Antineutrophil Cytoplasmic Antibody Specificity Research Articles

Key advances in the clinical approach to ANCA-associated vasculitis.

The updated nomenclature for vasculitis defines this varied group of disorders by aetiology, specific features of pathogenesis and clinical symptoms; diagnostic and classification criteria for clinical practice are in development. Here, I review some important advances in the management of vasculitis within the category of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), which encompasses microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA) and eosinophilic granulomatosis with polyangiitis (EGPA). The clinical approach to the management of the patient with AAV should include testing for ANCA specificity; proteinase 3 (PR3)-specific ANCAs are most often associated with GPA, whereas myeloperoxidase (MPO)-ANCAs are usually associated with MPA. Also important to the management of AAV is an assessment of the disease stage and severity, to enable tailored treatment based on an algorithm derived from controlled-trial data. Remaining questions pertain to the dosage and duration of corticosteroid treatment, the selection of patients for, and duration of, maintenance treatment after induction of remission, and the identification of safer and more effective therapies than are currently in use. Outcome measures should assess not only disease activity, but also damage and quality of life. Infections, cardiovascular events and malignancies also contribute to outcome, and their prevention should therefore be part of the clinical approach to managing patients with AAV.

Brief Report: Prevalence of Antineutrophil Cytoplasmic Antibodies in Infective Endocarditis

Infective endocarditis (IE) mimics primary systemic vasculitis, and there are sporadic reports of positivity for antineutrophil cytoplasmic antibodies (ANCAs) among patients with IE. Because the frequency of ANCAs in IE is unknown, this study was undertaken to assess the seroprevalence of ANCAs in a large number of patients with IE. The study was conducted in the framework of a single-center prospective cohort study of incident IE cases. Demographic, clinical, laboratory, and microbiologic data were collected, and magnetic resonance imaging of the brain was performed at diagnosis. For those patients whose serum had been stored at diagnosis, ANCAs were assessed by indirect immunofluorescence assay in ethanol-, formalin-, and methanol-fixed neutrophils. In addition, ANCA specificity for proteinase 3 (PR3) and myeloperoxidase (MPO) was assessed by enzyme-linked immunosorbent assay. Rheumatoid factor (RF), antinuclear antibodies (ANAs), anticardiolipin antibodies (aCL), and serum Ig levels were also measured. Comparisons between groups were made using Wilcoxon's rank sum and chi-square or Fisher's exact tests. Among 109 patients with IE, 18% had cytoplasmic ANCAs (cANCA) and/or perinuclear ANCAs (pANCA) and 8% had PR3-ANCAs or MPO-ANCAs, some with very high titers. Positivity for both cANCA or pANCA and PR3-ANCAs or MPO-ANCAs was found in 6% of patients, and RF, ANAs, and aCL were detected in 35%, 16%, and 23% of samples, respectively. No consistent clinical pattern of IE was observed in the anti-PR3/anti-MPO-positive IE patients, whereas positivity for cANCA/pANCA was associated with younger age (P = 0.022), more frequent occurrence of echocardiographic vegetations (P = 0.043), and above-normal serum IgG levels (P = 0.017). ANCAs, including PR3- and MPO-ANCAs, occur in a substantial proportion of patients with IE. The link between cANCA/pANCA and specific features of IE requires further study.

Genetics of ANCA-associated Vasculitides.

The distribution of the anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitides (AAV) is not uniform across geographical regions and ethnic and racial groups, suggesting that genetic and environmental factors affect the pathogenesis of these diseases. In addition, genetic factors affect not only the clinical syndrome phenotypes and their prognosis, but also ANCA specificity; these data suggest that AAV may need reclassification. Several genes have been evaluated, including ANCA targets and those of the immune system, for example co-stimulatory molecules, signaling regulators, cytokines, Fc and other receptors, and other proteins. This article provides a review of genetic factors affecting the pathogenesis and prognosis of AAV. Further studies to determine the effect of genetic factors on the clinical syndrome phenotypes and ANCA specificity need to be performed across different ethnic groups.

Levamisole-adulterated cocaine induced skin necrosis of nose, ears, and extremities: Case report.

