when combined with specific apoptotic bodies, it enhances the intensity of multiple lupus-associated events. These findings deepen mechanistic insight into the hormone's links with autoreactive responses in lupus-prone mice and humans.

Dynamically modeling the effective range of IL-2 dosage in the treatment of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex systemic autoimmune disease characterized by an overactive immune response to self-antigen. The overactivation of CD4+ Foxp3- conventional T cells (Tcons) and the inactivation of CD4+ CD25+ Foxp3+ regulatory T cells (Tregs) play important roles in the progression of SLE. Clinical trials showed that low-dose interleukin-2 (IL-2) is effective in treating SLE. Here, we developed a mathematical model involving Tcons, Tregs, natural killer (NK) cells, and IL-2 to simulate the dynamic processes involved in the treatment of SLE. We found an effective range of IL-2 dosage defined by the Tcon/Treg ratio in SLE treatment, termed the IL-2 dosage therapeutic window (IDTW). Our results showed that high levels of self-antigen result in a narrow IDTW and high post-treatment Tcon/Treg ratio. Furthermore, we proposed a classification method based on the ratio of pre-treatment Treg to CD4+ T cells to predict the treatment outcome of SLE patients.

Overview on the role of complement-specific autoantibodies in diseases

The complement system is recognized as a major pathogenic or contributing factor in an ever-growing number of diseases. In addition to inherited factors, autoantibodies to complement proteins have been detected in various systemic and organ-specific disorders. These include antibodies directed against complement components, regulators and receptors, but also protein complexes such as autoantibodies against complement convertases. In some cases, the autoantibodies are relatively well characterized and a pathogenic role is incurred and their detection has diagnostic value. In other cases, the relevance of the autoantibodies is rather unclear. This review summarizes what we know of complement specific autoantibodies in diseases and identifies unresolved questions regarding their functional effect and relevance.

Metabolic profiling reveals new serum signatures to discriminate lupus nephritis from systemic lupus erythematosus

Background

Lupus nephritis (LN) occurs in 50% of patients with systemic lupus erythematosus (SLE), causing considerable morbidity and even mortality. Previous studies had shown the potential of metabolic profiling in the diagnosis of SLE or LN. However, few metabonomics studies have attempted to distinguish SLE from LN based on metabolic changes. The current study was designed to find new candidate serum signatures that could differentiate LN from SLE patients using a non-targeted metabonomics method based on ultra high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS).

Method

Metabolic profiling of sera obtained from 21 healthy controls, 52 SLE patients and 43 LN patients. We used SPSS 25.0 for statistical analysis. Principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and metabolic pathway analysis were used to analyze the metabolic data.

Results

Upon comparison of SLE and LN groups, 28 differential metabolites were detected, the majority of which were lipids and amino acids. Glycerolphospholipid metabolism, pentose and glucuronate interconversions and porphyrin and chlorophyll metabolism were obviously enriched in LN patients versus those with SLE. Among the 28 characteristic metabolites, five key serum metabolites including SM d34:2, DG (18:3(9Z,12Z,15Z)/20:5(5Z,8Z,11Z,14Z,17Z)/0:0), nervonic acid, Cer-NS d27:4, and PC (18:3(6Z,9Z,12Z)/18:3(6Z,9Z,12Z) performed higher diagnostic performance in discriminating LN from SLE (all AUC &gt; 0.75). Moreover, combined analysis of neuritic acid, C1q, and CysC (AUC = 0.916) produced the best combined diagnosis.

Conclusion

This study identified five serum metabolites that are potential indicators for the differential diagnosis of SLE and LN. Glycerolphospholipid metabolism may play an important role in the development of SLE to LN. The metabolites we screened can provide more references for the diagnosis of LN and more support for the pathophysiological study of SLE progressed to LN.

1,25-dihydroxyvitamin D3 ameliorates lupus nephritis through inhibiting the NF-κB and MAPK signalling pathways in MRL/lpr mice

Background

Lupus nephritis (LN) is a common and serious complication of systemic lupus erythematosus (SLE). However, the aetiology and pathogenesis of LN remain unknown. 1,25-dihydroxyvitamin D3 [1,25-(OH)2-VitD3] is the active form of vitamin D, and it has been shown to perform important functions in inflammatory and immune-related diseases. In this study, we investigated the time-dependent effects of 1,25-dihydroxyvitamin D3 and explored the underlying mechanism in MRL/lpr mice, a well-studied animal model of LN.

Methods

Beginning at 8 weeks of age, 24-h urine samples were collected weekly to measure the levels of protein in the urine. We treated female MRL/lpr mice with 1,25-dihydroxyvitamin D3 (4 μg/kg) or 1% DMSO by intraperitoneal injection twice weekly for 3 weeks beginning at the age of 11 weeks. The mice were separately sacrificed, and serum and kidney samples were collected at the ages of 14, 16, 18, and 20 weeks to measure creatinine (Cr) levels, blood urea nitrogen (BUN) levels, histological damage, immunological marker (A-ds DNA, C1q, C3, IgG, IgM) levels, and inflammatory factor (TNF-α, IL-17, MCP-1) levels. Furthermore, the nuclear factor kappa B (NF-κB) and the mitogen-activated protein kinase (MAPK) signalling pathways were also assessed to elucidate the underlying mechanism.

Results

We found that MRL/lpr mice treated with 1,25-dihydroxyvitamin D3 displayed significantly attenuated LN. VitD3-treated mice exhibited significantly improved renal pathological damage and reduced proteinuria, BUN, SCr, A-ds DNA antibody and immune complex deposition levels (P < 0.05) compared with untreated MRL/lpr mice. Moreover, 1,25-dihydroxyvitamin D3 inhibited the complement cascade, inhibited the release of proinflammatory cytokines, such as TNF-α, IL-17, and MCP-1, and inhibited NF-κB and MAPK activation (P < 0.05).

Conclusion

1,25-dihydroxyvitamin D3 exerts a protective effect against LN by inhibiting the NF-κB and MAPK signalling pathways, providing a potential treatment strategy for LN. Interestingly, the NF-κB and MAPK signalling pathways are time-dependent mediators of LN and may be associated with lupus activity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02870-z.

Can Antinuclear Antibodies Have a Pathogenic Role in Systemic Sclerosis?

