Biomedical subjects

M Segelmark

Publications and source records attributed to M Segelmark.

At least 19 recordsLinked to original sources

PubMed2006

Polyarteritis nodosa when applying the Chapel Hill nomenclature--a descriptive study on ten patients.

OBJECTIVES: Polyarteritis nodosa (PAN) is a term that has been used to describe a wide variety of vasculitic conditions. In 1994, the Chapel Hill Consensus Conference on the nomenclature of systemic vasculitides proposed that the name classical PAN should be restricted to diseases where there is arteritis in small and medium-sized arteries without the involvement of smaller vessels. Our aim was to describe the symptoms and course of disease in PAN when the microscopic forms are excluded. METHODS: All patients with a diagnosis of PAN treated in our departments during the period 1990-2002 were eligible for this study. The diagnosis had to be confirmed by biopsy, angiography or electromyography. RESULTS: Ten patients were eligible for the study. The median age was 46 yrs. Renal involvement was seen in 70% at diagnosis. After 5 yrs, 57% had experienced a relapse, which is equivalent to the relapse rate seen in microscopic polyangiitis. Organ damage was assessed by the Vasculitis Damage Index (VDI) and after 5 yrs cardiovascular and neuropsychiatric damage dominated, followed by renal damage. During the follow-up, two patients developed end-stage renal disease. The annual incidence of PAN in our local catchment area was estimated to 1.6 per million and year. CONCLUSIONS: When applying the Chapel Hill nomenclature, PAN is a rare but severe disease with a high incidence of renal involvement and frequent relapses.

Adolescent↗

PubMed2006

Increased neutrophil membrane expression and plasma level of proteinase 3 in systemic vasculitis are not a consequence of the - 564 A/G promotor polymorphism.

Several findings link proteinase 3 (PR3) to small vessel vasculitis. Besides being a major target of anti-neutrophil cytoplasm antibodies (ANCA), previous findings have shown increased circulating levels of PR3 in vasculitis patients, increased levels of neutrophil membrane-PR3 (mPR3) expression and a skewed distribution of the - 564 A/G polymorphism in the promotor region of the PR3 gene. In this study we elucidate how these three findings relate to each other. The plasma concentration of PR3 was measured by enzyme-linked immunosorbent assay (ELISA), mPR3 expression by fluorescence activated cell sorter (FACS) and the gene polymorphism by real-time polymerase chain reaction (PCR). We compared results from 63 patients with ANCA-associated systemic vasculitis (AASV) with 107 healthy blood donors. In accordance with previous reports, AASV patients had increased plasma concentrations of PR3 compared to healthy controls (mean 224 microg/l versus 155 microg/l, P < 0.0001). They also showed an increased number of mPR3-positive neutrophils (60%versus 42%, P < 0.001). However, contrary to a previous report, we found no skewed distribution of the polymorphism in PR3 gene. There was a weak correlation between mPR3 mean fluorescence intensity (MFI) and plasma PR3 among healthy controls and myeloperoxidase-ANCA (MPO-ANCA)-positive patients (r = 0.24, P = 0.015 and r = 0.52, P = 0.011, respectively). In conclusion, increased plasma PR3 and high expression of mPR3 are associated with small vessel vasculitis, but neither of them is a consequence of the - 564 A/G polymorphism of the PR3 gene promotor.

Case-Control Studies↗

PubMed2005

Deficiency of the mannan-binding lectin pathway of complement and poor outcome in cystic fibrosis: bacterial colonization may be decisive for a relationship.

In cystic fibrosis (CF) prognosis concerning lung damage development is highly variable and difficult to predict. Mannan-binding lectin (MBL) deficiency has been reported to be associated with poor outcome in CF lung disease. MBL is a recognition molecule of the MBL pathway of the complement system and is encoded by a gene characterized by a high degree of polymorphism. Some genotypes result in low serum concentrations of MBL. MBL-associated serine protease 2 (MASP-2) is another protein belonging to the MBL pathway. A mutation resulting in low levels of MASP-2 in serum has been described recently. In the present study, 112 CF patients aged 4-54 years were investigated for MBL and MASP-2 genotypes, serum levels of MBL and MASP-2 and the MBL pathway function in serum. No correlation to reduced lung function or need for lung transplantation was seen, either for MBL deficiency, MASP-2 gene mutation or reduced MBL pathway function. However, in the 27 patients colonized with Staphylococcus aureus, MBL-deficient genotypes were associated with decreased lung function. As expected, MBL pathway function in serum was reduced both in MBL-deficient patients and in patients carrying a mutant MASP-2 allele. An unexpected finding was that CF patients had higher serum levels of MBL than healthy controls when corrected for MBL genotype. In conclusion, MBL pathway function was affected both by MBL and by MASP-2 genotypes. However, MBL or MASP-2 levels in serum did not affect the clinical outcome in the cohort of CF patients studied.

