Researchers have taken a major step towards identifying millions of ‘silent spreaders’ of tuberculosis. A new study led by researchers from the NIHR Southampton Biomedical Research Centre (BRC) has identified a group of biological markers that are found in high levels among infectious patients.
Scientists hope that the findings will pave the way for a simple test to speed up diagnosis of tuberculosis (TB). This could help stop the spread of the infection, which affects an estimated 10 million people around the world each year. The study was supported by the NIHR and the Medical Research Council. Findings have been published in the Journal of Clinical Investigation Insight.
TB is the world's deadliest infectious disease. It kills more than one million people each year according to the World Health Organization. The illustration shows Mycobacterium tuberculosis bacteria, the cause of TB.
Researchers from Southampton BRC collaborated with experts around the world on this new study. They carried out the most detailed analysis ever undertaken of blood markers for the bacterial infection.
The team used a novel technique to identify a set of six proteins that are highly accurate in pinpointing TB. Lead author Dr Hannah Schiff, an NIHR Clinical Lecturer at the University of Southampton, said as many as three million cases were missed last year. Most of the undiagnosed cases were in developing countries.
Dr Schiff said: “TB remains a global catastrophe. Our efforts to control the spread are hindered by inadequate testing, which is slow and reliant on specialist equipment and labs. A third of people who get infected go undiagnosed and remain infectious. In our study, we combined a new measurement technique with deep mathematical analysis to identify these six new markers of TB disease. It could lead to a transformative alternative to diagnosing the condition – a simple test that detects proteins in the bloodstream whose levels differ between people with TB, healthy individuals, and those suffering from other respiratory illnesses.”
TB is spread when infectious people cough, sneeze or spit. While it mostly affects the lungs, it can devastate any part of the body. Cases in the UK increased to around 5,000 last year. They are expected to continue rising in 2024, according to the UK Health Security Agency.
The study was undertaken with experts from the University of Cape Town in South Africa and Cayetano Heredia University in Peru. Academics leading the investigation studied proteins found in the blood of people with active TB in Africa and South America.
They compared the biomarkers to those found in healthy people and patients with lung infections. They identified 118 proteins that differed significantly between the groups. The experts then narrowed these down to six proteins that can be used to distinguish contagious patients with TB from people in good health or with lung conditions.
The research was published for World TB Day on Sunday 24 March, which is held to raise awareness and to step up efforts to end the global tuberculosis pandemic.
Study co-director Dr Diana Garay-Baquero, also from the University of Southampton, said the findings are a roadmap to developing a new TB test, whuich could be similar to the lateral flows used to identify COVID-19.
Dr Garay-Baquero said: “The new markers we discovered are truly exciting. The important work now is to develop these into tests that can be used for the millions of people who are transmitting TB without knowing it. As the COVID-19 pandemic confirmed, we ignore highly infectious airborne diseases at our peril.”
- Schiff HF, Walker NF, Ugarte-Gil C et al. Integrated plasma proteomics identifies tuberculosis-specific diagnostic biomarkers. JCI Insight. 2024 Mar 21: e173273. doi: 10.1172/jci.insight.173273. Online ahead of print.