Production Of Antinuclear Autoantibodies Research Articles

Rab4A-directed endosome traffic shapes pro-inflammatory mitochondrial metabolism in T cells via mitophagy, CD98 expression, and kynurenine-sensitive mTOR activation

Activation of the mechanistic target of rapamycin (mTOR) is a key metabolic checkpoint of pro-inflammatory T-cell development that contributes to the pathogenesis of autoimmune diseases, such as systemic lupus erythematosus (SLE), however, the underlying mechanisms remain poorly understood. Here, we identify a functional role for Rab4A-directed endosome traffic in CD98 receptor recycling, mTOR activation, and accumulation of mitochondria that connect metabolic pathways with immune cell lineage development and lupus pathogenesis. Based on integrated analyses of gene expression, receptor traffic, and stable isotope tracing of metabolic pathways, constitutively active Rab4AQ72L exerts cell type-specific control over metabolic networks, dominantly impacting CD98-dependent kynurenine production, mTOR activation, mitochondrial electron transport and flux through the tricarboxylic acid cycle and thus expands CD4+ and CD3+CD4−CD8− double-negative T cells over CD8+ T cells, enhancing B cell activation, plasma cell development, antinuclear and antiphospholipid autoantibody production, and glomerulonephritis in lupus-prone mice. Rab4A deletion in T cells and pharmacological mTOR blockade restrain CD98 expression, mitochondrial metabolism and lineage skewing and attenuate glomerulonephritis. This study identifies Rab4A-directed endosome traffic as a multilevel regulator of T cell lineage specification during lupus pathogenesis.

The axis of complement C1 and nucleolus in antinuclear autoimmunity.

Antinuclear autoantibodies (ANA) are heterogeneous self-reactive antibodies that target the chromatin network, the speckled, the nucleoli, and other nuclear regions. The immunological aberration for ANA production remains partially understood, but ANA are known to be pathogenic, especially, in systemic lupus erythematosus (SLE). Most SLE patients exhibit a highly polygenic disease involving multiple organs, but in rare complement C1q, C1r, or C1s deficiencies, the disease can become largely monogenic. Increasing evidence point to intrinsic autoimmunogenicity of the nuclei. Necrotic cells release fragmented chromatins as nucleosomes and the alarmin HMGB1 is associated with the nucleosomes to activate TLRs and confer anti-chromatin autoimmunogenecity. In speckled regions, the major ANA targets Sm/RNP and SSA/Ro contain snRNAs that confer autoimmunogenecity to Sm/RNP and SSA/Ro antigens. Recently, three GAR/RGG-containing alarmins have been identified in the nucleolus that helps explain its high autoimmunogenicity. Interestingly, C1q binds to the nucleoli exposed by necrotic cells to cause protease C1r and C1s activation. C1s cleaves HMGB1 to inactive its alarmin activity. C1 proteases also degrade many nucleolar autoantigens including nucleolin, a major GAR/RGG-containing autoantigen and alarmin. It appears that the different nuclear regions are intrinsically autoimmunogenic by containing autoantigens and alarmins. However, the extracellular complement C1 complex function to dampen nuclear autoimmunogenecity by degrading these nuclear proteins.

Effects of Ruxolitinib on fibrosis in preclinical models of systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune fibrotic disorder notably characterized by the production of antinuclear autoantibodies, which have been linked to an excess of apoptotic cells, normally eliminated by a macrophagic efferocytosis. As interferon (IFN) signature and phosphorylation of JAK-STAT proteins are hallmarks of SSc tissues, we tested the hypothesis that a JAK inhibitor, ruxolitinib, targeting the IFN signaling, could improve efferocytosis of IFN-exposed human macrophages in vitro as well as skin and lung fibrosis.In vivo, BLM- and HOCl-induced skin thickness and fibrosis is associated with an increase of caspase-3 positive dermal cells and a significant increase of IFN-stimulated genes expression. In BLM-SSc model, ruxolitinib prevented dermal thickness, fibrosis and significantly decreased the number of cleaved caspase-3 cells in the dermis. Ruxolitinib also improved lung architecture and fibrosis although IFN signature was not entirely decreased by ruxolitinib. In vitro, ruxolitinib improves efferocytosis capacity of human monocyte-differentiated macrophages exposed to IFN-γ or IFN-β. In human fibroblasts derived from lung (HLF) biopsies isolated from patients with idiopathic pulmonary fibrosis, the reduced mRNA expression of typical TGF-β-activated markers by ruxolitinib was associated with a decrease of the phosphorylation of SMAD2 /3 and STAT3.Our finding supports the anti-fibrotic properties of ruxolitinib in a systemic SSc mouse model and in vitro in human lung fibroblasts.