Adolescent↗

PubMed2005

Increased monocyte transcription of the proteinase 3 gene in small vessel vasculitis.

Proteinase 3 (PR3) is a pleiotropic and destructive serine protease and it is also a major target for autoantibodies in systemic small vessel vasculitis. We have shown recently that patients in stable remission have increased circulating levels of PR3, independent of autoantibody titre, inflammation, neutrophil degranulation and renal function. Here we explore the possibility of increased PR3 gene transcription. RNA was purified from peripheral blood monocytes from vasculitis patients and controls. Specific mRNA was measured by TaqMan real-time polymerase chain reaction (PCR). The monocyte-like cell lines THP-1 and U937 and human peripheral blod monocytes from healthy controls were stimulated with cytokines and lipopolysaccharide (LPS) for different time periods. PR3 protein was measured in plasma with enzyme-linked immunosorbent assay (ELISA). The median result for PR3 mRNA was 9.6 (1.8-680) for 22 patients, compared to 1 (0.1-2.8) for the 15 healthy controls. Elastase expression was also significantly increased, whereas myeloperoxidase and interleukin-8 were not. Stimulation of monocytes with tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma or LPS did not result in any increase of PR3 or elastase transcription, whereas interleukin (IL)-8 transcription was increased 10-fold. Circulating monocytes from patients with systemic vasculitis display increased PR3 gene transcription compared to healthy controls and patients with sytemic lupus erythematosus (SLE). This may be important for the development of vasculitis. Our results do not favour a role for cytokines, antineutrophil cytoplasmic antibodies (ANCA) or immunosuppressive medication in the upregulation of PR3 transcription in vasculitis.

Adult↗

PubMed2005

Alport syndrome in southern Sweden.

AIM: The aim of the present investigation is to study the epidemiology of Alport syndrome in southern Sweden, to search for mutations in the COL4A5 gene and to estimate the mutation frequency. PATIENTS AND METHODS: Patients with suspected Alport syndrome were identified in an area with a population of 1.45 million. Clinical criteria were used to establish the diagnosis and samples for mutation analysis were collected. Mutation analyses were performed with Single-Stranded Conformation Polymorphism analysis (SSCP) of PCR-amplified genomic DNA. RESULTS: Altogether 25 families with hereditary nephritis were identified. Alport syndrome with X-linked transmission was evident in 14 families, with juvenile (< 31 years) progression to end-stage renal failure (ESRF) in ten, and adult (> or = 31 years) in four families. CONCLUSION: The frequency of males with X-linked disease was calculated to one in 17,000 male births (95% confidence interval (CI) 1/10,500-1/28,600), and the prevalence to one in 40,000. A total of seven females with ESRF were identified, with a median age at ESRF of 45 years. The male to female ratio of cases with ESRF was 4.9 to 1. The risk of developing ESRF among females was from the expected incidence roughly estimated to 12%. Patients with X-linked disease constituted 1.8% of patients with ESRF in the examined area. A mutation was identified positive in 10 of 14 families with X-linked disease, but never in families not fulfilling the clinical criteria for Alport syndrome. In families with juvenile phenotype and positive mutation analysis, the mutation frequency was calculated to between 1/78,000 and 1/198,000 (95% CI 1/42,000-1/177,000) if the effective fertility was estimated to be between 0 and 0.2.

Adolescent↗

PubMed2004

Epitope mapping of anti-PR3 antibodies using chimeric human/mouse PR3 recombinant proteins.

Autoantibodies against proteinase 3 (PR3) and myeloperoxidase (MPO) (ANCA = anti-neutrophil cytoplasmic antibodies) are used as diagnostic tools for patients with small vessel vasculitis. ANCA are detected by different assays, but the correlation between the results of these assays is generally poor. The overall aim of the study was to provide a framework for the future development of new assays with an increased diagnostic yield. In order to express discrete epitopes of human PR3 (hPR3), the nonantigenic molecules murine PR3 (mPR3) and human leucocyte elastase (HLE) were used as a framework. We constructed recombinant chimeric vectors and were able to produce 6 hPR3/mPR3 proteins and 3 hPR3/HLE proteins. Anti-PR3 monoclonal antibodies differed in their binding pattern to the chimeras, but no distinct binding region could be identified for any monoclonal antibody. The recombinant hPR3/mPR3 were also tested in ELISA with sera from patients with Wegener's granulomatosis with renal involvement. The results show that patients have antibodies to different constructs, indicating that the patients vary in their antibody repertoire from the beginning of the disease, and that patients may have antibodies from a broad range of clones early in the course of the disease. Recombinant hPR3/mPR3 chimeric proteins have a potential to be used as antigens in future ANCA assays.

