Biomedical subjects

E Csernok

Publications and source records attributed to E Csernok.

At least 55 records · Page 3Linked to original sources

PubMed1998

Costimulatory molecules in Wegener's granulomatosis (WG): lack of expression of CD28 and preferential up-regulation of its ligands B7-1 (CD80) and B7-2 (CD86) on T cells.

T cells are most likely to play an important role in the pathogenesis of WG, and recently a predominant Th1 pattern of immune response has been demonstrated in granulomatous inflammation. Since the expression of costimulatory molecules has a significant impact on the cytokine profile and proliferation response of T cells, the goal of this study was to characterize the expression of costimulatory molecules (CD28, CTLA-4 (CD152), B7-1 (CD80), B7-2 (CD86)) on T cells, monocytes and B cells in WG, and to correlate the findings with clinical parameters such as disease activity, extent and therapy. WG patients (n = 24) and healthy controls (HC; n = 17) were examined for the expression of costimulatory molecules by fluorescence-activated cell sorter analysis, both in whole peripheral blood and after in vitro activation of T cells and antigen-presenting cells. Results were correlated with clinical data. The expression of CD28 on CD4+ and CD8+ cells was significantly lower in WG than in HC (CD28+ 81.4% in WG versus 97.9% of CD4+ cells (P < 0.0001); CD28+ 44.6% in WG versus 68.5% of CD8+ cells (P < 0.00001)), both in peripheral blood and after in vitro activation. A lower percentage of monocytes was B7-2+ in WG than in HC in peripheral blood, whereas no significant differences in the expression of B7-1 and B7-2 were observed after in vitro stimulation of monocytes and B cells. After in vitro activation a significantly higher percentage of B7-1+ and B7-2+ T cells was seen in WG. There was no significant difference in the CTLA-4 expression pattern between WG and HC. The percentage of CD28+ lymphocytes correlated negatively with the Disease Extent Index cumulated over the course of disease (r = -0.46, P = 0.03), indicating a more severe manifestation in patients with lower CD28 expression. Correlations with other clinical parameters such as activity or therapy were not seen. WG patients show a lack of CD28 expression on T cells and an unusual up-regulation of its ligands B7-1 and B7-2 on T cells after in vitro activation as well as a lower expression of B7-2 on freshly isolated monocytes compared with HC. These features might promote the Th1 cytokine pattern and thereby contribute to persistently high levels of immune activation in WG.

Adult↗

PubMed1998

Diagnostic value of standardized assays for anti-neutrophil cytoplasmic antibodies in idiopathic systemic vasculitis. EC/BCR Project for ANCA Assay Standardization.

Anti-neutrophil cytoplasmic antibodies (ANCA) are widely used as diagnostic markers for Wegener's granulomatosis (WG), microscopic polyangiitis (MPA), Churg-Strauss syndrome (CSS) and idiopathic rapidly progressive glomerulonephritis (iRPGN). The objective of this study was to evaluate the diagnostic value of ANCA measurement by the indirect immunofluorescence (IIF) test, and by anti-PR3 and anti-MPO ELISA performed in different locations, in patients with idiopathic small vessel vasculitis. Fourteen centers participated in a standardization study of ANCA assays, and entered a total number of 169 newly diagnosed and 189 historical patients with idiopathic systemic vasculitis or iRPGN. Patients were classified according to a pre-defined diagnostic classification system. Results were compared with those of 184 disease controls and 740 healthy controls. The IIF test was performed according to standard methodology; ELISAs had been standardized among the participants in a previous phase of the study. The sensitivities of assays in patients were as follows. The sensitivity in WG was: cANCA 64%, pANCA 21%, anti-PR3 66%, anti-MPO 24%. In MPA the sensitivity was: cANCA 23%, pANCA 58%, anti-PR3 26%, anti-MPO 58%. Sensitivity in iRPGN was: cANCA 36%, pANCA 45%, anti-PR3 50%, anti-MPO 64%. The specificity of assays (related to disease controls) was: cANCA 95%, pANCA 81%, anti-PR3 87%, anti-MPO 91%. When the results of the IIF test were combined with those of the ELISAs (cANCA/anti-PR3 positive, pANCA/anti-MPO positive), the diagnostic specificity increased to 99%. The sensitivity of the combination of cANCA + anti-PR3 or pANCA + anti-MPO for WG, MPA or iRPGN was 73%, 67% and 82%, respectively. From this study we conclude that the value of the IIF test for ANCA detection can be greatly increased by the addition of a well standardized antigen-specific ELISA. In a significant number of patients with idiopathic small vessel vasculitis, however, the ANCA test results (either in IIF or ELISA) are negative.

