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At least 19 recordsLinked to original sources

PubMed1983

Estimation of polymeric IgA in human serum: an assay based on binding of radiolabeled human secretory component with applications in the study of IgA nephropathy, IgA monoclonal gammopathy, and liver disease.

Binding of 125I-human secretory component (SC) to human polymeric immunoglobulin A (pIgA) was employed to measure quantitatively the pIgA present in human sera. Interference by IgM in some sera was prevented by removal of IgM with glutaraldehyde polymerized anti-IgM antibodies. 125I-SC complexed to pIgA was measured by precipitation with anti-IgA antibodies and the quantity of pIgA in human serum was estimated by comparing the quantity of 125I-SC bound by several dilutions of human serum to that bound by standard quantities of human monoclonal pIgA proteins. The assay was specific for pIgA because heat-aggregated monomeric IgA or hypogammaglobulinemic serum did not bind 125I-SC greater than a precipitate formed with human monoclonal IgG and anti-IgG. Moreover, analysis of a series of IgA myeloma sera indicated no correlation between the IgA content of the serum and the quantity of pIgA measured. The quantity of pIgA found in 30 normal human sera was 0.13 +/- 0.08 mg/ml (1S.D.), which consisted of 11.3 +/- 5.3% (1 SD) of the total IgA. Patients with IgA monoclonal gammopathy were most often found to have predominantly monomeric IgA. Patients with IgA nephropathy also showed an elevation of pIgA, but this appeared to be a consequence of an overt IgA elevation. IgA nephropathy patients with elevated serum IgA in fact showed a significant elevation of monomeric IgA. Selective elevation of pIgA was observed in patients with primary biliary cirrhosis and alcoholic liver disease. A comparison of this assay with other assays to measure pIgA is discussed.

Aged↗

PubMed1997

Fish oil therapy in IgA nephropathy.

IgA nephropathy often progresses to endstage renal failure over a period of many years, and any therapy directed to IgA nephropathy will most likely have to be administered over an extended period of time. Therefore, optional therapy should be effective and free of long-term adverse effects. Besides fish oil, prednisone has also been investigated for treatment of IgA nephropathy, with a lack of consistent results; severe adverse effects are common with long-term use. Several studies have shown positive although not overly impressive results; therefore optimal therapy for slowing the progression of renal failure secondary to IgA nephropathy has not been established. Problematic issues with available studies included the following: (1) most of the clinical studies previously discussed were short-term, contained small numbers of patients, and most but not all were uncontrolled; (2) early reports involving fish oil therapy demonstrated conflicting results regarding its efficacy, including one study that observed increased progression of renal disease in patients treated with fish oil; however, recent studies have shown more promise for fish oil therapy for up to 2 years of treatment; and (3) since most of the studies were conducted over a short period of time, it is difficult to assess long-term effects and safety of oil treating IgA nephropathy, a disease that progresses to ESRD over 10-20 years. However, given the low number of adverse effects and apparent low risks associated with this relatively safe food supplement therapy observed in most clinical trials of up to 2 years duration, fish oil may slow the progression of renal failure in patients with IgA nephropathy. Therefore, with appropriate monitoring of renal function and blood tests, treatment with fish oil 6-12 g/d should be considered in patients with IgA nephropathy.

Anticonvulsants↗

PubMed1984

Detection of IgA class circulating immune complexes bound to anti-C3d antibody in patients with IgA nephropathy.

IgA class circulating immune complexes (CIC) were detected by solid-phase fluorescent enzyme immunoassay of F(ab')2 anti-C3d antibody in the serum of 52 patients with IgA nephropathy. Conglutinin (Kg) binding IgA class CIC were also measured, and results by these assays were compared. Kg binding IgA class CIC and anti-C3d binding IgA class CIC were detected in 27% and 44%, respectively, of the patients with IgA nephropathy. Either or both of the two were found in 65% of the patients. There was no significant correlation between IgA class CIC detected by these methods and serum IgA. Although all samples with a very high level of anti-C3d binding IgA class CIC did not also have a very high level of Kg binding IgA class CIC, there was a slight quantitative correlation between the 2 assays. Ultracentrifugation analysis showed that anti-C3d binding IgA class CIC were of various sizes between polymeric (21 S) and monomeric IgA (7 S), whereas Kg binding IgA class CIC were mostly monomeric IgA (8 S) with a minor component of heavy fractions (14 S). Both IgA class CIC fixed iC3b and IgA class CIC fixed C3d are present in IgA nephropathy. These observations suggest that the different types of complement bound to IgA class CIC have different roles in IgA nephropathy.