Amino Acid Sequence↗

PubMed2003

Increased expression of the secretory leukocyte proteinase inhibitor in Wegener's granulomatosis.

The secretory leucocyte proteinase inhibitor (SLPI) is a low molecular weight, tissue-specific inhibitor of proteases, such as elastase and cathepsin G. It is the major local protease inhibitor in the upper airways. Proteinase 3, the main autoantigen in Wegener's granulomatosis (WG), can degrade SLPI proteolytically. In addition, SLPI is sensitive to oxidative inactivation by myeloperoxidase-generated free oxygen radicals. SLPI also has an antimicrobial capacity that can be of interest, as infection is considered to play a role in the pathogenesis of WG. This study focuses on SLPI expression in patients suffering from WG, something that to our knowledge has not been explored hitherto. Serum samples and nasal biopsies were obtained from 12 Swedish WG patients, while buffy coats were obtained from 33 American WG patients. SLPI levels in serum were measured by means of ELISA and the protein was detected by means of immunohistochemistry in nasal biopsies. mRNA expression was studied by means of in situ hybridization on nasal biopsies and RT-PCR on leucocytes. IL-6 or ESR were measured as markers of inflammatory activity. Cystatin C or creatinine was measured as a marker of renal filtration. White blood cell counts were registered. In serum, we found close to normal SLPI levels, without any correlation to IL-6. Two patients had greatly elevated values, both of them suffering from severe renal engagement. Strong SLPI mRNA expression was found in nasal biopsies. RT-PCR on leucocyte mRNA showed normal or greatly elevated expression of SLPI mRNA, correlating with disease activity. Leukocyte SLPI expression seems to be up-regulated in active WG. Serum levels were measured in a small number of patients and were found to be close to normal. Lack of correlation to the acute phase response indicates a specific regulation. This might be linked to an altered protease/antiprotease balance. These findings could indicate that SLPI locally participates in the anti-inflammatory and perhaps antimicrobial response in WG.

Analysis of Variance↗

PubMed2003

Increased circulating levels of proteinase 3 in patients with anti-neutrophilic cytoplasmic autoantibodies-associated systemic vasculitis in remission.

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 rabbit-anti-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 micro g/l, range 110-3,940, n = 59) compared with healthy blood donors (350 micro 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.

Adult↗

PubMed2001

Internalization of proteinase 3 is concomitant with endothelial cell apoptosis and internalization of myeloperoxidase with generation of intracellular oxidants.

The important issue addressed by the studies presented here is the mechanism of neutrophil-mediated damage to endothelial and epithelial cells during inflammation. Binding of neutrophil-released granule proteins to endothelial cells may be involved in vascular damage in patients with inflammatory vascular diseases. We have determined whether granule proteins proteinase 3(PR3) and/or myeloperoxidase (MPO) are internalized into endothelial cells, as examined by UV light, confocal, and electron microscopy. Coincident induction of apoptosis and/or the generation of intracellular oxidants were monitored. The results indicate that human endothelial cells (human umbilical vein endothelial cells, human umbilical arterial endothelial cells, human lung microvascular endothelial cells) internalize both PR3 and MPO, which are detected on the cell surface, in the cytoplasm, and possibly nuclear. Epithelial cells (small airway epithelial cells) internalized MPO but not PR3, implying that the mechanism of PR3 internalization may be cell-type specific and different from that of MPO. Internalization of PR3, but not MPO, correlated with activation of apoptosis. Internalization of MPO correlated with an increase in intracellular oxidant radicals. The requirement for the proteolytic activity of PR3 for the induction of apoptosis was examined by generating PR3-truncated fragments that did not contain the components of the catalytic triad. An apoptotic function was localized to the C-terminal portion of PR3. These studies reveal novel mechanisms by which the neutrophil granule proteins PR3 and MPO contribute to tissue injury at sites of inflammation.

Apoptosis↗

PubMed2001

Novel distribution of the secretory leucocyte proteinase inhibitor in kidney.