Levamisole is an immunomodulatory and antihelminthic drug, previously removed from the United States market, and now estimated to be present in the vast majority of cocaine distributed in the United States. Levamisole-adulterated cocaine (LAC) exposure can result in neutropenia, thrombocytopenia, and vasculitis with a predilection for subsites of the face. The objective of this review is to increase awareness among otolaryngologists of the manifestations of LAC exposure. We present the case of a 33-year-old woman with a history of cocaine use, consulted for purpuric, necrotic lesions of the nose, cheeks, and ears, with accompanying leukopenia, thrombocytopenia, and positive antineutrophil cytoplasmic antibodies (ANCA). The effects of levamisole are immune mediated, with antibodies directed against neutrophils causing neutropenia, and vasculitis caused by antibody deposition or secondary to induction of antiphospholipid antibodies causing thrombosis. LAC exposure can be differentiated from other similar appearing pathologies by evaluating serology for specific ANCA. The most important treatment is cessation of cocaine use, which most often results in complete resolution of symptoms. Awareness of the presentation, complications, and treatment of LAC exposure may be especially important for otolaryngologists, who may be one of the firsts to evaluate an affected patient.

Proposal of anti-moesin as a novel biomarker for ANCA-associated vasculitis

Myeloperoxidase (MPO)-specific antineutrophil cytoplasmic antibody (ANCA) is associated with rapidly progressive glomerulonephritis (RPGN) in microscopic polyangiitis (MPA). MPO-ANCA activates neutrophils by binding to cell surface MPO expressed on tumor necrosis factor-α (TNF-α)-primed neutrophils and induces neutrophil degranulation and production of reactive oxygen species, consequently resulting in glomerular endothelial damage. Recently, anti-MPO antibody has been found to activate glomerular endothelial cells, leading to an upregulation of adhesion molecules. MPO-ANCA, however, is not always correlated with disease activity in MPA. Accordingly, the molecule(s) responsible for the anti-MPO antibody have been explored on mouse glomerular endothelial cells. The molecule was identified as moesin, which is a heparin-binding protein and belongs to the ezrin/radixin/moesin family of proteins distributed in the plasma membrane in the cellular cortex. Interestingly, anti-moesin is observed in sera of SCG/Kj mice, which spontaneously develop MPO-ANCA-associated RPGN, and of patients with MPO-AAV. The activation of glomerular endothelial cells by the anti-MPO antibody appears to be associated with signaling through moesin.

Epidemiology and clinical features of systemic vasculitis

Different vasculitic syndromes present in different age groups. Immunoglobulin (Ig)A vasculitis and Kawasaki disease usually present in children whereas giant cell arteritis (GCA) and anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis usually present in the middle aged/elderly. In Northern Europe, granulomatosis with polyangiitis (GPA; Wegener's) is commoner than microscopic polyangiitis (MPA) and MPA is more common than eosinophilic granulomatosis with polyangiitis (EPGA; Churg-Strauss syndrome). In Southern Europe, MPA is commoner than GPA and in Japan MPA is much more common than GPA. Major differences exist worldwide in ANCA specificity which are not entirely related to different phenotypes. GPA, like GCA, has a cyclical pattern of onset suggesting possible infection as an aetiological agent. International studies have given important clues to possible aetiology including silica dust and infection and genetic influences, as shown by the recently published genome-wide association study which revealed that single-nucleotide polymorphisms associate more strongly with ANCA than clinical syndromes. A brief description of the main clinical features of ANCA-associated vasculitis is also given.

Study about correlation of anti-neutrophil cytoplasmic antibodies and anticardiolipin antibodies with thromboangiitis obliterans

