On the specificity of assays to detect circulating immunoglobulin A-fibronectin complexes: implications for the study of serologic phenomena in patients with immunoglobulin A nephropathy.

1994 ◽  
Vol 5 (6) ◽  
pp. 1400-1406
Author(s):  
F Eitner ◽  
M Schulze ◽  
R Brunkhorst ◽  
K M Koch ◽  
J Floege
Keyword(s):  
Iga Nephropathy ◽  
Binding Assay ◽  
Immunoglobulin A ◽  
Negative Control ◽  
Plasma Samples ◽  
Binding Assays ◽  
Collagen Binding ◽  
Capture Assay ◽  
Iga Antibody ◽  
Normal Controls

Immunoglobulin A (IgA)-fibronectin complexes have been proposed as specific serologic markers of IgA nephropathy. They have been detected by the use of ELISA composed of an immobilized antifibronectin antibody (or albumin as a negative control) and an enzyme-conjugated anti-IgA antibody (antifibronectin capture assay). By the use of this type of assay, plasma samples from 32 normal controls, 38 IgA nephropathy patients, and 81 patients with other types of glomerulonephritis were analyzed. Extinction values in IgA nephropathy patients were higher (P = 0.06) than in patients with other glomerulonephritis types and significantly higher than in normals. Markedly lower values were obtained when the plates were coated with albumin. However, when the antifibronectin antibody was replaced by normal IgG or F(ab')2 fragments, almost identical extinctions were measured. The use of different antifibronectin antibodies, IgG, ELISA plates, or blocking regimens did not modify these results. Extinction values could not be suppressed by the addition of exogenous fibronectin. Similar extinctions were observed when plasma samples were replaced by physiologic concentrations of fibronectin-free IgA. Extinction values measured in the plasma samples correlated significantly with IgA concentrations in plasma as analyzed by nephelometry. A collagen binding assay, a second type of assay used to measure IgA-fibronectin complexes, also allowed the detection of fibronectin-free IgA, and again, extinctions measured in plasma could not be suppressed by exogenous fibronectin. In conclusion, both antifibronectin capture ELISA and collagen binding assays do not specifically detect only IgA-fibronectin complexes, but also total plasma IgA, which is frequently, but nonspecifically, elevated in IgA nephropathy.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals The role of C1GALT1C1 in lipopolysaccharide-induced IgA1 aberrant O-glycosylation in IgA nephropathy

2010 ◽  
Vol 33 (1) ◽  
pp. 5 ◽  
Author(s):  
Lin-Shen Xie ◽  
Wei Qin ◽  
Jun-Ming Fan ◽  
Jun Huang ◽  
Xi-Sheng Xie ◽  
...  
Keyword(s):  
Correlation Analysis ◽  
Western Blot ◽  
Iga Nephropathy ◽  
Blot Analysis ◽  
Real Time Pcr ◽  
Binding Assay ◽  
Lectin Binding ◽  
Vicia Villosa ◽  
Normal Controls

Purpose: IgA1 aberrant O-glycosylation is one of the main pathogenetic features of IgA nephropathy (IgAN). This study attempted to determine the role of C1GALT1C1 in aberrant IgA1 O-glycosylation induced by lipopolysaccharide (LPS) and identify potential therapeutic targets in IgAN. Methods: Lymphocytes isolated from 22 patients with IgAN and 17 normal controls were cultured for 3 to 7 days with or without LPS and 5-azacytidine (5-AZA). Expression levels of C1GALT1C1 mRNA and protein were measured by real-time PCR and Western blot analysis, respectively. Concentration of IgA1 and level of O-glycosylation were determined by ELISA and Vicia villosa (VV) lectin-binding assay. Correlation analysis was performed between the expression of C1GALT1C1 protein and IgA1 O-glycosylation. Results: Lymphocytes from patients with IgAN secreted more IgA1 than that from normal controls after LPS stimulation (P=0.26, 0.002 and 0.005 on the 3rd, 5th and 7th day, respectively) which could be inhibited by 5-AZA (P=0.001, 0.025 and 0.001 on the 3rd, 5th and 7th day, respectively). Moreover, LPS stimulation could obviously inhibit C1GALT1C1 expression in patients with IgAN (decreased by 71%, 82% and 92% on the 3rd, 5th and 7th day, respectively; P < 0.001), and cause a significant decrease of IgA1 O-glycosylation compared with normal controls (P=0.004, 0.003 and 0.03 on the 3rd, 5th and 7th day, respectively). When 5-AZA was added, the level of C1GALT1C1 expression increased dramatically (1.98, 5.53 and 8.97 times on the 3rd, 5th and 7th day, respectively; P < 0.001) along with an increase of IgA1 O-glycosylation (P=0.295, 0.09 and 0.003 on the 3rd, 5th and 7th day, respectively). However, normal controls showed no significant change in C1GALT1C1 expression and IgA1 O-glycosylation after LPS stimulation (P > 0.05). Conclusion: LPS induced IgA1 aberrant O-glycosylation and suppressed C1GALT1C1 expression in patients with IgAN. Upregulation of C1GALT1C1 expression by 5-AZA could reverse the IgA1 aberrant O-glycosylation. These results suggest that C1GALT1C1 may play a key role in the regulation of IgA1 O-glycosylation.

