Circumvention of Normal Constraints on Granule Protein Gene Expression in Peripheral Blood Neutrophils and Monocytes of Patients with Antineutrophil Cytoplasmic Autoantibody–Associated Glomerulonephritis (original) (raw)
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Journal of physiology and pharmacology : an official journal of the Polish Physiological Society, 2012
Granulomatosis with polyangiitis (Wegener's ) is a rare autoimmune disease associated with the presence of antibodies directed against neutrophil antigen, proteinase-3 (PR3). The mechanisms by which anti-neutrophil cytoplasmic antibodies (ANCA) may activate neutrophils are still not well understood. In the present study we analyzed neutrophil gene expression profile after anti-PR3 antibodies stimulation. Briefly neutrophils isolated from 12 healthy volunteers, who tested negative for anti-PR3 autoantibodies, were stimulated with anti-PR3 IgG and activation of 147 genes was analyzed with the use of TaqMan low-density arrays. In stimulated neutrophils we observed up-regulation of 13 genes (CCL2, CXCL2, VCAM1, MMP9, PLCB4, PDE4C, PLA2G4C, RAC1, RHOA, IRAK1, CACNA1D, CACNB2, PTGDR), further 11 genes were up-regulated only in some donors (IL13, PF4, IL2RG, ITGB1, CD83, PLA2G7, ALOX12, AXNA1, AXNA5, LTA4H, MCR2) yet two others (HRH3 and PLA2G2D) were up-regulated in a few samples and ...
Nephrology Dialysis Transplantation, 2014
Anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) is strongly associated with autoantibodies against myeloperoxidase (MPO) and proteinase 3 (PR3). No clear consensus has been reached on the pathogenicity of these autoantibodies. Animal models for MPO-ANCA, in vitro data suggesting pathogenicity of ANCA, and one case of a neonate showing symptoms of vasculitis after transplacental transfer of MPO, argue in favour of a pathogenic role for ANCA. On the other hand, the presence of natural MPO and PR3 autoantibodies in healthy individuals, lack of a strong correlation between ANCA titres and disease activity, and the occurrence of ANCA-negative AAV patients argue against pathogenicity of ANCA. Recent papers have drawn attention to the possibility of epitope specificity defining ANCA pathogenicity. Certain MPO epitopes were found to be specific for active disease, and others remained present during remission or were also present in healthy individuals. One linear epitope, aa447-459, was not only exclusive for active disease, but also detected in the total Ig fraction of ANCA-negative patients, reactivity being masked in serum by ceruloplasmin. So, not all ANCA seems to be equal, some could be pathogenic while others are not. For development of an autoimmune response, a specific ANCA repertoire is required, which may occur through intra-molecular epitope spreading in patients.
Clinical and Experimental Immunology, 2003
In systemic small vessel vasculitides, patients form autoantibodies against neutrophil granular proteins, anti-neutrophilic cytoplasmic autoantibodies (ANCA). Some correlation is seen between ANCA titre and disease activity, but whether this is cause or effect is still unknown. It has been reported that levels of proteinase 3 (PR3), one of the main ANCA antigens, are increased in patients with active disease. An increased level of circulating antigen could mean a predisposition to autoimmunity. In order to explore this we measured PR3 levels in patients with stable disease. In addition we measured neutrophil gelatinase-associated lipocalin (NGAL) as a specific marker of neutrophil degranulation, cystatin C as a marker of renal function as well as C-reactive protein (CRP), IL-6 and sTNFr1 as markers of inflammation. PR3, NGAL, IL-6 and sTNFr1 were measured in plasma by the ELISA technique. In the PR3 ELISA, we used anti-PR3 monoclonal antibodies as capture-antibodies and affinity-purified rabbitanti-PR3 antibodies for detection. PR3-ANCA, myeloperoxidase (MPO)-ANCA, CRP and cystatin C were measured by routine methods. PR3 was significantly raised ( P < 0·0001) in vasculitis patients (median 560 m g/l, range 110-3940, n = 59) compared with healthy blood donors (350 m g/l, 110-580, n = 30) as well as disease controls (360, 110-580, n = 46). No correlation was seen with disease activity, inflammation or renal function. The raised NGAL levels correlated strongly with decreased renal function ( r = 0·8, P < 0·001). After correcting for this, slightly increased levels (110, 42-340, n = 59) were observed compared with healthy blood donors (81, 38-130, n = 25), but not compared with the disease controls (120, 57-260, n = 48). In the disease controls, there was a significant correlation between NGAL and proteinase 3 ( r = 0·3, p < 0·05), but this was not the case in the vasculitis patients. Whether patients had PR3-ANCA or MPO-ANCA was of no significance. In our measurements, we found significantly raised levels of PR3 in plasma from patients with small vessel vasculitis, regardless of ANCA specificity. This was not due to decreased renal function, ongoing inflammation or neutrophil activation. Plausible mechanisms for this include defects in the reticuloendothelial system, genetic factors and selective neutrophil degranulation or leakage.
