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Biomedical subjects

J Wieslander

Publications and source records attributed to J Wieslander.

At least 37 records · Page 2Linked to original sources
PubMed1997

Seminiferous tubule basement membrane. Composition and organization of type IV collagen chains, and the linkage of alpha3(IV) and alpha5(IV) chains.

Seminiferous tubule basement membrane (STBM) plays an important role in spermatogenesis. In the present study, the composition and structural organization of type IV collagen of bovine STBM was investigated. STBM was found to be composed of all six alpha-chains of type IV collagen based upon immunocytochemical and biochemical analysis. The content of alpha3(IV) chain (40%) and the alpha4(IV) chain (18%) was substantially higher than in any other basement membrane collagen. The supramolecular structure of the six alpha(IV) chains was investigated using pseudolysin (EC 3.4.24.26) digestion to excise triple-helical molecules, subsequent collagenase digestion to produce NC1 hexamers and antibody affinity chromatography to resolve populations of NC1 hexamers. The hexamers, which reflect specific arrangements of alpha(IV) chains, were characterized for their alpha(IV) chain composition using high performance liquid chromatography, two-dimensional electrophoresis, and immunoblotting with alpha(IV) chain-specific antibodies. Three major hexamer populations were found that represent the classical network of the alpha1(IV) and alpha2(IV) chains and two novel networks, one composed of the alpha1(IV)-alpha6(IV) chains and the other composed of the alpha3(IV)-alpha6(IV) chains. The results establish a structural linkage between the alpha3(IV) and alpha5(IV) chains, suggesting a molecular basis for the conundrum in which mutations in the gene encoding the alpha5(IV) chain cause defective assembly of the alpha3(IV) chain in the glomerular basement membrane of patients with Alport syndrome.

Animals↗
PubMed1997

Systemic vasculitis in a kidney transplant population.

BACKGROUND: Systemic vasculitis as original disease might adversely influence the result of kidney transplantation. METHODS: The clinical course after 32 transplantations to 26 patients with microscopic polyangiitis, Wegener's granulomatosis, Henoch-Schonlein purpura, thrombotic thrombocytopenic purpura/hemolytic uremic syndrome, or Goodpasture's disease was evaluated. The median follow-up time was 82 months (range, 4-132 months). Frozen sera from 25 transplantations were analyzed for Goodpasture antibodies, myeloperoxidase antineutrophil cytoplasmic antibodies (ANCA), and proteinase 3 ANCA. RESULTS: Survival of patients and grafts did not differ between patients and matched controls. Recurrent vasculitis occurred with seven grafts (four patients with microscopic polyangiitis or Wegener's granulomatosis, two patients with Henoch-Schonlein purpura, and one patient thrombotic thrombocytopenic purpura). New-onset hematuria was the initial renal symptom in five patients. Treatment with corticosteroids, cyclophosphamide, and/or plasma exchange was most often effective, but two grafts were lost. Proteinase 3 ANCA titers were increased to 12-738 U/ml before seven transplants. The patient with the lowest titer lost his graft due to recurrence, two other patients had reversible recurrence after 1 year and 5 years, two patients lost their grafts due to unknown/unrelated causes, and two patients' grafts remain without recurrence. Myeloperoxidase ANCA were increased to 22-39 U/ml before two transplants, which have been uneventful for 4 years. CONCLUSIONS: An awareness of the small but perpetual risk of recurrence facilitates early treatment that may save the transplant. Testing for hematuria and early transplant biopsies, and possibly monitoring of ANCA titers, are essential, but pretransplant ANCA titers have no predictive value in asymptomatic patients. Results of kidney transplantation in patients with vasculitis are as good as in other patients.

Adult↗
PubMed1997

A study of autoantibodies and circulating immune complexes in mercury-exposed chloralkali workers.

