anti-dsDNA Autoantibodies Research Articles

Early peripheral B cells in inactive SLE are transcriptionally and epigenetically primed for T-dependent activation

Abstract Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease characterized by repeated episodes of increased disease activity followed by periods of inactivity and remission. Increased titer of anti-dsDNA autoantibodies is often associated with active disease and the proliferation of autoreactive B cells are thought to play a major role in the progression of disease. In this study we investigated the transcriptional and epigenetic profile of early peripheral B cells—transitional (T1T2) and resting naïve (rN)—in inactive and active disease from a large cohort (n=46) of African American SLE patients. Our results show that the transcriptome of these B cells show a dysregulated signature as previously reported, but this signature is distinct between inactive and active SLE. Active disease is characterized by a greater number of differentially expressed genes (DEG) compared to healthy controls (HC), however, rN B cells in inactive disease patients express high levels of genes associated with T-dependent activation, IL4 signaling, and germinal center reactions. Chromatin accessibility across the genome of inactive disease B cells show that they share a subset of differentially accessible regions (DAR) from HC that are similarly dysregulated in both inactive and active flaring individuals, but inactive SLE B cells also have acquired several hundred unique DAR regions—some of which correspond with motifs or loci encoding important B cell development transcription factors. These findings suggest a distinct profile in early B cells from inactive disease patients that remains present during disease remission and may predispose these cells towards T-dependent activation as a response to long-term disease. Supported by grants from NIH (T32 GM0008490, 3U19 AI110483-08S2 8744)

Modulation of murine lupus by Aconitate Decarboxylase 1

Abstract Mitochondrial synthesis of itaconate by myeloid cells (monocytes and macrophages) is mediated by the TCA cycle enzyme Aconitate Decarboxylase 1 (Acod1). Upregulation of Acod1–itaconate pathway, occurs after activation of various Toll-like receptors (TLRs) or cytokine stimulation (TNF or type I Interferons). While various anti-inflammatory effects of the Acod1 – Itaconate pathway have been previously reported (e.g. decreases in IL-6 and IL-1β synthesis) the contribution of impairments in endogenous itaconate synthesis in systemic lupus erythematosus (SLE) remain poorly characterized. First, we explored and characterized Acod1 expression in bone marrow or monocyte-derived macrophages (BMDM and MDM, respectively) following in vitro imiquimod (IMQ) treatment. Then, we investigated the role of endogenous itaconate modulation in the development and severity of TLR-7 induced lupus using the IMQ model. 10-week-old wild type and Acod1 −/−mice were treated with topical IMQ cream for 5 weeks to induce an SLE phenotype. We found that Acod1 protein expression is induced in BMDM and MDM after 12 hours of IMQ stimulation, and this induction is partially dependent on IFNRa1 signaling. Moreover, Acod1 −/−BMDM treated with IMQ for 12 h displayed higher mRNA expression of il6, il1b, il18, ccl2, cxcl2, and cxcl9, together with an increase in pro-IL-1β protein levels. IL-6 and IL-1β production were also increased. After 5 weeks of in vivo IMQ topical treatment, Acod1 −/−mice have a higher concentration of circulating anti-dsDNA autoantibodies but a decrease in splenomegaly compared to the treated WT mice. These results, demonstrate a putative role for endogenous Acod1-itaconate pathway in the regulation of autoimmunity. This work is support by the NIH/NIAMS Intramural Research Program