Systemic sclerosis (SSc) is a connective tissue disease characterized by extensive fibrosis of the skin and internal organs, associated with vasculopathy and autoimmune features. Antinuclear antibodies (ANA) are found in almost all SSc patients and constitute strong diagnosis and prognosis biomarkers. However, it remains unclear whether ANA are simple bystanders or if they can have a role in the pathophysiology of the disease. One might think that the nuclear nature of their targets prevents any accessibility to autoantibodies. Nevertheless, recent data suggest that ANA could be pathogenic or at least contribute to the perennation of the disease. We review here first the indirect clues of the contribution of ANA to SSc: they are associated to the disease subtypes, they may precede disease onset, their titer correlates with disease activity and severity, there is an association between molecular subsets, and some patients can respond to B-cell targeting therapy. Then, we describe in a second part the mechanisms of ANA production in SSc from individual genetic background to post-transcriptional modifications of neoantigens. Finally, we elaborate on the potential mechanisms of pathogenicity: ANA could be pathogenic through immune-complex-mediated mechanisms; other processes potentially involve molecular mimicry and ANA penetration into the target cell, with a focus on anti-topoisomerase-I antibodies, which are the most probable candidate to play a role in the pathophysiology of SSc. Finally, we outline some technical and conceptual ways to improve our understanding in this field.

Diet and Hygiene in Modulating Autoimmunity During the Pandemic Era

The immune system is an efficiently toned machinery that discriminates between friends and foes for achieving both host defense and homeostasis. Deviation of immune recognition from foreign to self and/or long-lasting inflammatory responses results in the breakdown of tolerance. Meanwhile, educating the immune system and developing immunological memory are crucial for mounting defensive immune responses while protecting against autoimmunity. Still to elucidate is how diverse environmental factors could shape autoimmunity. The emergence of a world pandemic such as SARS-CoV-2 (COVID-19) not only threatens the more vulnerable individuals including those with autoimmune conditions but also promotes an unprecedented shift in people's dietary approaches while urging for extraordinary hygiene measures that likely contribute to the development or exacerbation of autoimmunity. Thus, there is an urgent need to understand how environmental factors modulate systemic autoimmunity to better mitigate the incidence and or severity of COVID-19 among the more vulnerable populations. Here, we discuss the effects of diet (macronutrients and micronutrients) and hygiene (the use of disinfectants) on autoimmunity with a focus on systemic lupus erythematosus.

Abnormalities of the type I interferon signaling pathway in lupus autoimmunity

Type I interferons (IFNs), mostly IFNα and IFNβ, and the type I IFN Signature are important in the pathogenesis of Systemic Lupus Erythematosus (SLE), an autoimmune chronic condition linked to inflammation. Both IFNα and IFNβ trigger a signaling cascade that, through the activation of JAK1, TYK2, STAT1 and STAT2, initiates gene transcription of IFN stimulated genes (ISGs). Noteworthy, other STAT family members and IFN Responsive Factors (IRFs) can also contribute to the activation of the IFN response. Aberrant type I IFN signaling, therefore, can exacerbate SLE by deregulated homeostasis leading to unnecessary persistence of the biological effects of type I IFNs. The etiopathogenesis of SLE is partially known and considered multifactorial. Family-based and genome wide association studies (GWAS) have identified genetic and transcriptional abnormalities in key molecules directly involved in the type I IFN signaling pathway, namely TYK2, STAT1 and STAT4, and IRF5. Gain-of-function mutations that heighten IFNα/β production, which in turn maintains type I IFN signaling, are found in other pathologies like the interferonopathies. However, the distinctive characteristics have yet to be determined. Signaling molecules activated in response to type I IFNs are upregulated in immune cell subsets and affected tissues of SLE patients. Moreover, Type I IFNs induce chromatin remodeling leading to a state permissive to transcription, and SLE patients have increased global and gene-specific epigenetic modifications, such as hypomethylation of DNA and histone acetylation. Epigenome wide association studies (EWAS) highlight important differences between SLE patients and healthy controls in Interferon Stimulated Genes (ISGs). The combination of environmental and genetic factors may stimulate type I IFN signaling transiently and produce long-lasting detrimental effects through epigenetic alterations. Substantial evidence for the pathogenic role of type I IFNs in SLE advocates the clinical use of neutralizing anti-type I IFN receptor antibodies as a therapeutic strategy, with clinical studies already showing promising results. Current and future clinical trials will determine whether drugs targeting molecules of the type I IFN signaling pathway, like non-selective JAK inhibitors or specific TYK2 inhibitors, may benefit people living with lupus.

Upregulation of miR-210-5p impairs dead cell clearance by macrophages through the inhibition of Sp1-and HSCARG-dependent NADPH oxidase pathway

The deficiency of dead cell clearance is a prominent pathogenic factor in systemic lupus erythematosus (SLE). In this study, the overexpression of miR-210-5p resulted in the accumulation of secondary necrotic cells (SNECs) in macrophages through the reduction of protein degradation. The upreguation of miR-210-5p inhibited NADPH oxidase (NOX) activation, reactive oxygen species (ROS) generation, and SNEC clearance. miR-210-5p overexpression suppressed Sp1 and HSCARG expression, and the knockdown of SP1 and HSCARG inhibited NOX expression and superoxide production in macrophages. Furthermore, patients with active SLE expressed a higher level of miR-210-5p and lower expression of SP1 and HSCARG in peripheral blood mononuclear cells. In summary, our findings indicate that the upregulation of miR-210-5p increases the accumulation of SNECs through a decrease in the Sp1-and HSCARG-mediated NOX activity and ROS generation in macrophages. Our results also suggest that targeting miR-210-5p may have therapeutic potential for SLE.

