New TB Diagnostic Method

New TB Diagnostic Method

Context:

Researchers from the U.K. and the U.S. have developed a new method to scan for tuberculosis using positron emission tomography (PET) with a novel radiotracer called FDT.

Relevance:

GS-02 (Health, Science and technology)

 

Key highlights:

• Function of Radiotracers: Radiotracers are radioactive compounds that emit radiation detectable by scanners, creating 3D images. The new radiotracer FDT is specifically taken up by live TB bacteria.
• Accuracy and Specificity: The FDT radiotracer allows PET scans to accurately pinpoint active TB in a patient’s lungs, improving specificity over current methods.
• Pre-Clinical Trials and Phase I Trials: The new radiotracer has undergone extensive pre-clinical trials without adverse effects and is ready for Phase I trials in humans. The study was published in the journal Nature Communications.
• Current TB Diagnosis Limitations: Current methods include sputum tests and PET scans using FDG to detect inflammation, both of which have limitations in specificity and can lead to incorrect treatment durations.

Advantages of the New Approach:

• The new radiotracer uses a carbohydrate processed only by TB bacteria, making it more specific.
• It requires only standard radiation control and PET scanners, which are increasingly available globally.

Production and Accessibility:

• The new molecule can be produced from FDG using a simple enzymatic process, making it feasible for low- and middle-income countries with less developed healthcare systems.
• This is significant as these countries account for over 80% of global TB cases and deaths.

Tuberculosis:

• TB, caused by Mycobacterium tuberculosis, is a treatable and curable disease with a long history dating back to 3000 BC in Egypt.
• Spread through the air when infected individuals cough or sneeze, TB commonly affects the lungs but can also impact other organs.
• MultiDrug Resistant Tuberculosis (MDR-TB) and Extensively Drug Resistant Tuberculosis (XDR-TB) pose significant health threats.
• The BCG vaccine, developed in 1921, plays a crucial role in TB prevention. Initially introduced in India in 1948, BCG became part of the National TB Control Programme in 1962.
• Besides TB protection, the vaccine safeguards against respiratory infections, mycobacterial diseases, and serves as immunotherapy for certain cancers.
• Interestingly, BCG’s efficacy varies geographically, demonstrating higher efficiency in countries farther from the equator.