Ophiopogonin D attenuates the progression of murine systemic lupus erythematosus by reducing B cell numbers.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by immune abnormalities leading to multi-organ damage. The activation of autoreactive B cell differentiation will lead to the production of pathogenic autoantibodies, contributing to the development of SLE. However, the effects of Ophiopogonin D (OP-D) on B cell activation and autoantibody production as well as renal injury in the pathogenesis of SLE remain unclear. MRL/lpr mice, one of the most commonly used animal models of SLE, were intragastrically administered with 5 mg/kg/d OP-D at 17 weeks of age for 3 weeks. The survival rates of mice in each group were monitored for 6 weeks until 23 weeks of age. Proteinuria and serum creatinine levels were measured. Serum levels of immunoglobulin (Ig)G, IgM, and anti-dsDNA autoantibodies were detected by enzyme-linked immunosorbent assay. Numbers of CD19+ B cells in the blood, spleen and bone marrow and numbers of splenic germinal center (GC) B cells were calculated by using flow cytometry. OP-D treatment prolonged survival in MRL/lpr mice. OP-D treatment reduced proteinuria and serum creatinine levels as well as mitigated renal pathological alternation in MRL/lpr mice. Furthermore, serum levels of IgG, IgM, and anti-dsDNA autoantibodies were reduced by OP-D treatment. OP-D lessened not only CD19+ B cells in the spleen and bone marrow but also plasma cells that secreted anti-dsDNA autoantibodies, IgG and IgM in the spleen and bone marrow. OP-D ameliorated the progression of SLE by inhibiting the secretion of autoantibodies though reducing B cell numbers.

Mouse models, antibodies, and neuroimaging: Current knowledge and future perspectives in neuropsychiatric systemic lupus erythematosus (NPSLE).

As a chronic autoimmune disease systemic lupus erythematosus (SLE) can also affect the central and the peripheral nervous system causing symptoms which are summed up as neuropsychiatric systemic lupus erythematosus (NPSLE). These symptoms are heterogenous including cognitive impairment, seizures, and fatigue, leading to morbidity or even mortality. At present, little is known about the pathophysiological processes involved in NPSLE. This review focuses on the current knowledge of the pathogenesis of NPSLE gained from the investigation of animal models, autoantibodies, and neuroimaging techniques. The antibodies investigated the most are anti-ribosomal P protein antibodies (Anti-rib P) and anti-N-Methyl-D-Aspartic Acid Receptor 2 antibodies (Anti-NR2), which represent a subpopulation of anti-dsDNA autoantibodies. Experimental data demonstrates that Anti-rib P and Anti-NR2 cause different neurological pathologies when applied intravenously (i.v.), intrathecally or intracerebrally in mice. Moreover, the investigation of lupus-prone mice, such as the MRL/MpJ-Fas lpr/lpr strain (MRL/lpr) and the New Zealand black/New Zealand white mice (NZB × NZW F1) showed that circulating systemic antibodies cause different neuropsychiatric symptoms compared to intrathecally produced antibodies. Furthermore, neuroimaging techniques including magnetic resonance imaging (MRI) and positron emission tomography (PET) are commonly used tools to investigate structural and functional abnormalities in NPSLE patients. Current research suggests that the pathogenesis of NPSLE is heterogenous, complex and not yet fully understood. However, it demonstrates that further investigation is needed to develop individual therapy in NPSLE.

Anti-dsDNA B-Cell ELISpot as a Monitoring and Flare Prediction Tool in SLE Patients.

Anti-dsDNA autoantibodies quantification and complement levels are widely used to monitor disease activity in systemic lupus erythematosus (SLE). However, better biomarkers are still needed. We hypothesised whether the dsDNA antibody-secreting B-cells could be a complementary biomarker in disease activity and prognosis of SLE patients. Fifty-two SLE patients were enrolled and followed for up to 12 months. Additionally, 39 controls were included. An activity cut-off (comparing active and non-active patients according to clinical SLEDAI-2K) was established for SLE-ELISpot, chemiluminescence and Crithidia luciliae indirect immunofluorescence tests (≥11.24, ≥374.1 and ≥1, respectively). Assays performances together with complement status were compared regarding major organ involvement at the inclusion and flare-up risk prediction after follow-up. SLE-ELISpot showed the best performance in identifying active patients. High SLE-ELISpot results were associated with haematological involvement and, after follow-up, with an increased hazard ratio for disease flare-up (3.4) and especially renal flare (6.5). Additionally, the combination of hypocomplementemia and high SLE-ELISpot results increased those risks up to 5.2 and 32.9, respectively. SLE-ELISpot offers complementary information to anti-dsDNA autoantibodies to evaluate the risk of a flare-up in the following year. In some cases, adding SLE-ELISpot to the current follow-up protocol for SLE patients can improve clinicians' personalised care decisions.