Doctors often have difficulties in clinical diagnosis and clinical stage of thromboangiitis obliterans (TAO). Immunolesion was important in the initiation and progression of various kinds of vasculitis diseases, including TAO. Several kinds of immune complexes were developed by immunolesion, including anti-neutrophil cytoplasmic antibodies (ANCA) and anticardiolipin antibodies (ACA). Our aim was to determine if it is an effective way for clinical diagnosis and clinical stage of TAO by detection of the presence of ANCA and ACA in blood serum of patients with TAO and the relationship among the presence of ANCA, ACA and patients with different grades of TAO. Blood samples and clinical characteristics were collected from 38 patients with Rutherford grade I TAO, 30 patients with Rutherford grade II–III TAO, 75 patients with arteriosclerosis obliterans (ASO) and 65 healthy volunteers. Their serum samples were investigated for ANCA by indirect immunofluorescent (IIF), and for ACA and ANCA specificity antigens including reactivity to proteinase 3(PR3), myeloperoxidase (MPO), cathepsin G (CG), bactericidal/permesbility-increasing protein (BPI), elastase (HLE) and lactoferrin (LF) by enzyme linked immunosorbent assay (ELISA). (1) ANCA positive rate and titre were much higher in cases with Rutherford grade I TAO (52.6%, 20/38, 0.386 ± 0.458) and Rutherford grade II–III TAO (73.3%, 22/30, 0.847 ± 0.658) than those in cases with ASO (4%, 3/75, 0.011 ± 0.002) and healthy volunteers (0%,0/65, 0.010 ± 0.002) (P < 0.01). ANCA positive rate and titre were higher in cases with Rutherford grade II–III TAO (73.3%, 22/30, 0.847 ± 0.658) than those in cases with Rutherford grade I TAO (52.6%, 20/38, 0.386 ± 0.458) (P < 0.05). (2) ACA concentration was much higher in cases with Rutherford grade I TAO (270.13 ± 13.05 IU/mL) and Rutherford grade II–III TAO (279.33 ± 19.98 IU/mL) than that in cases with ASO (236.85 ± 17.32 IU/mL) and healthy volunteers (229.16 ± 15.55 IU/mL) (P < 0.05) respectively. (3) In 42 cases of ANCA-positive samples, there were 20 cases reacted with MPO, 14 cases reacted with LF, five cases reacted with HLE, five cases reacted with BPI and no one reacted with PR3 and CG. All cases were Rutherford grade II–III TAO. Our results indicate that ANCA, ANCA specificity antigens and ACA were detected susceptibly and availably in patients with TAO. Thus, detection of ANCA, ANCA specificity antigens and ACA was helpful for clinical diagnosis of TAO and detection of ANCA and ANCA specificity antigens was helpful for clinical staging of TAO. They are important assistance for clinical diagnosis and stage of TAO.

Granulomatosis with polyangiitis presenting as an orbital inflammatory pseudotumor: a case report

IntroductionGranulomatosis with polyangiitis is a systemic inflammatory disease that often presents with necrosis, granuloma formation and vasculitis of small- to medium-sized vessels. Affected patients usually present with disease of the upper respiratory tract, lungs and kidneys, but this disease has been reported to involve almost any organ. We report the case of a patient with ocular manifestations of granulomatosis with polyangiitis after the remission of renal and auditory manifestations.Case presentationAn 81-year-old Japanese woman had a four-year history of biopsy-proven antineutrophil cytoplasmic antibody-related glomerulonephritis that had been treated with oral prednisolone and was in serological remission. She had also recovered from a one-year history of complete hearing loss immediately following the steroid treatment for glomerulonephritis. She gradually experienced right eye visual disturbance and exophthalmos over a two-month period. Radiographic and histopathological findings revealed an orbital inflammatory pseudotumor. The administration of prednisolone completely restored her right eye visual acuity and eye movement after two weeks. Considering this case retrospectively, our patient had an orbital inflammatory pseudotumor caused by granulomatosis with polyangiitis including a medical history of reversible hearing loss, although her glomerulonephritis had remitted with an undetectable level of specific antineutrophil cytoplasmic antibody.ConclusionsIn this patient, hearing loss and visual loss occurred at different times during the course of treatment of granulomatosis with polyangiitis. Clinicians should consider a differential diagnosis of granulomatosis with polyangiitis in patients with treatable hearing and visual loss.

Classification of antineutrophil cytoplasmic autoantibody vasculitides: The role of antineutrophil cytoplasmic autoantibody specificity for myeloperoxidase or proteinase 3 in disease recognition and prognosis