Antigen-Antibody Complex↗

PubMed1999

IgA interaction with carboxy-terminal 43-kD fragment of fibronectin in IgA nephropathy.

IgA deposition in the glomerular mesangial matrix is a prerequisite for the diagnosis of IgA nephropathy, and circulating IgA-containing complex has been implicated in this process. Since fibronectin is known to be involved in the assembly of extracellular matrix, this study was conducted to investigate whether fibronectin and its fragments are present in sera of patients and are capable of binding IgA1. Sera from patients with IgA nephropathy were purified by heparin-affinity chromatography, and column eluate were analyzed for the presence of fibronectin using Western blot and a set of anti-fibronectin monoclonal antibodies. Native fibronectin was digested with cathepsin D to obtain fragments similar to those of serum fibronectin. The capacity of fibronectin to bind IgA was examined with a mixture of purified IgA1 and cathepsin D-digested fibronectin fragments. A 43-kD carboxy-terminal fragment of fibronectin was detected in samples derived from sera of patients with IgA nephropathy but not in healthy control subjects. A similar-sized fragment was generated by cathepsin D digestion of the native molecule and was shown to bind to IgA1 in vitro. Since the carboxy-terminal domain is known to be critical in assembling exogenous fibronectin into the extracellular matrix, the affinity to IgA1 to a fragment found in patients may have pathogenic potential to mediate extracellular IgA deposition in IgA nephropathy.

Chromatography, Affinity↗

PubMed1991

Role for specific complement phenotypes and deficiencies in the clinical expression of IgA nephropathy.

IgA nephropathy, the most commonly occurring type of chronic glomerulonephritis in individuals of European and Asian descent, exhibits marked heterogeneity of clinical signs and ultimate prognosis. Based upon their studies of regional clustering of the ancestors of related patients in eastern Kentucky, the authors have postulated the existence of an inherited disease susceptibility for IgA nephropathy. They examined serum concentrations of individual complement proteins and phenotypes for C3, C4A, C4B, and factor B (Bf) for related and unrelated patients with IgA nephropathy from Kentucky and for patients from the Mid-South region of Tennessee, Mississippi, and Alabama. In these populations, they have described partial complement deficiencies or specific phenotypes which may be associated with the disease. Their findings include the following: (1) partial deficiencies for C2, beta 1H (H), properdin (P), or C4 binding protein (C4BP) in four patients with end-stage renal disease, (2) an association between the C3*F allele with IgA nephropathy in the combined group of unrelated patients from Kentucky and the Mid-South, (3) the occurrence of C4B deficiency in two siblings with IgA nephropathy, and (4) an association between C4A deficiency and poor outcome in patients with IgA nephropathy diagnosed as adults. In addition, the related patients differ from the unrelated patients from Kentucky with respect to frequencies of Bf*F and the BfF (FF + FS + F1F + F1S) phenotype, suggestive of immunogenetic difference between these groups. Important functional differences exist between C4A and C4B isotypes and functional differences are also possible based upon C3 or Bf phenotype.(ABSTRACT TRUNCATED AT 250 WORDS)

Carrier Proteins↗

PubMed1994

Haemophilus parainfluenzae antigen and antibody in renal biopsy samples and serum of patients with IgA nephropathy.