scholarly journals AB1257 SCREENING FOR IMMUNOGLOBULIN A ANTIBODY REACTIVITY IN EARLY AXIAL SPONDYLOARTHRITIS IDENTIFIES NOVEL ANTIGENIC TARGETS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1920.3-1920
Author(s):  
P. Vandormael ◽  
D. Quaden ◽  
P. Ruytinx ◽  
J. Janssens ◽  
J. Vanhoof ◽  
...  
Keyword(s):  
Axial Spondyloarthritis ◽  
Immunoglobulin A ◽  
Positive Likelihood Ratio ◽  
Phage Display Library ◽  
Mucosal Inflammation ◽  
Plasma Samples ◽  
Research Support ◽  
Antibody Reactivity ◽  
Iga Antibody ◽  
Antigenic Targets

Background:Although autoantibodies are not generally considered to be a hallmark of axial spondyloarthritis (axSpA), increasing evidence suggests the presence of autoantibodies in a subset of axSpA patients. Most of these described antibodies are of the immunoglobulin G (IgG) isotype while other antibody isotypes are less well studied. Antibodies of the IgA isotype can be of interest due to the strong link between gut inflammation and spondyloarthropathies.Objectives:The aim of this study was to identify and characterize novel IgA isotype (auto)antibodies specific for early axSpA patients.Methods:An axSpA cDNA phage display library, representing the antigenic repertoire from axSpA hip synovium, was constructed and screened for reactivity with IgA antibodies in plasma of early axSpA patients (n=10). Using enzyme-linked immunosorbent assays (ELISA), antibody reactivity against 173 identified targets was initially determined in pooled plasma of early axSpA patients (n=60) and healthy controls (HC,n=30), collected at Hasselt University. Antigenic targets that showed increased IgA reactivity in axSpA plasma pools were further validated in individual plasma samples of early axSpA patients (n=79) and HC (n=101).Results:We identified 10 novel Hasselt University (UH) axSpA peptide targets with increased IgA antibody reactivity in pooled axSpA plasma. At present, validation of 8 UH-axSpA-IgA peptide targets in individual plasma samples revealed antibody reactivity against at least one of these targets in 32% of early axSpA patients (25/79) compared to 26% in HC (31/101,p=0.4082). By combining the 3 UH-axSpA-IgA peptides with the highest positive likelihood ratio (LR+) into a panel, an increased overall specificity of 90% (10/101) could be achieved, with an associated sensitivity of 24% (19/79,p=0.0138) resulting in a LR+ of 2.4. Antibody reactivity testing of the remaining 2 UH-axSpA-IgA peptide targets is currently ongoing.Conclusion:The increased reactivity of IgA (auto)antibodies against several novel antigenic peptide targets underscores the role of the humoral immune response in axSpA, and might indicate a potential link with mucosal inflammation. IgA antibody reactivity against these novel peptide targets will be further validated in independent cohorts of early axSpA patients as well as in patients with chronic low back pain.Disclosure of Interests:Patrick Vandormael: None declared, Dana Quaden: None declared, Pieter Ruytinx: None declared, Joyce Janssens: None declared, Johan Vanhoof: None declared, Piet Geusens Grant/research support from: Pfizer, Abbott/Abbvie, Janssen, Celgene, Lilly, Amgen, MSD, UCB, Will, Roche, BMS, Novartis, Sanofi, Consultant of: Pfizer, Abbott/Abbvie, Janssen, Celgene, Lilly, Amgen, MSD, UCB, Will, Roche, BMS, Novartis, Sanofi, Veerle Somers Grant/research support from: Research grant from Pfizer and BMS