To compare the usefulness of 3 currently used classification systems in predicting the outcomes of treatment resistance, disease relapse, end-stage renal disease (ESRD), and death in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Three classification systems were applied to 502 patients with biopsy-proven AAV: 1) the Chapel Hill Consensus Conference (CHCC) definition with categories for granulomatosis with polyangiitis (GPA) (Wegener's), microscopic polyangiitis (MPA), and kidney-limited disease; 2) the European Medicines Agency (EMA) system with categories for GPA and MPA; and 3) classification based on ANCA with specificity for myeloperoxidase (MPO ANCA) versus ANCA with specificity for proteinase 3 (PR3 ANCA). Outcomes included treatment resistance, relapse, ESRD, and death. Proportional hazards models were compared between systems using an information-theoretic approach to rank models by predictive fit. Hazard ratios (HRs) with 95% confidence intervals (95% CIs) and P values are reported. ANCA specificity was predictive of relapse, with PR3 ANCA-positive patients almost twice as likely to relapse as those with MPO ANCA (HR 1.89 [95% CI 1.33-2.69], P = 0.0004), and ANCA specificity had the best predictive model fit (model rank 1) compared to the CHCC and EMA systems. The CHCC and EMA systems did not predict relapse. By ANCA specificity, categories of GPA, MPA, and kidney-limited disease did not distinguish differences in probability of relapse-free survival. None of the systems predicted treatment resistance, ESRD, or death. ANCA specificity independently predicts relapse among patients with AAV with renal disease. Classification and diagnostic systems that incorporate ANCA specificity, such as PR3 ANCA-positive MPA and MPO ANCA-positive MPA, provide a more useful tool than the clinical pathologic category alone for predicting relapse.

Anti-neutrophil cytoplasmic antibodies (ANCA) specific for one or several antigens: useful markers for subtypes of ulcerative colitis and associated primary sclerosing cholangitis

Dysregulation of antimicrobial response may trigger inflammatory bowel diseases (IBD). This study analyzed specificity of anti-neutrophil cytoplasmic antibodies (ANCA) in IBD patients and its clinical significance. Data from 52 ulcerative colitis (UC) patients with 32 Crohn's disease (CD) patients were compared. Primary sclerosing cholangitis (PSC) was present in 12/84 patients. ANCA, ANA and anti-smooth muscle antibodies (ASMA) were detected by IIF. ANCA were tested by ELISA for proteinase 3 (PR3), myeloperoxidase, bactericidal/permeability increasing protein, elastase, cathepsin G, lysozyme and lactoferrin. pANCA were more frequently present in UC than in CD patients (p<0.001). ANCA titer correlated with the disease activity only in UC patients (p<0.05). UC patients more frequently had two or more ANCA specificities compared to CD patients (p<0.01). Multi-specific ANCA in medium and/or high concentrations were associated with long-lasting (p<0.05) and left-sided UC (p<0.001). Multi-specific ANCA with ANA and ASMA had sensitivity of 67% for PSC. Higher concentrations of multi-specific ANCA in long-lasting, left-sided UC suggest an influence of bacterial stimulation on the break of tolerance. Multi-specific ANCA with ANA and ASMA could be markers for PSC. ANCA specific to several antigens may worsen inflammation by reducing antimicrobial capacity of neutrophil proteases and cationic proteins.

Relationship Between Markers of Platelet Activation and Inflammation with Disease Activity in Wegener’s Granulomatosis

There remains a need for biomarkers to guide therapy in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Our objective was to determine whether measures of platelet activation or inflammation are associated with disease activity in Wegener's granulomatosis (WG). Study subjects were participants in a clinical trial. Soluble CD40 ligand (sCD40L), C-reactive protein, interleukin 6 (IL-6), IL-8, monocyte chemoattractant protein 1 (MCP-1), P-selectin, vascular endothelial growth factor, and proteinase 3 (PR3)-specific ANCA were measured by ELISA using plasma samples obtained at baseline (active disease), at remission, and prior to, during, and after first flares. Disease activity was assessed by the Birmingham Vasculitis Activity Score for WG (BVAS/WG). Association of biomarkers with disease activity was determined with conditional logistic and linear regression. Over a mean followup of 27 months, 180 subjects underwent 2044 visits; markers were measured in 563 samples. Longitudinally, all markers other than IL-6 were associated with disease activity. The strongest associations for active disease at baseline versus remission were observed for sCD40L (OR 4.72, 95% CI 2.47-9.03), P-selectin (OR 6.26, 95% CI 2.78-14.10), PR3-ANCA (OR 9.41, 4.03-21.99), and inversely for MCP-1 (OR 0.36, 95% CI 0.22-0.57). BVAS/WG increased by 0.80 (95% CI 0.44-1.16), 0.83 (95% CI 0.42-1.25), and 0.81 (95% CI 0.48-1.15) per unit-increase in PR3-ANCA, sCD40L, and P-selectin, respectively; and decreased by 1.54 (95% CI 0.96-2.12) per unit-increase in MCP-1. Cytokines arising from within the circulation, including those of platelet activation, correlate with disease activity in WG.