Adolescent↗

PubMed1998

Elevated procalcitonin levels in active Wegener's granulomatosis.

OBJECTIVE: To compare serum levels of procalcitonin (PCT) in patients with Wegener's granulomatosis (WG) in both active and inactive disease states to determine if PCT levels are increased in active WG without infection. METHODS: Sera were tested from 26 patients with generalized histologically proven WG, one sample taken during an active and one during an inactive disease state. PCT serum levels were measured using an immunoluminometric assay. RESULTS: PCT levels were in the normal range (0-0.5 ng/ml) in 23 of 26 sera taken during active WG and in all 26 sera taken during inactive WG. In sera from 3 patients with highly active WG, serum PCT concentrations were markedly elevated (0.8-3.3 ng/ml). There was a slight but significant difference in PCT concentrations between sera taken during active versus inactive disease. PCT values were found to correlate slightly with other disease activity variables (erythrocyte sedimentation rate, C-reactive protein, soluble interleukin 2 receptor, antineutrophil cytoplasmic antibodies) and with the Disease Extent Index score. CONCLUSION: PCT serum levels may be a potentially useful variable in the differential diagnosis of flares and bacterial infection in patients with WG. Interpretation of the values must be supported by laboratory and clinical findings, since PCT levels can be elevated in rare cases of highly active WG without infection.

Bacterial Infections↗

PubMed1998

Pathogenesis of Wegener's granulomatosis.

Although a single disease entity, Wegener's granulomatosis (WG) displays a set of clinical manifestations, each with a different immunopathogenesis. Granuloma formation, "pauci-immune" vasculitis and glomerulonephritis (= renal vasculitis) are the histologic hallmarks of WG which can occur together (WG triad) in full-blown disease, or separately in "initial phase" disease or the formes frustes. The different clinical manifestations are characterised by multiple immune abnormalities that culminate in the over-production of autoantibodies directed mainly against proteinase 3 (PR3-ANCA). A number of in vitro observations point to the potential mechanisms by which ANCA could induce neutrophil-mediated vascular injury, i.e. vasculitis. The most commonly postulated scenario for ANCA-mediated vasculitis involves the interaction of polymorphonuclear neutrophils (PMN) and endothelial cells (EC) via cell adhesion molecule interactions. The initiating event is ANCA-induced leukocyte activation, in which PMN-derived mediators (i.e. cytokines, lipid metabolites, etc.) are intimately involved. The result is necrotizing inflammation of blood vessel walls. However, the clinical and pathological hallmark of WG is the coexistence of vasculitis and granuloma. The causative agent(s) leading to granuloma formation, predominantly in the respiratory tract, is still unknown, but the presence of T cells in the granulomatous inflammation indicates T-cell hyperactivity. Immunohistochemical studies have shown that the cellular infiltrations in renal and pulmonary lesions of WG primarily contain CD4+ T-cells and macrophages. Recent investigations have demonstrated that CD4+ T-cells from granulomatous lesions in the nose and from bronchoalveolar lavage (BAL) mainly express the Th1 cytokine profile, which stimulates predominantly cell-mediated immune responses. This result supports the hypothesis that due to the two-phase course of WG there occurs a polarisation of the T-cell sub-population (Th1 versus Th2 type) which may explain the transition from the initial (granulomatous) phase of WG (so-called localized or locoregional restricted WG) to the generalized (vasculitic) phase. In conclusion, although the initiating events in the development of WG are still unknown, remarkable advances have been made in characterizing the infiltrating inflammatory cells and their products, which is of major importance in understanding the pathogenesis of this disease. In this regard, the use of specific mediators (i.e. cytokines, adhesions molecule antagonists, anti-Id ANCA, etc.) to modulate the inflammatory response may prove beneficial in the therapy of WG.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1997

Comparison of eight commercial kits for quantitation of antineutrophil cytoplasmic antibodies (ANCA).