Fecal immunoglobulin A (IgA) and its subclasses in systemic lupus erythematosus patients are nuclear antigen reactive and this feature correlates with gut permeability marker levels

Systemic lupus erythematosus (SLE) is characterized by the production of anti-nuclear autoantibodies. Here, for the first time, we show that the abundances of gut permeability marker Zonulin and IgA1- and IgA2- subclasses are significantly higher in the fecal samples of SLE patients compared to HCs. Importantly, IgA-total, and IgA1- and IgA2-subclasses from SLE patients showed higher nAg reactivity titers. Notably, we found that not only the nuclear antigen (nAg) reactive fecal IgA1:IgA2 ratio is higher in SLE patients, but also the abundance and nAg reactivity of fecal IgA and subclasses, IgA1 particularly, correlate with the fecal levels of Zonulin, which is produced primarily in the small intestine. These observations that higher amounts of nAg-reactive IgA and gut permeability marker are produced, particularly, in the proximal gut suggest a compromised epithelial barrier function and pro-inflammatory characteristics of small intestine in SLE patients.

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.

Impaired B cell anergy is not sufficient to breach tolerance to nuclear antigen in Vκ8/3H9 lupus-prone mice.

BackgroundSystemic lupus erythematosus (SLE) is a severe autoimmune disease in which immune tolerance defects drive production of pathogenic anti-nuclear autoantibodies. Anergic B cells are considered a potential source of these autoantibodies due to their autoreactivity and overrepresentation in SLE patients. Studies of lupus-prone mice have shown that genetic defects mediating autoimmunity can breach B cell anergy, but how this breach occurs with regards to endogenous nuclear antigen remains unclear. We investigated whether B and T cell defects in congenic mice (c1) derived from the lupus-prone New Zealand Black strain can breach tolerance to nuclear self-antigen in the presence of knock-in genes (Vκ8/3H9; dKI) that generate a ssDNA-reactive, anergic B cell population.MethodsFlow cytometry was used to assess splenic B and T cells from 8-month-old c1 dKI mice and serum autoantibodies were measured by ELISA. dKI B cells stimulated in vitro with anti-IgM were assessed for proliferation and activation by examining CFSE decay and CD86. Cytokine-producing T cells were identified by flow cytometry following culture of dKI splenocytes with PMA and ionomycin. dKI B cells from 6-8-week-old mice were adoptively transferred into 4-month-old wild type recipients and assessed after 7 days via flow cytometry and immunofluorescence microscopy.Resultsc1 dKI mice exhibited B cell proliferation indicative of impaired anergy, but had attenuated autoantibodies and germinal centres compared to wild type littermates. This attenuation appeared to stem from a decrease in PD-1hi T helper cells in the dKI strains, as c1 dKI B cells were recruited to germinal centres when adoptively transferred into c1 wild type mice.ConclusionAnergic, DNA-specific autoreactive B cells only seem to drive profound autoimmunity in the presence of concomitant defects in the T cell subsets that support high-affinity plasma cell production.

Impacts of GFP-FoxP3+ regulatory T cells on lupus hallmarks differ by genetic background and type of GFP knock-in

FoxP3 reporter mice expressing green fluorescence protein (GFP) have been used as a very convenient tool to investigate the impact of regulatory T (Treg) cells on pathogenesis in autoimmune diseases. Here, we found that GFP-FoxP3+ knock-in (KI) mice showed alterations in the production of anti-nuclear autoantibodies (ANAs) and nephritis with different extent, depending on the presence or absence of lupus susceptibility gene locus 1 (Sle1) and KI method: contrasting with B6.Sle1.fGFP-FoxP3 mice, expressing GFP via N-terminal insertion, B6.Sle1.iGFP-FoxP3, expressing GFP via bicistronic internal ribosome entry site-driven promotion, exhibited significantly lower penetrance of serum ANA, comparing to control B6.Sle1 mice. Moreover, B6.Sle1.GFP-FoxP3+ mice reduced the Sle1-induced splenomegaly and B-cell expansion independently of the KI method employed, mainly by reducing the numbers of transitional 1 (T1) B cells and CD21–CD23– B cells, including plasmablasts and plasma cells. The absolute numbers of both splenic CD4+ T cells and Treg cells from B6.Sle1.GFP-FoxP3 KI mice were significantly reduced but their proportion was not changed, compared to B6.Sle1 mice. Although the glomerular basement membranes were thickened in both B6.Sle1 and B6.Sle1.iGFP-FoxP3 mice, they were thinner in B6.Sle1.fGFP-FoxP3 mice. The latter mice expressed more nephrophilic autoantibodies and deposited more complement component 3 in glomeruli compared to B6.iGFP-FoxP3 mice. FoxP3+ Treg cells may modulate B-cell tolerance in lupus-prone B6.Sle1 mice, presumably by modulating pathogenic, nephrophilic autoantibody production and nephritis.