The secretory leucocyte proteinase inhibitor (SLPI) is a low molecular weight, tissue-specific inhibitor of, for example, elastase and cathepsin G, which also have antimicrobial capacity. SLPI has been localised to the respiratory, gastrointestinal and genital tracts, but so far not to the kidney. The presence of SLPI in renal tubuli cells was demonstrated using immunohistochemistry and, by means of in situ hybridisation on human renal biopsies, we were able to demonstrate SLPI production. In various inflammatory conditions in the kidneys, the protease-antiprotease balance is disturbed. For this reason, as well as the possible role in the defence against ascending urinary tract infections, it is interesting to establish a source of SLPI in renal tubuli cells.

Biopsy↗

PubMed2000

Expression of p300-truncated fragments results in the modulation of apoptosis in rat mesangial cells.

BACKGROUND: Mesangial cell proliferation, apoptosis, and matrix deposition have pivotal roles in the pathogenesis of renal diseases such as diabetic nephropathy and glomerulonephritis. The behavior of mesangial cells depends on the integration of intracellular signals elicited by hormones and cytokines. We hypothesized that p300 is primarily involved in the integration of signal transduction pathways in rat mesangial cells (RMCs) and that interference with p300 function will alter apoptotic signals. METHODS: We established an RMC cell line expressing the Tet-activator (tTA). RMC-tTA cells were transiently transfected with vectors coding for either the N-terminal third or the C-terminal third of p300. Expression was induced by the addition of doxycycline [Dox; 1 microg/mL; 5% fetal bovine serum (FBS)]. The percentage of apoptosis was determined using the TUNEL technique. Specific protein-protein interactions were determined by Western blot analysis of immunoprecipitated complexes. Cells were treated with 5% FBS or with H2O2 (500 micromol/L, 1 h) with and without Dox. RESULTS: The expression of p300-C resulted in increased susceptibility to low serum-induced (20.0 +/- 4.6 vs. 3.0 +/- 1.7%) and to H2O2-induced apoptosis (75.3 +/- 13.3 vs. 50.8 +/- 6.5%) compared with controls. Immunoprecipitation of p300-C showed an interaction with the transcription factor c-Fos, which was enhanced by H2O2 treatment. Expression of the p300-N resulted in a rescue (34.8 +/- 6. 4 vs. 50.8 +/- 6.5%) from H2O2-induced apoptosis compared with controls. P300-N was shown to form a complex with the transcription factor nuclear factor-kappaB (NF-kappaB). CONCLUSIONS: The data indicate that endogenous p300 is involved in apoptosis in mesangial cells. We propose that interference or enhancement of endogenous p300 function, by expression of exogenous fragments, can alter interactions with c-Fos or NF-kappaB and modulate signals during cellular stress.

Animals↗

PubMed2000

ANCA antigens, proteinase 3 and myeloperoxidase, are not expressed in endothelial cells.

BACKGROUND: One hypothesis for the pathogenesis of vasculitis associated with antineutrophil cytoplasmic autoantibodies (ANCAs) proposes that ANCAs bind to ANCA antigens, such as proteinase 3 (PR3) or myeloperoxidase (MPO), which are produced by endothelial cells and expressed on their surfaces. There are conflicting reports, however, on whether endothelial cells express the ANCA antigen PR3, and there are no reports on endothelial expression of MPO. The aim of this study was to determine the presence or absence of PR3 and MPO mRNA in both venous and arterial endothelial cells, employing standard reverse transcription-polymerase chain reaction (RT-PCR) techniques and also the quantitative and highly specific method, TaqMan PCR. METHODS: RT-PCR (with 3 primer sets) and TaqMan PCR, a method for detecting low copy transcripts, were used to probe for PR3 and MPO transcripts in human endothelial cells from umbilical vein (HUVEC) and artery (HUAEC) and from lung microvascular (HLMVEC). Cells were treated with interferon-gamma (200 units/mL) or tumor necrosis factor-alpha (3 or 10 ng/mL) or both. RESULTS: Transcripts for PR3 and/or MPO were not detected in HUVEC, HUAEC, and HLMVEC by standard RT-PCR. Analyses for PR3 protein confirmed that PR3 is not expressed in HUVEC. HUVEC and HUAEC were negative for PR3 and MPO by TaqMan PCR. CONCLUSIONS: PR3 and MPO are not expressed in HUVEC, HUAEC, or HLMVEC. Endothelial cell presentation of endogenous PR3 and MPO antigens is not involved in the pathogenesis of ANCA-associated vasculitis. Alternative explanations need to be explored to determine the pathogenic effect of ANCAs.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1999

C3 and C4 allotypes in anti-neutrophil cytoplasmic autoantibody (ANCA)-positive vasculitis.

