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Query: UMLS:C0409974 (lupus)
 22,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Antiphospholipid antibodies, including anticardiolipin antibodies (ACA), are strongly associated with recurrent thrombosis in patients with the antiphospholipid syndrome (APS). To date, reports about the binding specificities of ACA and their role(s) in causing and/or sustaining thrombosis in APS are conflicting and controversial. The plasmas of patients with APS, usually containing a mixture of autoantibodies, vary in binding specificity for different phospholipids/cofactors and vary in in vitro lupus anticoagulant activity. Although in vivo assays that allow assessment of the pathogenic procoagulant activity of patient autoantibodies have recently been developed, the complex nature of the mixed species prevented determination of the particular species responsible for in vivo thrombosis. We have generated two human IgG monoclonal ACA from an APS patient with recurrent thrombosis. Both bound to cardiolipin in the presence of 10% bovine serum, but not in its absence, and both were reactive against phosphatidic acid, but were nonreactive against purified human beta-2 glycoprotein 1, DNA, heparan sulfate, or four other test antigens. Both monoclonal autoantibodies lacked lupus anticoagulant activity and did not inhibit prothrombinase activity. Remarkably, one of the monoclonal antibodies has thrombogenic properties when tested in an in vivo mouse model. This finding provides the first direct evidence that a particular antiphospholipid antibody specificity may contribute to in vivo thrombosis.
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PMID:A monoclonal IgG anticardiolipin antibody from a patient with the antiphospholipid syndrome is thrombogenic in mice. 871 Sep 18

Heparin and heparan sulfate are related glycosaminoglycans which demonstrate high-affinity interactions with a number of proteins, including antithrombin III. The immunogenicity of heparin has been reported previously employing heparin-protein conjugates as immunogens and as antigens in solid-phase assays. Previous studies also demonstrate that anti-heparin antibodies play a role in autoimmune diseases including systemic lupus and anti-phospholipid syndrome and in patients who receive heparin for therapeutic purposes. In the current study, we investigated the expression of monoclonal anti-heparin antibodies in nonimmunized, autoimmune MRL/lpr/lpr++ mice employing a liquid-phase radioimmunoassay. The Kd of monoclonal IgG2b autoantibodies for heparin was approximately 10(-8)M. Anti-heparin antibodies were precipitating, and were not polyreactive. The IgG monoclonal antibodies described in this study represent an immunological instance of a specific, high-affinity heparin-protein interaction.
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PMID:Autoimmune MRL mice express high-affinity IgG2b monoclonal autoantibodies to heparin. 880 43

Programmed cell death, an essential function in all cells, plays a central role in maintaining immune system homeostasis and controlling autoimmune reactions. Cell death may be an essential element in disseminated lupus erythematosus: defective cell death could lead to the development of autoreactive lymphocyte clones and degradation products of cell death could be implicated in autoimmunity induction and onset of renal lesions. Anomalies in programmed cell death have been demonstrated in murine models of lupus: mutations of the fas and fas-ligand genes, which play a known role in programmed cell death, produce the lpr and gld phenotypes associating lymphoproliferation and lupus. Transgenic mice which express Bcl-2 (the product of Bcl-2 inhibits programmed cell death) on B lymphocytes develop a lupus-type autoimmune disease. The role of these types of anomalies in human disease is not yet elucidated. However, cell death, via the degradation fragments of chromatin, could play a role in inducing antibody production and development of renal lesions. The anti-DNA antibodies, with characteristic antigen-induced immune response (clone expansion, class computation and somatic mutations) could be induced by nucleosomes released during cell death. Several arguments favor this mechanism including cation residues of histone nucleosomes which would bind to anionic residues of sulfate heparan and lead to deposit of autoantibodies in the glomerulus. The dual role of cell death is not really contradictory in autoimmune disease controlled by several independent genes, but would be compatible with several different genetic backgrounds.
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PMID:[Cell death and lupus]. 909 57