UNLABELLED: Inorganic mercury may cause immunologically mediated disease: e.g., glomerulonephritis, acrodynia, and contact allergy. Animal models have demonstrated the importance of genetic factors in determining susceptibility and resistance to autoimmunity, as well as the specific manifestation of the autoimmune response. Findings in groups of workers with occupational exposure to inorganic mercury have been inconsistent. OBJECTIVE: To investigate whether an immune response, caused by exposure to inorganic mercury (Hg), could be shown in occupationally exposed workers. METHODS: Immunoglobulin G (IgG), antinuclear autoantibodies, antibodies against thyroid, stomach or kidney antigens using indirect immunofluorescence, antibodies against glomerular basement membrane using ELISA, and circulating immune complexes in serum, and albumin in urine, were examined in Hg-exposed workers and controls. The two groups, 41 male chloralkali workers exposed to Hg vapour (mean exposure time 9 years) and 41 unexposed controls were age-matched and recruited from the same company. Hg concentrations in whole blood (B-Hg), plasma (P-Hg), and urine (U-Hg) were determined using cold vapor atomic spectrometry. DESIGN: Cross-sectional study. RESULTS: The mean B-Hg, P-Hg and U-Hg levels were 46 nmol/l, 37 nmol/l, and 27 micrograms/g creatinine in the exposed group, and 17 nmol/l, 6.9 nmol/l, and 3.4 micrograms/g creatinine in the referents. No statistically significant differences were found regarding IgG levels, urinary albumin excretion, prevalence of abnormal titers of autoantibodies or circulating immune complexes. There were no statistically significant associations between autoantibodies or immune complexes on the one hand and mercury exposure indices on the other. CONCLUSION: The results indicate that, if and when lasting autoimmune response occurs at the mercury exposure levels of the present study, it is uncommon. A small fraction of humans may, however, be susceptible to the development of autoimmunity, and there is also a possible "healthy worker" selection. Thus cross-sectional studies of moderate numbers of active workers will have low power to demonstrate autoimmune effects.

Adolescent↗
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↗
PubMed1997

Rapid screening assay for anti-GBM antibody and ANCAs; an important tool for the differential diagnosis of pulmonary renal syndromes.

BACKGROUND: Pulmonary renal syndrome is encountered in several diseases such as Goodpasture's syndrome, antineutrophil cytoplasmic antibody (ANCA) associated systemic vasculitis, systemic lupus erythematosus (SLE) and infection-associated or drug-induced glomerulonephritis. To preserve organ function it is of vital importance to make the correct diagnosis and institute adequate therapy early, in the acute phase. METHOD: An enzyme-linked immunosorbent assay (ELISA), specially designed as a rapid screening assay for antiglomerular basement membrane (anti-GBM) antibody, proteinase-3 (PR3-) ANCA and myeloperoxidase-(MPO-) ANCA were evaluated from 1060 serum samples drawn from patients with clinically suspected pulmonary renal syndrome or rapidly progressive glomerulonephritis (RPGN). RESULTS: Of the 1060 serum samples, 142 were positive for anti-GBM antibody (n = 19), PR3-ANCA (n = 60), or MPO-ANCA (n = 73). Of the 142 samples, 10 were double positive. Reanalysis of positive sera with a quantitative ELISA yielded results manifesting good correlation with those of the the rapid screening assay. Of 918 sera found to be negative in the rapid screening assay, 105 were also tested with IIF, 11 being found to be positive. However, these 11 sera manifested no specificity for PR3 or MPO, but some were specific for bactericidal/permeability-increasing proteins, lactoferrin or elastase ANCAs. Two of the patients whose sera yielded negative results in the rapid assay had systemic vasculitis. CONCLUSION: The ELISA thus detects the true antibodies to PR3, MPO, and GBM, whereas IIF detects additional specificities. The findings suggest the rapid assay results to be of high positive predictive value, and the assay to be of high diagnostic specificity and sensitivity and thus useful in the diagnostic workup in suspected cases of RPGN or pulmonary renal syndrome.

Anti-Glomerular Basement Membrane Disease↗
PubMed1997

Human autoimmune anti-proteinase 3 scFv from a phage display library.

