The research group went onto induce FNGN by injection of LAMP-2 IgG antibody in 15 WKY rats, thus providing evidence for vascular pathogenicity. we discuss its potential impact for diagnosis and therapy. Furthermore, high throughput methods are starting to identify genetic patterns that may identify patients likely to respond to specific therapy or having a high probability of relapse. Summary It has become progressively obvious, over the last two decades that ANCA IgG is usually pathogenic in vasculitis. Novel therapies aimed at selected cell populations or blocking specific pathogenic pathways offer hope for more selectively treating this heterogeneous group of patients, while avoiding non-specific immunosuppression and its adverse effects. evidence for the pathogenicity of ANCA in humans comes from a single case report of pulmonary hemorrhage and glomerulonephritis in a neonate with transplacental transfer of ANCA IgG from a mother with active MPO-ANCA vasculitis[7]. experiments show that ANCA induce neutrophil activation by engagement of their target antigens MPO and PR3 . ANCA bind to neutrophils by Fc receptor engagement. This prospects to neutrophil activation and release of oxygen radicals, lytic enzymes, and inflammatory cytokines, such as IL-8 [8]. This in turn impedes neutrophil migration [9] and results in excessive neutrophil accumulation within the vasculature and subsequent damage to the endothelium and vessel inflammation [10]. Adhesion studies under flow conditions, in which neutrophils are perfused through glass microslides coated with platelets or endothelial cells, show that ANCA play an important role in adhesion and migration. Activation of endothelial cells with low concentrations of TNF followed by infusion of ANCA IgG resulted in stabilised adhesion and a 10-fold increase in the number of transmigrating neutrophils [11, 12*]. Adhesion and migration require activation of neutrophil 2 integrins and involve the chemokine receptor CXCR2 [13]. A number of experimental models provide evidence that MPO-ANCA can induce crescentic glomerulonephritis, pulmonary capillaritis and systemic vasculitis. Immunisation of MPO-knockout mice with murine MPO induced MPO-ANCA, and when these were injected, immunodeficient or wild (S)-Rasagiline mesylate type (S)-Rasagiline mesylate mice developed pauci-immune focal necrotising glomerulonephritis [14]. A similar approach did generate PR3-ANCA, but passive transfer of these did not induce vasculitis [15], but significantly aggravated the local inflammatory response induced by subcutaneous TNF- administration, thus providing evidence to support PR3-mediated tissue damage have extended their animal model experiments to examine different genetic strains in addition to the initial WKY model. Despite the induction of significant ANCA titres, they were unable to replicate disease in 4 genetically unique rat models (Lewis, Wistar Furth, Brown (S)-Rasagiline mesylate & Norway), thus alluding to a genetic basis for vasculitis resistance [17**]. Genetic preponderance is usually further illustrated by the induction of a vasculitis syndrome in SCID mice CFD1 following the transfer of splenocytes harvested from NOD mice immunised with recombinant mouse PR3 but not following the transfer of splenocytes harvested in genetically unique C57BL/6 mice and transferred to immunodeficient C57BL/6-RAG-I?/? mice [18*]. ANCA mediated match activation It has been assumed that match activation is not involved in the pathogenesis of AAV because of the paucity of immunoglobulin and match deposits in affected blood vessels and the absence of hypocomplementaemia. Recent evidence, however, points to an important role of match activation in AAV; in vitro activation of human neutrophils by MPO-ANCA or PR3-ANCA prospects to complement activation including activation of C3a [19]. In vivo match depletion with cobra venom factor prevented the development of vasculitis following injection of MPO IgG or transfer of anti-MPO splenocytes. Furthermore, a common match pathway inhibiting C5 antibody prevented or ameliorated MPO IgG mediated glomerulonephritis when given before or after disease induction, respectively [20]. Studies using mice deficient in specific match pathways show that MPO IgG mediated glomerulonephritis is dependent on the alternative complement pathway [19]. Immunofluorescence microscopy shows deposition of the complement component C3c in glomerular capillaries or mesangium in 33% of patients with AAV and this was associated with elevated proteinuria and more severe renal injury [21]. Overall, these studies support a crucial role for alternative (S)-Rasagiline mesylate pathway complement activation in AAV and suggest that complement inhibition may be a target for (S)-Rasagiline mesylate future therapies. ANCA and T cell activation T cells may play a major.
Categories