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Research article
Highly Specific and Ultrasensitive Plasma Test Detects Abeta(1-42) and Abeta(1-40) in Alzheimer’s Disease
Elisabeth H Thijssen
Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam
Corresponding Author
ORCiD: https://orcid.org/0000-0002-9723-5441
License:
This work is licensed under a CC BY 4.0 License. Read Full License
BACKGROUND
Plasma biomarkers that reflect specific amyloid beta (Abeta) proteoforms are essential to monitor treatment effects of Alzheimer’s disease (AD) therapies. Our aim was to develop and validate ready-to-use Simoa ‘Amyblood’ assays that measure full length Abeta1-42 and Abeta1-40 and compare their performance with two commercial assays.
METHODS
Linearity, intra- and inter-assay %CV were compared between Amyblood, Quanterix Simoa triplex, and Euroimmun ELISA. Sensitivity and selectivity were assessed for Amyblood and the Quanterix triplex. Clinical performance was assessed in CSF biomarker confirmed AD (n=43, 68±6 years) and controls (n=42, 62±5 years).
RESULTS
Prototype and Amyblood showed similar calibrator curves and differentiation (20 AD vs 20 controls, p<0.001). Amyblood, Quanterix triplex, and ELISA showed similar linearity (96%-122%) and intra-assay %CVs (≤3.1%). A minor non-specific signal was measured with Amyblood of +2.4 pg/mL Abeta1-42 when incubated with 60 pg/mL Abeta1-40. A substantial non-specific signal of +24.7 pg/mL Abetax-42 was obtained when 40 pg/mL Abeta3-42 was measured with the Quanterix triplex. Selectivity for Abeta1-42 at physiological Abeta1-42 and Abeta1-40 concentrations was 125% for Amyblood and 163% for Quanterix. Amyblood and Quanterix ratios (p<0.001) and ELISA Abeta1-42 concentration (p=0.025) could differentiate AD from controls.
CONCLUSIONS
We successfully developed and upscaled a prototype to the Amyblood assays with similar technical and clinical performance as the Quanterix triplex and ELISA, but better specificity and selectivity than the Quanterix triplex assay. These results suggest leverage of this specific assay for monitoring treatment response in trials.
Keywords
Plasma biomarkers, amyloid beta, Alzheimer’s disease, commercial assays
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This is a preprint. It has not completed peer review.
Research article
Highly Specific and Ultrasensitive Plasma Test Detects Abeta(1-42) and Abeta(1-40) in Alzheimer’s Disease
Elisabeth H Thijssen
Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam
Corresponding Author
ORCiD: https://orcid.org/0000-0002-9723-5441
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
History
CURRENT STATUS: Posted
Version 1
Posted 18 Sep, 2020
No community comments so far
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Cellular & Molecular Neuroscience
License:
This work is licensed under a CC BY 4.0 License. Read Full License
BACKGROUND
Plasma biomarkers that reflect specific amyloid beta (Abeta) proteoforms are essential to monitor treatment effects of Alzheimer’s disease (AD) therapies. Our aim was to develop and validate ready-to-use Simoa ‘Amyblood’ assays that measure full length Abeta1-42 and Abeta1-40 and compare their performance with two commercial assays.
METHODS
Linearity, intra- and inter-assay %CV were compared between Amyblood, Quanterix Simoa triplex, and Euroimmun ELISA. Sensitivity and selectivity were assessed for Amyblood and the Quanterix triplex. Clinical performance was assessed in CSF biomarker confirmed AD (n=43, 68±6 years) and controls (n=42, 62±5 years).
RESULTS
Prototype and Amyblood showed similar calibrator curves and differentiation (20 AD vs 20 controls, p<0.001). Amyblood, Quanterix triplex, and ELISA showed similar linearity (96%-122%) and intra-assay %CVs (≤3.1%). A minor non-specific signal was measured with Amyblood of +2.4 pg/mL Abeta1-42 when incubated with 60 pg/mL Abeta1-40. A substantial non-specific signal of +24.7 pg/mL Abetax-42 was obtained when 40 pg/mL Abeta3-42 was measured with the Quanterix triplex. Selectivity for Abeta1-42 at physiological Abeta1-42 and Abeta1-40 concentrations was 125% for Amyblood and 163% for Quanterix. Amyblood and Quanterix ratios (p<0.001) and ELISA Abeta1-42 concentration (p=0.025) could differentiate AD from controls.
CONCLUSIONS
We successfully developed and upscaled a prototype to the Amyblood assays with similar technical and clinical performance as the Quanterix triplex and ELISA, but better specificity and selectivity than the Quanterix triplex assay. These results suggest leverage of this specific assay for monitoring treatment response in trials.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5