Anti-DNA antibodies cross-reactive with ß2-glycoprotein I induce monocyte tissue factor through the TLR9 pathway.

Antibodies specific for cardiolipin (CL)-ß2-glycoprotein I (ß2GPI) are known to induce tissue factor (TF) expression by monocytes and endothelial cells which leads to a prothrombotic state in antiphospholipid syndrome (APS), but the mechanism is not fully elucidated. Previously, we reported that the mouse monoclonal anti-CL-ß2GPI antibody WB-6 cross-reacts with DNA, enters monocytes via binding to cell surface DNA, and induces TF expression. The current study aimed to identify the intracellular signaling pathways involved in this process. The binding of WB-6 to CL-ß2GPI or DNA, and endocytosis was not prevented by chloroquine, but pre-treatment of the cells with chloroquine significantly suppressed TF expression. TLR9 inhibitory oligodeoxynucleotide also suppressed the WB-6-induced TF expression, suggesting a pivotal role of the TLR9 pathway in TF production. Serum antibodies obtained from a patient with APS accompanying systemic lupus erythematosus (SLE) bound to both CL-ß2GPI and DNA, and induced TF in normal monocytes. This effect was suppressed by chloroquine, and abolished by removal of the DNA-binding activity. These results suggest that induction of TF expression results from TLR9 activation by DNA which was internalized together with cross-reactive antibodies produced in secondary APS accompanying SLE.

Antinuclear antibodies and cancer: A literature review.

Antinuclear antibodies (ANAs) are a spectrum of autoantibodies targeted to various nuclear and cytoplasmic components of the cells. They are very useful as serological markers for different autoimmune disease, like systemic lupus erythematosus (SLE), Sjögren's syndrome (SS), scleroderma, polymyositis, or mixed connective tissue disease. In these years, an increasing attention has been focussed in the relationship between tumours and autoimmunity. Different authors have demonstrated that ANAs are presented, not only in autoimmune diseases, also in serum of patients with different types of cancers. These data suggested that ANAs could be involved in the pathogenesis of cancer as well as other premalignant disease. In this review, we are going to describe all data reported about the presence of these antibodies in samples from patients with cancer as well as the potential role of some of these proteins in early detection and prognosis.

Heparan sulfate proteoglycans (HSPGs) and chondroitin sulfate proteoglycans (CSPGs) function as endocytic receptors for an internalizing anti-nucleic acid antibody.

A subset of monoclonal anti-DNA autoantibodies enters a variety of living cells. Here, we aimed to identify the endocytic receptors recognized by an internalizing anti-nucleic acid autoantibody, the 3D8 single-chain variable fragment (scFv). We found that cell surface binding and internalization of 3D8 scFv were inhibited markedly in soluble heparan sulfate (HS)/chondroitin sulfate (CS)-deficient or -removed cells and in the presence of soluble HS and CS. 3D8 scFv colocalized intracellularly with either HS proteoglycans (HSPGs) or CSPGs in HeLa cells. 3D8 scFv was co-endocytosed and co-precipitated with representative individual HSPG and CSPG molecules: syndecan-2 (a transmembrane HSPG), glypican-3 (a glycosylphosphatidylinositol (GPI)-anchored HSPG); CD44 (a transmembrane CSPG); and brevican (a GPI-anchored CSPG). Collected data indicate that 3D8 scFv binds to the negatively charged sugar chains of both HSPGs and CSPGs and is then internalized along with these molecules, irrespective of how these proteoglycans are associated with the cell membrane. This is the first study to show that anti-DNA antibodies enter cells via both HSPGs and CSPGs simultaneously. The data may aid understanding of endocytic receptors that bind anti-DNA autoantibodies. The study also provides insight into potential cell membrane targets for macromolecular delivery.

[Anti-Hu antibody syndrome: diagnostic and therapeutic difficulties]. / Syndrome des anticorps anti-Hu: difficultés diagnostiques et thérapeutiques.