Direct activation of glomerular endothelial cells by anti-moesin activity of anti-myeloperoxidase antibody

Glomerular neutrophil infiltration has been thought to be a key pathological event in the development of myeloperoxidase (MPO)-specific anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis involving glomerulonephritis. Accordingly, we sought to explore the molecules responsible for glomerular neutrophil accumulation. Glomerular neutrophil infiltration and renal chemokine expression in mice treated with anti-MPO IgG were evaluated. Chemokine expression in vitro induced by anti-MPO IgG was measured in the primary mouse glomerular endothelial cells (mGEC). The target molecule reacted with anti-MPO IgG on the mGEC was determined by peptide mass fingerprint analysis. A significant glomerular neutrophil infiltration was observed in the mice administered with anti-MPO IgG. The expressions of CXC chemokines, keratinocyte-derived chemokine (KC) and macrophage inflammatory protein-2 (MIP-2), were significantly increased in the renal cortex, indicating that these chemokines contribute to the neutrophil infiltration. Based on the previous findings of upregulation of adhesion molecule expression in mGEC treated with anti-MPO IgG, we examined whether mGEC secrete these chemokines in response to anti-MPO IgG. Indeed, anti-MPO IgG induced secretion of KC and MIP-2, leading to neutrophil chemotaxis in vitro. Furthermore, complete depletion of MPO in mGEC and serum using MPO-deficient mice showed an upregulation of intercellular adhesion molecule-1, indicating cross-reactive molecule(s) were existing on mGEC. We identified the molecule as moesin by a proteomic approach. The endothelial CXC chemokines, KC and MIP-2, contribute to infiltration of neutrophils in MPO-ANCA-associated vasculitis involving glomerulonephritis. The activation of glomerular endothelial cells by anti-MPO IgG appeared to directly involve a signaling through moesin.

Discrimination and variable impact of ANCA binding to different surface epitopes on proteinase 3, the Wegener’s autoantigen

Proteinase 3 (PR3)-specific antineutrophil cytoplasmic antibodies (ANCA) are highly specific for the autoimmune small vessel vasculitis, Wegener’s granulomatosis (WG). PR3-ANCA have proven diagnostic value but their pathogenic potential and utility as a biomarker for disease activity remain unclear. PR3-ANCA recognize conformational epitopes, and epitope-specific PR3-ANCA subsets with variable impact on biological functions of PR3 have been postulated. The aims of this study were to identify specific PR3 surface epitopes recognized by monoclonal antibodies (moAbs) and to determine whether the findings can be used to measure the functional impact of epitope-specific PR3-ANCA and their potential relationship to disease activity. We used a novel flow cytometry assay based on TALON-beads coated with recombinant human (H) and murine (M) PR3 and 10 custom-designed chimeric human/mouse rPR3-variants (Hm1-5/Mh1-5) identifying 5 separate non-conserved PR3 surface epitopes. Anti-PR3 moAbs recognize 4 major surface epitopes, and we identified the specific surface location of 3 of these with the chimeric rPR3-variants. The ability of PR3-ANCA to inhibit the enzymatic activity of PR3 was measured indirectly using a capture-ELISA system based on the different epitopes recognized by capturing moAbs. Epitope-specific PR3-ANCA capture-ELISA results obtained from patient plasma ( n = 27) correlated with the inhibition of enzymatic activity of PR3 by paired IgG preparations ( r = 0.7, P < 0.01). The capture-ELISA results also seem to reflect disease activity. In conclusion, insights about epitopes recognized by anti-PR3 moAbs can be applied to separate PR3-ANCA subsets with predictable functional qualities. The ability of PR3-ANCA to inhibit the enzymatic activity of PR3, a property linked to disease activity, can now be gauged using a simple epitope-based capture-ELISA system.

