Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024141 (systemic lupus erythematosus)
 44,322 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It is known that activation of neutrophils or monocytes leads to the formation of hydrogen peroxide and the release of myeloperoxidase (MPO). We found that sulfamethoxazole was chlorinated by the combination of MPO, hydrogen peroxide, and chloride. The product, N-chlorosulfamethoxazole, is reasonably stable but reacts rapidly with a variety of compounds. The same product was formed by the reaction between sulfamethoxazole and hypochlorous acid, and dapsone was also N-chlorinated by the MPO system or hypochlorous acid. Although N-chlorination was not observed when sulfamethoxazole or dapsone was incubated with activated neutrophils, this is presumably because the chloramine products react rapidly with the cells. When radiolabeled sulfamethoxazole was incubated with activated neutrophils, covalent binding was observed. When radiolabeled sulfamethoxazole was incubated with MPO and hydrogen peroxide in the presence of albumin, covalent binding to the albumin occurred. Although binding to albumin occurred in the absence of chloride, it was increased by the presence of chloride. This suggests that N-chlorosulfamethoxazole may be one of several reactive metabolites of sulfamethoxazole that covalently bind to neutrophils. We suspect that covalent binding of arylamine drugs, such as sulfamethoxazole, to activated leukocytes is responsible for some of the adverse reactions associated with these drugs, especially adverse reactions that involve leukocytes such as agranulocytosis or drug-induced lupus.
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PMID:N-chlorination of sulfamethoxazole and dapsone by the myeloperoxidase system. 790 44

We describe 2 cases of a lupus syndrome induced by sulfasalazine in rheumatoid arthritis. All symptoms resolved and antihistone antibodies disappeared when sulfasalazine was discontinued. In one patient, perinuclear antineutrophil cytoplasmic antibodies with specificity for myeloperoxidase were found critically increased just before the occurrence of vasculitis.
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PMID:Sulfasalazine induced lupus in rheumatoid arthritis. 791 4

Antineutrophil cytoplasmic autoantibodies (ANCA) have been used as markers of systemic vasculitides, including microscopic polyarteritis (MPA) and Wegener's granulomatosis. The diagnostic potential of ANCA assays together with antibodies against the neutrophil enzymes myeloperoxidase (MPO) and proteinase 3 for detecting a systemic vasculitis was tested in a Chinese patient population. 672 sera were received for ANCA assay, and ANCA detected by indirect immunofluorescence was positive in 73 sera from 42 patients. Of the 42 patients, 3 had cytoplasmic ANCA, while 39 had a perinuclear pattern. There was no patient with Wegener's granulomatosis. Two cytoplasmic ANCA positive patients suffered from ulcerative colitis. Another cytoplasmic ANCA positive patient was a carrier of human immunodeficiency virus. Of the 39 perinuclear ANCA positive patients, 10 had MPA. Eight of them were tested for anti-MPO antibody, and all were positive. Other immune disorders that were perinuclear ANCA positive included: 13 patients with systemic lupus erythematosus, 3 with mixed connective tissue disease, 1 with Goodpasture's syndrome, 2 with inflammatory bowel disease, and 2 patients with IgA nephropathy. Anti-MPO antibody was not specific for MPA, and 7 out of the 13 patients with systemic lupus erythematosus were anti-MPO antibody positive. Our study suggests that ANCA and anti-MPO antibody are not specific for MPA in a Chinese population. They would alert the clinician of the possibility of vasculitis, but a clinicopathological correlation is essential in making the diagnosis.
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PMID:Use of antineutrophil cytoplasmic autoantibodies in diagnosing vasculitis in a Chinese patient population. 791 85