Prolactin promotes proliferation of germinal center B cells, formation of plasma cells, and elevated levels of IgG3 anti-dsDNA autoantibodies.

Systemic lupus erythematosus (SLE) mainly affects females at reproductive age, which has been associated with hormones, such as prolactin (PRL). Different studies suggest that PRL exacerbates the clinical manifestations of SLE both in patients and in mouse models (e.g., the MRL/lpr strain), increasing the production of autoantibodies, which can be deposited as immune complexes and trigger inflammation and damage to different tissues. The objective of this work was to explore the potential mechanisms by which PRL increases the concentration of self-reactive antibodies in the MRL/lpr SLE model. To this end, we determined the role of PRL on the activation and proliferation of germinal center B cells (B-GCs) and their differentiation into antibody-secreting cells (ASCs). We show that the absolute number and percentage of B-GCs were significantly increased by PRL in vivo or upon in vitro treatment with anti-IgM and anti-CD40 antibodies and PRL. The augmented B-GC numbers correlated with enhanced proliferation, but we did not observe enhanced expression of CD80 and CD86 activation markers or the BCL6 transcription factor, arguing against a more effective differentiation. Nevertheless, we observed enhanced phosphorylation of STAT1, secretion of IL-6, expression of IRF4, numbers of ASCs, and levels of IgG3 antibodies directed against dsDNA. Altogether, these results support the hypothesis that a PRL-mediated expansion of B-GCs yields more self-reactive ASCs, potentially explaining the pathogenic immune complexes that steadily lead to tissue damage during SLE.

P2X7 purinergic receptor plays a critical role in maintaining T-cell homeostasis and preventing lupus pathogenesis.

The severe lymphoproliferative and lupus diseases developed by MRL/lpr mice depend on interactions between the Fas lpr mutation and MRL genetic background. Thus, the Fas lpr mutation causes limited disease in C57BL/6 mice. We previously found that accumulating B220+ CD4–CD8– double negative (DN) T cells in MRL/lpr mice show defective P2X7 receptor ( P2X7)-induced cellular functions, suggesting that P2X7 contributes to T-cell homeostasis, along with Fas. Therefore, we generated a B6/lpr mouse strain (called B6/lpr-p2x7KO) carrying homozygous P2X7 knockout alleles. B6/lpr-p2x7KO mice accumulated high numbers of FasL-expressing B220+ DN T cells of CD45RBhighCD44high effector/memory CD8+ T-cell origin and developed severe lupus, characterized by leukocyte infiltration into the tissues, high levels of IgG anti-dsDNA and rheumatoid factor autoantibodies, and marked cytokine network dysregulation. B6/lpr-p2x7KO mice also exhibited a considerably reduced lifespan. P2X7 is therefore a novel regulator of T-cell homeostasis, of which cooperation with Fas is critical to prevent lymphoaccumulation and autoimmunity.

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.

Comparison of circulating miR-148a and miR-126 with autoantibodies as biomarkers of lupus nephritis in patients with SLE

ABSTRACT Lupus nephritis (LN) is the main manifestation of systemic Lupus Erythematosus (SLE). MicroRNAs (miRNAs) and autoantibodies could be suitable candidate biomarkers of LN. This study evaluates the expression of circulating miR-148a and miR-126 along with anti-dsDNA, anti-C1q, and anti-C3b autoantibodies in SLE patients with LN (SLE + LN). 30 women with SLE, 30 women with SLE + LN, and 25 women as healthy controls (HCs) were enrolled in this study. The plasma expression of selected miRNAs was evaluated by real-time PCR. The serum level of anti-dsDNA, C1q, and C3b antibodies was measured by the ELISA. The expression of miR-148a was significantly increased in SLE and SLE+LN groups compared with the control group. No significant difference was found in the expression of miR-126 among the groups. The frequency of autoantibodies was significantly higher in the SLE + LN group than SLE. The Higher levels of circulating miR-148a in the SLE samples compared with the HCs suggest that this miRNA could be a reliable biomarker for SLE patients (with or without LN). Also, autoantibodies against dsDNA, C1q, and, C3 could be used for the prediction of SLE nephritis, independently. However, further studies are needed to confirm these findings.