Pulse Versus Daily Oral Cyclophosphamide in ANCA-Associated Vasculitis

Letters5 January 2010Pulse Versus Daily Oral Cyclophosphamide in ANCA-Associated VasculitisLorraine Harper, MD, PhD, Kirsten de Groot, MD, and Caroline O. Savage, MD, PhDLorraine Harper, MD, PhDFrom Klinikum Offenbach GmbH, 63069 Offenbach/Main, Germany; and University of Birmingham, Edgbaston B15 2TT, United Kingdom.Search for more papers by this author, Kirsten de Groot, MDFrom Klinikum Offenbach GmbH, 63069 Offenbach/Main, Germany; and University of Birmingham, Edgbaston B15 2TT, United Kingdom.Search for more papers by this author, and Caroline O. Savage, MD, PhDFrom Klinikum Offenbach GmbH, 63069 Offenbach/Main, Germany; and University of Birmingham, Edgbaston B15 2TT, United Kingdom.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-152-1-201001050-00022 SectionsAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail IN RESPONSE:We appreciate our colleagues' comments and are glad that our analysis has stimulated further thought among clinicians. We agree with Dr. Padhan that Wegener granulomatosis may be difficult to differentiate from tuberculous infection. However, studies suggest that the presence of both positive cytoplasmic ANCA by immunofluorescence and proteinase 3 enzyme-linked immunosorbent assay has a low prevalence in tuberculosis (1). Even in those rare patients in whom the diagnosis of Wegener granulomatosis is doubted and the balance of evidence favors ANCA-associated vasculitis, we believe that patients should be treated with pulse cyclophosphamide rather than with daily oral cyclophosphamide. The ...Reference1. Teixeira L, Mahr A, Jaureguy F, Noël LH, Nunes H, Lefort A, et al. Low seroprevalence and poor specificity of antineutrophil cytoplasmic antibodies in tuberculosis. Rheumatology (Oxford). 2005;44:247-50. [PMID: 15546964] CrossrefMedlineGoogle Scholar Author, Article, and Disclosure InformationAffiliations: From Klinikum Offenbach GmbH, 63069 Offenbach/Main, Germany; and University of Birmingham, Edgbaston B15 2TT, United Kingdom.Disclosures: None disclosed. PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetailsSee AlsoPulse Versus Daily Oral Cyclophosphamide for Induction of Remission in Antineutrophil Cytoplasmic Antibody—Associated Vasculitis Kirsten de Groot , Lorraine Harper , David R.W. Jayne , Luis Felipe Flores Suarez , Gina Gregorini , Wolfgang L. Gross , Rashid Luqmani , Charles D. Pusey , Niels Rasmussen , Renato A. Sinico , Vladimir Tesar , Philippe Vanhille , Kerstin Westman , Caroline O.S. Savage , and Pulse Versus Daily Oral Cyclophosphamide in ANCA-Associated Vasculitis Prasanta Padhan Pulse Versus Daily Oral Cyclophosphamide in ANCA-Associated Vasculitis Lee A. Hebert and Brad H. Rovin Pulse Versus Daily Oral Cyclophosphamide in ANCA-Associated Vasculitis Stuart M. Levine Metrics 5 January 2010Volume 152, Issue 1Page: 65KeywordsCyclophosphamideHeart rateProteinuriaRenal analysisRenal failureSafetyToxicityVasculitisWegener granulomatosis ePublished: 5 January 2010 Issue Published: 5 January 2010 CopyrightCopyright © 2010 by American College of Physicians. All Rights Reserved.PDF DownloadLoading ...

Prediction of ESRD in Pauci-immune Necrotizing Glomerulonephritis: Quantitative Histomorphometric Assessment and Serum Creatinine