A variety of autoantibodies have been associated with vasculitis, including that to neutrophils or to endothelial cells. Anti-neutrophil cytoplasmic antibodies (ANCA) have been described as sensitive and specific markers for active Wegener's granulomatosis (WG). ANCA in WG produces a characteristic cytoplasmic staining pattern (cANCA) and are directed against proteinase 3 (PR3-ANCA). PR3-ANCA occur in more than 90% of patients with extended WG, in 75% of patients with limited WG without renal involvement and in some 40% to 50% of patients with vasculitic overlap syndrome such as microscopic polyarteritis. Change in levels of cANCA precede disease activity and may be used as guidelines for treatment. Antibodies producing a perinuclear staining of ethanol-fixed neutrophils (pANCA) occur in a wide range of disease. They are directed against different cytoplasmic constituents of neutrophils. Among these, antibodies to myeloperoxidase (MPO-ANCA) are found in patients with idiopathic crescentic glomerulonephritis, the Churg-Strauss syndrome, polyarteritis nodosa and vasculitic overlap syndromes. Anti-endothelial cell antibodies (AECA) have been described in various autoimmune (systemic lupus erythematosus, scleroderma, rheumatoid arthritis) and vasculitic disorders (WG, polyarteritis nodosa, Kawasaki syndrome). They have been implicated in the pathogenesis of vascular injury common to these disorders.
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PMID:[Autoantibodies associated with vasculitis]. 793 81

Serum soluble HLA (SHLA) class I antigens in patients with systemic lupus erythematosus (SLE) were examined by enzyme-linked immunosorbent assay. The primary antibody used was W6/32, anti-HLA class I mouse monoclonal antibody, and the secondary antibody was peroxidase-conjugated anti-mouse IgG antibody. The reactivity of SHLA class I antigens, the number of peripheral lymphocytes, and the clinical state of SLE were compared. The results were as follows; 1) Sixteen of 55 samples from SLE patients were SHLA class I antigen-positive (29%). 2) The reactivity of SHLA class I antigens was closely related to disease activity. 3) The number of lymphocytes and the reactivity of SHLA class I antigens were negatively correlated. 4) Nine of 23 samples from the active SLE patients were SHLA class I antigen-negative. Of these, 7 were from patients with a nephrotic syndrome due to lupus nephritis. It is concluded that SHLA class I antigens can be an useful marker for monitoring the clinical state of SLE.
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PMID:Clinical significance of serum soluble HLA class I antigens in systemic lupus erythematosus. 794 Jun 9

Drug-induced lupus is a serious side effect of certain medications, but the chemical features that confer this property and the underlying pathogenesis are puzzling. Prototypes of all six therapeutic classes of lupus-inducing drugs were highly cytotoxic only in the presence of activated neutrophils. Removal of extracellular hydrogen peroxide before, but not after, exposure of the drug to activated neutrophils prevented cytotoxicity. Neutrophil-dependent cytotoxicity required the enzymatic action of myeloperoxidase, resulting in the chemical transformation of the drug to a reactive product. The capacity of drugs to serve as myeloperoxidase substrates in vitro was associated with the ability to induce lupus in vivo.
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PMID:Transformation of lupus-inducing drugs to cytotoxic products by activated neutrophils. 772 10

The kidney is affected in a variety of vasculitic syndrome. Vasculitis represent an heterogeneous group of inflammatory disease concerning vessels. They can be considered as secondary in systemic lupus erythematosus, cryoglobulinemia, rheumatoid polyarthritis but also in infectious diseases (Streptococci, hepatitis B) in malignant disease and after drugs. However, in many circumstances, no causes are found. The discovery of autoantibodies directed against components of neutrophil cytoplasm (ANCA) represent a great progress in the understanding of vasculitis. ANCA are autoantibodies directed against neutrophil lysosomial enzymes, preferentially myeloperoxidase and proteinase 3. They are frequently found in patients with idiopathic necrotizing vasculitis, systemic or localized to the kidney (Wegener granulomatosis, microscopic periarteritis, pauci-immune necrotizing glomerulonephritis, Churg and Strauss syndrome and polyarteritis nodosa). Diagnostic and prognostic values are sure, although their presence is unconstant with variable percentage in relation with the type of vasculitis. The increase of ANCA level is not always related with disease relapse. Conversely, a permanent low level means a quiescent disease. At the present time, it is not known if ANCA play a pathogenetic role or if they constitute a marker of the disease.
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PMID:[Kidney and vasculitis]. 805 72