INTRODUCTION: Anti-Hu antibody syndrome is a paraneoplastic syndrome usually associated with small cell lung carcinoma which induces various symptoms, particularly neurological ones. CASE REPORT: We describe the case of a 49-year old woman with a small cell lung carcinoma who initially experiences a spontaneous regression but then developed neurological symptoms associated with severe autonomic dysfunction manifesting as chronic intestinal pseudo-obstruction and leading finally to hemodynamic failure. CONCLUSION: Anti-Hu antibody syndrome remains a rare entity. Its diagnosis must be considered in the face of neurologic symptoms associated with small cell lung cancer.

The pathogenesis of lupus nephritis.

Lupus nephritis is an immune complex GN that develops as a frequent complication of SLE. The pathogenesis of lupus nephritis involves a variety of pathogenic mechanisms. The extrarenal etiology of systemic lupus is based on multiple combinations of genetic variants that compromise those mechanisms normally assuring immune tolerance to nuclear autoantigens. This loss of tolerance becomes clinically detectable by the presence of antinuclear antibodies. In addition, nucleic acids released from netting or apoptotic neutrophils activate innate and adaptive immunity via viral nucleic acid-specific Toll-like receptors. Therefore, many clinical manifestations of systemic lupus resemble those of viral infection. In lupus, endogenous nuclear particles trigger IFN-α signaling just like viral particles during viral infection. As such, dendritic cells, T helper cells, B cells, and plasma cells all contribute to the aberrant polyclonal autoimmunity. The intrarenal etiology of lupus nephritis involves antibody binding to multiple intrarenal autoantigens rather than the deposition of circulating immune complexes. Tertiary lymphoid tissue formation and local antibody production add to intrarenal complement activation as renal immunopathology progresses. Here we provide an update on the pathogenic mechanisms that lead to lupus nephritis and provide the rationale for the latest and novel treatment strategies.

Autoimmune kidney disease and impaired engulfment of apoptotic cells in mice with macrophage peroxisome proliferator-activated receptor gamma or retinoid X receptor alpha deficiency.

Autoimmune glomerulonephritis is a common manifestation of systemic lupus erythematosus (SLE). In this study, we show that mice lacking macrophage expression of the heterodimeric nuclear receptors PPARγ or RXRα develop glomerulonephritis and autoantibodies to nuclear Ags, resembling the nephritis seen in SLE. These mice show deficiencies in phagocytosis and clearance of apoptotic cells, and they are unable to acquire an anti-inflammatory phenotype upon feeding of apoptotic cells, which is critical for the maintenance of self-tolerance. These results demonstrate that stimulation of PPARγ and RXRα in macrophages facilitates apoptotic cell engulfment, and they provide a potential strategy to avoid autoimmunity against dying cells and to attenuate SLE.

Regulatory B cells (B10 cells) have a suppressive role in murine lupus: CD19 and B10 cell deficiency exacerbates systemic autoimmunity.

B cells play critical roles in the pathogenesis of lupus. To examine the influence of B cells on disease pathogenesis in a murine lupus model, New Zealand Black and New Zealand White F(1) hybrid (NZB/W) mice were generated that were deficient for CD19 (CD19(-/-) NZB/W mice), a B cell-specific cell surface molecule that is essential for optimal B cell signal transduction. The emergence of anti-nuclear Abs was significantly delayed in CD19(-/-) NZB/W mice compared with wild type NZB/W mice. However, the pathologic manifestations of nephritis appeared significantly earlier, and survival was significantly reduced in CD19(-/-) NZB/W mice compared with wild type mice. These results demonstrate both disease-promoting and protective roles for B cells in lupus pathogenesis. Recent studies have identified a potent regulatory B cell subset (B10 cells) within the rare CD1d(hi)CD5(+) B cell subset of the spleen that regulates acute inflammation and autoimmunity through the production of IL-10. In wild type NZB/W mice, the CD1d(hi)CD5(+)B220(+) B cell subset that includes B10 cells was increased by 2.5-fold during the disease course, whereas CD19(-/-) NZB/W mice lacked this CD1d(hi)CD5(+) regulatory B cell subset. However, the transfer of splenic CD1d(hi)CD5(+) B cells from wild type NZB/W mice into CD19(-/-) NZB/W recipients significantly prolonged their survival. Furthermore, regulatory T cells were significantly decreased in CD19(-/-) NZB/W mice, but the transfer of wild type CD1d(hi)CD5(+) B cells induced T regulatory cell expansion in CD19(-/-) NZB/W mice. These results demonstrate an important protective role for regulatory B10 cells in this systemic autoimmune disease.