In ANCA-associated small vessel vasculitis few genetic factors have proven to be of importance for disease susceptibility, an exception being deficiency of alpha1-anti-trypsin, the main inhibitor of proteinase 3 (PR3). Alerted by our finding that myeloperoxidase has affinity for C3, and the finding of an increased frequency of the C3F allele in systemic vasculitis in a British cohort, we examined polymorphism of C3 and C4 in patients with ANCA+ small vessel vasculitis. After identification of all patients at our department with a positive ANCA test during the period 1991-95 and a diagnosis of small vessel vasculitis, blood samples were collected after informed consent. The 67 included patients were grouped according to ANCA serology and disease phenotype using the Chapel Hill nomenclature. The gene frequency of C3F was found to be increased (0. 32) compared with controls (0.20; P < 0.05) in the PR3-ANCA+ subgroup. The frequency of C4A3 was increased in the group as a whole, but no increase of C4 null alleles was seen. The findings imply a role for the complement system in the pathogenesis of ANCA-associated small vessel vasculitis.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1999

Recurrent ANCA-associated small vessel vasculitis after transplantation: A pooled analysis.

BACKGROUND: Recurrent antineutrophil cytoplasmic antibody (ANCA)-associated small vessel vasculitis (ANCA-SVV) after renal transplantation has been described in case series. However, general information regarding the frequency, character, and predictors of recurrent disease after transplantation is currently lacking. We considered the rate of relapse, whether a positive ANCA at the time of transplantation predicted relapse, and whether cyclosporine A prevented recurrent disease. METHODS: We performed a pooled analysis of published data, added to the experience at the Universities of North Carolina (14 patients) and Lund, Sweden (11 patients). To avoid reporting bias, only case series were included for analysis. Subgroup analysis was performed by disease category (Wegener's granulomatosis, microscopic polyangiitis, or necrotizing crescentic glomerulonephritis) and ANCA staining pattern. RESULTS: ANCA-SVV recurred in 17.3% of all patients (N = 127), in 20% of cyclosporine A-treated patients (N = 85), and in 25.6% of patients with circulating ANCA at the time of transplantation (N = 39). There was no statistically significant difference in the relapse rate between patients treated and those not treated with cyclosporine A (P = 0.45), between those with and without circulating ANCA at the time of transplant (P = 0.75), or between patients with Wegener's granulomatosis and those with microscopic polyangiitis or necrotizing crescentic glomerulonephritis alone (P = 0.62). CONCLUSION: There is a substantial relapse rate in the ANCA-SVV population. Therapy with cyclosporine A does not protect against recurrent ANCA-SVV, and the presence of a positive ANCA at the time of transplantation does not preclude transplantation. These conclusions must be substantiated with a prospective study of renal transplantation in patients with ANCA-SVV so as to optimize their management.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1999

Identification of a clinically relevant immunodominant region of collagen IV in Goodpasture disease.

BACKGROUND: The characteristic feature of Goodpasture disease is the occurrence of an autoantibody response to the noncollagenous domain of the alpha3 chain of type IV collagen [alpha3(IV)NC1] in the alveolar and glomerular basement membrane. These antibodies are associated with the development of a rapidly progressive glomerulonephritis, with or without lung hemorrhage, whereas autoantibodies specific for the other alpha chains of the heterotrimeric type IV collagen probably do not cause disease. In this study, we have investigated whether differences in fine specificity of autoimmune recognition of the alpha3(IV)NC1 correlate with clinical outcome. METHODS: For mapping of antibody binding to type IV collagen, chimeric collagen constructs were generated in which parts of the alpha3(IV)NC1 domain were replaced by the corresponding sequences of homologous nonreactive alpha1(IV). The different recombinant collagen chimeras allowed the analysis of antibody specificities in 77 sera from well-documented patients. RESULTS: One construct that harbors the aminoterminal third of the alpha3(IV)NC1 was recognized by all sera, indicating that it represents the dominant target of the B-cell response in Goodpasture disease. Seventy percent of the samples recognized other parts of the molecule as well. However, only reactivity to the N-terminus of the alpha3(IV)NC1 correlated with prognosis, that is, kidney survival after six months of follow-up. CONCLUSION: The results indicate the crucial importance of antibody recognition of this particular domain for the pathogenesis of Goodpasture disease, thereby opening new avenues for the development of better diagnostic and therapeutic procedures.

