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Biomedical subjects

J Wieslander

Publications and source records attributed to J Wieslander.

At least 73 records · Page 4Linked to original sources
PubMed1994

Type IV collagen alpha 5 chain. Normal distribution and abnormalities in X-linked Alport syndrome revealed by monoclonal antibody.

Although the evidence indicates that mutation of the gene for the alpha 5 chain of type IV collagen, alpha 5-(IV), is the primary defect in X-linked Alport syndrome, protein data for the alpha 5(IV) chain with regard to its normal distribution and its distribution in patients with Alport syndrome is lacking. We produced a rat monoclonal antibody (H51) by immunizing rats with a synthetic peptide corresponding to the nonconsensus amino acid sequence of alpha 5(IV) NC1 domain. H51 reacted by Western blotting with 26-kd cationic monomers and associated dimers of human type IV collagen NC1 domain. Immunohistochemical studies demonstrated that in normal human kidney alpha 5(IV) was present in the glomerular basement membrane and basement membranes of the Bowman's capsule and in some tubules (collecting ducts). The alpha 5(IV) chain was also detected in the basement membranes of normal skin, eye, and lung. Male patients with X-linked Alport syndrome revealed no reactivity of renal and epidermal basement membranes with H51, whereas alpha 5(IV) staining was normal in the glomerular basement membrane of patients with other types of glomerular diseases, including benign familial hematuria. The staining was also normal in the skin of nonaffected males in X-linked Alport families. Female heterozygous for Alport syndrome exhibited a discontinuous or mosaic pattern in the immunofluorescent staining of the epidermal basement membrane. These findings confirm that in patients with X-linked Alport syndrome there are abnormalities in alpha 5(IV) in renal and epidermal basement membranes at the protein level. Immunofluorescent staining of skin biopsies with this antibody may be of value in making a diagnosis of Alport syndrome, and, furthermore, may aid in detecting carrier females in whom urinary abnormalities are often mild or silent.

Adolescent↗
PubMed1993

ANCA and IgG subclasses.

We studied IgG subclass distribution of ANCA in 247 patients with ELISA. We used monoclonal subclass specific antibodies and purified MPO and proteinase 3 as antigen. We found that IgG1 and IgG4 yield high values in both groups. We also found that high IgG2 titers were rare among the anti-proteinase 3 positive, while it was common among anti-MPO sera. In the assays for IgG3 the situation was the opposite.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1993

IgG subclasses of antineutrophil cytoplasm autoantibodies (ANCA).

Sera that had been positive in routine ELISA for ANCA were studied retrospectively for the IgG subclass distribution of these autoantibodies. An ELISA previously developed for measurement of IgG subclasses of anti-GBM antibodies was modified for this purpose. Of a total of 247 sera, 114 were found to be positive in at least one of the assays for IgG subclasses of anti proteinase 3, 72 of these patients were men and 42 were women, giving a ratio of 1.8. Also 134 sera were positive in at least one of the IgG subclass assays for antimyeloperoxidase (MPO), with a male/female ratio of 0.97. The ANCA seem to consist mainly of IgG1 and IgG4 autoantibodies. Among the anti-MPO group, IgG2 is relatively common and IgG3 is scarce. Contrasting with this, IgG3 is relatively common in the antiproteinase 3 group. In this group high IgG2 titres are rare. Twelve sera were found to be positive for both autoantigens. Clinical data were studied for 44 patients. Prognosis for old patients was found to be poor. Patients with inactive disease were often positive in only one subclass assay, while patients with active disease were positive in two or more subclass assays (P < 0.01).

Adolescent↗
PubMed1993

Characterization of a non-Goodpasture autoantibody to type IV collagen.

