# US 11,112,403 B2 · Assessment of preeclampsia using assays for free and dissociated placental growth factor

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- Number: US 11,112,403 B2
- Document ID: US11112403B2
- Status: Granted
- Kind: B2
- Application number: 17/119,410
- Filed: 2020-12-11
- Published: 2021-06-10
- Granted: 2021-09-07
- Earliest claimed: 2019-12-04
- Assignees: Progenity, Inc.
- Applicants: Progenity, Inc.
- Inventors: Pankaj Oberoi; Sharat Singh; Amin Mazloom
- Web page: https://patentgrep.com/patent/US11112403B2

## CPC

- G01N 33/5375: {by changing the physical or chemical properties of the medium or immunochemicals, e.g. temperature, density, pH, partitioning}
- G01N 33/6863: {Cytokines, i.e. immune system proteins modifying a biological response such as cell growth proliferation or differentiation, e.g. TNF, CNF, GM-CSF, lymphotoxin, MIF or their receptors}
- G01N 33/689: {related to pregnancy or the gonads}
- G01N 33/74: involving hormones {or other non-cytokine intercellular protein regulatory factors such as growth factors, including receptors to hormones and growth factors}
- G01N 2333/471: Pregnancy proteins, e.g. placenta proteins, alpha-feto-protein, pregnancy specific beta glycoprotein
- G01N 2800/368: Pregnancy complicated by disease or abnormalities of pregnancy, e.g. preeclampsia, preterm labour
- G01N 2800/50: Determining the risk of developing a disease
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## 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.

## Claims

### Claim 1

A method for determining levels of free and dissociated PlGF in a biological sample from a pregnant human female subject, the method comprising:
(a) isolating a first aliquot of the biological sample for the detection of PlGF-f and a second aliquot of the biological sample for the detection of PlGF-d;
(b) determining an amount of PlGF-f in the first aliquot;
(c) applying a treatment to the second aliquot to dissociate PlGF complexes; and
(d) determining an amount of PlGF-d in the second aliquot.

### Claim 2 (depends on 1)

The method of claim 1, further comprising determining a ratio of the amounts of PlGF-f and PlGF-d.

### Claim 3 (depends on 1)

The method of claim 1, wherein the biological sample has not been stored at a temperature above about 20° C.

### Claim 4 (depends on 1)

The method of claim 1, wherein the amount of PlGF-f and the amount of PlGF-d are determined using the same reagents.

### Claim 5 (depends on 1)

The method of claim 1, wherein the PlGF complex comprises PlGF and s-FLT.

### Claim 6 (depends on 1)

The method of claim 1, wherein the treatment is applied for at least 5, 10, 15, 20, 25, 30, 40, 50, 60, 90, or 120 minutes.

### Claim 7 (depends on 1)

The method of claim 1, wherein the treatment comprises increasing the temperature of the second portion of the biological sample.

### Claim 8 (depends on 7)

The method of claim 7, wherein the treatment comprises increasing the temperature to at least 30° C. for at least 1 hour.

### Claim 9 (depends on 1)

The method of claim 1, wherein the treatment comprises increasing or decreasing the pH of the second portion of the biological sample.

### Claim 10 (depends on 1)

The method of claim 1, wherein the treatment comprises contacting the second portion of the biological sample with an agent that prevents PlGF from assembling into a PlGF complex or disables PlGF from a PlGF:sFLT1 complex.

### Claim 11 (depends on 10)

The method of claim 10, wherein the agent is selected from: a surfactant, a detergent, a chaotropic agent, a PlGF-binding protein, and an s-FLT-binding protein.

### Claim 12 (depends on 1)

The method of claim 1, wherein the method has a LLOQ for PlGF of 20 pg/ml or less.

### Claim 13 (depends on 1)

The method of claim 1, wherein the biological sample is blood, serum, plasma, amniotic fluid, or urine.

### Claim 14 (depends on 1)

The method of claim 1, wherein the biological sample is serum or plasma.

### Claim 15 (depends on 1)

The method of claim 1, wherein the pregnant human female has been pregnant for at least 20 weeks.

### Claim 16 (depends on 15)

The method of claim 15, wherein the pregnant human female has been pregnant for no more than 30 weeks.

### Claim 17 (depends on 1)

The method of claim 1, wherein the amount of PlGF-f, PlGF-d, or both is determined by an immunoassay.

### Claim 18 (depends on 17)

The method of claim 17, wherein the immunoassay is selected from a capture ELISA, an indirect ELISA, a TR-FRET assay, a proximity extension assay, an amplified luminescent proximity (LOCI) assay, an electrochemiluminescence immunoassay, a luminescent oxygen channeling assay, or a lateral flow assay.

### Claim 19 (depends on 1)

The method of claim 1, wherein (b) or (d) involve contacting the first aliquot, second aliquot, or both with a capture reagent.

### Claim 20 (depends on 19)

The method of claim 19, wherein the capture agent comprises an antibody or an antigen-binding fragment thereof.