It is generally assumed that anti-dsDNA antibodies play an important role in the pathogenesis of lupus nephritis. This is mainly based on the facts that an increase in anti-dsDNA titer often precedes onset of renal disease, that immune deposits are present in glomeruli and that eluates of glomeruli are enriched for anti-dsDNA. This led to the classical concept that deposition of DNA-anti-DNA complexes incites the glomerular inflammation. However, important pieces of evidence are lacking to support this hypothesis. Free, naked, DNA is not present in the circulation. The existence of DNA/anti-DNA complexes is highly questionable and injection of these complexes hardly leads to glomerular localization. As an alternative concept cross-reactivity of anti-dsDNA with glomerular constituents like heparan sulfate (HS) and laminin has been proposed. However, subsequent research has indicated that this cross-reactivity is due to nucleosomal antigens (histones and DNA) complexed to the auto-antibodies. The cationic histone part of the complex is responsible for the binding to the anionic HS. This binding also occurs in vivo since renal perfusion of nucleosome complexed antibodies leads to abundant binding of auto-antibodies to the GBM, while enzymatic removal of HS from the GBM, decreases this binding considerably. Non-complexed antibodies did not bind at all. This mechanism of binding is also consistent with the decrease of HS staining in the GBM in human and murine lupus due to masking of HS with nucleosome-complexed auto-antibodies. Furthermore the presence of histones and nucleosomes in glomerular deposits in lupus nephritis was recently shown. Elution of auto-antibodies from glomeruli not only showed anti-dsDNA but also anti-nucleosome specificities. Nucleosomes are not only important for the induction of glomerular lesions, but there is now also increasing evidence that the nucleosome is the auto-antigen that drives the auto-immune response in SLE. There is ample evidence that this response is antigen-driven and T cell dependent. However immunization with DNA in general fails to induce pathogenic anti-dsDNA antibodies. Recently, in SLE T helper cells were identified specific for nucleosomes. These nucleosome specific T helper cells were not only able to induce anti-nucleosome antibodies but also anti-dsDNA and anti-histone antibodies. This is in line with the finding that in SLE nucleosome specific antibodies are formed. These antibodies react exclusively with nucleosomes and not with its constituents DNA or histones. The formation of these nucleosome specific antibodies precedes the development of anti-dsDNA or anti-histone suggesting that the loss of tolerance for nucleosomes is a primary event. The systemic release of nucleosomes is due to an aberrant apoptosis. There is now growing evidence that apoptosis is disturbed both in certain murine lupus models as well as in human lupus. In conclusion, nucleosomes seem to play a central role in the induction and the effector phase of SLE.
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PMID:Autoimmunity against nucleosomes and lupus nephritis. 909 59

The nature of the antibodies responsible for lupus erythematosus (LE) cells in systemic lupus erythematosus (SLE) remains obscure. We examined whether polyanion-restricted anti-histone antibodies were present in serum of patients with SLE using Western blotting analysis. Dextran sulfate or alginate was used as a polyanion compound in place of DNA. Antibodies which recognized dextran sulfate-histone complexes were present in serum of patients with SLE (17/34, 50%). These antibodies were detected in most SLE patients positive for LE cells (17/18, 94%) but not in those negative for LE cells or in patients with other collagen diseases. Similar results were obtained using alginate-histone complexes as antigens for Western blotting analysis. The antibodies to dextran sulfate-histone or alginate-histone complexes in serum of SLE patients were completely absorbed by treatment of serum with DNA-histone complexes, while they were unaffected by treatment with DNA only. The presence of antibodies to free histones and dextran sulfate-histone complexes did not seem to be related to the titer of anti-single stranded DNA antibody and anti-double stranded DNA antibody. We demonstrated the presence of polyanion-restricted antibodies in SLE, which may be responsible for the LE factor.
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PMID:Detection of polyanion-restricted anti-histone antibodies in patients with systemic lupus erythematosus. 939 49

As endothelial cells (EC) express heparin-like glycosaminoglycans, such as heparan sulfate, it was essential to investigate the relation of anti-EC antibody (AECA) to heparin reactivity. AECA were detected in 43 of 131 autoimmune sera and anti-heparin antibodies (AHA) in 25. These autoimmune reactivities were significantly associated (P corrected < 0.0005). Seven AECA-positive/AHA-positive and three AECA-negative/AHA-positive sera were affinity-purified using protein G column followed by a heparin-Sepharose column. Two populations of AECA were recovered from the second column. One was eluted with 0.4 M NaCl which bound to EC and to solid-phase heparin with low affinity, but not to soluble heparin. The second population of AECA, which was eluted with 4 M guanidine HCl/2 M NaCl, recognized EC and solid-phase heparin with high affinity, but also soluble heparin. The latter population of AECA might thus be an important cause of autoimmune vascular thrombosis in systemic diseases.
Lupus 1998
PMID:Two populations of endothelial cell antibodies cross-react with heparin. 954 Oct 88

Antiphospholipid (aPL) syndrome, or APS,--a cluster of conditions that includes arterial or venous thromboses and thrombocytopenia, as well as recurrent fetal loss associated with elevation of aPL antibody--has been reported to occur 2-5 times more frequently in women than men. Strong familial associations lead to the suspicion that aPL positivity, estimated to be present in 2% of the population, is a heritable trait in some cases. Currently, 2 major categories of the illness are recognized--primary and secondary. Secondary APS may be associated with autoimmune disease, malignancy, infectious disease, or drug-induced states. Two assays, one for lupus anticoagulant antibodies and the other for anticardiolipin (aCL) antibodies, are recognized to be the gold standards for serologic diagnosis of the disease. Despite extensive attempts at international standardization of aCL test results, no consensus exists for a value beyond which the test is considered positive. Interestingly, a "dose-effect" relationship for aCL antibody titers has been noted--higher titers of the antibody correlate with increased numbers of thrombotic events. An experimental assay for antibody against beta 2-glycoprotein 1 (beta-2-GP1), a phospholipid-binding protein, may become the most important assay for aPL. Skin findings in APS include livedo reticularis, ulceration, gangrene, or purpura, and, when present, may be the key to diagnosis of this sometimes insidious syndrome. Anticoagulation, usually with warfarin, is the mainstay of therapy, although steroids, immunosuppressive agents, hydroxychloroquine sulfate, and plasmapheresis may all be beneficial adjunctive therapy.
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PMID:Impact of the Antiphospholipid Syndrome: A Critical Coagulation Disorder in Women. 974 73