A single infection with a malaria parasite protects mice from lethal autoimmune glomerulonephritis

Abstract The progression of autoimmune diseases such as Systemic Lupus Erythematous (SLE) can be altered by environmental factors, including parasitic infections. Epidemiological studies have shown a relative absence of SLE in West Africa (areas of endemic malaria), even though SLE is highly prevalent in populations of African descent living outside of Africa. We hypothesize that malaria infections might reduce the incidence of lupus. In the present work, we assess the effect of the non-lethal Plasmodium yoelii 17XNL in a well-characterized animal model of SLE (FcγRIIB−/−). Mice deficient in the inhibitory Fc receptor for IgG (FcγRIIB) develop spontaneous disease driven by the production of anti-nuclear autoantibodies, a broad immune activation, splenomegaly, anemia and lethal glomerulonephritis with a pathology similar to human SLE. We infected FcγRIIB−/− mice at 2 months of age with P. yoelii and followed the progression of autoimmune disease for 5 months. Infection with P. yoelii increased the titer of a broad range of autoantibodies, with concomitant immune-complex deposition and complement fixation in the kidney. While lupus-prone mice succumbed from renal disease detected by protein in urine, malaria-infected lupus-prone mice did not develop proteinuria or lethal disease. Infection with the parasite did not alter tolerance mechanisms leading to lupus but instead prevented end-point tissue pathology. P. yoelii infection seems to inhibit pathogenic leukocyte infiltration without affecting the autoimmune inflammation of glomeruli. These results indicate a possible route for lupus protection that specifically targets renal function, which remains a cause of the substantial morbidity and mortality in SLE patients.

A single infection with a malaria parasite protects mice from lethal autoimmune glomerulonephritis

Abstract Infections can alter the prevalence of autoimmune diseases such as SLE. Epidemiological studies have showed a relative absence SLE in West Africa (areas of endemic malaria), even though SLE is highly prevalent in populations of African descent living outside of Africa. We hypothesize that malaria infections might reduce the incidence of autoimmune lupus. In the present work, we assess the effect of the non-lethal Plasmodium yoelii 17XNL in a well-characterized animal model of SLE (FcγRIIB−/−). Mice deficient in the inhibitory Fc receptor for IgG (FcγRIIB) develop spontaneous disease driven by the production of anti-nuclear autoantibodies, a broad immune activation, splenomegaly, anemia and lethal glomerulonephritis with a pathology similar to human SLE. We infected FcγRIIB−/− mice at 2 months of age with P.yoelii and followed the progression of autoimmune disease for 5 months. Infection with P. yoelii increased the titer of a broad range of autoantibodies, with concomitant immune-complex deposition and complement fixation in the kidney. While lupus-prone mice succumbed from renal disease detected by protein in urine and serum urea nitrogen, malaria-infected lupus-prone mice did not develop proteinuria or lethal disease. Infection with the parasite did not alter tolerance mechanisms leading to lupus but instead prevented end-point tissue pathology. P. yoelii infection seems to inhibit pathogenic leukocyte infiltration without affecting the autoimmune inflammation of glomeruli. These results indicate a possible route for lupus protection that specifically targets renal function, which remains a cause of the substantial morbidity and mortality in SLE patients.