Clinical and Experimental Immunology, 1999
Although circulating anti-neutrophil cytoplasmic antibodies (ANCA) specific for myeloperoxidase (MPO) are strongly associated with the presence of vasculitis, they have been described in sera from patients with other conditions. High levels of anti-MPO antibodies can also persist in sera from patients with vasculitis despite the achievement of clinical remission. One possible interpretation is that a potentially pathogenic subset of anti-MPO antibodies exists, which is only present in patients with active vasculitis. We therefore compared the characteristics of anti-MPO antibodies in sera from patients with active vasculitis (n ¼ 18) with those present in remission (n ¼ 9) and in a disease control group (n ¼ 10) without clinical evidence of vasculitis. The class, subclass and ability of anti-MPO antibodies from the three groups of patients to recognize three different conformational epitopes were analysed using ELISA-based techniques. The expression of an idiotope, designated 9G4, was also examined. Epitope recognition by anti-MPO antibodies from all patients tested was found to be similar. Sera from patients with active vasculitis showed an over-representation of IgG4 subclass anti-MPO antibodies and a more frequent presence of IgM class anti-MPO antibodies. In disease controls, IgG1 anti-MPO antibodies were predominant. In vitro, neutrophil activation by ANCA has been shown to be dependent on engagement of neutrophil FcgRIIa receptors following binding of these autoantibodies to surface-expressed ANCA antigens. We found that active vasculitis may be associated with the presence of circulating anti-MPO antibodies which do not significantly bind this receptor, suggesting that mechanisms other than those dependent on FcgRIIa binding should be explored. In addition, the expression of the 9G4 idiotope on anti-MPO antibodies in 60% (12/18) of patients with active vasculitis and 20% (2/10) of disease control patients may indicate a common origin for anti-MPO antibodies in different individuals.
Scientific Reports, 2015
ANCA vasculitis encompasses several autoimmune conditions characterised by destruction of small vessels, inflammation of the respiratory tract and glomerulonephritis. Most patients harbour autoantibodies to myeloperoxidase (MPO) or proteinase 3 (PR3). Clinical and experimental data suggest that pathogenesis is driven by ANCA-mediated activation of neutrophils and monocytes. We investigated a potential role for distinct monocyte subsets. We found that the relative proportion of intermediate monocytes is increased in patients versus control individuals, and both MPO and PR3 are preferentially expressed on these cells. We demonstrate that MPO and PR3 are expressed independently of each other on monocytes and that PR3 is not associated with CD177. MPO expression correlates with that of Fc receptor CD16 on intermediate monocytes. Monocyte subsets respond differently to antibodies directed against MPO and PR3, with anti-MPO but not anti-PR3 leading to increased IL-1β, IL-6 and IL-8 production. In concordance with the observed higher surface expression of MPO on intermediate monocytes, this subset produces the highest quantity of IL-1β in response to anti-MPO stimulation. These data suggest that monocytes, specifically, the intermediate subset, may play a role in ANCA vasculitis, and also indicate that substantial differences exist between the effect of anti-MPO and anti-PR3 antibodies on these cells. Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) refers to a group of severe multi system autoimmune diseases affecting the microvasculature 1. This encompasses microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA, formally known as Wegner's granulomatosis) and eosinophilic granulomatosis with polyangiitis (EGPA, formerly known as Churg-Strauss syndrome). In most cases AAV is characterised by autoantibodies to myeloperoxidase (MPO) or proteinase-3 (PR3) 2,3. These proteins are primarily found in the cytoplasmic granules of neutrophils and lysosomes of monocytes. Substantial clinical and experimental evidence indicates that these autoantibodies drive pathogenesis of the disease 4,5. GPA, EGPA and MPA share the same pathology of necrotising vasculitis of small vessels, the primary difference between them being the development of granuloma in EGPA and GPA but not MPA, with marked eosinophilia and asthma in EGPA. The majority of AAV research to date has