The Akt-mTORC1 pathway mediates Axl receptor tyrosine kinase-induced mesangial cell proliferation

Glomerulonephritis (GN), an important pathologic feature of many renal diseases, is frequently characterized by mesangial cell proliferation. We and others have previously shown that the TAM family receptor tyrosine kinases Axl, Mer, and Tyro-3 contribute to cell survival, proliferation, migration, and clearance of apoptotic cells (ACs); that Axl contributes to GN by promoting mesangial cell proliferation; and that small molecule inhibition of Axl ameliorates nephrotoxic serum-induced GN in mice. We now show that stimulation of renal mesangial cell Axl causes a modest increase in intracellular Ca²⁺ and activates NF-κB, mTOR, and the mTOR-containing mTORC1 complex, which phosphorylates the ribosomal protein S6. Axl-induction of Akt activation is upstream of NF-κB and mTOR activation, which are mutually codependent. Axl-induced NF-κB activation leads to Bcl-xl up-regulation. Axl is more important than Mer at mediating AC phagocytosis by mesangial cells, but less important than Mer at mediating phagocytosis of ACs by peritoneal macrophages. Taken together, our data suggest the possibility that Axl mediates mesangial cell phagocytosis of ACs and promotes mesangial cell proliferation by activating NF-κB and mTORC1.

Resolving inflammation by TAM receptor activation

The control of inflammation is strictly regulated to ensure the adequate intensity and duration of an inflammatory response, enabling the removal of the trigger factors and the restoration of the integrity of the tissues and their functions. This process is coordinated by anti-inflammatory and pro-resolving mediators that regulate the cellular and molecular events necessary to restore homeostasis, and defects in this control are associated with the development of chronic and autoimmune diseases. The TAM family of receptor tyrosine kinases-Tyro3, Axl, and MerTK-plays an essential role in efferocytosis, a key process for the resolution of inflammation. However, new studies have demonstrated that TAM receptor activation not only reduces the synthesis of pro-inflammatory mediators by different cell types in response to some stimuli but also stimulates the production of anti-inflammatory and pro-resolving molecules that control the inflammation. This review provides a comprehensive view of TAM receptor family members as important players in controlling inflammatory responses through anti-inflammatory and pro-resolving actions.

Interferon-α activates interleukin-1 receptor-associated kinase 1 to induce regulatory T-cell apoptosis in patients with systemic lupus erythematosus

Impaired regulatory T-cell (Treg) responses and upregulated interleukin-1 receptor-associated kinase 1 (IRAK1) expression are associated with the development of human systemic lupus erythematosus (SLE). Here, we show that the levels of upregulated IRAK1 expression in circulating Tregs are correlated with the percentages of apoptotic Tregs, Systemic Lupus Erythematosus Disease Activity Index scores, and serum complement C3 levels in SLE patients. High levels of plasma interferon (IFN)-α in SLE patients induced IRAK1 phosphorylation to trigger Treg apoptosis, which was mitigated by IRAK1 inhibitor (IRAK-Inh) treatment. Bioinformatics indicated that IRAK1 activation was related to the IFN-α/β and mitogen-activated protein kinase (MAPK) signaling in Tregs and IFN-α treatment induced the p38 and MAPK/ERK kinase 3/6 phosphorylation, which was attenuated by IRAK-Inh in Tregs. Treatment with IRAK-Inh effectively alleviated renal injury and promoted the survival of lupus-prone B6.MRL-Fas^lpr /Nju mice. Therefore, IFN-α induced IRAK1 activation to promote Treg apoptosis, contributing to the pathogenesis of SLE and IFN-α/IRAK1 may be therapeutic targets for SLE.

Harnessing Tolerogenic Histone Peptide Epitopes From Nucleosomes for Selective Down-Regulation of Pathogenic Autoimmune Response in Lupus (Past, Present, and Future)

Autoantigen-directed tolerance can be induced by certain nucleosomal histone peptide epitope/s in nanomolar dosage leading to sustained remission of disease in mice with spontaneous SLE. By contrast, lupus is accelerated by administration of intact (whole) histones, or whole nucleosomes in microparticles from apoptotic cells, or by post-translationally acetylated histone-peptides. Low-dose therapy with the histone-peptide epitopes simultaneously induces TGFβ and inhibits IL-6 production by DC in vivo, especially pDC, which then induce CD4+CD25+ Treg and CD8+ Treg cells that suppress pathogenic autoimmune response. Both types of induced Treg cells are FoxP3+ and act by producing TGFβ at close cell-to-cell range. No anaphylactic adverse reactions, or generalized immunosuppression have been detected in mice injected with the peptides, because the epitopes are derived from evolutionarily conserved histones in the chromatin; and the peptides are expressed in the thymus during ontogeny, and their native sequences have not been altered. The peptide-induced Treg cells can block severe lupus on adoptive transfer reducing inflammatory cell reaction and infiltration in the kidney. In Humans, similar potent Treg cells are generated by the histone peptide epitopes in vitro in lupus patients’ PBMC, inhibiting anti-dsDNA autoantibody and interferon production. Furthermore, the same types of Treg cells are generated in lupus patients who are in very long-term remission (2-8 years) after undergoing autologous hematopoietic stem cell transplantation. These Treg cells are not found in lupus patients treated conventionally into clinical remission (SLEDAI of 0); and consequently they still harbor pathogenic autoimmune cells, causing subclinical damage. Although antigen-specific therapy with pinpoint accuracy is suitable for straight-forward organ-specific autoimmune diseases, Systemic Lupus is much more complex. The histone peptide epitopes have unique tolerogenic properties for inhibiting Innate immune cells (DC), T cells and B cell populations that are both antigen-specifically and cross-reactively involved in the pathogenic autoimmune response in lupus. The histone peptide tolerance is a natural and non-toxic therapy suitable for treating early lupus, and also maintaining lupus patients after toxic drug therapy. The experimental steps, challenges and possible solutions for successful therapy with these peptide epitopes are discussed in this highly focused review on Systemic Lupus.

Immune responses against oxidized LDL as possible targets for prevention of atherosclerosis in systemic lupus erythematosus

Patients suffering from systemic lupus erythematosus (SLE) are at increased risk of developing cardiovascular disease (CVD) and traditional therapies including statins provide insufficient protection. Impaired removal of apoptotic material is a common pathogenic mechanism in both SLE and atherosclerosis and is considered to be a key factor in the development of autoimmunity. Since oxidized LDL and apoptotic material bind to the same receptors, we aimed to investigate if targeting the oxidized LDL autoimmunity can affect atherosclerosis in SLE. To investigate the possible role of oxidized LDL autoimmunity in the accelerated atherosclerosis associated with SLE we used a hypercholesterolemic SLE mouse model (B6.lpr.ApoE^-/- mice). Promoting LDL tolerance through mucosal immunization with an apolipoprotein B-100 peptide p45 (amino acids 661-680) and cholera toxin B-subunit fusion protein increased regulatory T cells and B cells in mesenteric lymph nodes and reduced plaque development in the aorta by 33%. Treatment with the oxidized LDL-specific antibody Orticumab reduced aortic atherosclerosis by 43%, subvalvular plaque area by 50% and the macrophage content by 31%. The present study provides support for oxLDL as a possible target for prevention of cardiovascular complications in SLE.

