Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.11.1.7 (peroxidase)
65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Antibodies directed against myeloperoxidase (anti-MPO) were detected, using a solid-phase ELISA and purified sputum myeloperoxidase as the substrate, in 54 sera from 22 patients. Anti-MPO were present in 17 patients with crescentic glomerulonephritis (CGN), Wegener's granulomatosis (WG) and microscopic polyarteritis (MPA), and thus are associated with different forms of vasculitis. Anti-MPO were also present in five out of 20 patients with systemic lupus erythematosus (SLE). Anti-MPO activity in SLE sera was low, in contrast to the high titers observed in patients with vasculitis. All positive sera had IgG anti-MPO (except two SLE sera) and most of them also contained low-titered IgM anti-MPO. Only three patients had high IgM anti-MPO activities, the significance of which remains to be determined. In patients with CGN, WG or MPA, the anti-MPO titer decreased following therapy and paralleled the disease activity. Thus, anti-MPO constitute a useful diagnostic tool and a sensitive marker of disease activity in this group of patients with vasculitis.
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PMID:Anti-myeloperoxidase antibodies: immunological characteristics and clinical associations. 165 17

Polymorphonuclear leukocyte (PMN) respiratory burst was stimulated by heterologous antibodies against PMN granule proteins but not by control antibodies. Fluorescence-activated cell sorter (FACS) analysis of activated PMN demonstrated the presence of two primary granule proteins, proteinase 3 (PR-3) and cationic protein 57 (CAP-57) at the membrane surface. The presence of myeloperoxidase (MPO) at the cell surface of primed and unprimed PMN was confirmed by immunoelectron microscopy. Priming doses of recombinant tumor necrosis alpha (rTNF alpha) enhanced the rate of superoxide (O2-) production by these antibodies and increased the amount of surface protein accessible to these antibodies. Anti-neutrophil cytoplasmic autoantibodies (ANCA) with specificities for PMN granule proteins are present in patients with Wegener's granulomatosis, polyarteritis nodosa, and idiopathic and crescentic glomerulonephritis. The demonstration that antibodies against granule proteins activate PMN supports the hypothesis that the vasculitis seen in these diseases is due in part to PMN mediated oxidative injury following PMN stimulation by ANCA.
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PMID:Antibodies against granule proteins activate neutrophils in vitro. 165 70

We have studied 495 sera that were referred to us from patients suspected on clinical and/or histological grounds to have a small vessel vasculitis. These sera were tested for antibodies against neutrophil cytoplasm antigens (anti-neutrophil cytoplasm antibodies, ANCA) using assays based on neutrophil acid extract, myeloperoxidase and elastase. Such antibodies are commonly found in Wegener's granulomatosis (WG) and microscopic polyarteritis (MPA), and sometimes in other small vessel vasculitides. One hundred and twenty-six of these sera (25%) were positive in the acid extract ELISA, 68 (14%) in the assay for anti-myeloperoxidase antibodies and 35 (16%) in the assay for anti-elastase antibodies. A total of 166 sera (34%) were positive for antibodies against neutrophil cytoplasm constituents. No ANCA, anti-myeloperoxidase or anti-elastase antibodies were detected in 26 convalescent sera from patients either with WG or MPA, or who had previously been positive. The mean time between positive and negative sera was eight weeks (range three weeks to six months) and three out of three who relapsed again developed ANCA of the same specificity as the original sera. Of the 228 sera also tested for anti-GBM antibodies, 13 (5.7%) were positive. All these contained antibodies against neutrophil cytoplasm constituents (three against the acid extract, eight against myeloperoxidase and two against elastase). Forty-nine of the 74 sera (66%) tested for ANA were positive. Twenty-nine (39%) had a speckled and 20 (27%) had a homogeneous pattern.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Autoantibodies in systemic vasculitis. 132 37