Antiproteinase 3- and antimyeloperoxidase-associated vasculitis
Kidney International, 2000
Antiproteinase 3-and antimyeloperoxidase-associated vasculipatients with necrotizing crescentic glomerulonephritis tis. Wegener's granulomatosis, microscopic polyangiitis, and (NCGN) and microscopic polyangiitis [3]. In these paidiopathic pauci-immune necrotizing crescentic glomerulonetient categories, proteinase 3 (PR3) and myeloperoxiphritis (NCGN) are strongly associated with antineutrophil dase (MPO) were identified as the principle target anticytoplasmic autoantibodies (ANCAs) directed against either proteinase 3 (anti-PR3) or myeloperoxidase (anti-MPO). This gens of C-ANCA and P-ANCA, respectively [3-6]. Later, has led some investigators to prefer combining these diseases it became apparent that ANCA, predominantly P-ANCA, under the common heading of ANCA-associated vasculitides. could also be found in patients with a wide range of However, it is increasingly recognized that there are characternonvasculitic disorders such as inflammatory bowel disistic differences between patients with anti-PR3 and those with anti-MPO-associated vasculitis. This review focuses on the ease, primary sclerosing cholangitis, autoimmune liver clinical, histopathologic, and possibly pathophysiologic differdisease, rheumatoid arthritis, malignancies, and infecences between anti-PR3-and anti-MPO-associated vasculitis. tions [7-18]. ANCAs in these disorders are almost always Although there is considerable overlap, the anti-PR3-and directed against neutrophil constituents other than PR3 anti-MPO-associated vasculitides are each characterized by or MPO or against unknown antigens [17-22]. This indiparticular clinical and histopathological findings. Extrarenal organ manifestations and respiratory tract granulomas occur cates that sera that are ANCA positive by indirect immumore frequently in patients with anti-PR3 than in those with nofluorescence microscopy should be further characteranti-MPO. Anti-PR3-positive patients with NCGN generally ized by an antigen-specific assay such as enzyme-linked have a more dramatic deterioration of their renal function immunosorbent assay (ELISA). compared with anti-MPO-positive patients. The term "ANCAassociated vasculitis" is considered as a useful concept in the In this review, we use the definitions of vasculitis presence of systemic vasculitis. Likewise, in the presence of adopted by the Chapel Hill consensus conference on the vasculitis, the terms "anti-PR3-associated vasculitis" and "antinomenclature of systemic vasculitis [23]. In this proposal, MPO-associated vasculitis" are useful concepts. vasculitides are, in part, classified on the basis of the predominant size and type of vessel affected. ANCA are predominantly found in patients with small-vessel vasculi-Antineutrophil cytoplasmic autoantibodies (ANCA) tis such as Wegener's granulomatosis and microscopic powere first described in 1982 by Davies et al in a few lyangiitis. Small-vessel vasculitis is defined as vasculitis patients with necrotizing glomerulonephritis [1]. In 1985, van der Woude et al showed that ANCAs producing a that affects vessels smaller than arteries, such as arterioles, diffuse granular cytoplasmic staining pattern on ethanolvenules, and capillaries. However, small-vessel vasculitis fixed neutrophils (C-ANCA) are sensitive markers for sometimes also affects arteries, and thus, the vascular dis-Wegener's granulomatosis [2]. Subsequently, ANCAs tribution overlaps with that of the medium-vessel and producing a perinuclear cytoplasmic staining pattern on large-vessel vasculitides. Wegener's granulomatosis is ethanol-fixed neutrophils (P-ANCA) were described in defined as granulomatous inflammation involving the respiratory tract and necrotizing vasculitis affecting smallto medium-sized vessels. Microscopic polyangiitis is de