The Role of Natural Killer Cells in Autoimmune Diseases

Natural killer (NK) cells, the large granular lymphocytes differentiated from the common lymphoid progenitors, were discovered in early 1970's. They are members of innate immunity and were initially defined by their strong cytotoxicity against virus-infected cells and by their important effector functions in anti-tumoral immune responses. Nowadays, NK cells are classified among the recently discovered innate lymphoid cell subsets and have capacity to influence both innate and adaptive immune responses. Therefore, they can be considered as innate immune cells that stands between the innate and adaptive arms of immunity. NK cells don't express T or B cell receptors and are recognized by absence of CD3. There are two major subgroups of NK cells according to their differential expression of CD16 and CD56. While CD16+CD56dim subset is best-known by their cytotoxic functions, CD16-CD56bright NK cell subset produces a bunch of cytokines comparable to CD4+ T helper cell subsets. Another subset of NK cells with production of interleukin (IL)-10 was named as NK regulatory cells, which has suppressive properties and could take part in immune-regulatory responses. Activation of NK cells is determined by a delicate balance of cell-surface receptors that have either activating or inhibitory properties. On the other hand, a variety of cytokines including IL-2, IL-12, IL-15, and IL-18 influence NK cell activity. NK-derived cytokines and their cytotoxic functions through induction of apoptosis take part in regulation of the immune responses and could contribute to the pathogenesis of many immune mediated diseases including ankylosing spondylitis, Behçet's disease, multiple sclerosis, rheumatoid arthritis, psoriasis, systemic lupus erythematosus and type-1 diabetes. Dysregulation of NK cells in autoimmune disorders may occur through multiple mechanisms. Thanks to the rapid developments in biotechnology, progressive research in immunology enables better characterization of cells and their delicate roles in the complex network of immunity. As NK cells stand in between innate and adaptive arms of immunity and "bridge" them, their contribution in inflammation and immune regulation deserves intense investigations. Better understanding of NK-cell biology and their contribution in both exacerbation and regulation of inflammatory disorders is a requisite for possible utilization of these multi-faceted cells in novel therapeutic interventions.

Toll-like receptor signalling in B cells during systemic lupus erythematosus

B lymphocytes have a central role in autoimmune diseases, which are often defined by specific autoantibody patterns and feature a loss of B cell tolerance. A prototypic disease associated with B cell hyperactivity is systemic lupus erythematosus (SLE). In patients with SLE, the loss of B cell tolerance to autoantigens is controlled in a cell-intrinsic manner by Toll-like receptors (TLRs), which sense nucleic acids in endosomes. TLR7 drives the extrafollicular B cell response and the germinal centre reaction that are involved in autoantibody production and disease pathogenesis. Surprisingly, TLR9 seems to protect against SLE, even though it is required for the production of autoantibodies recognizing double-stranded DNA-associated antigens, which are abundant in SLE and are a hallmark of this disease. The protective function of TLR9 is at least partly mediated by its capacity to limit the stimulatory activity of TLR7. The roles of TLR7 and TLR9 in the effector function of B cells in lupus-like disease and in patients with SLE, and the unique features of TLR signalling in B cells, suggest that targeting TLR signalling in SLE might be therapeutically beneficial.

Loss of B cell tolerance to autoantigens in systemic lupus erythematosus (SLE) is driven by TLR7, whereas TLR9 appears to protect against SLE by limiting the stimulatory activity of TLR7. The unique features of Toll-like receptor signalling in B cells implicate it as a therapeutic target in SLE.

Intrinsic TLR7 and TLR9 signalling in B cells plays an important role in the development and pathogenesis of systemic lupus erythematosus (SLE).

In patients with SLE, effector plasma cells are generated via the extrafollicular response and via the formation of spontaneous germinal centres.

TLR7 plays key roles in the extrafollicular response and the response mediated by germinal centres.

Some plasma cells produce IL-10 and can have protective roles in lupus-like disease.

Revisiting B cell tolerance and autoantibodies in seropositive and seronegative autoimmune rheumatic disease (AIRD)

Autoimmune rheumatic diseases (AIRD) are categorized seropositive or seronegative, dependent upon the presence or absence of specific autoreactive antibodies, including rheumatoid factor and anti-citrullinated protein antibodies. Autoantibody-based diagnostics have proved helpful in patient care, not only for diagnosis but also for monitoring of disease activity and prediction of therapy responsiveness. Recent work demonstrates that AIRD patients develop autoantibodies beyond those contained in the original categorization. In this study we discuss key mechanisms that underlie autoantibody development in AIRD: defects in early B cell development, genetic variants involved in regulating B cell and T cell tolerance, environmental triggers and antigen modification. We describe how autoantibodies can directly contribute to AIRD pathogenesis through innate and adaptive immune mechanisms, eventually culminating in systemic inflammation and localized tissue damage. We conclude by discussing recent insights that suggest distinct AIRD have incorrectly been denominated seronegative.

Lupus animal models and neuropsychiatric implications

Systemic lupus erythematosus (SLE) that involves neurological complications is known as neuropsychiatric systemic lupus erythematosus (NPSLE). Research in humans is difficult due to the disease's great heterogeneity. Animal models are a resource for new discoveries. In this review, we examine experimental models of lupus that present neuropsychiatric manifestations. Spontaneous animal models such as NZB/W F1 and MRL/lpr are commonly used in NPSLE research; these models present few SLE symptoms compared to induced animal models, such as pristane-induced lupus (PIL). The PIL model is known to present eight of the main clinical and laboratory manifestations of SLE described by the American College of Rheumatology. Many cytokines associated with NPSLE are expressed in the PIL model, such as IL-6, TNF-α, and IFN. However, to date, NPSLE manifestations have been poorly studied in the PIL model. In this review article, we discuss whether the PIL model can mimic neuropsychiatric manifestations of SLE. Key Points • PIL model have a strong interferon signature. • Animals with PIL express learning and memory deficit.