IgA nephropathy may be associated with colonisation with Haemophilus parainfluenzae. In patients with glomerular diseases, we examined renal-biopsy specimens for presence of bacterial antigen by immunofluorescence microscopy with rabbit antiserum against H parainfluenzae, and by enzyme-linked immunosorbent assay looked for IgA antibody against H parainfluenzae in patient sera. The rabbit antiserum recognised by immunoblotting four components of H parainfluenzae outer membranes (OMHP) of molecular weights 19.5, 30, 33, and 40.5 kDa. All 44 patients with IgA nephropathy and 2 of 39 patients with other glomerular diseases showed mesangial deposition of OMHP antigens (p < 0.001). Patients with IgA nephropathy had significantly more IgA antibody against H parainfluenzae than did patients with other glomerular diseases. IgA antibody in the sera of patients with IgA nephropathy recognised by immunoblotting the same four components of OMHP as recognised by rabbit antiserum. Glomerular deposition of OMHP antigens and the presence of IgA antibody against OMHP in patients with IgA nephropathy suggest that H parainfluenzae has a role in the aetiology of this disease.

Adult↗

PubMed1996

[The role of the interaction between macrophages and mesangial cells in the progression of IgA nephropathy].

IgA nephropathy is the most common form of glomerulonephritis in the world. Approximately, 20 to 30% of IgA nephropathy patients progress to end stage renal failure in 20 years. However, the mechanism (s) underlying the progression of IgA nephropathy has not been fully understood. The purpose of this study was to elucidate the role of the interaction between macrophages and mesangial cells in the progression of IgA nephropathy. Renal biopsy specimens from 40 patients with IgA nephropathy were examined to investigate the relationship between glomerular infiltration of monocytes/macrophages (Mo/M phi), glomerular expression of monocyte-specific chemoattractant, and their clinicopathological findings. The results led to the following conclusions. 1. The localization of Mo/M phi within the glomerulus was identified as intracapillary or intramesangial by immuno-cytochemistry with monoclonal antibody against CD68. 2. Close relationships between mesangial expressions of M-CSF and MCP-1, and mesangial localization of Mo/M phi strongly suggested that mesangial production of these factors, in concert with glomerular ICAM-1 expression, enhances the recruitment and survival of Mo/M phi in the mesangium. 3. It was suggested that Mo/M phi localized in the mesangium play an important role in the progression of IgAN through increasing the production of matrix by mesangial cells.

Adolescent↗

PubMed1992

Glomerular deposition of complex-forming glycoprotein heterogenous in charge (protein HC) in IgA nephropathy.

IgA immune complexes and polymeric IgA are presumed to play important roles in the development and progression of IgA nephropathy. Complex-forming glycoprotein heterogenous in charge (protein HC), being inhibitors of neutrophilic chemotaxis, has been reported as binding to IgA. As a working hypothesis it was assumed that complexes of protein HC and IgA are present in glomeruli from IgA nephropathy patient in stable state. In this study, we examined the glomerular deposition of protein HC in 40 patients with IgA nephropathy and in 10 patients with non-IgA nephropathy. We used highly specific antibody against protein HC, that does not cross-react with alpha-1-microglobulin. An immunofluorescent study revealed that 10 out of the 40 patients (25%) showed an intensity of 1+, 16 (40%) showed weak positive (+/-), and the other 14 (35%) were negative. There was no deposition of protein HC in non-IgA nephropathy patients. Histopathological analysis demonstrated a significant correlation between the intensity of glomerular-deposited protein HC and pathological activity (p less than 0.005); the latter was defined as having either crescents in more than 15% of the remaining glomeruli (excluding global sclerotic glomeruli), or segmental necrosis or sclerosis in more than 30% of the remaining glomeruli. A significant correlation was observed between pathological activity and the intensity of deposited IgG, IgA and IgM (p = 0.01), and lambda chain (p less than 0.005). Considering anti-inflammatory activity of protein HC, these results suggest that protein HC cannot protect sufficiently acute inflammation or tissue damages due to co-deposited IgG and IgM and/or other factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

[Proto-oncogene, proliferating cell nuclear antigen, perforin and growth factor gene expression in peripheral blood mononuclear cells from patients with IgA nephropathy].