Prevalence of IgA Nephropathy: A 10 Years’ Experience from Jinnah Postgraduate Medical Centre, Karachi, Pakistan

2020 ◽  
Keyword(s):  
Body Mass Index ◽  
Iga Nephropathy ◽  
Body Mass ◽  
Immunoglobulin A ◽  
Medical Centre ◽  
Male Dominance ◽  
Clinical Indication ◽  
Glomerular Lesion ◽  
Female Ratio ◽  
Nephritic Syndrome

Background: Immunoglobulin A (IgA) is considered the most frequently dealt primary glomerulonephritis, worldwide. The Berger’s disease or IgA nephropathy is a mesangial proliferative glomerulonephritis characterized by deposition of immunoglobulin A in kidneys. The aim of the study was to report the prevalence of IgA nephropathy and the associated parameters (age, gender, and body mass index) in our population. Methods: This was a retrospective study, accomplished at Jinnah Postgraduate Medical Centre, Karachi, Pakistan, from June 2009-May 2019. The histopathology and immunofluorescence of renal biopsies of 519 patients were studied and the prevalence of biopsy proven IgA nephropathy was determined. The Chi-square test was used for association of biopsy proven IgA nephropathy with age, gender, and body mass index. A p-value of 0.05 or less was considered statistically significant. Results: A total of 519 biopsies were studied, out of those, only 4 (0.8%) had IgA nephropathy with male dominance in the last 10 years at Karachi, Pakistan. Male to female ratio was found to be 3:1. The most common clinical indication for renal biopsy was isolated hematuria in 50% of the cases followed by acute kidney injury and nephritic syndrome with 25% each respectively. Most of the patients suffering from proteinuria (> 3.5gm/24 hours), microscopic hematuria in 80% cases, high blood pressure in 50% cases, with other associated symptoms including edema, gastrointestinal, and skin-related symptoms reported. Conclusion: Immunoglobulin A (IgA) nephropathy is not a commonly diagnosed glomerular lesion. Further large-scale cohorts can aid in determining the other factors associated with a low frequency of IgA nephropathy. Keywords: Biopsy; Glomerulonephritis; Immunoglobulin A; Nephropathy.

scholarly journals Characteristics of patients with coexisting DNAJB9-associated fibrillary glomerulonephritis and IgA nephropathy

2020 ◽  
Author(s):  
Samar M Said ◽  
Alejandro Best Rocha ◽  
Anthony M Valeri ◽  
Mohamad Sandid ◽  
Anhisekh Sinha Ray ◽  
...  
Keyword(s):  
Iga Nephropathy ◽  
Immunoglobulin A ◽  
Renal Survival ◽  
Hepatitis C Infection ◽  
Clinicopathologic Characteristics ◽  
Fibrillary Glomerulonephritis ◽  
Kaplan Meier ◽  
Dense Deposits ◽  
End Stage

Abstract Background Coexistence of fibrillary glomerulonephritis (FGN) and immunoglobulin A (IgA) nephropathy (IgAN) in the same kidney biopsy (FGN–IgAN) is rare, and the clinicopathologic characteristics and outcome of this dual glomerulopathy are unknown. Methods In this study, 20 patients with FGN–IgAN were studied and their characteristics were compared with 40 FGN and 40 IgAN control patients. Results Concurrent IgAN was present in 1.8% of 847 consecutive FGN cases and was the second most common concurrent glomerulopathy after diabetic nephropathy. FGN–IgAN patients were overwhelmingly White (94%) and contrary to FGN patients were predominantly (60%) males. Compared with IgAN patients, FGN–IgAN patients were older, had higher proteinuria, a higher incidence of renal insufficiency, and a lower incidence of microhematuria and gross hematuria at diagnosis. Six (30%) patients had malignancy, autoimmune disease or hepatitis C infection, but none had a secondary cause of IgAN or clinical features of Henoch–Schonlein purpura. Histologically, all cases exhibited smudgy glomerular staining for immunoglobulin G and DnaJ homolog subfamily B member 9 (DNAJB9) with corresponding fibrillary deposits and granular mesangial staining for IgA with corresponding mesangial granular electron-dense deposits. On follow-up (median 27 months), 10 of 18 (56%) FGN–IgAN patients progressed to end-stage kidney disease (ESKD), including 5 who subsequently died. Serum creatinine at diagnosis was a poor predictor of renal survival. The proportion of patients reaching ESKD or died was higher in FGN–IgAN than in IgAN. The median Kaplan–Meier ESKD-free survival time was 44 months for FGN–IgAN, which was shorter than IgAN (unable to compute, P = 0.013) and FGN (107 months, P = 0.048). Conclusions FGN–IgAN is very rare, with clinical presentation and demographics closer to FGN than IgAN. Prognosis is guarded with a median renal survival of 3.6 years. The diagnosis of this dual glomerulopathy requires careful evaluation of immunofluorescence findings, and electron microscopy or DNAJB9 immunohistochemistry.