Deletion of microRNA-183-96-182 Cluster in Lymphocytes Suppresses Anti-DsDNA Autoantibody Production and IgG Deposition in the Kidneys in C57BL/6-Faslpr/lpr Mice.

Dysregulated miRNAs have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). Our previous study reported a substantial increase in three miRNAs located at the miR-183-96-182 cluster (miR-183C) in several autoimmune lupus-prone mice, including MRL/lpr and C57BL/6-lpr (B6/lpr). This study reports that in vitro inhibition of miR-182 alone or miR-183C by specific antagomirs in activated splenocytes from autoimmune-prone MRL/lpr and control MRL mice significantly reduced lupus-related inflammatory cytokines, interferon-gamma (IFNγ), and IL-6 production. To further characterize the role of miR-182 and miR-183C cluster in vivo in lupus-like disease and lymphocyte phenotypes, we used hCD2-iCre to generate B6/lpr mice with conditional deletion of miR-182 or miR-183C in CD2+ lymphocytes (miR-182−/−B6/lpr and miR-183C−/-B6/lpr). The miR-182−/−B6/lpr and miR-183C−/−B6/lpr mice had significantly reduced deposition of IgG immunocomplexes in the kidney when compared to their respective littermate controls, although there appeared to be no remarkable changes in renal pathology. Importantly, we observed a significant reduction of serum anti-dsDNA autoantibodies in miR-183C−/−B6/lpr mice after reaching 24 weeks-of age compared to age-matched miR-183Cfl/flB6/lpr controls. In vitro activated splenocytes from miR-182−/−B6/lpr mice and miR-183C−/−B6/lpr mice showed reduced ability to produce lupus-associated IFNγ. Forkhead box O1(Foxo1), a previously validated miR-183C miRNAs target, was increased in the splenic CD4+ cells of miR-182−/−B6/lpr and miR-183C−/−B6/lpr mice. Furthermore, in vitro inhibition of Foxo1 with siRNA in splenocytes from miR-182−/−B6/lpr and miR-183C−/-B6/lpr mice significantly increased IFNγ expression following anti-CD3/CD28 stimulation, suggesting that miR-182 and miR-183C miRNAs regulate the inflammatory IFNγ in splenocytes via targeting Foxo1. The deletion of either miR-182 alone or the whole miR-183C cluster, however, had no marked effect on the composition of T and B cell subsets in the spleens of B6/lpr mice. There were similar percentages of CD4+, CD8+, CD19+, as well as Tregs, follicular helper T (TFH), germinal center B (GCB), and plasma cells in the miR-183C−/−B6/lpr and miR-182−/−B6/lpr mice and their respective littermate controls, miR-183Cfl/flB6/lpr and miR-182fl/flB6/lpr mice. Together, our data demonstrate a role of miR-183C in the regulation of anti-dsDNA autoantibody production in vivo in B6/lpr mice and the induction of IFNγ in in vitro activated splenocytes from B6/lpr mice.