Atherosclerotic plaque vulnerability is increased in mouse model of lupus

Anti-apolipoprotein A-1 (anti-apoA-1 IgG) and anti-double stranded DNA (anti-dsDNA IgG) autoantibodies have been described as mediators of atherogenesis in mice and humans. In the present study, we aim to investigate the association between atherosclerotic parameters, autoantibodies and plaque vulnerability in the context of systemic lupus erythematosus (SLE). We therefore bred a lupus prone-mouse model (Nba2.Yaa mice) with Apoe^−/− mice resulting in Apoe^−/−Nba2.Yaa mice spontaneously producing anti-apoA-1 IgG antibodies. Although Apoe^−/−Nba2.Yaa and Apoe^−/− mice subject to a high cholesterol diet displayed similar atherosclerosis lesions size in aortic roots and abdominal aorta, the levels of macrophage and neutrophil infiltration, collagen, MMP-8 and MMP-9 and pro-MMP-9 expression in Apoe^−/−Nba2.Yaa mice indicated features of atherosclerotic plaque vulnerability. Even though Apoe^−/−Nba2.Yaa mice and Apoe^−/− mice had similar lipid levels, Apoe^−/−Nba2.Yaa mice showed higher anti-apoA-1 and anti-dsDNA IgG levels. Apoe^−/−Nba2.Yaa mice displayed a reduction of the size of the kidney, splenomegaly and lymph nodes (LN) hypertrophy. In addition, anti-apoA-1 and anti-dsDNA IgG increased also in relation with mRNA levels of GATA3, IL-4, Bcl-6 and CD20 in the spleen and aortic arch of Apoe^−/−Nba2.Yaa mice. Our data show that although atherosclerosis-lupus-prone Apoe^−/−Nba2.Yaa mice did not exhibit exacerbated atherosclerotic lesion size, they did show features of atherosclerotic plaque destabilization in correlation with the increase of pro-atherogenic autoantibodies.

Quaternary Ammonium Compound Disinfectants Reduce Lupus-Associated Splenomegaly by Targeting Neutrophil Migration and T-Cell Fate

Hypersensitivity reactions and immune dysregulation have been reported with the use of quaternary ammonium compound disinfectants (QACs). We hypothesized that QAC exposure would exacerbate autoimmunity associated with systemic lupus erythematosus (lupus). Surprisingly, however, we found that compared to QAC-free mice, ambient exposure of lupus-prone mice to QACs led to smaller spleens with no change in circulating autoantibodies or the severity of glomerulonephritis. This suggests that QACs may have immunosuppressive effects on lupus. Using a microfluidic device, we showed that ambient exposure to QACs reduced directional migration of bone marrow-derived neutrophils toward an inflammatory chemoattractant ex vivo. Consistent with this, we found decreased infiltration of neutrophils into the spleen. While bone marrow-derived neutrophils appeared to exhibit a pro-inflammatory profile, upregulated expression of PD-L1 was observed on neutrophils that infiltrated the spleen, which in turn interacted with PD-1 on T cells and modulated their fate. Specifically, QAC exposure hindered activation of splenic T cells and increased apoptosis of effector T-cell populations. Collectively, these results suggest that ambient QAC exposure decreases lupus-associated splenomegaly likely through neutrophil-mediated toning of T-cell activation and/or apoptosis. However, our findings also indicate that even ambient exposure could alter immune cell phenotypes, functions, and their fate. Further investigations on how QACs affect immunity under steady-state conditions are warranted.

Biologics targeting type I interferons in SLE: A meta-analysis and systematic review of randomised controlled trials

Objective

The feed-forward loop of type I interferons (IFNs) production and subsequent immunopathology of systemic lupus erythematosus (SLE) has been hypothesised to be disrupted with inhibition of IFNα or type I IFN receptor subunit 1 (IFNAR). This systematic review and meta-analysis present the treatment efficacy and safety profile of monoclonal antibodies inhibiting IFNα or IFNAR.

Methods

A search was done using Medline, Embase and ClinicalTrials.gov for biologics targeting IFNα or IFNAR in SLE up to 3 Jan 2020. For the meta-analysis, analyses of binary variables were pooled using odds ratio (OR) with the Mantel Haenszel model.

Results

Anifrolumab 300 mg (n = 3 studies, 927 patients) was more effective than placebo in achieving SRI(4) (pooled OR = 1.91, CI 1.11-3.28, P = 0.02) and BICLA response (pooled OR = 2.25, CI 1.72-2.95, P < 0.00001). In SLE patients with high type I IFN gene signature, SRI(4) response was not achieved with anifrolumab in 2 studies, 450 patients. Treatment with IFNα and IFNAR inhibitors (n = 7 studies, 1590 patients) increased the risk of herpes zoster infection (pooled OR = 3.72, CI 1.88–7.39, P = 0.0002), upper respiratory tract infections, nasopharyngitis and bronchitis.

Conclusion

This meta-analysis substantiates IFNAR as a therapeutic target in SLE. Inhibition of type I IFNs predisposes to herpes zoster and other viral infections.

Single Nucleotide Polymorphisms in PPARD Associated with Systemic Lupus Erythematosus in Chinese Populations

Background

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease characterized by apoptotic clearance deficiency provoking autoimmune responses and leading to multiple organ damage. PPAR-δ, encoded by the PPARD gene, was induced in macrophages promoting the timely disposal of apoptotic cells. Biological studies had provided solid foundation of PPARD involvement in SLE; it is worthwhile to further explore the genetic contribution of PPARD to SLE.

Methods

We performed a discovery-replication genetic association study. The discovery study was based on previous reported GWAS data. And the replication study was conducted in 1003 SLE patients and 815 healthy controls from Henan, Middle East of China. Further, we analyzed the eQTL effect to identify possible functional significance.

Results

In the genetic association analysis, we observed significant association between the risk C allele of rs4713853 (p = 0.03, OR 1.167, 95% CI 1.015-1.341) and increased SLE susceptibility. Moreover, individuals with the risk C allele were associated with lower expression of PPARD and DEF6. Our clinical analysis showed that SLE patients with the risk C allele of rs4713853 were more likely to present a higher proportion of anti-Sm antibody presence (CC+CT vs. TT, 20.0% vs. 14.2%, p = 0.039) and higher level of Scr (median inter quarter range CC+CT vs. TT, 56 48-71 vs. 54 46-64 μmol/L, p = 0.002).

