Non-Invasive Transplant Rejection Detection via Donor DNA
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Solution Overview
Problem
Current methods for monitoring tissue transplantation status, such as histological examination, are invasive, prone to sampling errors, and have low sensitivity, making it difficult to detect early organ rejection, which can lead to increased organ failure and costs.
Innovation Solution
A genetic-based diagnostic assay that utilizes copy number variant (CNV) polymorphisms to detect donor-derived nucleic acids in a recipient's circulation, allowing for non-invasive monitoring of tissue damage and rejection through quantitative PCR, without the need to genotype the donor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If histological examination of biopsied material is used to determine transplantation success, then tissue status can be assessed, but the method is invasive, has high sampling error, low sensitivity, and high cost
Solution Approach 1:
The patent replaces the mechanical/invasive biopsy system with a molecular detection system. Instead of physically removing and examining tissue samples under a microscope, the invention uses PCR-based molecular assays to detect donor-specific DNA sequences in circulating cell-free DNA from blood samples. This substitution eliminates the need for invasive tissue sampling while achieving higher sensitivity in detecting rejection events.
Solution Approach 2:
The patent uses circulating cell-free DNA as an intermediary marker to indirectly assess transplant status. Rather than directly examining the transplanted tissue, the method detects donor-derived DNA fragments that circulate in the recipient's bloodstream following tissue damage or rejection. This intermediary approach allows non-invasive monitoring of graft health with high sensitivity.
2Reliability
If early rejection detection is achieved through current methods, then intervention can be made, but the methods lack the sensitivity to detect early rejection
Solution Approach 1:
The patent changes the detection parameter from macroscopic tissue morphology (histology) to molecular-level DNA sequence detection. By using PCR amplification and sequencing to detect specific donor DNA sequences in circulating cell-free DNA, the method achieves much higher sensitivity and can detect rejection events at earlier stages when only minimal tissue damage has occurred, well before histological changes become apparent.
Solution Approach 2:
The patent replaces the low-sensitivity histological examination system with a high-sensitivity molecular detection system based on PCR and DNA sequencing. This substitution enables detection of rejection at much lower thresholds of tissue damage, allowing for earlier intervention and improved transplant outcomes.
3Measurement precision
If donor and recipient genotyping is performed to detect donor nucleic acids, then rejection can be monitored, but the process becomes complex and requires direct donor genotyping
Solution Approach 1:
The patent extracts and utilizes only the essential information needed for detection - specifically, known polymorphic sites in the donor's genome that can be targeted with specific primers. Rather than performing comprehensive genotyping of both donor and recipient, the method focuses on detecting the presence or absence of specific donor-specific DNA sequences in the recipient's circulation, greatly simplifying the assay while maintaining high detection accuracy.
Solution Approach 2:
Instead of the conventional approach of genotyping both donor and recipient to identify matching and mismatching alleles, the patent inverts the approach by directly detecting donor-specific sequences in the recipient's sample. This reverse strategy eliminates the need for complex comparative genotyping and directly provides information about donor DNA presence and tissue integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables early detection of tissue rejection, facilitating timely immunosuppressive treatment, reducing organ failure, and optimizing the use of donor organs, while providing a cost-effective solution for monitoring transplantation success.
Implementation Method 1
A genetic-based diagnostic assay that utilizes copy number variant (CNV) polymorphisms to detect donor-derived nucleic acids in a recipient's circulation, allowing for non-invasive monitoring of tissue damage and rejection through quantitative PCR
Data Source
AI summary
A method of detecting circulatory nucleic acids from a transplanted tissue in a transplant recipient, the method comprising: amplifying circulatory nucleic acids from a transplanted tissue in a blood sample from the transplant recipient, and detecting amplification of a copy number deletion (CND) polymorphism from the transplanted tissue, and related methods for determining the status of a donor tissue transplanted into a recipient.