Long-term bacterial exposure can trigger nonsuppurative destructive cholangitis associated with multifocal epithelial inflammation.

Bacterial infection has become a focus of attention in the pathogenesis of primary biliary cirrhosis (PBC). We earlier reported that the bacterial lipoteichoic acid was detected at the sites of inflammation around damaged bile ducts in the livers of PBC, and PBC patients' sera showed high titers against streptococcal histone-like protein. Here, we investigated whether chronic bacterial exposure could trigger PBC-like epithelial cell damage in normal mouse. BALB/c mice were repeatedly inoculated with various bacteria for 8 weeks. At 1 week (Group 1) and 3, 4, or 20 months (long term; Group 2) after the final inoculation, mice were killed to obtain samples. In the livers of the Streptococcus intermedius (S.i.)-inoculated mice in Group 1, cellular infiltration was predominantly observed around the bile ducts over the hepatic parenchyma. In the S.i.-inoculated mice in Group 2, portal but not parenchymal inflammation was observed in the livers, and periductal cellular infiltrates were detected in the salivary glands. Both S.i.-inoculated Groups 1 and 2 BALB/c mice sera had antibodies against HuCCT1 biliary epithelial cells, anti-nuclear antibodies, and anti-gp210 antibodies, but not anti-mitochondrial antibodies. Immunoreactivity to histone-like DNA-binding protein of S.i. (S.i.-HLP) was detectable around the sites of chronic nonsuppurative destructive cholangitis in the portal area in the livers of both S.i.-inoculated Groups 1 and 2 BALB/c mice. Furthermore, anti-S.i.-HLP antibody bound to synthetic gp210 peptide, as well. Bacteria triggered PBC-like cholangitis, multifocal epithelial inflammation, and autoantibody production. Bacteria are likely involved in the pathogenesis of PBC and of associated multifocal epithelial inflammation.

Genetic complementation results in augmented autoantibody responses to lupus-associated antigens.

Lupus-prone female New Zealand Mixed (NZM)2328 mice develop high titers of anti-nuclear and anti-dsDNA autoantibodies. Despite high expression of type I IFNs, these mice do not develop autoantibodies to the small nuclear ribonucleoprotein (snRNP) complex. Thus, additional genetic factors must regulate the generation of anti-snRNP autoantibodies. In contrast, despite much lower expression of type 1 IFNs, the diabetes-prone NOD mice spontaneously make anti-snRNP autoantibodies, albeit at a low incidence. To determine whether combination of high type I IFN response of NZM mice with appropriate susceptibility genes of NOD mice would result in anti-snRNP Ab response, cohorts of (NZM2328 x NOD)F(1) mice were generated and characterized for development of autoimmunity. In comparison with parental strains, the PBMCs from F(1) mice showed intermediate expression of type I IFN-responsive genes and augmented expression of IL-6 transcripts. TLR7 expression was similar in all strains. The F(1) mice had very high incidence and titer of anti-snRNP autoantibodies, anti-nuclear Abs, and anti-dsDNA autoantibodies. The levels of anti-snRNP autoantibody correlated with the expression levels of type I IFN-responsive genes. None of the F(1) mice developed diabetes, and only female mice developed severe renal disease. Our data demonstrate that only in presence of appropriate susceptibility genes, anti-snRNP autoantibodies are induced and type I IFNs amplify this response. A synergy between IL-6 and type I IFNs might be critical for amplifying overall autoantibody responses in systemic lupus erythematosus. In NZM/NOD F(1) mouse, genetic complementation between NZM and NOD genes leads to expression of phenotypes similar to those seen in certain lupus patients.