Conclusions

In conclusion, our study identified a novel association between PPARD rs4713853 and SLE susceptibility in Chinese populations. By integrating multiple layers of analysis, we suggested that PPARD might be a main candidate in the pathogenesis of SLE.

Systemic lupus erythematosus favors the generation of IL-17 producing double negative T cells

Mature double negative (DN) T cells are a population of αβ T cells that lack CD4 and CD8 coreceptors and contribute to systemic lupus erythematosus (SLE). The splenic marginal zone macrophages (MZMs) are important for establishing immune tolerance, and loss of their number or function contributes to the progression of SLE. Here we show that loss of MZMs impairs the tolerogenic clearance of apoptotic cells and alters the serum cytokine profile, which in turn provokes the generation of DN T cells from self-reactive CD8+ T cells. Increased Ki67 expression, narrowed TCR V-beta repertoire usage and diluted T-cell receptor excision circles confirm that DN T cells from lupus-prone mice and patients with SLE undergo clonal proliferation and expansion in a self-antigen dependent manner, which supports the shared mechanisms for their generation. Collectively, our results provide a link between the loss of MZMs and the expansion of DN T cells, and indicate possible strategies to prevent the development of SLE.

Prepregnancy Endocrine, Autoimmune Disorders and the Risks of Gestational Hypertension-Preeclampsia in Primiparas: A Nationwide Population-Based Study in Taiwan

(1) Objective: To assess the risks of gestational hypertension/preeclampsia (GH-PE) in women with prepregnancy endocrine and autoimmune disorders such as polycystic ovarian syndrome (PCOS) and systemic lupus erythematosus (SLE). (2) Methods: In a nationwide population-based longitudinal study, data were retrieved from the 1998 to 2012 Taiwan National Health Insurance Research Database. ICD9-CM codes 256.4, 710.0, and 642.X were identified for the corresponding diagnoses of PCOS, SLE, and GH-PE, respectively, which were further confirmed by inspection of medical claims data for ultrasonography findings, laboratory tests, blood pressure measurements and examinations of urine protein to ensure the accuracy of the diagnoses. To clarify the risks of primiparous GH-PE, the study excluded women diagnosed with PCOS or SLE at <15 or >45 years of age, pre-existing chronic hypertension, GH-PE before PCOS and SLE, and abortion or termination before 20 weeks' gestation. For women affected by prepregnancy PCOS or SLE individually, each pregnant woman was age-matched to four pregnant women without PCOS or SLE. Logistic regression analyses were applied to report odds ratios (ORs) for the risks of GH-PE after adjustment for age, occupation, urbanization, economic status, and other co-morbidities. (3) Results: Among 8070 and 2430 women with prepregnancy PCOS and SLE retrieved from a population of 1,000,000 residents, 1953 (24.20%) and 820 (33.74%) had subsequent primiparous pregnancies that were analyzable and compared with 7812 and 3280 pregnancies without prepregnancy PCOS and SLE, respectively. GH-PE occurred more frequently in pregnancies with prepregnancy PCOS (5.79% vs. 2.23%, p < 0.0001) and SLE (3.41% vs. 1.80%, p < 0.01) as compared to those without PCOS and SLE. Further analysis revealed that prepregnancy PCOS (adjusted OR = 2.36; 95%CI: 1.83-3.05) and SLE (adjusted OR = 1.95; 95%CI: 1.23-3.10) were individually associated with GH-PE. The risk of GH-PE was not reduced in women with prepregnancy PCOS receiving metformin treatment (p = 0.22). (4) Conclusions: Prepregnancy PCOS and SLE are independent and significant risk factors for the occurrence of GH-PE. Because the peripartum complications are much higher among pregnancies with GH-PE, the at-risk woman should be informed and well-prepared during her pregnancy and delivery.

Revisiting the complement system in systemic lupus erythematosus

Introduction: Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease, characterized by the production of autoantibodies. Numerous mechanisms contribute to the pathogenesis and autoimmunity in SLE. One of the most important mechanisms is the defective function of the early complement components that are involved in clearing the immune-complexes and apoptotic debris. Major evidence supporting this hypothesis is the development of severe lupus in individuals with monogenic defects in any one of the early complement components such as C1q, C1 s, C1 r, C2, or C4.Areas covered: In this review, we discuss hereditary defects in classical complement components and their clinical manifestations, acquired defects of complements in lupus, the role of complements in the pathogenesis of antiphospholipid antibody syndrome and lupus nephritis, and laboratory assessment of complement components and their functions. Articles from the last 20 years were retrieved from PubMed for this purpose.Expert opinion: Complements have a dual role in the pathogenesis of SLE. On one hand, deficiency of complement components predisposes to lupus, while, on the other, excess complement activation plays a role in the organ damage. Understanding the intricacies of the role of complements in SLE can pave way for the development of targeted therapies.

Biological Function and Immunotherapy Utilizing Phosphatidylserine-based Nanoparticles

Phosphatidylserine (PS) is a naturally occurring anionic phospholipid that is primarily located in the inner leaflet of eukaryotic cell membranes. The role of PS during apoptosis is one of the most studied biological functions of PS. Externalization of PS during apoptosis mediates an "eat me" signal for phagocytic uptake, leading to clearance of apoptotic cells and thus maintain self-tolerance by immunological ignorance. However, an emerging view is that PS exposure-mediated cellular uptake is not an immunologically silent event, but rather promoting an active tolerance towards self and foreign proteins. This biological property of PS has been exploited by parasites and viruses in order to evade immune surveillance of the host immune system. Further, this novel immune regulatory property of PS that results in tolerance induction can be harnessed for clinical applications, such as to treat autoimmune conditions and to reduce immunogenicity of therapeutic proteins. This review attempts to provide an overview of the biological functions of PS in the immune response and its potential therapeutic applications.