The NET-effect of combining rituximab with belimumab in severe systemic lupus erythematosus

ObjectiveIn systemic lupus erythematosus (SLE) patients, excessive formation of neutrophil extracellular traps (NETs) is observed and their degradation is impaired. In vitro, immune complexes (ICx) trigger NET formation while NET-derived DNA is a postulated autoantigen for anti-nuclear autoantibodies (ANAs), found in SLE. Based on these self-perpetuating mechanisms in SLE, this study investigates whether interfering with ICx formation using a combination of rituximab (RTX) and belimumab (BLM) could decrease NET formation and ameliorate disease. MethodsA phase 2A, open-label, single arm proof-of-concept study was performed wherein 16 SLE patients with severe, refractory disease were treated with a combination of CD20-mediated B-cell depletion with rituximab and sustained inhibition of B-cell activating factor BlyS with belimumab. Besides safety, the study's endpoints were chosen to address the concept of autoantibodies in relation to excessive NET formation. ResultsWe demonstrated a surge of BlyS levels upon RTX-mediated B-cell depletion which was abrogated by subsequent BLM treatment. As such, therapeutic intervention with RTX + BLM led to specific reductions in ANAs and regression of excessive NET formation. RTX + BLM appeared to be safe and achieved clinically significant responses: low lupus disease activity state was achieved in 10 patients, renal responses in 11 patients and concomitant immunosuppressive medication was tapered in 14 out of the 16 patients. ConclusionsThis study provides novel insights into clinical beneficence of reducing excessive NET formation in SLE by therapeutic targeting ANA production with RTX + BLM. Altogether putting forward a new treatment concept that specifically ameliorates underlying SLE pathophysiology. Trial registrationClinicalTrials.gov NCT02284984.

A Novel Human Systemic Lupus Erythematosus Model in Humanised Mice

Mouse models have contributed to the bulk of knowledge on Systemic Lupus Erythematosus (SLE). Nevertheless, substantial differences exist between human and mouse immune system. We aimed to establish and characterise a SLE model mediated by human immune system. Injection of pristane into immunodeficient mice reconstituted with human immune system (humanised mice) recapitulated key SLE features, including: production of human anti-nuclear autoantibodies, lupus nephritis, and pulmonary serositis. There was a reduction in the number of human lymphocytes in peripheral blood, resembling lymphopenia in SLE patients. Concurrently, B cells and T cells were systemically hyperactivated, with a relative expansion of CD27+ and CD27−IgD− memory B cells, increased number of plasmablasts/plasma cells, and accumulation of effector memory T cells. There was also an increased production of human pro-inflammatory cytokines, including: IFN-γ, IL-8, IL-18, MCP-1, and IL-6, suggesting their role in SLE pathogenesis. Increased expression of type I IFN signature genes was also found in human hepatocytes. Altogether, we showed an SLE model that was mediated by human immune system, and which recapitulated key clinical and immunological SLE features. The advancements of humanised mice SLE model would provide an in vivo platform to facilitate translational studies and pre-clinical evaluations of human-specific mechanisms and immunotherapies.

Sex and the Nba2 lupus susceptibility interval are differentially associated with specific costimulatory molecule expression profiles on dendritic cells in mice.

Abstract Systemic lupus erythematosus (SLE), an autoimmune disorder that primarily affects women, is characterized by the production of autoreactive antinuclear autoantibodies and elevated levels of serum interferon-alpha (IFN-α). Female B6 mice congenic for the Nba2 lupus susceptibility interval develop a lupus-like disease with elevated serum IFN-α secreted by plasmacytoid dendritic cells (pDC). We hypothesized that genetic and/or sex-specific differences in DC activation states may contribute to differential susceptibility to lupus. Therefore, we compared the expression levels of CD80, CD86, CD40, CD40L, ICOSL, and MHC Class II with flow cytometry on DCs in male and female control (B6) and lupus-prone (B6.Nba2) mice. pDCs from pre-disease, 8-week old, B6.Nba2 lupus-prone mice expressed greater levels of CD80 than did those from B6 controls, while levels did not vary by sex. Additionally, CD19+ Siglec H-pDCs were found to express greater levels of costimulatory molecules as a whole than other pDC subsets. Interestingly, a greater proportion of male conventional dendritic cells (cDCs) expressed ICOSL as compared to female cells, regardless of genetics. These data indicate that Nba2 pDCs exist in a more activated state as compared to control cells, while male cDCs (regardless of lupus-susceptibility) may maintain a larger regulatory T cell population, via increased expression of ICOSL, as compared to female cells. It will be important to test these and other possible functional consequences of sex- and Nba2-specific costimulatory profiles and to determine if they are reflective of developmental events unique to each sex and strain.

