Assessment of preeclampsia using assays for free and dissociated placental growth factor
Inventors
Oberoi, Pankaj • Singh, Sharat • Mazloom, Amin
Assignees
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Publication Number
US-11327071-B2
Publication Date
2022-05-10
Expiration Date
Abstract
Described herein are methods, compositions, kits, and systems for detecting free and bound PlGF, and using detection of such species to distinguish between pregnant women with or without preeclampsia or related conditions.
Core Innovation
The invention relates to a method for determining levels of free and dissociated placental growth factor (PlGF) in a biological sample from a pregnant human female subject. The method determines an amount of free PlGF (PlGF-f) in the biological sample, applies a treatment to dissociate PlGF complexes, and determines an amount of dissociated PlGF (PlGF-d).
The approach distinguishes free PlGF from dissociated PlGF by using separate determinations of PlGF-f and PlGF-d in the same biological sample after dissociation. The disclosure centers on dissociation of PlGF complexes, including PlGF:sFLT1 complexes, followed by quantification of the resulting dissociated PlGF species.
The document further describes using a ratio or percentage relationship between free and dissociated PlGF, including % free PlGF, in order to distinguish elevated versus reduced preeclampsia risk or to rule out preeclampsia for defined future intervals. In addition, secondary biomarkers may be included and algorithms may be used in combination with PlGF-f and PlGF-d measurements.
The dissociation and quantification workflow is supported by different immunoassay formats and capture reagent types for measuring PlGF-f and PlGF-d, including capture ELISA, indirect ELISA, TR-FRET, proximity extension, LOCI, electrochemiluminescence, luminescent oxygen channeling, and lateral flow, with capture agents such as aptamers, antibodies, and antigen-binding fragments. Kits and systems are also described that include dissociation reagents and specific binding probes.
Claims Coverage
Independent claim coverage centers on a two-stage measurement of PlGF-f followed by dissociation to measure PlGF-d in a biological sample from a pregnant human female. The claim set includes six inventive features, with dependent features specifying immunoassay modalities, capture-agent types, pregnancy-duration constraints, and dissociation treatments targeting PlGF complexes, including PlGF:sFLT1.
Determine free PlGF then dissociate PlGF complexes
Determining an amount of PlGF-f in the biological sample; applying a treatment to the biological sample to dissociate PlGF complexes; and determining an amount of PlGF-d in the biological sample.
Select an immunoassay format for measuring PlGF-f and PlGF-d
Determining the amounts of PlGF-f and PlGF-d by using an immunoassay selected from capture ELISA, indirect ELISA, TR-FRET assay, proximity extension assay, amplified luminescent proximity (LOCI) assay, electrochemiluminescence immunoassay, luminescent oxygen channeling assay, or lateral flow assay.
Use an aptamer, antibody, or antigen-binding fragment as capture agent
A capture agent comprises an aptamer, or an antibody, or an antigen-binding fragment thereof.
Apply method to subjects with a pregnancy duration of at least 20 weeks
The pregnant human female has been pregnant for at least 20 weeks.
Apply method to subjects with a pregnancy duration of no more than 30 weeks
The pregnant human female has been pregnant for no more than 30 weeks.
Treat sample to prevent PlGF assembly or disable PlGF:sFLT1 complexes
The treatment comprises contacting the biological sample with an agent that prevents PlGF from assembling into a PlGF complex or disables PlGF from a PlGF:sFLT1 complex.
Overall, the claim coverage emphasizes measuring PlGF-f, dissociating PlGF complexes, and then measuring PlGF-d, with further claim refinements specifying immunoassay modalities and capture-agent types, restricting subject pregnancy duration, and defining dissociation treatments that prevent PlGF complex assembly or disable PlGF:sFLT1 complexes.
Stated Advantages
Improved discrimination between preeclampsia and non-preeclampsia using PlGF-f or % free PlGF, as indicated by improved performance metrics (AUC/AUP).
Establishing optimized assay conditions to improve dissociation-dependent measurement behavior influenced by assay temperature and sFLT levels for PlGF-f versus PlGF-d measurement discrimination.
Documented Applications
In vitro diagnostic use for assessing preeclampsia versus non-preeclampsia in pregnant human females, including threshold analysis across gestational windows.
Use of multiplex antigen-binding reagent panels combining PlGF species with additional biomarkers in multiplex homogeneous and multiplex non-homogeneous assay configurations.
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