Tuberculosis Diagnosis via Multi-Parameter Flow Cytometry
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Solution Overview
Problem
Current diagnostic methods for tuberculosis (TB) face challenges in distinguishing between active and latent infections, predicting progression to active TB, and accurately determining TB disease activity, especially in HIV-co-infected individuals and those with extrapulmonary TB, due to low specificity and sensitivity of existing tests.
Innovation Solution
A method involving the simultaneous measurement of cellular phenotype and function using multi-parameter flow cytometry to identify specific subsets of CD4+ T-cells that secrete TNF-α without IFN-γ, and are CD45RA−CCR7−CD127−, providing a detailed immune response profile that correlates with TB disease stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If immune-based diagnostic assays (TST or IGRAs) are used to detect TB infection, then the presence of infection can be demonstrated, but the ability to distinguish between active and latent TB is poor due to low specificity and sensitivity
Solution Approach 1:
The patent segments the diagnostic process into multiple distinct steps: initial screening with TST or IGRA, followed by phenotypic analysis of T-cell subsets using flow cytometry, and finally functional assessment of cytokine production. This segmentation allows each step to contribute specific information, progressively refining the diagnosis from simple infection detection to precise active vs. latent differentiation, thereby improving measurement precision without overwhelming complexity at any single stage.
Solution Approach 2:
The patent transitions from traditional single-parameter immune assays to multi-dimensional flow cytometry analysis. By measuring multiple phenotypic markers (CD45RA, CCR7, CD127) and functional parameters (cytokine production) simultaneously across different T-cell subsets, the diagnosis moves from a one-dimensional yes/no infection status to a multi-dimensional profile that precisely distinguishes active from latent TB, significantly improving diagnostic accuracy.
2Measurement precision
If microbiological culture is used as the gold standard for diagnosing active TB, then accurate diagnosis can be achieved, but the method is time-consuming and difficult to interpret in paucibacillary disease
Solution Approach 1:
The patent performs preliminary phenotypic characterization of T-cell subsets and assessment of immune response patterns before relying on time-consuming microbiological culture. By evaluating CD45RA−CCR7−CD127− T-cell subsets and their cytokine production capacity in advance, the method provides early indicators of active TB that can guide clinical decision-making and reduce reliance on prolonged culture procedures, thereby decreasing overall diagnosis time while maintaining accuracy.
Solution Approach 2:
The patent replaces the mechanical/biological process of microbiological culture with an immunological assay system based on flow cytometry. This substitution eliminates the need for prolonged bacterial growth and manual interpretation of paucibacillary samples, providing rapid automated analysis of immune responses that correlates with active TB status, thus achieving the same diagnostic goal without the time and interpretive challenges of culture.
3Productivity
If PCR-based approaches (e.g., GeneXpert) are used for rapid TB diagnosis, then quicker results are obtained, but the ability to distinguish active from latent TB is lost
Solution Approach 1:
The patent merges the rapid detection capability of molecular methods with the disease activity differentiation power of immunological assays. By combining phenotypic analysis of T-cell subsets (CD45RA−CCR7−CD127−) with functional assessment of cytokine production, the method achieves both speed and precision, distinguishing active from latent TB while maintaining rapid turnaround time, thus resolving the trade-off between productivity and measurement precision.
Solution Approach 2:
The patent creates a composite diagnostic approach that integrates multiple assay types (phenotypic flow cytometry and functional cytokine assessment) into a unified diagnostic system. This composite method leverages the strengths of each component—rapid cell surface marker detection combined with functional immune response evaluation—to simultaneously achieve high diagnosis speed and accurate differentiation of TB disease activity, overcoming the limitations of single-method approaches.
4Reliability
If multiple invasive tests (CT with contrast, bronchoscopy, biopsy, PET scanning) are performed to investigate TB infection, then comprehensive evaluation can be achieved, but the process becomes time-consuming, expensive, and more invasive for patients
Solution Approach 1:
The patent develops a universal blood-based immunological assay that can evaluate TB infection status, differentiate active from latent disease, and assess disease activity across various TB manifestations (pulmonary, extrapulmonary, HIV-coinfected) through a single non-invasive blood draw. This multi-functional test replaces the need for multiple site-specific invasive procedures, maintaining comprehensive evaluation capability while dramatically reducing patient burden and improving ease of operation.
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 achieves a high sensitivity of 100% and specificity of 93% in differentiating active from latent TB, and stratifies individuals by risk of progression, offering the most accurate proxy for TB disease activity to date, independent of HIV co-infection and disease site.
Implementation Method 1
simultaneous measurement of cellular phenotype and function using multi-parameter flow cytometry to identify specific subsets of CD4+ T-cells
Implementation Method 2
secrete TNF-α without secreting IFN-γ
Data Source
AI summary
There is provided methods of determining tuberculosis (TB) infection status in an individual comprising: (i) providing a sample comprising T-cells; (ii) exposing the sample of (i) to one or more TB antigens; (iii) identifying T-cells in the sample that are CD4 positive and (a) secrete TNF-α without secreting IFN-γ; or (b) secrete IFN-γ without secreting TNF-α; (iv) identifying those cells of (iii) which are also CCR7 and, CD127 negative; and optionally (v) calculating the cells identified in (iv) as a percentage of those identified in (iii); wherein the identification of cells in (iv) and/or the percentage of T-cells calculated in (v) correlates to TB infection status of the individual, and wherein steps (iii) and (iv) can be carried out either sequentially or simultaneously. There are also provided compositions and kits for use in such methods.