IgG autoantibodies against antigen in the cytoplasm of cells of the neutrophil-monocyte cell lineage have been found in the sera of patients with Wegener's granulomatosis (WG). The indirect immunofluorescence test (IFT) is proving to be a valuable screening test for these antibodies, but obtaining neutrophils for substrate is time-consuming, and interpretation of the fluorescence patterns in ethanol-fixed cells requires considerable experience. We report an improved IFT using HL-60 cells as substrate. The myeloid reactivity of HL-60 cells was characterized and compared to that of neutrophils, with and without prior ethanol fixation. In contrast to neutrophils, myeloperoxidase (MPO) was more completely extracted from HL-60 cells by prior ethanol fixation, eliminating the confusion inherent in trying to distinguish anti-MPO antibodies from Wegener's granulomatosis associated anti-neutrophil cytoplasmic autoantibodies (WG-ANCA) in the IFT. The WG-ANCA reactivity remained intact with ethanol fixation, producing a distinct crescent and half-moon pattern of specific immunofluorescence. This WG-ANCA positive pattern was found in 25 sera from 11 WG patients and was absent in over 1200 control sera from patients referred for autoantibody testing.
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PMID:Detection of anti-neutrophil cytoplasmic autoantibodies using the promyelocytic HL-60 cell-line. 166 65

Classic anti-neutrophil cytoplasm antibodies (cANCA), perinuclear ANCA (pANCA) and antibodies directed against myeloperoxidase (MPO-Ab) were evaluated in 25 patients with either idiopathic or secondary rapidly progressive glomerulonephritis (RPGN). While cANCA were found almost exclusively in Wegener's granulomatosis, pANCA were detectable in several disorders, including microscopic polyarteritis (mPA), but also idiopathic RPGN. MPO-Ab were frequently found in sera from patients with all types of idiopathic but not of secondary RPGN. These results support the hypothesis that some cases of RPGN are early or limited forms of systematic vasculitis. We then looked for the presence of IgA-ANCA in Henoch-Schoenlein purpura (HSP): we found IgA-ANCA with immunoenzymatic assay but not with immunofluorescence in HSP, in primary IgA-GN and in membranous GN as well, thus suggesting the poor specificity of this type of ANCA. The possible pathologic implications of ANCA were examined in vitro. Serum samples from several patients with ANCA were assessed for their capacity to enhance chemiluminescence generation from resting or PMA-stimulated macrophages. Sera from RPGN and mPA patients displaying anti-MPO activity induced granulocytes to enhance the production of oxygen free radicals, thus suggesting a phlogistic effect of MPO-Ab positive sera.
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PMID:Classic and perinuclear anti-neutrophil cytoplasm antibodies and antimyeloperoxidase antibodies in rapidly progressive glomerulonephritis. 166 54

Antineutrophil cytoplasmatic autoantibodies (ANCA) have been tested in this laboratory for more than two years with a 3-fold increase in tests and positive results. The initial association with Wegener's granulomatosis has since been extended to microscopic polyarteritis and rapidly progressive glomerulonephritis. We review the published data. ANCA are not simply another laboratory test but have become an important tool for diagnosis, treatment monitoring and prevention of relapses in many vasculitis syndromes including some forms of rapidly progressive glomerulonephritis. The ANCA-associated antigens have been identified as a serin-proteinase and myeloperoxidase. This provides insights into the pathogenesis of the ANCA-related diseases.
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PMID:[Antineutrophil cytoplasma antibodies (ANCA): clinical indications and experience with these new autoantibodies]. 167 57

The antigenic specificity and clinical distribution of the antineutrophil cytoplasmic antibodies (ANCA) in kidney diseases have recently been extensively studied. In patients with systemic vasculitis, the great predominance of two major ANCA antigens, proteinase 3 (PR3) and myeloperoxidase (MPO), is now established. PR3 and MPO are colocalized in the azurophilic granules of neutrophils and translocated to the cell surface during activation, and thus are able to interact with autoantibodies after neutrophil preactivation. Furthermore, by comparison of amino acid and DNA sequences, it has been shown that PR3 is identical to myeloblastin, which has been described independently and is involved in the control of growth and differentiation of leukemic cells. Aside from the two major ANCA antigens, a number of neutrophil cytoplasmic antigens recognized by ANCA have been identified, including human leukocyte elastase, lactoferrin, CAP57, and cathepsin G. These rare ANCA specificities occur in a limited number of patients. The variety of ANCA antigen specificities contrasts, however, with the fact that the vast majority of ANCA-positive sera are monospecific for one single ANCA antigen. With regard to clinical distribution, ANCA have major diagnostic significance in the four conditions in which they are frequently detected: Wegener's granulomatosis (WG), Churg and Strauss Syndrome (CSS), microscopic periarteritis (MPA), and necrotic and crescentic glomerulonephritis (NCGN). However, the initial dichotomy between MPO-associated vasculitis (NCGN, MPA) and that associated with anti-PR3 antibodies (WG) appears far from absolute.
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PMID:Antigen specificities and clinical distribution of ANCA in kidney diseases. 172 65