Staphylococcus aureus peptidoglycan (PGN) induces pathogenic autoantibody production via autoreactive B cell receptor clonal selection, implications in systemic lupus erythematosus

ObjectivesThere is an intricate interplay between the microbiome and the immune response impacting development of normal immunity and autoimmunity. However, we do not fully understand how the microbiome affects production of natural-like and pathogenic autoantibodies. Peptidoglycan (PGN) is a component of the bacterial cell wall which is highly antigenic. PGNs from different bacteria can differ in their immune regulatory activities. MethodsC57BL/6 and MRL/lpr mice were intraperitoneally injected with saline or PGN from Staphylococcus aureus or Bacillus subtilis. Spleen anti-double-stranded DNA (dsDNA) IgG + B cells were sorted for B-cell receptor sequencing. Serum autoantibody levels and kidney damage were analyzed. Further, the association between plasma S. aureus translocation and systemic lupus erythematosus (SLE) pathogenesis was assessed in women. ResultsAdministration of B. subtilis PGN induced natural-like anti-dsDNA autoantibodies (e.g., IgM, short lived IgG response, and no tissue damage), whereas S. aureus PGN induced pathogenic anti-dsDNA autoantibodies (e.g., prolonged IgG production, low IgM, autoantibody-mediated kidney damage) in C57BL/6 and/or MRL/lpr mice. However, serum total IgG did not differ. S. aureus PGN induced antibodies with reduced clonality and greater hypermutation of IGHV3-74 in splenic anti-dsDNA IgG + B cells from C57BL/6 mice. Further, S. aureus PGN promoted IgG class switch recombination via toll-like receptor 2. Plasma S. aureus DNA levels were increased in women with SLE versus control women and correlated with levels of lupus-related autoantibodies and renal involvement. ConclusionsS. aureus PGN induces pathogenic autoantibody production, whereas B. subtilis PGN drives production of natural nonpathogenic autoantibodies.

FOXP3 exon 2 controls Treg stability and autoimmunity.

Differing from the mouse Foxp3 gene that encodes only one protein product, human FOXP3 encodes two major isoforms through alternative splicing-a longer isoform (FOXP3 FL) containing all the coding exons and a shorter isoform lacking the amino acids encoded by exon 2 (FOXP3 ΔE2). The two isoforms are naturally expressed in humans, yet their differences in controlling regulatory T cell phenotype and functionality remain unclear. In this study, we show that patients expressing only the shorter isoform fail to maintain self-tolerance and develop immunodeficiency, polyendocrinopathy, and enteropathy X-linked (IPEX) syndrome. Mice with Foxp3 exon 2 deletion have excessive follicular helper T (TFH) and germinal center B (GC B) cell responses, and develop systemic autoimmune disease with anti-dsDNA and antinuclear autoantibody production, as well as immune complex glomerulonephritis. Despite having normal suppressive function in in vitro assays, regulatory T cells expressing FOXP3 ΔE2 are unstable and sufficient to induce autoimmunity when transferred into Tcrb-deficient mice. Mechanistically, the FOXP3 ΔE2 isoform allows increased expression of selected cytokines, but decreased expression of a set of positive regulators of Foxp3 without altered binding to these gene loci. These findings uncover indispensable functions of the FOXP3 exon 2 region, highlighting a role in regulating a transcriptional program that maintains Treg stability and immune homeostasis.

EGR2 Deletion Suppresses Anti-DsDNA Autoantibody and IL-17 Production in Autoimmune-Prone B6/lpr Mice: A Differential Immune Regulatory Role of EGR2 in B6/lpr Versus Normal B6 Mice.