Autoantibodies involved in neuropsychiatric manifestations associated with systemic lupus erythematosus.

In the course of Systemic Lupus Erythematosus (SLE), a variety of neuropsychiatric disturbances is reported with a prevalence ranging from 17% to 75%. The diagnosis of these syndromes is difficult and requires a careful psychiatric evaluation. Distinct autoantibodies detectable in serum or cerebrospinal fluid of patients with SLE are associated with the presence of neuropsychiatric disorders. These autoantibodies may have a pathogenic relevance in neuropsychiatric SLE or they may be merely an epiphenomenon. This review describes the various autoantibodies reported to be associated with neuropsychiatric manifestations in SLE and discusses their possible role.

Influence of B cell antigen receptor expression level on pathways of B cell tolerance induction.

We have described an Ig-transgenic, autoreactive B cell clonotype that undergoes a novel tolerance pathway. Early in development this clonotype expresses average BCR levels, but these levels are progressively down-regulated as development proceeds efficiently to the mature, follicular compartment. This clonotype does not display conventional features of anergy and can be induced to undergo apoptosis and receptor editing in in vitro bone marrow cultures, but these pathways are not taken in vivo. These data suggested that autoantigen-driven down-regulation of BCR levels and, hence, avidity for autoantigen allows this clonotype to bypass conventional tolerance mechanisms. To test this idea, we enforced elevated levels of expression of BCR in this clonotype by making the transgenic Igh locus homozygous. This resulted in retarded clonotype development and L chain receptor editing in vivo. These data support a pivotal role for adaptive, autoantigen-induced adjustment of BCR expression levels in the regulation of primary B cell development and tolerance.

Predictive value of antinuclear autoantibodies: the lessons of the systemic sclerosis autoantibodies.

Physicians who provide care to patients with systemic sclerosis (SSc, scleroderma) ask themselves several questions: Is SSc the correct diagnosis? Can the disease course be predicted? Is there a greater risk for involvement of certain organs? Can the vital prognosis be predicted? In this brief review, we answer these questions by excerpting data from the literature focused on the 4 major SSc specific autoantibodies (aAbs) to nuclear autoantigens (ANAs): anti-centromere (anti-CENP-B), anti-Th/To, anti-topoisomerase I (anti-topo I) and anti-RNA polymerase III (anti-RNAPIII). The data show that these aAbs are highly valuable as markers for the diagnosis of SSc, as biomarkers for phenotypic subsets and as prognostic markers. We also identify areas for future clinical research.

Predictive value of anti-dsDNA autoantibodies: importance of the assay.

The predictive potential of anti-dsDNA autoantibodies (AAb) lays on their biological activity and their ability to cause the pathological changes typically found in patients with SLE. In this review, we discuss old and recent evidence that supports the idea of AAb against dsDNA may cause directly tissue damage. Tissue deposition, Ab isotype, affinity maturation, and its ability to activate complement and engage Fc receptors are the classical determinants of the pathogenicity of anti-dsDNA AAb. Furthermore, there is strong evidence that suggest that anti-dsDNA AAb of the IgG isotype are able to shuttle nuclei acid fragments through the plasma membrane causing activation and secretion of inflammatory cytokines. Nucleic acid-containing immune complexes may thus serve as a virus-mimeticum.

Anti-chromatin (anti-nucleosome) antibodies: diagnostic and clinical value.

Anti-chromatin (nucleosome) autoantibodies were one of the first autoantibodies ever detected since they make up the majority of antibodies causing LE Cell formation. The prevalence of anti-chromatin antibodies in systemic lupus erythematosus (SLE) varies from 50% to 100%, being similar to that of the classical positive LE cell. The presence of these antibodies can be used, in conjunction with clinical findings and other laboratory tests, to help in the diagnosis of SLE and drug-induced lupus. Anti-chromatin antibodies have also been found in a lesser percentage of other autoimmune disorders such as primary Sjögren's syndrome and primary antiphospholipid syndrome. The presence of anti-chromatin antibodies has also been linked to glomerulonephritis and disease activity in SLE patients. Recent studies demonstrated the induction of anti-chromatin (anti-nucleosome) antibodies after an anti-tumour necrosis factor (TNF)-alpha agent treatment.