Goodpasture's syndrome is a very severe and aggressive autoimmune kidney disease. The patients' autoantibodies, which are pathogenic, are restricted to the C-terminal region of the alpha 3-chain of type IV collagen. In this paper we characterize an anti-type IV collagen antibody from a patient with a non-progressive form of glomerulonephritis. ELISA and immunoblotting were used to study the specificity of this patient's antibodies. The patient had high titres of antibodies restricted to the C-terminal region of the alpha 1-chain of type IV collagen. The antibody recognized an epitope hidden in the NC1 molecule which was fully exposed after denaturation or reduction. It was an IgG3 antibody composed of only lambda light chains, indicating that it has a potential to induce inflammatory damage and that it is probably monoclonal. This patient also had MPO-ANCA which were of IgG1 subclass. Our patient had no disease progression during the 5 years of treatment. Even though the anti-alpha 1 (IV) antibodies react with the same domain, but of a different chain of type IV collagen compared to the Goodpasture's antibodies, they do not induce any severe damage. It is thus uncertain if the anti-alpha 1 (IV) antibodies have any pathogenic role; the kidney damage might have been caused by the MPO-ANCA. The findings support the theory that the anti-alpha 3 (IV) antibody causes disease in Goodpasture's syndrome and that antibodies restricted to other subunits of the C-terminal region of type IV collagen are less harmful.

Animals↗
PubMed1992

The structural organization of type IV collagen. Identification of three NC1 populations in the glomerular basement membrane.

Type IV collagen, which has long been assumed to contain two alpha 1(IV) and one alpha 2(IV) chains, also contains alpha 3(IV), alpha 4(IV), and alpha 5(IV) chains. Stoichiometry of collagenous alpha(IV) chains differs among tissues, suggesting the existence of subclasses of type IV collagen, each with a unique chain composition. This study seeks to define, by characterization of subunit compositions of NC1 domain populations, the structural organization of type IV collagen from bovine glomerular basement membrane. NC1 hexamers from type IV collagen were separated on two affinity chromatography columns, one containing monoclonal antibodies to the alpha 3 chain, and another, to the alpha 1 chain. SDS-polyacrylamide gel electrophoresis, immunoblotting, reversed phase high-performance liquid chromatography, and enzyme-linked immunosorbent assay identified three NC1 hexamer populations: 1) a hexamer composed of (alpha 1)2 and (alpha 2)2 homodimers; 2) a hexamer composed of (alpha 3)2 and (alpha 4)2 homodimers; 3) a hexamer containing all four alpha chains connected in heterodimers, alpha 1-alpha 3 and alpha 2-alpha 4. Results suggest that there are two distinct type IV collagen molecules, one composed of alpha 1(IV) and alpha 2(IV) chains and another composed of alpha 3(IV) and alpha 4(IV) chains. Furthermore, polymerization occurs between molecules with the same chain composition and between molecules with different chain composition. Moreover, crosslinking between different alpha chains is restricted, thus limiting the number of possible macromolecular structures.

Animals↗
PubMed1992

Tubular secretion of Tamm-Horsfall protein in type 1 (insulin-dependent) diabetes mellitus using a simplified enzyme linked immunoassay.

The relationship between glomerular and tubular dysfunction and metabolic control in type 1 diabetes was studied. To that end the urinary excretion rates of albumin and Tamm-Horsfall protein as well as HbA1c levels were measured in 58 patients with different degrees of diabetic nephropathy and in 76 apparently healthy subjects matched for sex and age. The urinary Tamm-Horsfall protein levels were measured by a simplified enzyme linked immunoassay. The intra- and interassay variations were 8.9% and 13.6%, respectively. The intraindividual variation was 41% and the sensitivity of the assay was 4 micrograms/l. The Tamm-Horsfall protein excretion rate was 42.1 x/2.0 micrograms/min (geometric mean x/tolerance factor) in the diabetic patients compared to 34 x/1.9 micrograms/min in the control subjects (NS). The diabetic patients had higher albumin excretion rate (38.5 x/7.3 micrograms/min) than the control subjects (4.7 x/2.3 micrograms/min; P less than 0.001). By using multivariate analysis of variance, HbA1c level was found to be the only independent variable associated with Tamm-Horsfall protein excretion rate in diabetic patients (r = -0.28; P = 0.04), while no relationship was found between Tamm-Horsfall protein excretion rate and age, age at onset and duration of diabetes, gender, serum creatinine, diuresis, urinary albumin excretion rate, systolic and diastolic blood pressure levels and antihypertensive treatment. The urinary albumin excretion rate was associated with diastolic blood pressure (r = 0.34; P = 0.02) but not with HbA1c levels when testing the above variables by multivariate analysis of variance. In conclusion, these results may indicate a lack of relationship between glomerular and tubular dysfunction. The former was influenced only by diastolic blood pressure levels and the latter only by the degree of metabolic control. However, the correlations were weak and do not provide any insight into what is actually responsible for glomerular and tubular dysfunction.