IgA nephropathy, which is widely recognized as one of the most common primary glomerulonephritides, is characterized by the constant presence of IgA in the glomerular mesangium. We investigated proto-oncogenes, proliferating cell nuclear antigen (PCNA), perforin, platelet-derived growth factor (PDGF) and insulin-like growth factor (IGF) mRNA expression in peripheral blood mononuclear cells (PBMC) obtained from patients with IgA nephropathy, patients with other types of glomerulonephritis and healthy age-matched controls. The majority of patients with IgA nephropathy showed elevated c-myc, c-fos, c-jun, c-raf, PCNA, perforin, PDGF-B chain, and IGF-I and -II mRNA expression in PBMC, while no these mRNA expression was detected in PBMC obtained from patients with other types of glomerulonephritis or normal controls. A positive correlation was noted between mRNA levels and urinary protein excretion. mRNA expression also correlated with the histopathological findings in the renal tissue of patients with IgA nephropathy. These studies suggest that abnormal regulation of proto-oncogenes, PCNA, perforin, PDGF and IGF gene expression in PBMC may be associated with the progression of IgA nephropathy and may be useful as an indicator of disease activity.

Gene Expression Regulation↗

PubMed1990

[Is hepatitis B virus (HBV) the pathogenic antigen of IgA nephropathy].

IgA nephropathy (IgA N) is one of the commonest glomerular diseases in China, where HBV carrier is not rare. In order to know whether HBsAg or HBcAg may induce IgA N, 105 cases of IgA N from most parts of China were studied. 8 of them were associated with HBs antigenemia. Neither HBsAg or HBcAg could be detected in the glomeruli of these 8 patients with and of 30 patients without HBs antigenemia by PAP method. IgA type anti HBc antibody was also negative in the serum of 21 cases of IgA N regardless of presence of absence of HBs antigenemia. It is concluded that HBsAg or HBcAg could not be confirmed to be pathogenic antigen of IgA N in our series.

Glomerulonephritis, IGA↗

PubMed1994

Charge distribution of plasma IgG and IgG immune complexes in IgA nephropathy.

IgA nephropathy is characterized by a predominant deposition of IgA in the glomerular mesangium. However, in many cases, deposition of IgG also occurs and the concentration of circulating IgG immune complexes is higher than that in controls. To examine further the possible role of the charge of immunoglobulins in the pathogenesis of IgA nephropathy, we used isoelectric focusing (IEF) and densitometry to investigate the charge distribution of plasma IgG and IgG immune complexes in patients with this disease. Blood samples were taken from patients and healthy adults, and plasma and samples treated with 7.0% polyethylene glycol (PEG) were used. All samples were focused with a Multiphor II flatbet electrofocusing unit apparatus on an agarose gel, then immunofixed with polyclonal goat anti-human IgG, and stained with Coomassie blue R 250. The stained gels were analyzed by densitometry. 1. In plasma, the areas of PI 10-8.9 and PI 10-8.6 in IgA nephropathy were higher in the patients than in the controls. 2. In the 7.0% PEG precipitation, the area PI 8.1-6.1 was higher in the patients than in the controls. These findings suggest that a change in charge distribution of IgG and IgG immune complexes may contribute to the pathogenesis of IgA nephropathy.

Adult↗

PubMedDate not supplied

[IgA nephropathy].

IgA nephropathy is glomerular disease first described in 1968 by Berger, named after him Morbus Berger. The disease is characterized by the presence of IgA dominant or codominant immunoglobulin deposits in glomerular mesangium which can be demonstrated by immunofluorescence. Clinical manifestations of IgA nephropathy in the majority of cases is hematuria which can be macro or microscopic, isolated or combined with proteinuria which can be of nephrotic range. In some cases nephrotic syndrome can be the first clinical presentation. In 10% renal insufficiency can be present at the onset of the disease. By light microscopy IgA can manifest any of the histologic phenotypes of immune complex mediated proliferative glomerulonephritis. According to light microscopy findings a classification system have been used to categorize the histologic patterns of IgA nephropathy. Glomerular changes in IgA nephropathy are proliferative and can be focal or diffuse accompanied by crescentic formation in many cases. Immune deposits seen by electron microscopy appear as electron dense deposits most numerous in mesangium.