Juvenile idiopathic arthritis profile in Turkish children.

BACKGROUND: Juvenile idiopathic arthritis (JIA) is a heterogeneous group of disorders. Publications from different countries point to differences in the disease manifestation of JIA among different populations. The aim of the present paper was to evaluate the clinical and laboratory features of JIA in Turkish children. METHODS: A total of 196 JIA patients who fulfilled International League of Associations for Rheumatology (ILAR) diagnostic criteria were included in this retrospective study. The data collected were age, gender, age at disease onset and at diagnosis, and follow-up duration. Antinuclear antibody (ANA), rheumatoid factor (RF), and human leukocyte antigen B-27 were evaluated for each patient. RESULTS: There were 102 boys and 94 girls with a mean duration of disease of 4.1 years. The mean age at the first visit was 8.8 years, and the mean age at onset of disease was 6.8 years (range, 8 months-15 years). Polyarticular JIA was the most frequent onset type (37.2%). Other subtypes included oligoarthritis (34.2%), systemic arthritis (15.3%), psoriatic arthritis (1%), enthesitis-related arthritis (9.7%), and other arthritis (2.2%). ANA was positive in 28 patients (14.2%). Chronic uveitis occurred in two patients with oligoarthritis; and two patients with enthesitis-related arthritis had acute uveitis. Three patients (1.4%) developed amyloidosis. CONCLUSION: Compared to reports from Western countries, remarkably different features of JIA were found in Turkish children, which included higher frequency of polyarticular JIA, higher prevalence among boys, lower rate of ANA positivity and uveitis. Further studies are required to understand how genetic and environmental differences affect JIA expression.

Dying right to live longer: positing apoptosis as a link between maternal autoantibodies and congenital heart block.

The association of isolated congenital heart block (CHB) with maternal autoantibodies to SSA/Ro and SSB/La ribonucleoproteins is approaching the predictable, even in mothers who are completely asymptomatic. Indeed, this model of passively acquired autoimmunity offers an exceptional opportunity to examine the effector arm of immunity and define the pathogenicity of an autoantibody in mediating tissue injury. The study of CHB exemplifies not only translational research, which inherently draws upon clinical observations and explores them in the laboratory, but "integrational" research which attempts to fit critical clinical and basic observations together, even those seemingly at odds. The spectrum of conduction abnormalities includes second and third-degree block, but injury can extend to the myocardium and endocardium, in rare cases without AV nodal dysfunction. The rarity of disease continues to drive the search for factors (fetal and environmental) that might amplify the effects of the maternal autoantibodies. The identification of exaggerated apoptosis, macrophage/myfibroblast crosstalk, TGF beta expression, and extensive fibrosis in the conducting system and in some cases surrounding myocardium in fetuses dying with CHB, provide in vivo support for several parallel lines of in vitro investigation. Specifically, the consideration of exaggerated apoptosis as the initial link between maternal antibody and tissue injury led to the observation that cardiocytes are capable of phagocytosing autologous apoptotic cardiocytes and anti-Ro/La antibodies inhibit this function. Recognizing that this perturbation of physiologic efferocytosis might divert uptake to professional Fc gamma R-bearing phagocytes fits well with experiments demonstrating macrophage secretion of pro-inflammatory and fibrosing cytokines when coincubated with apoptotic cardiocytes bound by Ro/La antibodies. While CHB is rare, its study should set precedent for defining the role of autoantibodies in driving end organ disease.

Anti-ribonucleoprotein antibodies mediate enhanced lung injury following mesenteric ischemia/reperfusion in Rag-1(-/-) mice.