This is the first study describing recombinant human antibody fragments directed to the autoantigen proteinase 3 (PR3) from an immune B cell source. Detection of these autoantibodies has proven valid for the diagnosis and monitoring of Wegener's granulomatosis. The described antibody fragment (scFv) was isolated from a phage display library prepared from the IgG-positive splenic lymphocytes of a patient with systemic autoimmunity. The cloning strategy was designed to maintain the diversity of the antibody variable gene repertoire, and sequencing of several variable genes demonstrated that all major heavy and light chain families were represented. We found an over-representation of particular heavy chain variable domains in splenic lymphocytes which differ from the ones frequently found in peripheral blood lymphocytes. It was possible to obtain specific scFv to PR3 after a single round of selection and the binding could be inhibited by the patients' sera. Although the antibody fragments in the splenic repertoire were found to be highly mutated, it was interesting to find that the selected scFv showed only limited somatic mutation. Furthermore, we could demonstrate that the removal of the mutations had no effect on binding specificity.

Amino Acid Sequence↗
PubMed1997

Prevalence of autoantibodies associated with glomerulonephritis, unaffected after extracorporeal shock wave lithotripsy for renal calculi, in a three-year follow-up.

Extracorporeal shock wave lithotripsy (ESWL) has become a useful tool in the treatment of renal calculi, but side effects may occur. Hitherto, two case reports have been published of an anti-glomerular basement membrane disease resulting in end-stage renal failure following ESWL treatment. In this prospective study of 59 consecutive patients undergoing ESWL for renal calculi, the prevalence of autoantibodies associated with glomerulonephritis was investigated before ESWL and at 3-year follow-up. The prevalences of antinuclear, anti-glomerular basement membrane, anti-neutrophil cytoplasmic and thyroid antibodies were found to be within the respective normal ranges prior to the first ESWL treatment and to be unaffected at follow-up.

Adult↗
PubMed1997

Glomerular basement membrane antibodies in hantavirus disease (hemorrhagic fever with renal syndrome).

The prevalence of antibodies against glomerular basement membrane (GBM) antigens in sera from 47 patients with serologically verified hantavirus (Puumala serotype) infection were investigated. Antibodies were measured by immunoassays using as antigen a crude human GBM preparation and the NC1 portion of type IV collagen (Goodpasture antigen), respectively. Seventy-seven percent of the patients had IgM antibodies against the non-Goodpasture glomerular basement membrane (non-GP GBM) in their acute phase serum samples as compared to only 4% seropositivity rate in convalescent phase samples. However, there was no correlation between the non-GP GBM IgM antibody levels and the decrease in GFR as measured by Cr EDTA clearance. None of the patients had antibodies against the Goodpasture antigen. In a control group of 10 patients with influenza and parainfluenza infections serum IgM against non-GP GBM could not be demonstrated, neither in acute phase nor in convalescent phase sera. The possible pathophysiological implications of these findings are discussed.

Adult↗
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

Epitope mapping of anti-glomerular basement membrane (GBM) antibodies with synthetic peptides.

Autoantibodies to the non-collagenous (NC1) domain of the alpha 3(IV)-chain of type IV collagen are found in sera from patients with anti-GBM nephritis. These antibodies have been shown to be pathogenic. In this study the antibody specificity has been investigated in patients with Goodpasture's syndrome and from a patient with atypical anti-GBM antibodies, recognizing the alpha 1(IV)-chain only. Overlapping synthetic peptides, covering the complete NC1 domains of the alpha 1(IV)- and alpha 3(IV)-chains were used in sandwich ELISA and competitive ELISA. None of the Goodpasture sera showed reactivity to the synthetic peptides. However, antibodies from the patient with atypical anti-GBM antibodies recognized a 20 amino acid peptide from the alpha 1(IV)-chain. The reactive peptide was further narrowed down with glycine substitution of the different amino acids. We have localized the epitope to the four last C-terminal amino acids of the alpha 1(IV)-chain, with the sequence 1754-MRRT. The two arginine residues were found to be essential for antibody binding. Threonine is important, while methionine is of less importance. These four amino acids are also determined to be the smallest peptide that could inhibit the binding of the autoantibodies to the native alpha 1(IV)-chain. This study shows that overlapping peptides can be used to map linear epitopes. However, for conformational epitopes such as the Goodpasture epitope, other methods must be used. It would be prognostically important to know the fine specificity of anti-GBM antibodies, since the patient with anti-alpha 1(IV) antibodies had a mild disease, while the Goodpasture patients with anti-alpha 3(IV) antibodies had a rapidly progressive disease.