Glomerulonephritis, IGA↗

PubMedDate not supplied

Histology and immunohistology of IgA nephropathy.

IgA nephropathy is a histologically diverse glomerular disease characterized by mesangial or mesangial plus peripheral glomerular capillary immune complex deposits that contain IgA as the dominant or co-dominant immunoglobulin type. The most common histologic manifestation of IgA nephropathy is mesangial proliferative glomerulonephritis (GN), most often focal but not infrequently diffuse. However, the light microscopic appearance of IgA nephropathy spans the entire range from histologically normal to diffuse proliferative and crescentic glomerulonephritis, much as is the case with lupus nephritis. This review examines the histologic diversity as well as the immunohistologic features of IgA nephropathy.

Antibodies, Anti-Idiotypic↗

PubMed1989

Clearance kinetics and fate of macromolecular IgA in patients with IgA nephropathy.

IgA glomerulonephritis is associated with macromolecules of polymeric IgA in the circulation and mesangial deposits. An impairment in the reticulophagocytic function of patients with IgA nephropathy has been postulated as the potential cause for persistence of IgA immune complexes in the circulation and their eventual glomerular deposition. Since the fate and removal mechanisms of circulating macromolecular IgA are unknown in humans, we examined the blood clearance and organ uptake of purified IgA polymers and macromolecules in patients with IgA nephropathy and normal controls. The IgA macromolecules were prepared by covalent cross-linking of purified human polymeric IgA with a heterobifunctional reagent, N-succinimidyl 3-(2-pyridyldithio) propionate. After intravenous injection, large IgA molecules were removed rapidly from the circulation of patients (t1/2 = 3.8 +/- 1.0 minutes) and controls (t1/2 = 4.9 +/- 1.5 minutes). Dynamic gamma camera scintigraphy revealed the liver as the major organ that mediated the removal of the macromolecular IgA with no significant difference in the rate of hepatic uptake for patients (t1/2 = 3.4 +/- 0.6 minutes) and controls (t1/2 = 3.3 +/- 0.9 minutes). No significant amount of radioactivity could be detected in the lungs, kidneys, and spleen. The small polymers had a slower and similar clearance rates for patients (t1/2 = 29.3 +/- 7.9 h) and controls (t1/2 = 29.0 +/- 8.6 h). These findings have general significance in showing the liver as a major organ for removal of macromolecular IgA. In addition, the results have specific importance in showing that patients with IgA nephropathy do not suffer from an IgA removal dysfunction.

Adolescent↗

PubMed1980

Controlled trial of phenytoin therapy in IgA nephropathy.

IgA nephropathy, a condition thought to cause slowly progressive renal damage, is frequently associated with high serum IgA levels. As phenytoin sodium lowers serum IgA concentrations, a controlled trial of therapy with this drug was conducted over a two-year period in patients with IgA nephropathy. Despite significant depression of serum IgA concentrations in the treatment group, there was no significant change in any other clinical, biochemical or pathological parameter, in either control or treatment groups. Indeed, there was evidence for a slow progression of renal damage in both groups. These observations suggest that the elevated serum IgA concentrations in IgA nephropathy are not of primary pahtogenetic significance but are rather a consequence of a basic abnormality in antigen processing and IgA production.

Adolescent↗

PubMed1990

Role of IgA in IgA nephropathy.