Previous studies have reported that deletion of the transcription factor, early growth response protein 2 (EGR2), in normal C57BL/6 (B6) resulted in the development of lupus-like autoimmune disease. However, increased EGR2 expression has been noted in human and murine lupus, which challenges the notion of the autoimmune suppressive role of EGR2 in B6 mice. In this study, we derived both conditional EGR2-/-B6/lpr and EGR2-/-B6 mice to elucidate the immune and autoimmune regulatory roles of EGR2 in autoinflammation (B6/lpr) versus physiologically normal (B6) conditions. We found that conditional EGR2 deletion increased spleen weight, enhanced T cell activation and IFNγ production, and promoted germinal center B cells and LAG3+ regulatory T cells development in both B6/lpr and B6 mice. Nevertheless, EGR2 deletion also showed strikingly differential effects in these two strains on T lymphocyte subsets profile, Foxp3+ Tregs and plasma cell differentiation, anti-dsDNA autoantibodies and immunoglobulins production, and on the induction of IL-17 in in vitro activated splenocytes. Specifically, EGR2 deletion in B6/lpr mice significantly decreased serum levels of anti-dsDNA autoantibodies, total IgG, IgM, IgG1, and IgG2a with reduced plasma cells differentiation. Furthermore, EGR2 deletion in B6/lpr mice had no obvious effect on IgG immunocomplex deposition, medium caliber vessel, and glomeruli inflammation but increased complement C3 immunocomplex deposition and large caliber vessel inflammation in the kidneys. Importantly, we demonstrated that EGR2 deletion in B6/lpr mice significantly reduced pathogenic CD4-CD8-CD3+B220+ double negative T cells, which correlated with the reduced anti-dsDNA autoantibodies in serum and decreased IL-17 production in splenocytes of EGR2-/-B6/lpr mice. Together, our data strongly suggest that the role of EGR2 is complex. The immunoregulatory role of EGR2 varies at normal or autoinflammation conditions and should not be generalized in differential experimental settings.

Brief report on the relation between complement C3a and anti\xa0dsDNA antibody in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by the production of a diverse array of autoantibodies and the dysfunctional activation of the complement system. The specific association between the complement component C3a (C3a) protein and antibodies specific for double-stranded DNA (anti-dsDNA), however, has not been studied in detail to date. This study was thus designed to more fully explore circulating C3a levels in SLE patients. In total, 13 SLE patients were enrolled in this study after having been diagnosed in accordance with the SLICC classification criteria, with 7 and 6 patients respectively exhibiting positivity for anti-dsDNA and anti-Sm autoantibodies. Serum complement component C1q (C1q) and C3a levels in samples from these patients were detected via Western blotting, while other serological, biochemical, and clinical parkers associated with disease activity were detected using standard laboratory techniques. The levels of serum C3a in anti-dsDNA+ patients were significantly elevated as compared to those in anti-Sm+ patients (P < 0.01), and a positive correlation between serum C3a levels and SLE Disease Activity Index scores was detected (P < 0.05, r = 0.6134). C3a levels are correlated with the degree of SLE disease activity and other clinically relevant readouts in SLE patients. C3a levels may also enable the differentiation between inactive and active SLE, while also offering value as an advantageous biomarker for thrombophilia monitoring in SLE patients.

Sustained NPSLE development in the absence of systemic lupus-like disease in TLR7- deficient B6.Nba2

Abstract Neuropsychiatric Lupus (NPSLE) is a common manifestation of systemic lupus erythematosus (SLE) which includes presentations of cognitive learning and memory deficits and anxiety disorders. The B6.Nba2 mouse model of SLE presents with anxiety and depression. Toll-like receptor (TLR7), a known driver of type I interferons and SLE, drives systemic autoimmunity in the B6.Nba2 model, but whether TLR7-deficient B6.Nba2 mice develop NPSLE remains unknown. Age-matched female B6, B6.Nba2, and B6.Nba2.TLR7 knockout mice (KO) were tested in open field (OFT), elevated plus maze (EPM), Y maze (YM) and novel object recognition (NOR) tests between the ages of 8–32 weeks. To determine levels of systemic autoimmunity and inflammation serum autoantibody and tumor necrosis factor-related of apoptosis (TWEAK) levels were determined by ELISA. Both B6.Nba2 and B6.Nba2.TLR7 KO mice presented with anxiety (OFT, EPM) and dysfunctional spatial memory (YM). B6.Nba2 mice displayed a general memory defect (NOR), but this was not seen in TLR7-KO mice. Only B6.Nba2 mice presented with elevated levels of anti-dsDNA autoantibodies and corresponding DWEYS-reactive antibodies. In contrast, serum levels of TWEAK were elevated in both B6.Nba2 and B6.Nba2.TLR7 KO mice, suggesting that signals other than TLR7 may drive inflammation in this model. In conclusion, both B6.Nba2 and B6.Nba2.TLR7KO presented with elevated serum TWEAK levels, anxiety and memory deficits, despite only B6.Nba2 mice displaying anti-dsDNA and DWEYS-reactive autoantibodies. Thus in this model, NPSLE appear to develop in an autoantibody-independent fashion. Studies are ongoing to determine the nature of TLR7/autoantibody-independent NPSLE. Supported by a grant from the Department of Defense (LR 180040)