Amino Acid Sequence↗
PubMed1996

Complexes between proteinase 3, alpha 1-antitrypsin and proteinase 3 anti-neutrophil cytoplasm autoantibodies: a comparison between alpha 1-antitrypsin PiZ allele carriers and non-carriers with Wegener's granulomatosis.

To test the hypothesis that anti-neutrophil cytoplasm autoantibodies (ANCAs) interfere with the functions of proteinase 3 (PR3) (the Wegener autoantigen) and alpha 1-antitrypsin (alpha 1AT), complexes of PR3/alpha 1 AT and PR3/PR3-ANCA-IgG were assayed Plasma samples were obtained from 44 patients with Wegener's granulomatosis (WG): 34 had active disease (88% ANCA positive) whereas 10 patients were in remission (20% ANCA positive). Plasma samples from 14 of the patients with active disease were also available at the time of remission. The complexes of PR3/alpha 1 AT and PR3/PR3-ANCA-IgG were detected by capture enzyme-linked immunoassays (ELISAs) alpha 1 AT deficiency was evaluated by determining PiZ alleles by ELISA. Eight (18%) of the patients were PiZ positive. The frequency of this alpha 1-antitrypsin phenotype in the Scandinavian population is 4.7% (P < 0.001). The median PR3/alpha 1AT complex level in the PiZ-positive group with active disease (n = 5) was similar to the level in the PiZ-negative group with active disease. During remission the median level for the PR3/alpha 1AT complex was significantly higher than in the acute group (P < 0.001) including both PiZ-positive and PiZ-negative patients. No difference between PiZ positivity and PiZ negativity could be found in the remission group. PR3/PR3-ANCA-IgG complexes were found in patients with acute disease as well as in patients in remission, in almost equal frequency. This complex was also present in 13/18 ANCA-negative samples from patients in remission. Finally, purified IgG fractions from WG patients were examined for their capacity to inhibit binding between PR3 and alpha 1AT. An effect on the binding between PR3 and alpha 1AT by PR3-ANCA could not be demonstrated. Thus, our results do not support the hypothesis that PR3-ANCA interferes with the binding between PR3 and alpha 1AT. However, the high prevalence of the PiZ alleles among WG patients suggests that an imbalance between proteinases and alpha 1AT may be of importance in this disease. The clinical usefulness of both the PR3/alpha 1AT and the PR3/PR3-ANCA-IgG complexes and the possible influence on ANCA detection need to be examined in prospective longitudinal studies.

Acute Disease↗
PubMed1996

Integrin-mediated interactions between primary/T-sv40 immortalized human glomerular epithelial cells and type IV collagen.

The use of human glomerular epithelial cells (HGEC) in research has been severely restricted by several obstacles, which have been circumvented by the generation of T-SV40 immortalized human visceral glomerular epithelial cells (Delarue et al, 1991). In this work, we compared the primary and immortalized HGEC for expression of integrin and some nonintegrin surface receptors. We also studied the adhesion of both types of HGEC to glomerular basement membrane (GBM), type IV collagen (tIV), and its major noncollagenous NC1 domain. The integrins mediating adhesion of HGEC to tIV were also examined. Expression of integrin and some nonintegrin cell surface receptors was analyzed by flow cytometry. Adhesion to GBM, tIV, and its major noncollagenous NC1 domain was studied by direct solid phase cell adhesion assays. Identification of integrins mediating adhesion of HGEC to tIV was achieved by inhibition of cell adhesion using monoclonal antibodies to integrin subunits. The primary and immortalized HGEC share phenotypic characteristics, and alpha3beta1 appeared to be the major integrin present on both HGEC types. The kinetics of binding to GBM, tIV, and its noncollagenous NCI domain were similar in both the primary and immortalized HGEC, although the latter displayed a somewhat weaker binding. Both the primary and immortalized HGEC displayed significantly better adhesion to NC1-alpha3 compared with NC1-alpha1, alpha3beta1 appears to be the major integrin mediating the adhesion of HGEC to tIV. Our studies suggest that alpha3beta1 is the major integrin present on HGEC. This has been confirmed by flow cytometric analysis. In addition, we demonstrated a functional role for this integrin in mediating attachment of HGEC to tIV. Our data also demonstrate a preference in binding of HGEC to alpha3 chains of NC1 compared with alpha1 chains of NC1. These findings were seen in both the primary and immortalized HGEC. The T-SV40 immortalized HGEC can therefore serve as a very useful tool to study glomerular visceral cell biology.