IgA nephropathy (Berger disease) is defined by the dominant or codominant deposition of IgA in the renal mesangium. There is much evidence in vitro to suggest up-regulation of the IgA immune response in patients. Data from tonsillar and bone marrow-derived lymphocytes and from in vivo immunization studies indicate that the primary defect is an up-regulated systemic one, rather than mucosal IgA production. Several lines of evidence suggest that increased IgA production alone is inadequate to explain the pathogenesis of Berger disease. Murine models of IgA nephropathy indicate that local complement activation mediated by deposited IgG is essential for mesangial cell proliferation and subsequent renal injury. Circulating immune complexes from patients with Berger disease contain IgA and IgG within the same lattice. In vitro studies of model immune aggregates containing various mixtures of IgA and IgG indicate that the IgG is the site of complement activation and fixation. The IgA in the aggregate actually inhibits both complement activation and binding to erythrocyte complement receptor CR1. This effect of IgA may prevent effective immune complex clearance. In future studies, more emphasis should be placed on the roles of IgG and complement in the pathogenesis of IgA nephropathy.

Animals↗

PubMed1991

Antigen as mediator of glomerular injury in experimental IgA nephropathy.

IgA immune complexes (IgA-IC) are considered the primary cause of IgA nephropathy. Despite the consistent findings of IgA and frequently C3 glomerular deposits in most patients, the renal histopathologic lesion may vary from mild mesangial involvement to severe sclerosis. In the IgA immune deposits, IgA and C3 are considered to be relatively constant, whereas the composition of the antigen is expected to vary according to its origin. This report explored th possibility that the histopathologic lesion is a function of the antigen in an IgA immune deposit. To test this hypothesis we developed a passive model of IgA nephropathy whereby glomerular IgA deposits can capture, in situ, circulating antigens. In this model, glomerular IgA deposits (IgA/IgA-IC) were induced by administration of a constant amount of IgA anti-dinitrophenyl (antibody) and dinitrophenyl-conjugated IgA anti-phosphorylcholine (PC) as an antigen. The latter also served as antibody to capture, in situ, circulating PC-containing antigens. Mice that received only IgA/IgA-IC developed glomerular IgA and C3 deposits and a focal increase in mesangial cells and matrix, but no evidence of renal damage. A diffuse increase in mesangial cells and matrix developed in mice treated with IgA/IgA-IC and either PC-Ficoll (carbohydrate antigen) or PC conjugate of bovine serum albumin (protein antigen). In contrast, mice that received IgA/IgA-IC and pneumococcal C polysaccharide, a PC-containing antigen, developed severe diffuse mesangial hypercellularity with segmental necrosis and thrombosis. These mice also developed proteinuria and hematuria. Our results demonstrate that the antigen plays a critical role in development of glomerulonephritis associated with IgA-IC.

Animals↗

PubMed1990

[New immunopathogenic aspects of IgA nephropathy].

IgA nephropathy (Berger's disease) has become recognized worldwide as one of the most common of the primary glomerulonephritis. The mesangial granular deposits suggested an immune complex disease. The available data evidence that the IgA circulating immune complexes in these patients are heterogeneous. Recent analysis, performed after dissociating the complexes, found both IgA1 and IgG. In fact, high serum levels of IgA rheumatoid factor and shared antibody idiotypes were found in a large proportion of those patients. A close relationship was noted between the presence of cross-reactive idiotypes on mesangial immunoglobulins and the existence of increase levels of serum idiotypes and many patients have increased rates of IgA synthesis either spontaneously or after stimulation of the peripheral blood mononuclear cells by various mitogens. A lot of abnormalities on B and T lymphocytes, related with the IgA immune regulation, have been described. Most of deposited IgA in the mesangium is polymeric and belongs to the IgA1 class. Patients with IgA nephropathy have very often antibodies against exogenous and endogenous antigens. Among the most frequently found are the antibodies against dietary, viral and bacterial antigens as well as against the Fc and Fab portions of immunoglobulins, nuclear and glomerular antigens. The mechanisms of mesangial damage in IgA nephropathy are not well known. Mesangial cells are capable of producing and releasing various lipidic and proteic mediators. The stimulation of mesangial cells, cultured in vitro by IgA or IgG immune complexes induced the release of PAF, PGE2 and superoxide anion. A better knowledge of the mechanism implicated in the abnormality of IgA immune regulation, as well as of the glomerular inflammation response could afford a new therapeutic approach to this nephropathy.

Antigen-Antibody Complex↗