Orofacial manifestations and dental management of systemic lupus erythematosus: A review

Systemic lupus erythematosus (SLE) is an autoimmune multisystem disease with numerous clinical manifestations. There is no consensus about the ideal oral management for this group of patients to date. This review aimed to describe the broad spectrum of orofacial and clinical manifestations and their therapeutic approaches. Studies concerning orofacial manifestations of SLE and dental treatment modalities were selected by a literature search (1978-2019) using Google Scholar, PubMed/MEDLINE electronic databases. The initial search strategy provided a total of 129 articles, and of these, 30 were included for qualitative synthesis. The reviewed studies revealed that SLE patients are more at risk of compromised oral and dental health exhibiting increased risk of periodontal diseases and temporomandibular joint disorders. The use of systemic drugs especially immunosuppressive and anticoagulants in SLE patients may also influence their oral management. Results emphasize the need to carry out, at an early stage of the disease, an appropriate oral management of these patients to improve oral health-related quality of life and to prevent the need of more invasive therapeutics. A multidisciplinary approach is needed for dental and medical management of such patients.

Cutaneous Lupus Erythematosus: Current and Future Pathogenesis-Directed Therapies

Cutaneous lupus erythematosus (CLE) is an autoimmune disease of the skin with significant morbidity. Current treatments are often inadequate to control disease and there are no Food and Drug Administration (FDA)-approved therapies for this potentially debilitating disease, underscoring an unmet medical need. Recent insights into disease pathogenesis have implicated innate and adaptive immune components, including type I and type III interferons in the development of CLE. Promising clinical trials based on these insights are now underway. However, the full spectrum of immune cells, cytokines, and environmental triggers contributing to disease remain to be elucidated. In this review, we will highlight the current understanding of CLE immunopathogenesis, the ongoing clinical trial landscape, and provide a framework for designing future therapeutic strategies for CLE based on new insights into disease pathogenesis.

Mitochondrial functions and rare diseases

Mitochondria are dynamic cellular organelles responsible for a large variety of biochemical processes as energy transduction, REDOX signaling, the biosynthesis of hormones and vitamins, inflammation or cell death execution. Cell biology studies established that 1158 human genes encode proteins localized to mitochondria, as registered in MITOCARTA. Clinical studies showed that a large number of these mitochondrial proteins can be altered in expression and function through genetic, epigenetic or biochemical mechanisms including the interaction with environmental toxics or iatrogenic medicine. As a result, pathogenic mitochondrial genetic and functional defects participate to the onset and the progression of a growing number of rare diseases. In this review we provide an exhaustive survey of the biochemical, genetic and clinical studies that demonstrated the implication of mitochondrial dysfunction in human rare diseases. We discuss the striking diversity of the symptoms caused by mitochondrial dysfunction and the strategies proposed for mitochondrial therapy, including a survey of ongoing clinical trials.

Systemic Lupus Erythematosus and Endothelial Dysfunction: A Close Relationship

BACKGROUND

Accelerated atherosclerosis, responsible for premature cardiovascular disease, has been estimated to develop or progress in 10% of systemic lupus erythematosus (SLE) patients each year and to be 6-fold more frequent in SLE compared with the general population. The mechanisms underlying accelerated atherosclerosis in SLE are complex and involve classical and "non-classical" cardiovascular risk factors. Subclinical and disseminated atherosclerosis is associated with endothelial dysfunction and arterial stiffness.

OBJECTIVE

The aim of this review is to analyze the association between SLE and endothelial dysfunction.

RESULTS AND CONCLUSION

Different mechanisms have been proposed to explain the prevalence of endothelial dysfunction in SLE, which are briefly reported in this review: impaired clearance of apoptotic cells, oxidative stress markers, B cell activation with different circulating autoantibodies, different subtypes of T lymphocytes, cytokine cascade. Several studies and meta-analyses show a significant trend towards a prevalence of subclinical accelerated atherosclerosis in patients with SLE compared with healthy controls, since childhood. Based on general considerations, we suggest a multidisciplinary management to assess endothelial dysfunction at the diagnosis of the disease and to periodically search for and treat the traditional cardiovascular risk factors. Prospective studies are needed to confirm the benefits of this management.

DNA Damage Response and Oxidative Stress in Systemic Autoimmunity

The DNA damage response and repair (DDR/R) network, a sum of hierarchically structured signaling pathways that recognize and repair DNA damage, and the immune response to endogenous and/or exogenous threats, act synergistically to enhance cellular defense. On the other hand, a deregulated interplay between these systems underlines inflammatory diseases including malignancies and chronic systemic autoimmune diseases, such as systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis. Patients with these diseases are characterized by aberrant immune response to self-antigens with widespread production of autoantibodies and multiple-tissue injury, as well as by the presence of increased oxidative stress. Recent data demonstrate accumulation of endogenous DNA damage in peripheral blood mononuclear cells from these patients, which is related to (a) augmented DNA damage formation, at least partly due to the induction of oxidative stress, and (b) epigenetically regulated functional abnormalities of fundamental DNA repair mechanisms. Because endogenous DNA damage accumulation has serious consequences for cellular health, including genomic instability and enhancement of an aberrant immune response, these results can be exploited for understanding pathogenesis and progression of systemic autoimmune diseases, as well as for the development of new treatments.

Neutrophils-Important Communicators in Systemic Lupus Erythematosus and Antiphospholipid Syndrome

Systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) are two autoimmune diseases that can occur together or separately. Insights into the pathogenesis have revealed similarities, such as development of autoantibodies targeting subcellular antigens as well as a shared increased risk of cardiovascular morbidity, potentially due to mutual pathologic mechanisms. In this review, we will address the evidence implicating neutrophils in the pathogenesis of these conditions, highlighting their shared features. The neutrophil is the most abundant leukocyte, recognized for its role in infectious and inflammatory diseases, but dysregulation of neutrophil effector functions, including phagocytosis, oxidative burst and formation of neutrophil extracellular traps (NETs) may also contribute to an autoimmune process. The phenotype of neutrophils in SLE and APS differs from neutrophils of healthy individuals, where neutrophils in SLE and APS are activated and prone to aggregate. A specific subset of low-density neutrophils with different function compared to normal-density neutrophils can also be found within the peripheral blood mononuclear cell (PBMC) fraction after density gradient centrifugation of whole blood. Neutrophil phagocytosis is required for regular clearance of cell remnants and nuclear material. Reactive oxygen species (ROS) released by neutrophils during oxidative burst are important for immune suppression and impairment of ROS production is seen in SLE. NETs mediate pathology in both SLE and APS via several mechanisms, including exposure of autoantigens, priming of T-cells and activation of autoreactive B-cells. NETs are also involved in cardiovascular events by forming a pro-thrombotic scaffolding surface. Lastly, neutrophils communicate with other cells by producing cytokines, such as Interferon (IFN) -α, and via direct cell-cell contact. Physiological neutrophil effector functions are necessary to prevent autoimmunity, but in SLE and APS these are altered.