Adult↗
PubMed1992

[Autoantibodies as serological markers in the diagnosis of glomerulonephritis].

Autoimmunity is now regarded as the unequivocally predominant pathogenic process underlying most forms of primary and secondary glomerulonephritis in humans, and a number of autoantibodies occurring in conjunction with glomerulonephritis have been discovered. However, apart from the anti-NC1 antibodies occurring in classic Goodpasture's syndrome, the exact pathogenic role of these autoantibodies in human glomerulonephritis remains to be established, though this in no way diminishes the importance of their study. They have been of enormous value in subclassifying glomerulonephritis, previously thought to be a homogeneous entity. Autoantibody analysis has become a vital aid in the early diagnosis of rapidly progressive glomerulonephritis, which in turn has enabled treatment to be started early, thus contributing to a decline in the morbidity and mortality resulting from these disorders. Moreover, investigation of these autoantibodies will be of immense value in future studies focused on the pathogenic mechanisms involved in glomerulonephritis.

Anti-Glomerular Basement Membrane Disease↗
PubMed1992

Anti-neutrophil cytoplasm antibodies, anti-GBM antibodies and anti-dsDNA antibodies in glomerulonephritis.

The diagnostic potential of assays detecting anti-neutrophil cytoplasm antibodies (ANCA), anti-GBM antibodies and anti-dsDNA antibodies was evaluated by examining sera from time of admission in a consecutive series of 455 patients with biopsy verified primary or secondary glomerulonephritis (GN). ANCA were classified into c- and p-ANCA by indirect immunofluorescence (IIF) and ELISAs using alfa-granule extract, proteinase-3, myeloperoxidase (MPO), elastase and lactoferrin. C-ANCA was virtually confined to 64 patients with systemic small vessel vasculitis, 66-74% being c-ANCA positive. P-ANCA against MPO, seen in 47 patients, segregated through many diagnostic categories of primary and secondary severe GN. ANCA against lactoferrin and elastase were rare. Anti-dsDNA positive patients constituted 57% of the 44 ANA-positive patients with systemic lupus erythematosus. It is concluded that the IIF and ELISAs for anti-proteinase-3, anti-MPO, anti-dsDNA and anti-GBM have an acceptable performance and are useful in the primary diagnostic work-up of patients suspected for secondary GN as the majority of such patients will be classified by these assays.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1992

Autoimmunity and glomerulonephritis.

Autoimmunity is now unequivocally regarded as the predominant pathogenic process underlying most forms of primary and secondary glomerulonephritis in humans. Most of the investigations so far have been focused upon humoral mechanisms. Consequently, the role of cell-mediated immunity in nephritis is still incompletely understood. Nonetheless, as a result of contemporary studies, a number of previously unidentified auto-antibodies in association with glomerulonephritis have been discovered. However, apart from anti-NC1 antibodies in the classical Goodpasture syndrome, the exact role of these auto-antibodies in the pathogenesis of glomerulonephritis yet remains undefined. This fact, however, does not undermine the relevance of exploring these auto-antibodies. They have been of immense help in sub-classifying glomerulonephritis previously thought homogeneous (Figure 3). Besides, analysis of auto-antibodies has assisted tremendously in the early diagnosis of rapidly progressive glomerulonephritis. This, in turn, has aided in early commencement of therapy thus contributing to regression in morbidity and mortality resulting from these disorders. Moreover, investigation of these auto-antibodies is of enormous value for future studies aimed at understanding the pathogenic mechanisms involved in glomerulonephritis.