In view of the supposed hypersensitivity, the elevated levels of IgE, and the occurrence of eosinophilia reported in Wegener's granulomatosis and related conditions, we studied the IgG subclass distribution of ANCA directed against a 29-kD serine protease and myeloperoxidase (MPO) in 41 untreated ANCA-positive patients with several forms of active vasculitis and/or glomerulonephritis. We found that both 29-kD ANCA and MPO ANCA were predominantly of the IgG1 and IgG4 subclass in all groups of patients. The additional presence of IgG3 subclass was associated with renal involvement. We compared the subclass distribution of ANCA with that of total IgG subclass levels, and with the IgG subclass distribution of antibodies to cytomegalovirus (CMV) as a persistent endogenous antigen and antibodies to tetanus toxoid (TT) as an exogenous recall antigen. Total levels of IgG4 were elevated in the majority of the patients together with elevated IgG1 levels. Antibodies to CMV and TT, however, had the same subclass distribution as found in normals and did not show enhanced IgG4 expression. ANCA belong predominantly to the IgG1 and IgG4 subclass, which may suggest that the production of ANCA is related to recurrent exposition to the antigen(s) involved, possibly as part of a hypersensitivity reaction.
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PMID:Predominance of IgG1 and IgG4 subclasses of anti-neutrophil cytoplasmic autoantibodies (ANCA) in patients with Wegener's granulomatosis and clinically related disorders. 184 89

Autoantibodies that produce a perinuclear pattern on indirect immunofluorescent examination of ethanol-fixed neutrophils (pANCA) are found in about half of all cases of microscopic polyarteritis. These antibodies are often directed against myeloperoxidase or elastase and we have developed sensitive reproducible ELISAs for their detection and study. Seven sera from 19 patients with microscopic polyarteritis or segmental necrotizing glomerulonephritis contained anti-myeloperoxidase or anti-elastase antibodies or both. In contrast, only one of 18 sera from patients with Wegener's granulomatosis, where the pattern of immunofluorescence is predominantly cytoplasmic, had anti-myeloperoxidase antibodies and no anti-elastase antibodies were detected. Using sera from patients with microscopic polyarteritis, both anti-myeloperoxidase and anti-elastase antibodies were demonstrated to be of high affinity. There was no immunoglobulin class, subclass or light chain restriction noted. Anti-myeloperoxidase and anti-elastase antibodies were also found occasionally in anti-glomerular basement membrane disease, mixed connective tissue disease, systemic lupus erythematosus, post-streptococcal glomerulonephritis and atypical pneumonia. In further studies these antibodies were not associated with other lung infections, although anti-elastase antibodies were noted in one of 14 sera positive for ASOT that were tested. Anti-myeloperoxidase antibodies were found more frequently than anti-elastase antibodies and these antibodies were occasionally present together. In addition some sera with pANCA had neither anti-myeloperoxidase nor anti-elastase antibodies. The target molecules in these cases remain unclear.
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PMID:Detection of anti-myeloperoxidase and anti-elastase antibodies in vasculitides and infections. 185 Oct 56

Five patients with subglottic stenosis, occurring either as a presenting symptom or as a manifestation in the course of a systemic disease, are described. Indirect immunofluorescence revealed the presence of circulating autoantibodies against both cytoplasmic and perinuclear constituents of neutrophils in all five. Antibodies directed against a 29 kDa antigen of the azurophilic granules (two patients), against myeloperoxidase (one patient), and against both the 29 kDa antigen and myeloperoxidase (one patient) were found by enzyme-linked immunosorbent assay. These autoantibodies have previously been found in patients with Wegener's granulomatosis, microscopic polyarteritis, (idiopathic) glomerulonephritis and Churg-Strauss syndrome. However, only one of these five patients fulfilled the criteria for these conditions. Since these autoantibodies are seldom observed in other conditions, and other diseases had been excluded by careful evaluation, we suggest that their presence places subglottic stenosis within the spectrum of necrotizing (granulomatous) vasculitis. Whether immunosuppressive therapy is always warranted in patients with subglottic stenosis and circulating anti-neutrophil cytoplasmic antibodies is a matter of debate.
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PMID:Circulating anti-neutrophil cytoplasmic autoantibodies in subglottic stenosis: a useful aid in diagnosing vasculitis in this condition? 194 37


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