scholarly journals The VP5 Domain of VP4 Can Mediate Attachment of Rotaviruses to Cells

2000 ◽  
Vol 74 (2) ◽  
pp. 593-599 ◽  
Author(s):  
Selene Zárate ◽  
Rafaela Espinosa ◽  
Pedro Romero ◽  
Ernesto Méndez ◽  
Carlos F. Arias ◽  
...  
Keyword(s):  
Cell Surface ◽  
Binding Assay ◽  
Cell Attachment ◽  
Wild Type ◽  
Binding Assays ◽  
Virus Binding ◽  
Binding Characteristics ◽  
Surface Receptors ◽  
Infectivity Assay ◽  
Fusion Products

ABSTRACT Some animal rotaviruses require the presence of sialic acid (SA) on the cell surface to infect the cell. We have isolated variants of rhesus rotavirus (RRV) whose infectivity no longer depends on SA. Both the SA-dependent and -independent interactions of these viruses with the cell are mediated by the virus spike protein VP4, which is cleaved by trypsin into two domains, VP5 and VP8. In this work we have compared the binding characteristics of wild-type RRV and its variant nar3 to MA104 cells. In a direct nonradioactive binding assay, both viruses bound to the cells in a saturable and specific manner. When neutralizing monoclonal antibodies directed to both the VP8 and VP5 domains of VP4 were used to block virus binding, antibodies to VP8 blocked the cell attachment of wild-type RRV but not that of the variant nar3. Conversely, an antibody to VP5 inhibited the binding of nar3 but not that of RRV. These results suggest that while RRV binds to the cell through VP8, the variant does so through the VP5 domain of VP4. This observation was further sustained by the fact that recombinant VP8 and VP5 proteins, produced in bacteria as fusion products with glutathione S-transferase, were found to bind to MA104 cells in a specific and saturable manner and, when preincubated with the cell, were capable of inhibiting the binding of wild-type and variant viruses, respectively. In addition, the VP5 and VP8 recombinant proteins inhibited the infectivity of nar3 and RRV, respectively, confirming the results obtained in the binding assays. Interestingly, when the infectivity assay was performed on neuraminidase-treated cells, the VP5 fusion protein was also found to inhibit the infectivity of RRV, suggesting that RRV could bind to the cell through two sequential steps mediated by the interaction of VP8 and VP5 with SA-containing and SA-independent cell surface receptors, respectively.

scholarly journals A Case of Hepatic Glomerulosclerosis with Monoclonal IgA1-κ Deposits

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Yusuke Okabayashi ◽  
Nobuo Tsuboi ◽  
Naoko Nakaosa ◽  
Kotaro Haruhara ◽  
Go Kanzaki ◽  
...  
Keyword(s):  
Liver Cirrhosis ◽  
Iga Nephropathy ◽  
Functional Decline ◽  
Immunoglobulin A ◽  
Myeloproliferative Disorders ◽  
Common Finding ◽  
Definitive Evidence ◽  
Number Of Patients ◽  
Glomerular Lesions ◽  
Laboratory Examinations

Glomerular immunoglobulin A (IgA) deposition is a common finding in hepatic glomerulosclerosis; thus, this disease is also called hepatic IgA nephropathy. However, only a small number of patients with hepatic IgA nephropathy have active glomerular lesions, so functional decline is slow in most cases. In this report, we describe a 60-year-old man who developed nephrotic syndrome and progressive renal impairment during follow-up for alcoholic liver cirrhosis. A renal biopsy showed a membranoproliferative glomerulonephritis-like pattern; diffuse double-contours of the glomerular basement membrane and focal active glomerular lesions with moderate-to-severe endocapillary proliferation and fibrocellular crescents. Immunofluorescence findings revealed granular staining for monoclonal IgA1-κ and C3 on the peripheral capillary walls. Laboratory examinations did not reveal any definitive evidence of myeloproliferative disorders. Therefore, this case may represent a previously unrecognized etiology of renal injury in relation to liver cirrhosis that is characterized by monoclonal IgA1-κ deposits and proliferative glomerulonephritis.

