Rapid, quantitative, and high-sensitivity detection of anti-phospholipase A2 receptor antibodies using a novel CdSe/ZnS-based fluorescence immunosorbent assay

Abstract

Autoantibodies 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.

Engineering innovative interfaces for point-of-care diagnostics

“…As an example, Li et al developed a quantum dot LFA that beat ELISA in speed, ease-of-use, analytical sensitivity (80.9% for the quantum dot LFA and 70.2% for the ELISA), and specificity (100% for the quantum dot LFA and 98.5% for the ELISA) for detection of autoantibodies against M-type phospholipase A2 receptor in human serum samples by using quantum dots made of cadmium selenide and zinc sulfide. [ 37 ] More efficient labeling, the authors claim, is the reason the quantum dot LFA outperformed the enzymatic detection mechanism used in ELISA. Similarly, up-converting phosphor nanoparticles have been used to increase LFA capabilities as POCTs.…”

Secretory expression and purification of recombinant PLA2R epitopes for the detection of anti-PLA2R autoantibody in serum

“…Numerous immunological methods based on antigen–antibody reactions have been established for the initial clinical diagnosis. 17–25 In these studies, either mammalian cells overexpressing full-length PLA2R protein or a soluble form of extracellular PLA2R were capable of recognizing serum anti-PLA2R. Few methods using truncated PLA2R that only contain the dominant epitopes have been reported.…”