Immunoadsorption offers some advantages over plasmapheresis; until recently the primary advantage has been avoidance of substitution fluids. In collagen vascular disorders, immunoadsorption is performed for the same indications as plasma exchange; most often adsorbers with binding capacities for IgG and circulating immune complexes are used. Tested ligands are protein A, anti-IgG antibodies, Clq, phenylalanine, and tryptophan. Human IgG was utilized to adsorb rheumatoid factor and dextran sulfate, DNA, or specific anti-idiotypes for anti-DNA antibodies in systemic lupus erythematous (SLE). Most applications have used immunoadsorbent columns in pretransplantation treatment of patients with high panel reactivity and in patients with idiopathic thrombocytopenic purpura (ITP). For these indications, as for systemic connective tissue diseases, randomized trials have yet to be conducted. SLE controlled trials have been completed for IMPH-350 and Ig-Therasorb. Results indicated excellent biocompatibility and good clinical responses. Using protein A in primary systemic vasculitis, histologically proven inactivation of renal involvement was demonstrated, but the patients were also treated with immunosuppressive drugs. Randomized controlled trials are mandatory to provide continued support to the therapeutical opportunities offered only by immunoadsorption.
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PMID:Immunoadsorption in systemic connective tissue diseases and primary vasculitis. 1022 54

The immune system interacts with the hypothalamo-pituitary-adrenal axis via so-called glucocorticoid increasing factors, which are produced by the immune system during immune reactions, causing an elevation of systemic glucocorticoid levels that contribute to preservation of the immune reactions specificities. Previous results from our laboratory had already shown an altered immuno-neuroendocrine dialogue via the hypothalamo-pituitary-adrenal axis in autoimmune disease-prone chicken and mouse strains. In the present study, we further investigated the altered glucocorticoid response via the hypothalamo-pituitary-adrenal axis in murine lupus. We established the circadian rhythms of corticosterone, dehydroepiandrosterone-sulfate, adrenocorticotropic hormone and melatonin, as well as the time response curves after injection of interleukin-1 of the first three parameters in normal SWISS and lupus-prone MRL/MP-fas(Ipr) mice. The results show that lupus-prone MRL/ MP-fas(Ipr) mice do not react appropriately to changes of the light/dark cycle, circadian melatonin rhythms seem to uncouple from the light/dark cycle, and plasma corticosterone levels are elevated during the resting phase. Diurnal changes of dehydroepiandrosterone-sulfate and adrenocorticotropic hormone were normal compared to healthy controls. These data indicate that MRL/ MP-fas(Ipr) mice not only show an altered glucocorticoid response mediated via the hypothalamo pituitary adrenal axis to IL-1, but are also affected by disturbances of corticosterone and melatonin circadian rhythms. Our findings may have implications for intrathymic T cell development and the emergence of autoimmune disease.
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PMID:Altered circadian rhythms of the stress hormone and melatonin response in lupus-prone MRL/MP-fas(Ipr) mice. 1088 59

This is a retrospective study of the clinicopathological characteristics of 50 systemic lupus erythematosus patients with nephritis who underwent a kidney biopsy and were admitted to the American University of Beirut Medical Center, in Lebanon, between 1979 and 1999. There were 43 females and seven males, with a median age of 24 y. Renal histology slides from these patients were assessed according to the World Health Organization classification, and were distributed as follows: class I (n = 3, 6%); class II (n = 14, 28%); class III (n = 11, 22%); class IV (n = 19, 38%); class V (n = 1, 2%); class VI (n = 2, 4%). All the patients received oral prednisone, in addition the following treatments were used: pulse intravenous (i.v.) cyclophosphamide (n = 23, 46%); azathioprine (n = 22, 44%); pulse i.v. steroids (n = 19, 38%); chloroquine sulfate (n = 17, 34%); methotrexate (n = 5, 10%); and plasmapheresis (n = 2, 4%). The median duration of follow-up was 5 y (range 1-33 y). On their last evaluation, out of 37 patients who were followed, 20 patients (54%) had controlled disease, eight patients (22%) were still on active medical treatment, four patients (11%) were on chronic hemodialysis, and five patients (13%) had died. Unlike three other Arab populations studies from Kuwait, United Arab Emirates and Saudi Arabia, where the most frequent histopathologic abnormality was class III, diffuse proliferative LN (class IV) was the most common type of lupus nephritis in Lebanon, similarly to reports from USA, France, Netherlands, South Africa, Thailand and Taiwan.
Lupus 2001
PMID:Lupus nephritis in Lebanon. 1140 72


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