CLL IGHV Mutation Kits for Template-Specific Sequencing
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Solution Overview
Problem
Existing methods for determining the mutational status of immunoglobulin heavy chain variable region (IGHV) genes in chronic lymphocytic leukemia (CLL) suffer from high failure rates due to the use of suboptimal primers, particularly in cases where the IGHJ region is mutated, leading to incomplete sequencing and inaccurate assessment.
Innovation Solution
A methodology using specific primer combinations for PCR amplification of IGHV regions, tailored for genomic DNA (gDNA) and complementary DNA (cDNA), combined with next-generation sequencing (NGS) or Sanger sequencing, ensuring complete amplification and accurate determination of IGHV mutational status, including an internal control for primer efficiency validation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If suboptimal primers are used for PCR amplification of IGHV regions, then the device complexity is reduced, but the measurement precision and reliability deteriorate due to high failure rates in cases where the IGHJ region is mutated
Solution Approach 1:
The patent divides the primer design into multiple specific combinations (first and second combinations) tailored for different template types (gDNA and cDNA). Each combination is optimized for specific regions: the first combination targets IGHV-L2 and IGHJ for gDNA, while the second combination targets IGHV-L1 and IGHC for cDNA. This segmentation allows accurate amplification in cases where IGHJ region mutations would otherwise cause failure, thereby improving measurement precision without requiring a single complex universal primer set.
Solution Approach 2:
The patent applies local quality by designing primers with specific binding characteristics for different regions. The forward primers are designed to bind to specific IGHV leader regions (L1 or L2) while reverse primers bind to IGHJ or IGHC regions respectively. This localized optimization ensures that each primer combination is specifically suited for its intended template type, improving amplification success rates and measurement accuracy for IGHV mutational status determination.
2Reliability
If a single primer combination is used for both gDNA and cDNA templates, then the ease of operation is improved, but the reliability deteriorates due to incomplete amplification when IGHJ region is mutated
Solution Approach 1:
The patent implements a dynamic protocol where the choice of primer combination is adapted based on the template type (gDNA or cDNA). The method dynamically selects the appropriate primer set: using the first combination for gDNA templates and the second combination for cDNA templates. This dynamic adaptation ensures high reliability of amplification by matching the primer characteristics to the template source, while maintaining ease of operation through clear guidelines for selection based on template type.
Solution Approach 2:
The patent changes key parameters of the PCR system by providing different primer sequences optimized for different templates. The first primer combination uses forward primers targeting IGHV-L2 and reverse primers targeting IGHJ, while the second combination uses forward primers targeting IGHV-L1 and reverse primers targeting IGHC. This parameter change in primer design ensures reliable amplification across different template types, particularly improving success rates when IGHJ region mutations are present.
3Measurement precision
If comprehensive primer combinations are used to cover all IGHV functional genes, then the measurement precision is improved, but the loss of time increases due to validation across multiple laboratories
Solution Approach 1:
The patent performs preliminary action by providing pre-validated primer combinations that have been tested and optimized before clinical use. The primer sets are designed to cover all functional IGHV genes with proven binding efficiency, and the protocol includes pre-established guidelines for template selection and amplification conditions. This preliminary optimization reduces the time required for validation across laboratories, as the core methodology is already established and proven to deliver high measurement precision for IGHV mutational status determination.
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
The method achieves a high success rate in determining CLL mutational status, validated across multiple laboratories, providing reliable and standardized assessment of IGHV genes, distinguishing unmutated and mutated CLL types.
Implementation Method 1
A methodology using specific primer combinations for PCR amplification of IGHV regions, tailored for genomic DNA (gDNA) and complementary DNA (cDNA)
Data Source
AI summary
The present invention relates to kits for determining the mutational status of a patient suffering from CLL from gDNA or cDNA extracted from a biological sample of said patient by NGS or Sanger sequencing, comprising forward and reverse amplification primers, and optionally an internal control containing a mixture of nucleic acid molecules encoding productive clonal IGH rearrangement representative of all IGHV segments. It further relates to methods for determining the mutational status of a patient suffering from CLL from a biological sample of said CLL patient using such kits. Such kits and methods are useful for the management of CLL, and especially of the prognosis and treatment choice of CLL patients.