Antineutrophil cytoplasmic antibodies (ANCA) are used as diagnostic markers for systemic vasculitis. However, the specificity and sensitivity of ANCA detection differs from centre to centre due in large part to variations in methodology. We compared 8 commercial ELISA kits and an in-house method (HM) for their specificity and sensitivity in detecting ANCA against proteinase 3 (PR3-ANCA, 7 kits) and meyloperoxidse (MPO-ANCA, 8 kits). Sera from 5 patients with systemic lupus erythematosus (SLE), 28 with Wegener's granulomatosis (WG), 22 with microscopic polyangiitis (MPA), 5 with idiopathic rapidly progressive glomerulonephritis (RPGN), and 5 healthy controls were examined by both the indirect immunofluorescence technique (IFT) and the ELISA kits. Sera from healthy controls and patients with SLE or cANCA-negative WG were shown to be PR3-ANCA negative by all 7 PR3-ANCA kits. In 25 cANCA-positive sera from WG patients, PR3-ANCA positivity ranged from 44% to 84%. An absolute concordance among the 7 kits was noted in 56% of the cANCA-positive samples. The PR3-ANCA levels in 5 of the 7 kits correlated with the cANCA titers in IFT. Sera from the healthy controls and 4 out of the 5 SLE and pANCA-negative patients were found to be MPO-ANCA negative in all 8 MPO-ANCA kits. In 20 pANCA-positive sera, MPO-ANCA positivity ranged from 25% to 75%. Thirty-five percent of MPO-ANCA-positive sera were confirmed by capture ELISA, immunoblot and inhibition assay. The concordance rate was only 30% among pANCA-positive sera in the 8 MPO-ANCA kits. No significant correlation was observed between pANCA titers and MPO-ANCA levels. The HM showed that 65% of cANCA-positive sera were PR3-ANCA positive, and 45% of pANCA-positive sera were MPO-ANCA positive. Our results indicate that the sensitivities and specificities for ANCA detection differ significantly among the commercial kits tested and underline the necessity of establishing uniform international standards for ANCA ELISA procedures in order to permit more reliable interpretation and comparison of data.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1997

[Bactericidal permeability increasing protein (BPI-ANCA marked chronic inflammatory bowel diseases and hepatobiliary diseases].

BACKGROUND: Bactericidal permeability increasing protein (BPI) is an antibacterial product of neutrophilic granulocytes that can serve as target antigen for antineutrophil cytoplasmic antibodies (ANCA). The clinical associations of autoantibodies against BPI (BPI-ANCA) are essentially unclear. PATIENTS AND METHODS: 587 sera from patients with chronic inflammatory bowel diseases, inflammatory hepatobiliary diseases, primary systemic vasculitides and other rheumatological diseases were examined for BPI-ANCA by mono-specific ELISA and a standard indirect immunofluorescence test for ANCA. (ACD-CPR versus S-CPR). The treatment groups were similar with respect to age, sex, time interval from collapse to CPR, defibrillation and first epinephrine medication. There was no difference between the ACD group and the standard CPR group in terms of survival rates and neurologic outcome. No differences occurred concerning complications of CPR. CONCLUSION: In our two-tiered EMS system with physician-staffed ambulances ACD-CPR neither improved nor impaired the survival rates and the neurological prognosis in patients with out-of-hospital cardiac arrest. Our results are in accordance with other studies carried out in EMS systems, with first tier call-response intervals between 4 and 6 min. RESULTS: The prevalence of BPI-ANCA was 43% in ulcerative colitis, 23% in Crohn's disease, 35% in primary sclerosing cholangitis, 25% in primary biliary cirrhosis and 29% in autoimmune hepatitides. In a spectrum of systemic vasculitides, inflammatory joint diseases and collagen vascular diseases the prevalence was only 3 to 11%. In contrast to PR3-ANCA and MPO-ANCA, BPI-ANCA was not associated with a particular pattern of fluorescence in the immuno-fluorescence test on ethanol- and formalin-fixed neutrophils. CONCLUSION: This study shows that BPI-ANCA is the third ANCA specificity, besides PR3-ANCA and MPO-ANCA, with a limited spectrum of clinical associations. The diagnostic and prognostic relevance of BPI-ANCA in the above clinical conditions is being examined prospectively.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1997

Use of native and recombinant bactericidal/permeability-increasing proteins (BPI) as antigens for detection of BPI-ANCA.