Autoantigens↗
PubMed1991

Fibronectin-immunoglobulin complexes in the early course of IgA and Henoch-Schönlein nephritis.

We have previously reported the presence of circulating IgA-fibronectin complexes in adult patients with primary IgA nephropathy. In the present study five children were serially investigated during the early course of IgA nephropathy and Henoch-Schönlein glomerulonephritis. Using affinity chromatography procedures and enzyme-linked immuno-sorbent assay, IgA, IgG and IgM in complex with fibronectin were repeatedly demonstrated during the follow-up period in both groups of patients. Most patients had, at the same time, IgA, IgG, as well as IgM deposits in the glomerular mesangium. The simultaneous presence of IgA and IgG in complexes purified from serum was furthermore demonstrated. The results are thus in contrast to the findings in adults with IgA nephropathy, in whom the immunoglobulin-fibronectin complexes only contained IgA. Whether this reflects different subgroups of patients or a different pathophysiology in children and adults remains to be elucidated.

Adolescent↗
PubMed1991

Serum IgA-fibronectin aggregates in patients with IgA nephropathy and Henoch-Schönlein purpura: diagnostic value and pathogenic implications. The Glomerular Disease Collaborative Network.

IgA nephropathy is a common form of glomerulonephritis that has varied clinical expressions, ranging from asymptomatic hematuria to rapidly progressive nephritis. We report the strong association (P less than 0.0001) of circulating IgA-fibronectin aggregates with IgA nephropathy. Of 30 patients with IgA nephropathy, 93.3% had serum IgA-fibronectin aggregates detected with an enzyme immunoassay using collagen as a substrate to bind the aggregates. Among the patients with IgA-fibronectin aggregates were patients with Henoch-Schönlein purpura and recurrent crescentic IgA nephropathy in transplants. Only 11.7% of 103 patients with other types of glomerular disease and 6.7% of normal controls had positive IgA-fibronectin aggregate assay levels. IgA-fibronectin aggregates also were detected in serum using an antifibronectin antibody capture assay; and could be depleted from serum by heparin-agarose affinity chromatography. The circulating IgA-fibronectin aggregates had the same unusual predominance of lambda relative to kappa light chains that is observed in the glomerular deposits of IgA nephropathy. The data indicate that IgA-fibronectin aggregates are a useful serologic marker for IgA nephropathy, Henoch-Schönlein purpura, and recurrent IgA nephropathy in transplants. The presence of fibronectin in the circulating aggregates may play an important role in the preferential deposition of nephritogenic IgA-containing immune complexes in the mesangium of patients with IgA nephropathy.

Antigen-Antibody Complex↗
PubMed1991

How are antineutrophil cytoplasmic autoantibodies detected?