Endogenous programmed death ligand-1 restrains the development and onset of Sjӧgren's syndrome in non-obese diabetic mice.

Programmed death-ligand 1 (PD-L1) down-modulates various immune responses by engaging the co-inhibitory receptor programmed death-1. Expression of PD-L1 and programmed death-1 is elevated in the salivary glands of patients with Sjögren’s syndrome (SS). The objective of this study is to define the role of endogenous PD-L1 in SS pathogenesis in non-obese diabetic (NOD) mouse model of this disease. We inhibited endogenous PD-L1 function by intraperitoneal administration of a blocking antibody to 6 week-old female NOD/ShiLtJ mice repeatedly during a 9-day period. PD-L1 blockade accelerated leukocyte infiltration and caspase-3 activation in the submandibular gland (SMG), production of antinuclear and anti-M3 muscarinic acetylcholine receptor (M3R) autoantibodies and impairment of saliva secretion, indicative of accelerated development and onset of SS. The effect of PD-L1 blockade was associated with increased T- and B cells and T helper 1 cytokine IFN-γ in the SMG. Local administration of exogenous IFN-γ to the SMG led to impaired salivary secretion accompanied by down-regulation of aquaporin 5 and an increase in anti-M3R autoantibodies. Conversely, neutralization of IFN-γ markedly improved salivary secretion and aquaporin 5 expression in anti-PD-L1-treated NOD/ShiLtJ mice. Hence, endogenous PD-L1 hinders the development and onset of SS in NOD mice, in part by suppressing IFN-γ production.

Characterizing surface costimulatory molecule expression on plasmacytoid dendritic cells in male and female B6.Nba2 lupus-prone mice.

Abstract Systemic lupus erythematosus (SLE) is an autoimmune disorder that primarily affects women and is characterized by the production of autoreactive antinuclear autoantibodies and elevated levels of serum interferon-alpha (IFN-α). Female B6 mice congenic for the Nba2 lupus susceptibility interval develop a lupus-like disease including antinuclear autoantibodies, glomerulonephritis, and elevated serum IFN-α. Plasmacytoid dendritic cells (pDC) are capable of secreting high amounts of IFN-α and also present antigen. Ablation of Siglec H+ plasmacytoid dendritic cells in female B6.Nba2 mice is sufficient to reduce serum IFN-α and prevent the production of antinuclear autoantibodies as well as the development of glomerulonephritis. We hypothesized that genetic and/or sex-specific differences in pDC activation states may contribute to differential susceptibility to lupus. Therefore, we compared the expression levels of specific costimulatory molecules on pDCs in male and female control (B6) and lupus-prone (B6.Nba2) mice. Plasmacytoid DCs were categorized into 3 subsets: Siglec H+ CD19−, CD19+ Siglec H−, or double negative. Using flow cytometry, the expression of CD80, CD86, CD40, CD40L, ICOS, B7RP1, and MHC Class II were quantified in each subset. This study may provide insights into the genetic and sex-specific mechanisms by which pDCs contribute to SLE pathogenesis.

Tracing cellular sources of pathogenic type I-interferon in the TREX1-/- mouse model of lupus like-disease

Loss of function mutations of the intracellular enzyme 3’ repair exonuclease (TREX) 1 cause Aicardi-Goutieres syndrome (AGS). As AGS clinically overlaps with systemic lupus erythematosus (SLE) and, like SLE, features a spontaneous activation of the antiviral type I-interferon (IFN) system as well as production of antinuclear autoantibodies, this condition may be considered a monogenic variant of SLE. TREX1-deficient mice spontaneously develop multiorgan autoimmune disease that is fully dependent on a functional type I-IFN system. This phenotype suggested a new concept of systemic autoimmunity arising from intracellular accumulations of (so far enigmatic) nucleic acid substrates of TREX1, which trigger chronic antiviral IFN responses and thereby autoimmunity. Nonhematopoietic cells were proposed to be the cellular source of the pathogenic IFN. Uncontrolled activity of endogenous retroelements was suspected to induce the chronic antiviral response.

