TREATS and King’s College London collaboration awarded funding to develop a new TB diagnostic

Tuberculosis (TB) is the world’s leading infectious disease killer, with 10 million people falling ill with active TB disease every year. A critical part of the End TB Strategy is to not only treat and cure the millions with active TB disease, but also to be able to prevent people from developing active disease in the first place.

An estimated quarter of the world’s population are infected with Mycobacterium tuberculosis (M. tuberculosis), and on average five to 15 percent of those who are infected will develop active TB disease over their lifetime.

If those infected with M. tuberculosis can be identified, they can be given a course of treatment to stop active TB disease ever developing. In 2018, the World Health Organization (WHO) recommended scaling up access to testing and treatment for TB infection, especially among groups who are particularly at risk, such as small children and people living with HIV.

Currently, TB infection is diagnosed by a tuberculin skin test or interferon-gamma release assay. However, these tests cannot predict which people will develop active TB disease. The ability to predict where infection will lead to active disease would be a critical breakthrough in the management of TB infection and a key factor in eliminating TB worldwide.

Through a recent Medical Research Council UK Confidence in Concept Scheme award through King’s Health Partners, in collaboration with King’s College London, the TREATS team will try to address this knowledge gap.

In this proof of concept study, the team will investigate if extracellular vesicles in the blood (sacs released from cells into blood) can differentiate between individuals with M. tuberculosis infection, active TB disease and healthy controls. The ultimate aim is to develop a diagnostic test to identify individuals at risk of progressing from infection to disease. There is currently no valid test for this.

The study will take 12 months and will involve using samples collected as part of the TREATS incidence of infection cohort study in Zambia, as well as some new samples collected from patients who already have active TB disease. There will be approximately 150 participants in the study.

The principal investigators of this study are Dr Lily Telisinghe from the London School of Hygiene & Tropical Medicine and Dr Rocio Martinez-Nunez from King’s College London.

The study findings are scheduled to be published in early 2020.

TREATS -- Tuberculosis Reduction through Expanded Antiretroviral Treatment and Screening for active TB -- has been set up by a consortium of organisations, including The Union, that is already running the largest ever trial of a combination HIV prevention strategy. This trial, called HPTN071, or PopART, is being conducted across 21 communities in Zambia and South Africa, covering around one million people in total. PopART involves universal testing and treatment for HIV through house-to-house visits across the 21 communities on an annual basis over four years. As part of PopART, all members of these communities are also screened for TB.

Building on PopART, TREATS will measure the impact of a combined TB-HIV intervention – of population level active case-finding for TB, combined with universal testing and treatment for HIV – on TB incidence, prevalence and incidence of infection. Find out more.