Anti-neutrophil cytoplasmic antibodies (ANCA) against native bactericidal/permeability-increasing protein (nBPI) have gained increasing diagnostic significance in inflammatory bowel disease and cystic fibrosis. However, routine detection of BPI-ANCA requires pure antigen in large quantities. As nBPI is difficult to isolate and is very susceptible to proteolytic cleavage with subsequent epitope loss, it was the aim of this study to determine whether recombinant BPI (rBPI) can be used as an alternative to nBPI as target antigen for ANCA in diagnostic procedures. Therefore, 93 BPI-ELISA-positive sera and controls were compared in different ELISAs using nBPI, rBPI, unglycosylated rBPI and a 21-kDa amino-terminal fragment of rBPI. ELISA results were confirmed by immunoblotting and all sera were tested in indirect immunofluorescence (IFT). There was an 88% (82/93) agreement in recognition of nBPI and rBPI by ANCA in both ELISA systems, yet the quantitation of BPI-ANCA in relative units showed a less optimal result and correlated only by 45% (p < 0.01). Most sera recognized nBPI, rBPI and unglycosylated rBPI equally suggesting that glycosylation has no influence on antigen recognition. Only two sera were positive for the 21-kDa nBPI indicating that the binding sites for ANCA are either conformational epitopes and/or are located mainly on the carboxy-terminal part of the BPI molecule. Most BPI-ELISA-positive sera were negative in IFT (43%), but a perinuclear (pANCA, 30%), a cytoplasmic (cANCA,10%) or an atypical ANCA (aANCA, 2%) staining pattern, as well as a cytoplasmic pattern only on formaldehyde-fixed granulocytes (13%) were also observed. Overall, no characteristic pattern was seen for BPI-ELISA-positive sera in IFT. Taken together, these data suggest that rBPI offers an excellent alternative to nBPI for broad-based BPI-ANCA ELISA and will be of great value in further investigations of BPI-ANCA interactions.

Animals↗

PubMed1997

Incidence and disease associations of a proteinase 3-antineutrophil cytoplasmic antibody idiotype (5/7 Id) whose antiidiotype inhibits proteinase 3-antineutrophil cytoplasmic antibody antigen binding activity.

OBJECTIVE: To evaluate the potential of a monoclonal proteinase 3-antineutrophil cytoplasmic antibody (PR3-ANCA) antiidiotype autoantibody (5/7 anti-Id) as a candidate for specific immunotherapy in Wegener's granulomatosis (WG), and to estimate the immunodiagnostic value of the corresponding idiotype (5/7 Id). METHODS: We analyzed the incidence of 5/7 Id in patients with ANCA-associated vasculitides (WG, microscopic polyangiitis, Churg-Strauss syndrome), in disease controls (systemic lupus erythematosus patients), and in healthy donors. We then investigated the presence of 5/7 Id in relation to disease stage, clinical activity, and organ manifestations in 86 patients with WG. Finally, we investigated the ability of the 5/7 anti-Id reagent to inhibit the binding of PR3-ANCA to corresponding antigen in 19 WG patients. RESULTS: The incidence of 5/7 Id was significantly more frequent in WG patients (43 of 86; 50%). We did not find a significant correlation between the prevalence of idiotype expression and disease activity or organ manifestations. Further, we demonstrated in vitro suppression of PR3-ANCA antigen binding activity by 5/7 anti-Id in 11 of 19 WG patients who were positive for 5/7 Id. CONCLUSION: This study shows that 5/7 Id is a common idiotype with a significantly increased incidence in WG and that 5/7 anti-Id inhibits PR3-ANCA antigen binding activity. Based on these observations, we conclude that 5/7 anti-Id is a promising tool for the development of a specific immunotherapy for WG.

Adolescent↗

PubMed1997

High plasma levels of the soluble form of CD30 activation molecule reflect disease activity in patients with Wegener's granulomatosis.