Antineutrophil cytoplasmic autoantibodies (ANCA) are present in patients with systemic vasculitis with or without renal involvement. These antibodies were first seen using indirect immunofluorescence (IIF). Two types of patterns are seen on ethanol-fixed neutrophils: the cytoplasmic and the perinuclear pattern. The cytoplasmic pattern is called C-ANCA (classical or cytoplasmic ANCA) and the perinuclear, P-ANCA. Antibodies to a serine proteinase, called proteinase 3 or myeloblastin, give rise to the C-ANCA pattern, while antibodies to myeloperoxidase give rise to the P-ANCA pattern. Proteinase 3, as well as myeloperoxidase, is present in the primary granules of neutrophils, and the P-ANCA pattern is thus an artifactual staining pattern. Myeloperoxidase, which is a basic protein, redistributes during ethanol fixation from the primary granules to the negatively charged nucleus. As an alternative to the IF technique, several solid-phase assays have been developed using either 125I or enzyme-labeled secondary antibodies. Depending on the degree of purification of the antigens used, such assays may be used for screening or as a complement to the IF method. Today it is possible to directly screen for both types of ANCA using enzyme-linked immunosorbent assay (ELISA). Simultaneous screening for antiglomerular basement membrane (GBM) antibodies (Goodpasture antibodies) increases the diagnostic yield, especially in patients with renopulmonary syndromes.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1991

Circulating anti-entactin antibodies in patients with glomerulonephritis.

Sera from 305 consecutive patients in a renal biopsy series were analyzed for the presence of anti-entactin antibodies by ELISA. Of these patients, 59% had primary glomerulonephritis, 21% had secondary glomerulonephritis, while 20% had other nephropathies (noninflammatory conditions like amyloidosis, diabetic nephropathy, nephrosclerosis, etc.). Forty-one of these patients (13.4%) were positive for IgG/IgM antibodies against entactin: 60% of them had primary glomerulonephritis, 35% had secondary glomerulonephritis, while the remaining 3 patients had other nephropathies. Fifteen (70%) of the 23 patients with primary glomerulonephritis had proliferative glomerulonephritis (PGN), whereas 13 (87%) of the 15 patients with secondary glomerulonephritis were due to systemic connective tissue diseases (SCTD): 7 due to SLE, 4 due to SLE like SCTD and two due to other SCTD. There was a peak of incidence corresponding to the group aged 18 to 30 years. A majority of these patients (12 of the total 17) had primary glomerulonephritis and were associated with nephrotic or subnephrotic grade proteinuria, poorly or nonresponsive to immunosuppressive treatment and associated, in several cases, with progressive deterioration of renal function. In addition, there was a tendency to another peak in the age group 51 to 60 years. Most of these patients (6 of the total 8) had glomerulonephritis secondary, mainly, to SLE or SLE like SCTD with milder degree of proteinuria and better preserved renal functions. Anti-entactin antibodies were not found in certain glomerulonephritides like IgA nephropathy and those secondary to systemic vasculitides and in control subjects (healthy subjects, and patients with a variety of non-renal disorders including inflammatory diseases).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Circulating autoantibodies in patients with extracapillary glomerulonephritis.

Circulating autoantibodies, namely c-ANCA, MPO-ANCA, anti-Goodpasture (anti-NC1), and anti-entactin antibodies were analysed in sera from 82 consecutive patients with crescentic involvement of more than 50% glomeruli in renal biopsy specimens. Sixty-eight (approximately 83%) patients possessed one or more of these autoantibodies. About two-thirds of all patients had ANCA (c-ANCA, MPO-ANCA or both). Most of the remaining positive patients had anti-NC1 antibodies. Very few patients had anti-entactin antibodies, thereby suggesting a poor association of these antibodies with extracapillary glomerulonephritis (ECGN). Thus two different categories of patients, one possessing ANCA and the other anti-NC1 antibodies, could be recognised. Patients with anti-NC1 antibodies were characterised by linear immune deposits along the glomerular basement membrane and the clinical outcome was invariably grim. On the other hand, despite no significant difference in renal morphology from patients with anti-NC1 antibodies, the disease in patients with ANCA, in general, had a milder course. Among patients with ANCA, those with c-ANCA mainly had systemic small-vessel vasculitis with widespread systemic manifestations, whereas most patients with renal restricted primary ECGN with non-linear immune deposits possessed MPO-ANCA. Furthermore, patients with c-ANCA had a more severe disease than those with MPO-ANCA. These observations indicate that a continuous spectrum of diseases exists between idiopathic small-vessel vasculitides and primary non-linear ECGN. Our study also demonstrates that the presence of auto-antibodies is a dominant feature of severe ECGN and that the type of immunological injury is more important than the extent of crescentic involvement of glomeruli in determining the course of illness in patients with ECGN.