BackgroundClinical and pathologic features that predict outcome have important potential application in patients with pauci-immune necrotizing glomerulonephritis (usually antineutrophil cytoplasmic antibody–associated vasculitis). This study examines the predictive value of simple quantitative renal histologic measurements in a large cohort with extended follow-up.Study DesignCohort study.Setting & Participants390 consecutive patients with pauci-immune necrotizing glomerulonephritis at a single hospital (1983-2002); 90 patients underwent repeated kidney biopsy during follow-up.PredictorsAge and serum creatinine concentration at biopsy, antineutrophil cytoplasmic antibody specificity, percentage of normal glomeruli, percentage of glomeruli with active lesions, and index of chronic damage (quantitative measurement of established cortical damage) in the initial kidney biopsy for all patients. The same factors were assessed in both biopsy specimens for patients undergoing an additional biopsy.Outcomes & MeasurementsEnd-stage renal disease and patient survival.ResultsMortality at 1 and 5 years was 23% and 40%, respectively: standardized mortality ratio, 4.74 (95% CI, 3.62-6.32). End-stage renal disease was reached by 14% and 18% at 1 and 5 years, respectively. In multivariable analysis, serum creatinine level at biopsy and percentage of normal glomeruli in the initial biopsy specimen were the best predictors of kidney survival. C Statistics were 0.80 for creatinine level alone and 0.83 for creatinine level with normal glomeruli. In patients undergoing an additional biopsy, rapid progression in the index of chronic damage and serum creatinine level at the second biopsy were associated with kidney survival in multivariable analysis.LimitationsRetrospective analysis. External validity of the index of chronic damage requires further assessment. Selection bias may influence repeated biopsy analyses.ConclusionsSerum creatinine level at biopsy best predicts kidney survival in patients with pauci-immune necrotizing glomerulonephritis overall.

6001 International randomised phase III study of capecitabine (Cap), bevacizumab (Bev) and mitomycin C (MMC) in first line treatment of metastatic colorectal cancer (mCRC): final results of the AGITG MAX trial

Background/Aims: Antineutrophil cytoplasmic antibodies are reported in patients with chronic liver disease, but controversy exists about their prevalence and specificity. We aimed to find the prevalence and specificity of antineutrophil cytoplasmic antibodies in chronic liver diseases by determination of antineutrophil cytoplasmic antibody titre and IgG subclass.Methods: One hundred and eight-four sera were studied: 63 primary sclerosing cholangitis, 28 autoimmune hepatitis, 34 primary biliary cirrhosis, 12 alcoholic liver disease, five large duct obstruction, four haemochromatosis, one chronic cholestatic syndrome, one cryptogenic cirrhosis and 36 normal individuals. Antineutrophil cytoplasmic antibodies were detected on alcohol-fixed neutrophils using an alkaline phosphates technique. The IgG subclass of antineutrophil cytoplasmic antibodies was determined using monoclonal antibodies: HP 6001 for IgG1, HP 6002 for IgG2, HP 6050 for IgG3 and SK 44 for IgG4 (Sigma Immunochemicals).Results: Antineutrophil cytoplasmic antibodies were detected in 65% of primary sclerosing cholangitis patients at a serum dilution of 1:5, dropping to 49% at 1:50. For autoimmune hepatitis, antineutrophil cytoplasmic antibodies were detected in 49% at 1:5, dropping to 11% at 1:50. Only 6% of primary biliary cirrhosis patients were antineutrophil cytoplasmic antibody-positive at 1:5, dropping to 3% at 1:50. All other controls were antineutrophil cytoplasmic antibody negative at 1:5. The presence of antineutrophil cytoplasmic antibodies in primary sclerosing cholangitis correlated with involvement of the intra- and extrahepatic biliary tree (p=0.016, Fisher's exact test), but no other clinical parameters. Determination of the IgG subclass of antineutrophil cytoplasmic antibody in 33 primary sclerosing cholangitis and 11 autoimmune hepatitis patients revealed a predominance of IgG1 in both groups (94% and 82% of all IgG antineutrophil cytoplasmic antibodies, respectively), with a similar distribution of IgG2, IgG3 and IgG4 antineutrophil cytoplasmic antibodies between the groups.Conclusions: Antineutrophil cytoplasmic antibodies are specific to the autoimmune liver diseases, particularly primary sclerosing cholangitis and autoimmune hepatitis. Titres are highest in primary sclerosing cholangitis, with a diagnostic sensitivity of 49% and specificity of 89% at 1:50, making it a useful serological marker for this disease. The lack of correlation with any marker of activity and the association of antineutrophil cytoplasmic antibody with extent of biliary tract involvement suggest that antineutrophil cytoplasmic antibodies arises as a result of the disease or related process rather than being a cause of it. The detection of antineutrophil cytoplasmic antibodies in autoimmune hepatitis, together with a similar IgG subclass distribution of primary sclerosing cholangitis and autoimmune hepatitis antineutrophil cytoplasmic antibodies, may reflect similar mechanisms of immune regulation and a possible overlap syndrome. Future identification of the antigens against which this antineutrophil cytoplasmic antibody are directed should help to clarify this point, as well as allowing the development of a more sensitive and specific serological test for diagnostic purposes.