EGR2 deletion displays similar and differential effects on immunological development and function in autoinflammation-prone B6/lpr and normal B6 mice

Abstract Transcription factor early growth response protein 2 (EGR2) prevents the development of lupus-like autoimmune disease in C57BL/6 (B6) mice by negatively regulating T cell activation, inflammatory cytokine IFNγ and IL-17 production and by suppressing humoral responses. However, increased EGR2 expression has been observed in lupus and also other autoimmune disorders, which contradicts the autoimmune suppressive role of EGR2. Here, we derived conditional EGR2−/−B6/lpr and EGR2−/−B6 mice to investigate and compare the immune regulatory role of EGR2 in autoinflammation (B6/lpr) versus normal physiological (B6) conditions. Significantly, we found that in B6/lpr mice, but not in B6 mice, EGR2 deletion dramatically suppressed serum levels of anti-dsDNA autoantibodies, total IgG, IgG1, IgG2a, and IgM. We further demonstrated that while EGR2 deletion promoted germinal center B (GCB) cell development in both B6 and B6/lpr mice, it significantly reduced the differentiation of plasma and plasmablasts cells in B6/lpr mice. EGR2 deletion promoted splenomegaly and T cell activation in both B6 and B6/lpr mice, but it differentially regulated the profiles of immune cell subpopulations in the spleens of B6 and B6/lpr mice. Especially, EGR2 deletion dramatically suppressed the development of double negative T cells in B6/lpr mice. Moreover, we found that EGR2 had an opposite role in regulating IL-17 production in in vitro activated splenocytes from B6/lpr and B6 mice, although EGR2 had a similar suppressive role for IFNγ production. Together, our data strongly suggest that the immune and autoimmune regulatory roles of EGR2 are context dependent, and should not be generalized in normal physiology and different pathological conditions. Supported by VMCVM-VCOM Center for One Heath Research Seed Grant Program

CD39 and CD326 Are Bona Fide Markers of Murine and Human Plasma Cells and Identify a Bone Marrow Specific Plasma Cell Subpopulation in Lupus.

Antibody-secreting cells (ASCs) contribute to immunity through production of antibodies and cytokines. Identification of specific markers of ASC would allow selective targeting of these cells in several disease contexts. Here, we performed an unbiased, large-scale protein screening, and identified twelve new molecules that are specifically expressed by murine ASCs. Expression of these markers, particularly CD39, CD81, CD130, and CD326, is stable and offers an improved resolution for ASC identification. We accessed their expression in germ-free conditions and in T cell deficient mice, showing that at least in part their expression is controlled by microbial- and T cell-derived signals. Further analysis of lupus mice revealed the presence of a subpopulation of LAG-3– plasma cells, co-expressing high amounts of CD39 and CD326 in the bone marrow. This population was IgM+ and correlated with IgM anti-dsDNA autoantibodies in sera. Importantly, we found that CD39, CD81, CD130, and CD326 are also expressed by human peripheral blood and bone marrow ASCs. Our data provide innovative insights into ASC biology and function in mice and human, and identify an intriguing BM specific CD39++CD326++ ASC subpopulation in autoimmunity.

