Stellenbosch University (SU) has collaborated with in an international consortium of researchers to develop a new simple blood test that can predict whether an at-risk individual will develop TB within the next two years.
“People in close contact with TB patients are at risk of also developing the disease; however it is not feasible to give preventative treatment to everyone that comes into contact with the patient,” said lead author of the study and Head of the Immunology Research Group at SU’s Faculty of Medicine and Health Sciences, Professor Gerhard Walzl.
“Our research group developed a blood test that can predict which contacts are more likely to progress to active TB, and these individuals can then be singled out for preventative treatment. Preventative treatment is several weeks long and has potential side effects. One wants to limit the number of people who have to undergo such treatment to those most at risk for developing active TB,” continued Prof Walzl.
The TB test measures the expression level of four genes associated with inflammatory responses. This four-gene signature, known as ‘RISK4’, was found to apply in populations from South Africa, The Gambia and Ethiopia.
“This study was the first step, and now the impact of this test on prevention of TB will have to be tested in multi-centre clinical trials. In addition, the validity of the prediction in high-risk individuals in Asia, South America and other high-priority areas needs to be assessed,” continued Prof Walzl.
The international research consortium included researchers from the Max Planck Institute for Infection Biology in Germany; the South African TB Vaccine Initiative (SATVI) at the University of Cape Town (UCT); the Medical Research Council Unit – The Gambia; the London School of Hygiene and Tropical Medicine in the UK; Case Reserve Western University and Sanquin Research in the Netherlands; the Ethiopian National Research Institute and the Armauer Hansen Research Institute (AHRI) in Ethiopia; Makerere University in Uganda; the Karonga Prevention Study in Malawi; Statens Serum Institute in Denmark; AERAS Global TB Vaccine Foundation and Stanford University in the US.
The study was published in the American Journal of Respiratory and Critical Care Medicine, an American Thoracic Society journal.