Anti-neutrophil cytoplasmic antibodies (ANCA) are antibodies directed against enzymes that are found mainly within the azurophil or primary granules of neutrophils. There are 3 types of ANCA that can be distinguished by the patterns they produce by indirect immunofluorescence when tested on normal ethanol-fixed neutrophils. Diffuse fine granular cytoplasmic fluorescence (cANCA) is typically found in Wegener's granulomatosis, in some cases of microscopic polyarteritis and Churg Strauss syndrome, and in some cases of crescentic and segmental necrotising glomerulonephritis, but it is rare in other conditions. The target antigen is usually proteinase 3. Perinuclear fluorescence (pANCA) is found in many cases of microscopic polyarteritis and in other cases of crescentic and segmental necrotising glomerulonephritis. These antibodies are often directed against myeloperoxidase but other targets include elastase, cathepsin G, lactoferrin, lysozyme and beta-glucuronidase. The third group designated "atypical" ANCA includes neutrophil nuclear fluorescence and some unusual cytoplasmic patterns, and while a few of the target antigens are shared with pANCA, the others have not been identified. Sera that produce a pANCA or atypical ANCA pattern on alcohol-fixed neutrophils result in cytoplasmic fluorescence when formalin acetone fixation is used. pANCA or atypical ANCA occur in about 2/3 of all individuals with ulcerative colitis or primary sclerosing cholangitis, and they are found in a third of patients with Crohn's disease. The reported incidence of ANCA in rheumatoid arthritis and SLE varies considerably but the patterns are predominantly pANCA and atypical ANCA.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Anti-neutrophil cytoplasmic antibodies (ANCA): their detection and significance: report from workshops. 809 May 92

Circulating antibodies to myeloperoxidase (MPO) have been described in a variety of vasculitic syndromes, drug-induced SLE and drug-induced nephritis. We have examined the autoantibody profile in acute sera from patients with antineutrophil cytoplasmic antibody-positive vasculitis (n = 8), drug-induced nephritis (n = 4), drug-induced lupus (n = 7), SLE (n = 27) and nephritis-associated with SLE (n = 17). Significant binding to purified MPO in ELISA was given by all sera from patients with vasculitis and drug-induced nephritis but ANA sought by indirect immunofluorescence on HEp-2 cells were not detected. Both anti-MPO and ANA were found in sera from patients with drug-induced lupus. Sera from patients with SLE or SLE nephritis did not contain high titres of anti-MPO antibodies but invariably contained ANA. Anti-MPO antibodies of both IgG and IgM classes were present in all sera from patients with drug-induced disease. Although the number of samples tested was small, sera from patients with drug-induced nephritis showed significantly greater median % binding of IgM to MPO compared with drug-induced SLE. Binding to MPO by IgG in these sera was not significantly different. These findings suggest that the mechanism of interaction between hydralazine and the immune system in the two drug-induced autoimmune diseases studied may contribute to their distinct clinical features.
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PMID:Autoantibodies to myeloperoxidase in idiopathic and drug-induced systemic lupus erythematosus and vasculitis. 816 72

Peripheral blood leukocytes contain a variety of enzymes that are capable of metabolising xenobiotics. The enzyme myeloperoxidase (MPO) appears to be the most important for drug metabolism. MPO is a peroxidase/oxidase and generates the powerful oxidant hypochlorous acid. MPO- or MPO-generated oxidants are capable of oxidizing a wide variety of compounds and a broad range of functional groups, especially those that contain nitrogen and sulfur. Leukocytes have a role in immune response; therefore, reactive intermediates generated by leukocyte metabolism of xenobiotics may have a role in idiosyncratic drug reactions, particularly those that are immune-mediated such as drug-induced lupus or agranulocytosis.
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PMID:Myeloperoxidase-mediated activation of xenobiotics by human leukocytes. 823 77


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