Macrophage depletion attenuates skin and kidney disease in lupus mice (BA7P.143)

Abstract Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of anti-nuclear autoantibodies and inflammatory damage in target organs, commonly the kidney and skin. Macrophages are thought to be important in the pathogenesis of lupus end organ disease, although studies to date have not been sufficiently conclusive. In this study, we investigated the role of macrophages in a spontaneous mouse model of SLE, the MRL/lpr mouse. PLX3397 (Plexxikon), a small molecule inhibitor of CSF1R, c-Kit, and FMS-like tyrosine kinase 3a, was administered in chow form to MRL/lpr mice starting at 9 weeks of age. Compared to matched control treated mice, PLX3397-treated MRL/lpr mice exhibited significantly less proteinuria and improved renal function. Furthermore, anti-dsDNA antibodies were significantly reduced at several time points. IBA-1 staining confirmed macrophage depletion within the kidneys of the PLX3397 treated mice. Interestingly, PLX3397-treated mice were also protected from the development of spontaneous skin lesions common to MRL/lpr mice, with control treated mice displaying significantly worse cutaneous disease macroscopically at 16 and 22 weeks of age. The improvement in skin lesions in PLX3397-treated mice was confirmed histologically in skin obtained at sacrifice. Our results indicate an important role for macrophages in the pathogenesis of skin and kidney disease in MRL/lpr mice, and implicate macrophages as a potential therapeutic target in SLE.

An Animal Model Using Metallic Ions to Produce Autoimmune Nephritis.

Autoimmune nephritis triggered by metallic ions was assessed in a Long-Evans rat model. The parameters evaluated included antinuclear autoantibody production, kidney damage mediated by immune complexes detected by immunofluorescence, and renal function tested by retention of nitrogen waste products and proteinuria. To accomplish our goal, the animals were treated with the following ionic metals: HgCl2, CuSO4, AgNO3, and Pb(NO3)2. A group without ionic metals was used as the control. The results of the present investigation demonstrated that metallic ions triggered antinuclear antibody production in 60% of animals, some of them with anti-DNA specificity. Furthermore, all animals treated with heavy metals developed toxic glomerulonephritis with immune complex deposition along the mesangium and membranes. These phenomena were accompanied by proteinuria and increased concentrations of urea. Based on these results, we conclude that metallic ions may induce experimental autoimmune nephritis.

Active systemic lupus erythematosus is associated with a reduced cytokine production by B cells in response to TLR9 stimulation.

IntroductionSystemic lupus erythematosus (SLE) is an autoimmune disease associated with a break in self-tolerance reflected by a production of antinuclear autoantibodies. Since autoantibody production can be activated via nucleic acid Toll-like receptor 9 (TLR9), the respective pathway has been implicated in the development of SLE and pathogenic B cell responses. However, the response of B cells from SLE patients to TLR9 stimulation remains incompletely characterized.MethodsIn the current study, the response of B cells from SLE patients and healthy donors upon TLR9 stimulation was analyzed in terms of proliferation and cytokine production and correlated with the lupus disease activity and anti-dsDNA titers.ResultsB cells from SLE patients showed a reduced response to TLR9 agonist compared to B cells from healthy donors in terms of proliferation and activation. B cells from SLE patients with higher disease activity produced less interleukin (IL)-6, IL-10, vascular endothelial growth factor, and IL-1ra than B cells from healthy donors. Further analyses revealed an inverse correlation of cytokines produced by TLR9-stimulated B cells with lupus disease activity and anti-dsDNA titer, respectively.ConclusionThe capacity of B cells from lupus patients to produce cytokines upon TLR9 engagement becomes less efficient with increasing disease activity, suggesting that they either enter an exhausted state or become tolerant to TLR stimulation for cytokine production when disease worsens.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-014-0477-1) contains supplementary material, which is available to authorized users.

THU0058 Intestinal Microbiota Plays A Critical Role in the Production of Antinuclear Antibodies in Lymphopenia-Induced Autoimmunity

BackgroundProduction of antinuclear autoantibodies (ANAs) is one of the major characteristics of the systemic autoimmune diseases, such as systemic lupus erythematosus (SLE), but the mechanisms of their production are not...

THU0042 Autoantibodies against High Mobility Group Box Protein-1 in Systemic Lupus Erythematosus: Association with Disease Activity and Other Antinuclear Antibodies

BackgroundSystemic lupus erythematosus (SLE) is a systemic autoimmune condition characterized by reduced ability to degrade and eliminate apoptotic cells. This probably contributes to the excessive production of antinuclear autoantibodies (ANA),...