Animals↗
PubMed1995

Phosphorylation of the Goodpasture antigen by type A protein kinases.

Collagen IV is the major component of basement membranes. The human alpha 3 chain of collagen IV contains an antigenic domain called the Goodpasture antigen that is the target for the circulating immunopathogenic antibodies present in patients with Goodpasture syndrome. Characteristically, the gene region encoding the Goodpasture antigen generates multiple alternative products that retain the antigen amino-terminal region with a five-residue motif (KRGDS). The serine therein appears to be the major in vitro cAMP-dependent protein kinase phosphorylation site in the isolated antigen and can be phosphorylated in vitro by two protein kinases of approximately 50 and 41 kDa associated with human kidney plasma membrane, suggesting that it can also be phosphorylated in vivo. Consistent with this, the Goodpasture antigen is isolated from human kidney in phosphorylated and non-phosphorylated forms and only the non-phosphorylated form is susceptible to phosphorylation in vitro. Since this motif is exclusive to the human alpha 3(IV) chain and includes the RGD cell adhesion motif, its phosphorylation might play a role in pathogenesis and influence cell attachment to basement membrane.

Amino Acid Sequence↗
PubMed1995

Characterization and expression of multiple alternatively spliced transcripts of the Goodpasture antigen gene region. Goodpasture antibodies recognize recombinant proteins representing the autoantigen and one of its alternative forms.

Collagen IV, the major component of basement membranes, is composed of six distinct alpha chains (alpha 1-alpha 6). Atypically among the collagen IV genes, the exons encoding the carboxyl-terminal region of the human alpha 3(IV) chain undergo alternative splicing. This region has been designated as the Goodpasture antigen because of its reactivity in the kidney and lung with the pathogenic autoantibodies causing Goodpasture syndrome. The data presented in this report demonstrate that, in human kidney, the gene region encompassing the Goodpasture antigen generates at least six alternatively spliced transcripts predicting five distinct proteins that differ in their carboxyl-terminus and retain, except in one case, the exon that harbors the characteristic amino-terminus of the antigen. Goodpasture antibodies specifically recognize recombinant proteins representing the antigen and the alternative form that retains the amino-half of the antigen, suggesting that this moiety could be involved in the in vivo binding of the pathogenic antibodies. Furthermore, the sera of control individuals contain autoantibodies against the antigen that can be differentiated from those causing the syndrome based on their specific reactivities, suggesting that the binding of the pathogenic autoantibodies to a specific determinant likely trigger a distinct and unique cascade of events causing the disease.

Alternative Splicing↗
PubMed1995

The PiZ gene of alpha 1-antitrypsin as a determinant of outcome in PR3-ANCA-positive vasculitis.

We have previously demonstrated that a strong correlation exists between systemic vasculitis with proteinase 3-anti-neutrophil cytoplasm antibodies (PR3-ANCA) and heterozygosity for alpha 1-antitrypsin (alpha 1-AT) deficiency, PiZ. In the present study we characterized the PiZ-positive subgroup by laboratory findings, clinical features and outcome. The series studied consisted of 18 PiZ-positive and 81 PiZ-negative PR3-ANCA patients, comparable in sex ratio, age, C-reactive protein concentrations and renal function at diagnosis, and treatment. PiZ-positive patients had a more disseminated disease as reflected by the number of affected organs (P < 0.01). We found no group differences in relapse tendency. Overall mortality was 39% (7 of 18) in the PiZ-positive and 16% (13 of 81) in the non-PiZ group (P = 0.048). When survival analysis was restricted to 66 patients included in the study at disease onset, the group difference was significant (P = 0.016). The results suggest that the subnormal response of plasma alpha 1-AT seen in PiZ-heterozygotes enhances the risk of dissemination of the vasculitic process and the risk of a fatal outcome. We consider alpha 1-AT phenotyping to be justified in cases of PR3-ANCA-positive vasculitis. Treatments decreasing plasma alpha 1-AT (such as plasmapheresis without plasma replacement) may be deleterious.

Adult↗