PURPOSE: To determine the plasma levels of soluble CD30 (sCD30) in Wegener's granulomatosis (WG) patients, and to investigate the possible correlation of sCD30 with disease extent and activity. PATIENTS AND METHODS: sCD30 was determined by radioimmunoassay in 57 WG patients, 25 patients with rheumatoid arthritis (RA), 23 patients with bacterial infections and 21 healthy controls (HC). The extent and activity of WG disease were assayed according to disease extent index (DEI) and standard laboratory parameters. RESULTS: Plasma sCD30 levels in generalized WG (22.5 +/- 1.5 U/mL), but not in initial phase WG (12.1 +/- 4.0 U/mL), were significantly increased compared with HC (8.8 +/- 0.9 U/mL, P < 0.0001). Furthermore, of 11 generalized WG patients who received long-term follow-up, sCD30 levels declined when the disease activity changed from active disease to remission (29.1 +/- 1.9 U/mL to 15.9 +/- 1.8 U/mL, P = 0.0001). Similar results were observed in the whole group of generalized WG, eg, sCD30 levels in active disease (29.4 +/- 1.4 U/mL) were significantly higher than in partial remission (17.9 +/- 1.9 U/mL, P < 0.001) and in complete remission (13.7 +/- 3.3 U/mL, P < 0.001). No significant difference was noted between complete remission and HC. In addition, sCD30 levels were correlated with other parameters of disease extent and activity such as DEI, plasma levels of sIL-2R, PR3-ANCA, ESR and CRP. The sCD30 levels were increased in RA patients compared with HC (15.2 +/- 2.1 U/mL, P < 0.05), but no correlation was found between disease activity parameters and sCD30 levels. In contrast, in patients with bacterial infections sCD30 levels (6.9 +/- 0.9 U/mL) were not significantly different compared with HC. CONCLUSION: Plasma levels of sCD30 are not only significantly increased but also correlate with disease extent and activity in generalized WG. These findings suggest that sCD30 can act as a useful marker for evaluation of disease extent and activity, and that generalized WG may be associated with Th2-type immune response.

Arthritis, Rheumatoid↗

PubMed1997

Interaction of transforming growth factor beta (TGF beta) with proteinase 3.

TGF beta is a multifunctional cytokine modulating onset and course of autoimmune diseases as shown in experimental models. Aim of this study was to investigate possible interactions of TGF beta with lysosomal enzymes identified as ANCA autoantigens (e.g. proteinase 3, PR3). This included TGF beta effects on the translocation the lysosomal enzymes to the cell surface of polymorphonuclear cells (PMN), and the presumabe activation of non bioactive, latent TGF beta by these enzymes. Flow cytometry analysis showed TGF beta 1 to be a potent translocation factor for PR3 comparable with other neutrophil activating factors such as interleukin 8 (IL8). The PR3 membrane expression on primed PMN increased by up to 51% after incubation with TGF beta 1. PR3 itself was revealed as a potent activator of latent TGF beta, thus mediating bioeffects of this cytokine. Patients with various types of systemic vasculitis (SV) showed marked TGF beta overexpression correlating with disease. Mean TGF beta 1 plasma levels in the ANCA associated vasculitis (AAV) patients ranged from 8.9 (Wegeners granulomatosis, WG) to 13.3 ng/ml (Churg-Strauss syndrome, CSS)(control: 4.2 ng/ml, p < 0.01) while TGF beta 2 levels were not elevated. Our findings, together with other features of TGF beta's such as induction of angiogenesis and its strong chemotactic capacity, indicate that TGF beta might serve as a proinflammatory factor in SV, especially in AAV.

Flow Cytometry↗

PubMed1997

Immunogenetic aspects of ANCA-associated vasculitides. Editorial overview.

The objective of this issue is to review the genetic bases and immunogenetic variations of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV), with particular emphasis on major histocompatibility complex class I and II molecules, the polymorphisms in the intercellular adhesion molecule-1 gene, tumor necrosis factor genes, alpha-1-antitrypsin (alpha1AT) and Fcgamma receptor (FcgammaR) genes. Although the aetiologies of the various AAV are unknown, the available genetic epidemiological data support the importance of genetic factors in susceptibility to these diseases. Moreover, there is considerable reason to believe that immunologic mechanisms contribute to the pathogenesis of AAV. The data presented here indicate that, in addition to immunospecific genes, such as HLA alleles, genes determining the level of the immune response (i.e. cytokines, adhesion molecules, protease inhibitors, FcgammaR) may contribute to AAV.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1997

Analysis of FcgammaRII gene polymorphisms in Wegener's granulomatosis.