Adolescent↗
PubMed1991

Antibodies to mouse laminin in patients with systemic sclerosis (scleroderma) recognize galactosyl (alpha 1-3)-galactose epitopes.

Employing radioimmunoinhibition assays with distinct oligosaccharides as inhibitors, this study demonstrates that the epitope recognized on mouse laminin by sera from patients with systemic sclerosis (scleroderma) is a terminal galactosyl (alpha 1-3)-galactose disaccharide. The reaction with this alpha-digalactose was further confirmed when the sera were tested in radioimmunoassay (RIA) binding assay and in ELISA with synthetic galactose alpha 1-3 galactose coupled to human serum albumin. The circulating antibody appeared restricted to the IgG class and mostly to the subclass IgG3 and IgG4. Antibodies with the same specificity can be found in patients with American cutaneous leishmaniasis and Chagas disease; however, whilst in these diseases the antibody production is triggered by antigenic determinants present on the surface of the parasites, the events eliciting their appearance in systemic sclerosis are unknown.

Disaccharides↗
PubMed1991

Urine and serum levels of the carboxyterminal domain (NCl) of collagen IV in membranous glomerulonephritis and diabetic nephropathy.

Serum and urinary concentrations of NCl, the non collagenous globular domain of collagen IV, were used as markers for turnover of basement membranes. NCl levels were studied in membranous glomerulonephritis and diabetic nephropathy. Thirteen patients with membranous glomerulonephritis and 8 insulin-dependent diabetic patients with diabetic nephropathy were compared to 16 apparently healthy control subjects. The patients with membranous glomerulonephritis had lower levels of NCl in serum and urine compared to the control subjects. In comparison, the patients with diabetic nephropathy had similar levels of NCl in serum and urine as the control subjects. Furthermore, among patients with membranous glomerulonephritis, those with hypertension had higher serum levels of NCl than those without, which may indicate that hemodynamic factors influence the basement membrane collagen metabolism. It is suggested that there are differences in basement membrane turnover in membranous glomerulonephritis and diabetic nephropathy although there are similarities in glomerular histopathological features. Other possible mechanism are discussed. Further studies are needed to confirm the suggested mechanism.

Adult↗
PubMed1991

Characterization of monoclonal antibodies to the globular domain of collagen IV.

Monoclonal antibodies were produced against NC1, the globular noncollagenous domain of collagen IV, isolated from bovine glomerular basement membrane. Cells from eight positive wells were cloned and the resulting monoclonal antibodies were studied in detail by immunofluorescence on human kidney sections, by Western blot and by ELISA against denatured subunits from NC1 hexamers and against native NC1 hexamers from different tissues. The monoclonal antibodies could be divided into two groups. Firstly, those monoclonal antibodies that, in ELISA and Western blot, reacted with peptides related to the alpha 1 chain of collagen IV and stained all basement membranes in the kidney. Secondly, a monoclonal antibody that, in ELISA and Western blot, reacted with peptides related to the Goodpasture antigen, the alpha 3 chain of collagen IV. When this antibody was applied to human kidney sections it stained the glomerular basement membrane very intensively. Bowman's capsule and some tubular basement membrane were also stained, although to a lesser extent. This staining pattern is the same as that observed with sera from patients with Goodpasture's syndrome. An attempt was made to separate different subtypes of the NC1 hexamer. A monoclonal antibody from the first group was used to make an affinity chromatography column. Glomerular basement membrane digested with collagenase was separated on this column and the collected fractions were analyzed by ELISA and SDS-PAGE. The result from this study support the idea that glomerular basement membrane is composed of at least two different subtypes of type IV collagen.

Animals↗