Natural Abs and autoantibodies bind antigens displayed by ischemia-conditioned tissues, followed by complement activation and enhanced tissue injury during reperfusion. Anti-ribonucleoprotein (RNP) Ab is associated with lung disease in patients with autoimmune disease but it is not known whether these abs contribute to lung injury. Mesenteric I/R in mice leads to local and remote lung injury. Accordingly, we used this model to investigate whether anti-RNP Abs would reconstitute I/R damage with prominent lung damage in injury-resistant Rag1(-/-) animals. Rag1(-/-) mice injected with anti-RNP Ab containing serum and subjected to mesenteric I/R suffered greater intestinal injury than control-treated and sham-operated animals. The magnitude of the reconstituted damage was anti-RNP Ab titer-dependent. Anti-RNP Ab-treated animals demonstrated a dose-dependent increase in lung histologic injury scores compared to control and sham animals. Anti-RNP mediated injury was shown to be complement dependent. These experiments reveal a novel mechanism whereby anti-RNP Abs contributes to the development of pulmonary pathology in patients with autoimmune diseases following exposure of remote organs to I/R injury.

Multiple specificities of autoantibodies against hnRNP A/B proteins in systemic rheumatic diseases and hnRNP L as an associated novel autoantigen.

Spliceosomal small nuclear ribonucleoproteins (U-snRNPs) are frequent and specific targets of autoantibodies in systemic rheumatic diseases. The abundant, functionally related heterogeneous nuclear ribonucleoprotein complexes (hnRNPs) have later defined as a new target of autoantibodies, of which their immunochemical/immunogenic and pathogenic properties are still under investigation. Among hnRNP proteins, those belonging to the A/B type are considered as the major autoantigens targeted by antibodies in sera of patients suffering with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD). By performing an extensive screening using rat liver 40S hnRNP antigenic material, we document here the existence of multiple specificities of anti-hnRNP A/B autoantibodies in sera of Greek patients suffering with a spectrum of systemic rheumatic diseases. This included patients with SLE, Sjogren's syndrome (SS), Scleroderma (SSc) and a specific group of patients mostly with undifferentiated disease (UD patients). In total, four distinct types of anti-hnRNP A/B autoantibodies have been recognized. The first two referred to the known anti-hnRNPA2(RA33) and anti-hnRNP A1; the latter appearing very rarely. The third was of the new type selectively reacting with hnRNP B2 and an hnRNP A3 variant, while the fourth was a rare case of anti-hnRNP B2 alone. In addition, a novel specificity of autoantibodies against hnRNP L protein was identified in association with anti-hnRNP A/B antibodies. The co-existence within a serum of autoantibodies having variable specificity for hnRNP A/B and L autoantigens was shown. Specific immunochemical features of the identified autoantibodies are presented and a possible mechanism of autoepitope spreading within protein components of hnRNP complexes is discussed.

Reduced placental growth and hCG secretion in vitro induced by antiphospholipid antibodies but not by anti-Ro or anti-La: studies on sera from women with SLE/PAPS.

Systemic lupus erythematosus (SLE) and primary anti-phospholipid syndrome (PAPS) are autoimmune diseases causing recurrent pregnancy loss. We hypothesized that anti-phospholipid antibodies (aPL), but not anti-Ro and anti-La antibodies, might have a role through direct placental damage. We cultured human placental explants in sera from women with SLE/PAPS with different antibodies. These sera were found to reduce placental growth and increase trophoblastic apoptosis. No effect was found on estradiol or progesterone secretion, but inhibition in betahCG secretion was detected. BetahCG was reduced in women with a history of recurrent pregnancy loss or thromboembolic events, and was also the most sensitive marker when examining the effects of specific antibodies. High titers of aPL were found to cause the largest reduction in betahCG. Anti-Ro and anti-La did not induce placental damage. A strong correlation was found between the rise in the number of different antibodies in the sera and the incidence of recurrent pregnancy loss, which was also accompanied by a decline in the betahCG levels. In conclusion, aPL, but not anti-Ro or anti-La, may cause placental damage in vitro. Thus betahCG levels might constitute a predictive marker for the risk of placental damage and pregnancy loss in women with SLE/PAPS.