Triggers of Autoimmunity: The Role of Bacterial Infections in the Extracellular Exposure of Lupus Nuclear Autoantigens

Infections are considered important environmental triggers of autoimmunity and can contribute to autoimmune disease onset and severity. Nucleic acids and the complexes that they form with proteins—including chromatin and ribonucleoproteins—are the main autoantigens in the autoimmune disease systemic lupus erythematosus (SLE). How these nuclear molecules become available to the immune system for recognition, presentation, and targeting is an area of research where complexities remain to be disentangled. In this review, we discuss how bacterial infections participate in the exposure of nuclear autoantigens to the immune system in SLE. Infections can instigate pro-inflammatory cell death programs including pyroptosis and NETosis, induce extracellular release of host nuclear autoantigens, and promote their recognition in an immunogenic context by activating the innate and adaptive immune systems. Moreover, bacterial infections can release bacterial DNA associated with other bacterial molecules, complexes that can elicit autoimmunity by acting as innate stimuli of pattern recognition receptors and activating autoreactive B cells through molecular mimicry. Recent studies have highlighted SLE disease activity-associated alterations of the gut commensals and the expansion of pathobionts that can contribute to chronic exposure to extracellular nuclear autoantigens. A novel field in the study of autoimmunity is the contribution of bacterial biofilms to the pathogenesis of autoimmunity. Biofilms are multicellular communities of bacteria that promote colonization during chronic infections. We review the very recent literature highlighting a role for bacterial biofilms, and their major components, amyloid/DNA complexes, in the generation of anti-nuclear autoantibodies and their ability to stimulate the autoreactive immune response. The best studied bacterial amyloid is curli, produced by enteric bacteria that commonly cause infections in SLE patients, including Escherichia coli and Salmonella spps. Evidence suggests that curli/DNA complexes can trigger autoimmunity by acting as danger signals, molecular mimickers, and microbial chaperones of nucleic acids.

The role of neutrophil extracellular traps in rheumatic diseases

Rheumatic diseases are a collection of disorders defined by the presence of inflammation and destruction of joints and internal organs. A common feature of these diseases is the presence of autoantibodies targeting molecules commonly expressed in neutrophils. These preformed mediators are released by neutrophils but not by other immune cells such as macrophages. Neutrophils, major players in the host innate immune response, initiate a cell death mechanism termed neutrophil extracellular trap (NET) formation as a way to ensnare pathogens. NETs are also a source of released self-molecules found in rheumatic diseases. Subsequently, research on the role of NETs in the onset, progression and resolution of inflammation in rheumatic diseases has intensified. This Review has two aims. First, it aims to highlight the mechanisms required for the generation of NETs, the research landscape of which is rapidly changing. Second, it aims to discuss the role of neutrophils and NETs in systemic lupus erythematosus, vasculitis (specifically anti-neutrophil cytoplasmic autoantibody-associated vasculitis), rheumatoid arthritis and gout. Our goal is to clarify the field of NET research in rheumatic diseases in the hope of improving the therapeutic approaches utilized for these diseases.

TNF-α promoter polymorphisms (G-238A and G-308A) are associated with susceptibility to Systemic Lupus Erythematosus (SLE) and P. falciparum malaria: a study in malaria endemic area

Tumor necrosis factor-α (TNF-α) is a proinflammatory cytokine associated with autoimmune and infectious diseases. Importance of TNF-α in P. falciparum malaria and systemic lupus erythematosus (SLE) have been demonstrated. However, association of functional promoter variants with SLE and malaria is lacking in malaria endemic population. A total of 204 female SLE patients and 224 age and sex matched healthy controls were enrolled in the study. Three hundred fourteen P. falciparum infected patients with different clinical phenotypes were included. TNF-α polymorphisms (G-238A & G-308A) were genotyped by PCR-RFLP. Plasma levels of TNF-α was quantified by ELISA. Heterozygous mutants and minor alleles of TNF-α (G-238A and G-308A) polymorphisms were significantly higher in SLE patients compared to healthy controls and associated with development of lupus nephritis. In addition, both promoter variants were associated with severe P. falciparum malaria. SLE patients demonstrated higher levels of plasma TNF-α compared to healthy controls. TNF-α (G-238A and G-308A) variants were associated with higher plasma TNF-α. In conclusion, TNF-α (G-238A & G-308A) variants are associated with higher plasma TNF-α levels in SLE patients residing in malaria endemic areas and could be a contributing factor in the development of SLE and susceptibility to severe P. falciparum malaria.

Systemic Lupus Erythematosus and DNA Degradation and Elimination Defects

Introduction: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that is characterized by the production of autoantibodies specific for components of the cell nucleus and that causes damage to body tissues and organs. The pathogenesis of SLE remains unclear, with numerous studies pointing to a combination of genetic and environmental factors. A critical stage in SLE development is cell necrosis, in which undegraded chromatin and nucleoproteins are released into the blood, resulting in circulating cell-free DNA and serum nucleoproteins that trigger anti-dsDNA autoantibody production. This systematic literature review aimed to examine whether SLE stems from a DNA degradation and elimination defect. Materials and Methods: An advanced literature search was conducted in PubMed using the following keywords: [("SLE" OR "Systemic Lupus Erythematosus" OR "Lupus")] AND [("DNA" OR "DNA Degradation")] AND [("Defect Elimination")]. More articles were obtained from the references of the identified articles and basic Google searches. Twenty-five peer-reviewed articles published within the past 10 years (2007-2018) were included for review. Results: The findings of each study are summarized in Tables 1, 2. Discussion and Conclusion: The etiopathogenesis of SLE remains controversial, which limits therapeutic inventions for this disease. However, SLE is a DNA degradation and elimination disorder caused by uncleared histones and nuclear material that leak into the extracellular space and form cell-free DNA, triggering an immune response that destroys tissues and organs. Under normal conditions, apoptosis allows DNA and other nuclear material to be efficiently cleared through degradation and additional complex mechanisms such that this material does not trigger the immune system to produce nuclear autoantibodies.