MPO-ANCA crescentic glomerulonephritis complicated by membranous nephropathy: MPO demonstrated in epimembranous deposits

An elderly woman presented with haematuria and proteinuria accompanied by elevated serum myeloperoxidase (MPO)-specific anti-neutrophil cytoplasmic antibodies (MPO-ANCA). A renal biopsy revealed mild mesangial proliferation with fibrocellular crescent formation and a membranous glomerular lesion. Immunofluorescence microscopy using FITC-labelled rabbit anti-human MPO antibodies revealed granular MPO deposition along the glomerular capillary walls (GCW) with a staining profile similar to that of glomerular IgG deposition. The one-year follow-up renal biopsy revealed minimal IgG and undetectable MPO deposition. Both MPO and MPO-ANCA might have been responsible for the IgG immune depositions along the GCW in this patient.

Epitope‐specific anti‐neutrophil cytoplasmic antibodies: Do they matter? Can they be detected?

Proteinase 3 (PR3)-anti-neutrophil cytoplasmic antibodies (ANCA) and myeloperoxidase (MPO)-ANCA are suggested to play a pathogenic role as they are closely related to the small-vessel vasculitis syndromes, Wegener's granulomatosis and microscopic polyangiitis. A large body of in vitro and animal experiments supports this concept. The mechanisms of action involve a direct interaction between ANCA and its antigen. The epitope specificity of ANCA may therefore influence the functional effects of ANCA and/or may reflect the mechanisms behind different disease manifestations or disease courses.

Successful Pregnancy and Delivery of a Healthy Newborn Despite Transplacental Transfer of Antimyeloperoxidase Antibodies From a Mother With Microscopic Polyangiitis

Myeloperoxidase (MPO)-specific antineutrophil cytoplasmic antibodies have been proposed as pathogenic for microscopic polyangiitis. Supporting this hypothesis, a case report of transplacental anti-MPO antibody transfer presumably causing a vasculitis-like syndrome in the newborn is cited frequently. Here, we report a case of transplacental transfer of high levels of anti-MPO antibodies not resulting in clinical compromise in the newborn. The mother developed microscopic polyangiitis 5 years before the pregnancy. After induction therapy, remission was maintained with low-dose prednisone and azathioprine for 4.5 years despite high levels of anti-MPO antibodies (>100 U/mL). The patient elected to become pregnant, immunosuppression was maintained during pregnancy, and a normal-term neonate was delivered. The newborn's venous blood anti-MPO antibody levels decreased gradually from greater than 100 U/mL at birth to undetectable by day 120. No clinical manifestation of vasculitis developed in the newborn. This case supports that anti-MPO antibodies alone are not pathogenic without additional cofactors.

CD45RC Isoform Expression Identifies Functionally Distinct T Cell Subsets Differentially Distributed between Healthy Individuals and AAV Patients

In animal models of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), the proportion of CD45RC T cell subsets is important for disease susceptibility. Their human counterparts are, however, functionally ill defined. In this report, we studied their distribution in healthy controls (HC), AAV patients and in Systemic lupus erythematous (SLE) patients as disease controls. We showed that CD45RC expression level on human CD4 and CD8 T cells identifies subsets that are highly variable among individuals. Interestingly, AAV patients exhibit an increased proportion of CD45RClow CD4 T cells as compared to HC and SLE patients. This increase is stable over time and independent of AAV subtype, ANCA specificity, disease duration, or number of relapses. We also analyzed the cytokine profile of purified CD4 and CD8 CD45RC T cell subsets from HC, after stimulation with anti-CD3 and anti-CD28 mAbs. The CD45RC subsets exhibit different cytokine profiles. Type-1 cytokines (IL-2, IFN-γ and TNF-α) were produced by all CD45RC T cell subsets, while the production of IL-17, type-2 (IL-4, IL-5) and regulatory (IL-10) cytokines was restricted to the CD45RClow subset. In conclusion, we have shown that CD45RC expression divides human T cells in functionally distinct subsets that are imbalanced in AAV. Since this imbalance is stable over time and independent of several disease parameters, we hypothesize that this is a pre-existing immune abnormality involved in the etiology of AAV.