EVALUATION OF A RECENTLY DEVELOPPED ENZYME LINKED IMMUNOSORBENT ASSAY FOR THE DETERMINATION OF ANTI-PHOSPHOLIPASE A2 RECEPTOR ANTIBODIES

Author(s):  
Anne-Sophie Messiaen
2020 ◽  
Author(s):  
Chenxi Li ◽  
Manyun Qian ◽  
Qiaozhen Hong ◽  
Xiaohong Xin ◽  
Zichun Sun ◽  
...  

Abstract Autoantibodies against M-type phospholipase A2 receptor (PLA2R) are specific biomarkers for idiopathic membranous nephropathy (IMN) and their quantification has been helpful to monitor disease activity. In this study, we describe a highly sensitive and rapid quantum dots-based immunochromatography assay (QD-ICA) for quantifying PLA2R autoantibodies. Serum samples from 135 biopsy-confirmed patients with nephrotic syndrome were analyzed for PLA2R autoantibodies using the novel QD-ICA as well as enzyme-linked immunosorbent assay (ELISA). The detection sensitivity and specificity of QD-ICA (80.9 and 100%, respectively) exceeded those of ELISA (72.1 and 98.5%, respectively). The optimum cut-off value of QD-ICA was 18.18 RU/mL and limit of detection was 2.86 relative units/mL. The novel QD-ICA outperforms ELISA in detecting PLA2R autoantibodies, with shorter detection time, fewer steps, smaller equipment size, and broader testing application, suggesting its capability to improve IMN diagnosis and monitor patient response to treatment.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chenxi Li ◽  
Manyun Qian ◽  
Qiaozhen Hong ◽  
Xiaohong Xin ◽  
Zichun Sun ◽  
...  

AbstractAutoantibodies against M-type phospholipase A2 receptor (PLA2R) serve as specific biomarkers for idiopathic membranous nephropathy (IMN), and its quantification helps monitor disease activity. In this study, we describe a rapid and highly sensitive quantum dots-based immunochromatography assay (QD-ICA) for quantifying PLA2R autoantibodies. Serum samples from 135 biopsy-confirmed patients with nephrotic syndrome were analyzed for PLA2R autoantibodies using the novel QD-ICA as well as commercialized enzyme-linked immunosorbent assay (ELISA). Areas under the receiver operating characteristic curve (AUC-ROC) of QD-ICA were significantly greater than those of ELISA (91.1% [95% CI 85.9–96.3%] and 83.9% [95% CI 76.5–91.2%] respectively; p < 0.01). The detection sensitivity and specificity of QD-ICA (80.9% [95% CI 69.2–89.0%] and 100% [95% CI 93.2–100.0%], respectively) exceeded those of ELISA (72.1% [95% CI 59.7–81.9%] and 98.5% [95% CI 90.9–100.0%], respectively). The optimum cut-off value of QD-ICA was 18.18 relative units (RU)/mL, and the limit of detection was 2.86 RU/mL. The novel QD-ICA outperforms ELISA in detecting PLA2R autoantibodies, with shorter detection time, fewer steps, smaller equipment size, and broader testing application, suggesting its capability to improve IMN diagnosis and monitor patient response to treatment.


Author(s):  
J Grøndahl-HANSEN ◽  
N Agerlin ◽  
L S Nielsen ◽  
K Danø

An enzyme-linked immunosorbent assay (ELISA) was developed for the measurement of human urokinase-type plasminogen activator (u-PA) in plasma and serum. Microtiter plates were coated with a monoclonal antibody and incubated with standard or sample. Bound u-PA was quantitated with polyclonal antibodies conjugated with biotin, followed by avidin-peroxidase. The assay was 10-fold as sensitive as other previously reported ELISAs, the detection limit being approximately 1 pg of u-PA in a volume of 100 μl with a linear dose-response up to 15 pg of u-PA. The assay detected active u-PA and its inactive proenzyme form equally well and the recovery of both forms was higher than 90% in plasma. A variety of structurally related proteins, including t-PA, were tested, but no reaction with proteins other than u-PA and its amino-terminal degradation product were observed. The intra-assay and inter-assay coefficients of variation for determination of u-PA in plasma were 7.6% and 8.4%, respectively. The assay was equally applicable to serum. The values obtained with plasma and serum were similar, and the results were not affected by small variations in the preparation of the samples. The ELISA was used to measure the concentration of u-PA in plasma from 34 healthy donors. The mean values for u-PA in plasma from healthy donors was 1.1 ng/ml ± 0.3 ng/ml (SD) (range 0.6 - 1.5 ng/ml). No significant differences were found between men and women and no correlation between u-PA concentration and age could be demonstrated.The mean u-PA concentration in plasma from healthy donors obtained in this study is substantially lower than that reported by others. This might be due to different methods of determination of the protein content of the standard preparations or to differences in the specificity of the assays.


1990 ◽  
Vol 10 (4) ◽  
pp. 439-448 ◽  
Author(s):  
Won O. Song ◽  
Allen Smith ◽  
Carl Wittwer ◽  
Bonita Wyse ◽  
Gaurth Hansen

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