Fcgamma receptors (FcgammaRs) are potent initiators of proinflammatory reactions and tissue injury programs through the oxidative burst, degranulation and the production of a variety of proinflammatory cytokines. Direct experimental evidence indicates that translocation of ANCA target from intracellular granules to the neutrophil membrane and subsequent binding of ANCA enables FcgammaR-mediated neutrophil activation. In the presence of ANCA, these data provide a framework from which to understand the importance of ANCA class, subclass, and titer in Wegener's granulomatosis and other ANCA-positive vasculitides. The well-characterized and functionally important alleles of neutrophil FcgammaR (FcgammaRIIa-H131/R131 and FcgammaRIIIb-NA1/NA2) are possible inheritable genetic elements that may alter disease severity and/or phenotype.

Alleles↗

PubMed1997

Polymorphisms in the tumor necrosis factor genes in Wegener's granulomatosis.

Two known di-allelic polymorphisms in the tumor necrosis factor (TNF) genes were investigated in 35 patients suffering from Wegener's granulomatosis (WG) in comparison to 111 healthy controls. The first polymorphism lay in the promotor region of the TNF-alpha gene at position -308, the second in the first intron of the TNF-beta gene. For both polymorphisms we could not find any statistically significant differences in allele frequencies between patients and healthy individuals. In the patient group the TNF 2/2 phenotype was slightly elevated, however (WG 5.7% vs. normal 1.8%). Investigating the clinical course of the disease according to TNF polymorphisms, TNF 1/1 patients were found to have a higher mean disease extension index (DEI) than TNF 1/2 individuals (TNF 1/1 10.5 vs. TNF 1/2 9.4).

Granulomatosis with Polyangiitis↗

PubMed1996

Neutrophil activation by anti-proteinase 3 antibodies in Wegener's granulomatosis: role of exogenous arachidonic acid and leukotriene B4 generation.

Among the anti-neutrophil cytoplasmic antibodies (ANCA), those targeting proteinase 3 (PR3) have a high specificity for Wegener's granulomatosis (WG). It is known that a preceding priming of neutrophils with cytokines is a prerequisite for membrane surface expression of PR3, which is then accessible to autoantibody binding. Employing a monoclonal antibody directed against human PR3 and ANCA-positive serum from WG patients with specificity for PR3, we now investigated the role of free arachidonic acid (AA) in autoantibody-related human neutrophil activation. Priming of neutrophils with tumor necrosis factor (TNF-alpha) for 15 min or exposure to anti-PR3 antibodies or incubation with free AA (10 microM) as sole events did not provoke superoxide generation, elastase secretion or generation of 5-lipoxygenase products of AA. Similarly, the combination of TNF-alpha-priming and AA incubation was ineffective. When TNF-alpha-primed neutrophils were stimulated by anti-PR3 antibodies, superoxide and elastase secretion was provoked in the absence of lipid mediator generation. However, when free AA was additionally provided, a strong activation of the 5-lipoxygenase pathway was demasked, with the appearance of excessive quantities of leukotriene (LT)B4, LTA4, and 5-hydroxyeicosatetraenoic acid. Moreover, superoxide and elastase secretion were markedly amplified, and studies with 5-lipoxygenase inhibitors and a LTB4-antagonist demonstrated this was due to an LTB4-related autocrine loop of cell activation. In contrast, the increased synthesis of platelet-activating factor in response to TNF-alpha-priming and anti-PR3 stimulation did not contribute to the amplification loop of neutrophil activation under the given conditions. We conclude that anti-PR3 antibodies are potent inductors of the 5-lipoxygenase pathway in primed human neutrophils, and extracellular free AA, as provided at an inflammatory focus, synergizes with the autoantibodies to evoke full-blown lipid mediator generation, granule secretion and respiratory burst. Such events may be enrolled in the pathogenesis of focal necrotizing vascular injury in Wegener's granulomatosis.

Arachidonate 5-Lipoxygenase↗

PubMed1996

Development and standardization of solid phase assays for the detection of anti-neutrophil cytoplasmic antibodies (ANCA). A report on the second phase of an international cooperative study on the standardization of ANCA assays.