Cytokines and autoantibodies profile during systemic lupus erythematosus and psoriasis diseases in Egypt

ObjectiveCytokine, a small secreted protein, is secreted from one cell types to exert a particular effect on other cell types and/or on itself. Cytokines are characterized by their redundancy in the function; they are secreted in a cascade and can work synergistically and/or antagonistically. Cytokines have an important role in thepathogenesis of autoimmune diseases like systemic lupus erythematosus (SLE) and psoriasis (PS).Due to their crucial roles in the immune cells’ development, differentiation and regulation; any dysregulation in their production and/or action can lead to the development of autoimmune diseases.The study population was composed of healthy control volunteers, SLE patients that were diagnosed as lupus nephritis (LN) patients or non-LN patients with developed atherosclerosis (As), and psoriasis patients that were diagnosed as psoriasis patients without arthritis (Ps) or psoriatic arthritis patients (PsA). MethodsThe current study aimed to measure and compare the levels of T helper (h)1, Th2 and Th17 cytokines (IFN-γ, TNF-α, IL-17, -1β, -12, -10, -4, -2, -23, -18, -34 and -6) among Egyptian SLE and Ps patients. In addition, the pathway and type of Th cells involved in autoimmune-mediated tissue injury was examined. Detection of autoantibodies (ANA, anti-dsDNA, anti-sm, anti-histone, anti-ribosomal, APLA and anti-Ro/SSA) was performed to find if there is a relation between disease development and their presence. ResultsDetection of autoantibodies and complement proteins were beneficial in the diagnosis of SLE and psoriasis. ANA and anti-dsDNA autoantibodies were a good marker for the diagnosis of SLE and monitoring disease activity; however, other autoantibodies like APLA, anti-sm, anti-histone and anti-ribosomal can be used to indicate the disease activity. ConclusionsCytokines can be used to determine the disease activity and autoimmune-mediated tissue injured in both SLE and psoriasis. Where, IL-17 recorded the highest level in LN and PsA patients; while the highest levels of IL-34, -23 and -6 were recorded in PsA patients and IL-1β was a characteristic cytokine in As patients.

Co-positivity of anti-dsDNA, anti-nucleosome, and anti-smith autoantibodies as serological biomarkers for disease activity in systemic lupus erythematosus

BackgroundEvaluation of disease activity in systemic lupus erythematosus (SLE) patients is important for modulating the therapeutic plan and decreasing organ damage. Autoantibodies are important serological biomarkers in SLE. We evaluated the effect of co-positivity of anti-dsDNA, anti-nucleosome, and anti-smith, autoantibodies on the SLEDAI score in SLE patients.ResultsEighty adult SLE patients were included in this study. The correlations of the three autoantibodies with the SLEDAI score in addition to their sensitivity and specificity for the assessment of disease activity were analyzed. There was a highly significant difference between anti-dsDNA, anti-nucleosome, and anti-smith positive and negative groups as regards the SLEDAI score. Increased number of autoantibody positivity was associated with an increased mean rank of SLEDAI, and the three autoantibodies were positively correlated with each other and with the SLEDAI score. Roc curve analysis revealed that anti-smith has the highest sensitivity (90%) followed by anti-dsDNA and anti-nucleosome (85% for each). Moreover, anti-dsDNA had the highest specificity (88%) followed by anti-nucleosome (86%) then anti-smith (84%).ConclusionsAnti-dsDNA, anti-nucleosome, and anti-smith autoantibodies have a positive correlation with the SLEDAI score, and they may be considered as good serological biomarkers for the assessment of disease activity in SLE patients.

IgA anti-dsDNA antibodies: A neglected serological parameter in systemic lupus erythematosus

Anti-double-stranded DNA (anti-dsDNA) autoantibodies are archetypal biomarkers found in systemic lupus erythematosus (SLE). Although they can exist in any isotype, very little is understood about the IgA isotype for which most of our knowledge is derived from observational studies. This review article summarises our knowledge of this autoantibody isotype to date. Attention will be spent on clinical associations as well as its potential links with lupus nephritis for which there is still some controversy. Further understanding of this serological parameter may facilitate diagnosis, prognosis and treatments of systemic lupus erythematosus patients.