Anti-Glomerular Basement Membrane Disease↗

PubMed1998

Clinical evaluation of a capture ELISA for detection of proteinase-3 antineutrophil cytoplasmic antibody.

Detection of antineutrophil cytoplasmic antibodies (ANCA) has become a useful tool in the diagnosis of Wegener's granulomatosis and microscopic polyangiitis. However, the results obtained with indirect immunofluorescence (IIF) and by ELISA for ANCA demonstration do not always correlate. A possible explanation for this finding could be that proteins are denatured during the process of antigen purification or during coating onto the solid phase. To avoid this possibility, a monoclonal antibody to PR3 that is precoated on the plate can be used. In the present study we have used the monoclonal antibody (MoAb) 4A3 for the capture of PR3 in an ELISA, and a clinical evaluation of the diagnostic properties of the new capture ELISA has been made. The sensitivity of the capture PR3-ANCA ELISA was 85% in a material of c-ANCA positive sera. A specificity of 90% was obtained in analyses from patients having various forms of glomerulonephritis. There was a significantly higher diagnostic sensitivity of the capture PR3-ANCA ELISA (85%) compared to c-ANCA by IIF (58%) in patients with Wegener's granulomatosis with renal involvement. Capture PR3-ANCA and direct ELISA for MPO-ANCA together gave a diagnostic sensitivity of 98%, versus 75% using IIF. In conclusion, the capture PR3-ANCA ELISA seems to be a valuable tool in the diagnosis of Wegener's granulomatosis with renal involvement. Preliminary data suggest that the technique may have an advantage over direct ELISA for PR3-ANCA, as well as in the follow-up of c-/PR3-ANCA associated vasculitides. However, further prospective studies are needed to clarify this premise.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1997

Preeclampsia is associated with a reduced response to activated protein C.

OBJECTIVE: Resistance to activated protein C is an inherited mutation of the coagulation factor V gene, a major factor predisposing to thromboembolic events. The purpose of this study was to investigate the occurrence of heterozygote and homozygote activated protein C resistance in women with preeclampsia. STUDY DESIGN: Activated protein C resistance and protein C and antithrombin III levels were determined in women (n = 50) with a history of preeclampsia and in controls (50 women with a previous normal pregnancy). The mutation of the factor V gene was analyzed. RESULTS: Activated protein C resistance was found in 22% of women with previous preeclampsia compared with 10% among controls. Two women in the previous preeclampsia group had a homozygote mutation of factor V; the others were heterozygous. There was a significant difference in the activated protein C ratio between women with previous preeclampsia and the control group, 2.6 +/- 0.4 versus 3.1 +/- 0.5 (p = 0.04). None of the women had protein C or antithrombin III deficiency. CONCLUSION: The results indicate that activated protein C resistance may be a contributory factor in the pathogenesis of preeclampsia.

Antithrombin III↗

PubMed1997

Binding and inhibition of myeloperoxidase (MPO): a major function of ceruloplasmin?

Interactions between plasma proteins and MPO were studied. The protein fraction of normal plasma and serum was shown to exhibit an inhibitory effect on the peroxidase activity of MPO. Most of the inhibitory effect could be retained on an MPO-coupled affinity chromatography column. In particular, a protein with apparent mol. wt of 130 kD showed affinity for MPO. The protein was identified as ceruloplasmin by N-terminal amino acid sequencing and immunochemistry. During separation procedures the peroxidase inhibitory effect was limited to ceruloplasmin-containing fractions of plasma. Purified ceruloplasmin inhibited the peroxidase activity of MPO in a concentration-dependent manner, and exhibited selective binding to MPO-coated microtitre plates. This binding could be inhibited by MPO dissolved in buffer. Correspondingly the binding of MPO to ceruloplasmin-coated plates could be blocked by ceruloplasmin in solution, showing a physical interaction to occur between the two proteins under physiological conditions. We also found affinity to exist between MPO and C3 (and its C3d-containing fragments). However, C3 and C3 fragments did not inhibit the peroxidase reaction in vitro. We propose that ceruloplasmin takes part in the clearance and inactivation of MPO, in vivo. We also speculate that impaired inactivation of MPO may have a pathophysiological role in inflammatory diseases characterized by autoantibodies to MPO, such as rapidly progressive glomerulonephritis with P-ANCA (perinuclear anti-neutrophil cytoplasmic antibodies).

Ceruloplasmin↗