Anti-neutrophil cytoplasmic antibodies (ANCA) are diagnostic markers for systemic vasculitis. They are classically detected by an indirect immunofluorescence test using normal donor neutrophils as substrate. This assay lacks antigenic specificity and is not quantitative. The 'EC/BCR Project for ANCA Assay Standardization' is an international collaboration study with the aim to develop and standardize solid phase assays for ANCA detection. In this part of the study the isolation and characterization of proteinase-3 and myeloperoxidase, the two main target molecules for ANCA, and the development and standardization of ELISAs with these antigens are described. Six laboratories successfully isolated purified proteinase-3 preparations that could be used. Three of these preparations, together with one myeloperoxidase preparation, were subsequently used for ANCA testing by ELISA. The ELISA technique was standardized in two rounds of testing in the 14 participating laboratories. The coefficient of variation of these new assays decreased from values of approx. 50% in the first round to approx. 20% in the second round. We conclude that purified proteinase-3 and myeloperoxidase can be used in standardized ELISAs for ANCA detection. Whether such procedures offer advantages over the IIF test will be determined in a prospective clinical study.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1996

Expression of the human autoantigen of Wegener's granulomatosis (PR3) in a baculovirus expression system.

Proteinase 3 (PR3) is a multifunctional serine protease found in myeloperoxidase-positive granula of PMN. It is also the main target antigen for antineutrophil cytoplasmic antibodies (ANCA) found in Wegener's granulomatosis (WG). There is ample evidence that these autoantibodies play an active role in the pathogenesis of this disease. We have established the expression of the autoantigen (PR3) in a baculovirus expression system using insect cells. Recombinant PR3 was identified by IIF, direct ELISA using 3 different MoAbs and by catching ELISA using a MoAb and a rat polyclonal Ab or cANCA-positive WG patient sera. As purification of human PR3 from blood-derived PMNs has been shown to be difficult and very inefficient, insect cell-derived recombinant PR3 offers new possibilities for obtaining sufficient amounts of this protein to facilitate further biochemical characterizations.

Animals↗

PubMed1996

Monoclonal antibody WGM1 directed against proteinase 3: an immunohistochemical marker for naphthol ASD chloroacetate.

Enzyme histochemistry for naphthol ASD chloroacetate (NASDCA, 'Leder's stain') is used to identify the granulocyte lineage ranging from promyelocytes to mature neutrophils and is an additional tool for the characterization of leukemias. We demonstrated for the first time that NASDCA activity can be detected by routine immunohistochemistry and immunocytochemistry using the monoclonal antibody WGM1 directed against proteinase 3 (PR3; synonyms: Wegener's autoantigen, myeloblastin). Immunohisto- and immunocytochemical staining with WGM1 against PR3 and enzyme histochemistry for NASDCA produced identical staining patterns in normal myelomonocytic cells and cells of myeloid leukemia. This was additionally proven by double immunostainings. We have also shown that PR3 is one of the specific proteinases responsible for hydrolysis of NASDCA.

Adolescent↗

PubMed1996

Anti-neutrophil cytoplasmic antibodies (ANCA) directed against bactericidal/permeability increasing protein (BPI): a new seromarker for inflammatory bowel disease and associated disorders.

It was our purpose to determine the immunodiagnostic value of ANCA directed against BPI in diseases known to be associated with ANCA, such as ANCA-associated vasculitides, inflammatory bowel disease (IBD) and the associated condition primary sclerosing cholangitis. The immunoreactivity of recombinant PBI (rBPI) was established in order to develop an ELISA specific for rBPI. By means of this assay, BPI-ANCA were assessed in sera of 178 patients with IBD or the associated disorder primary sclerosing cholangitis, 112 patients with ANCA-associated vasculitides, and in sera of 182 disease and 140 health controls. BPI-ANCA were found to be closely associated with IBD and primary sclerosing cholangitis (34% and 44% of ANCA-positive sera, respectively). By contrast, BPI-ANCA positivity was low (<10%) in the double-negative sera of patients with ANCA-associated vasculitides and in disease and health controls. BPI-ANCA appear to constitute an important marker for IBD and primary sclerosing cholangitis, but not for the ANCA-associated vasculitides.

Antibodies, Antineutrophil Cytoplasmic↗