scholarly journals Performance evaluation of the Simtomax® CoronaCheck rapid diagnostic test

2020 ◽  
Author(s):  
P. J. Ducrest ◽  
A. Freymond ◽  
J.-M. Segura
Keyword(s):  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Diagnostic Performance ◽  
High Sensitivity ◽  
High Specificity ◽  
Negative Control ◽  
List Type ◽  
Plasma Samples ◽  
Rt Pcr ◽  
Two Samples

AbstractThe aim of this study was to evaluate the diagnostic performance of Simtomax® CoronaCheck, a serology rapid diagnostic test (RDT) for the detection of IgG and IgM against SARS-CoV-2. 48 plasma samples positive for SARS-CoV-2 based on RT-PCR and 98 negative control samples were studied. Diagnostic performance of the IgG/IgM RDT was assessed against RT-PCR and the electro-chemiluminescence immunoassay (ECLIA) Elecsys® Anti-SARS-CoV-2 total Ig. Overall, the RDT sensitivity was 92% (95% confidence interval [95%CI]: 79-97), specificity 97% (95% CI: 91-99%), PPV 94% (95% CI: 81-98) and the NPV 96% (95% CI: 89-99). When considering only samples collected ≥ 15 days post-symptoms (DPS), the sensitivity increased to 98% (95%CI: 86-100) and the specificity was 97% (95% CI: 91-99%). Two samples with 180 DPS were still positive for IgG. Globally, this IgG/IgM RDT displayed a high diagnostic accuracy for SARS-CoV-2 IgG/IgM detection in plasma samples in high COVID-19 prevalence settings. It could be effectively used, in absence of facilities for routine diagnostic serology, for samples with a DPS between 15 and 180 days.Highlights–The rapid diagnostic test Simtomax CoronaCheck displays a high sensitivity of 98% and a high specificity of 97% for SARS-CoV-2 IgG/IgM detection in plasma samples after 15 days post-symptoms.–The rapid diagnostic test Simtomax CoronaCheck can detect SARS-CoV-2 antibodies in plasma up to 180 days after symptom onset.–The rapid diagnostic test Simtomax CoronaCheck could be effectively used as an alternative to serological analysis using laboratory facilities.

scholarly journals Immunoglobulin A Nephropathy as the First Clinical Presentation of Wilson Disease: A Case Report and Literature Review

2021 ◽  
Author(s):  
Yong-Zhe Zhang ◽  
Geng Jian ◽  
Ping He ◽  
Rui Yu ◽  
Mi Tian ◽  
...  
Keyword(s):  
Renal Function ◽  
Iga Nephropathy ◽  
Wilson Disease ◽  
Genetic Disorder ◽  
Immunoglobulin A ◽  
Elevated Serum ◽  
Clinical Manifestations ◽  
Kidney Injury ◽  
Copper Metabolism ◽  
Normal Liver

Abstract Background: Wilson disease (WD) is a rare genetic disorder of copper metabolism. The difference in copper tissue accumulation lead to various clinical manifestations, including some atypical presentations. The complex clinical picture makes it easy to miss and misdiagnose, even delay the best chance for treatment. Case presentation: A 26-year-old male patient who had nephritis-range proteinuria and elevated serum creatinine. The renal pathology indicated Immunoglobulin A (IgA) nephropathy and tubular injury which was inconsistent with glomerular lesions. Cirrhosis was also detected by imaging examination. Considering both kidney injury and liver damage, WD was suspected. According to further detected results of abnormal copper metabolism, corneal Kayser-Fleischer rings(K-F rings), and genetic disorder of ATP7B gene, he was finally diagnosed as a case of WD.The patient was given oral penicillamine and zinc sulfate daily and he was also prescribed losartan to control proteinuria on the premise of monitoring renal function and blood pressure. During the 2 years follow-up, the patient’s 24h uric cooper dropped to normal. The sign of tremor hands disappeared. The Urine protein and renal function keep stable. The patient had normal liver function and maintained good quality of daily life. Conclusions: In some cases, IgA nephropathy patients with suspicious and unexplained neurological and liver symptoms cannot be ignored. They may eventually be diagnosed with WD.

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