Brisbane researchers have uncovered why diabetes makes people more vulnerable to tuberculosis (TB)—and with Bali, Australia’s favourite holiday destination and among the world’s TB hotspots, experts warn the risk is closer to home than many realise.
The Mater Research study, led by Professor Katharina Ronacher with collaborators from Stellenbosch University in South Africa, is the first in the world to examine lung immune cells from people with diabetes who have been recently exposed to TB, the leading cause of death from a single infectious pathogen, claiming 1.25 million lives annually.
Until now, most research focused on blood samples or animal models, leaving a critical gap in understanding of what happens in the lungs—the primary site of TB infection.
Published in the latest The Lancet’s EBioMedicine, the paper titled ‘Human alveolar macrophage function is impaired in Tuberculosis contacts with Diabetes’ reveals that type 2 diabetes disrupts the lung’s frontline immune cells (alveolar macrophages), creating an environment where TB bacteria thrive.
Using advanced genomic and epigenetic analysis, researchers, found diabetic lung cells not only allowed more TB growth but also showed abnormal chemical signalling and DNA methylation patterns.
The study shows that these cells respond more slowly to infection, produce excessive inflammatory signals and fail to recruit enough neutrophils - another key infection-fighting cell.
Prof Ronacher, who leads the Infection, Immunity and Metabolism Research Group said that it is the first time researchers have been able to look directly at the lungs of people with diabetes who have been exposed to TB.
“We discovered a perfect storm - delayed immune activation, fewer protective cells in the lungs and epigenetic changes that lock in these defects,” she said.
“This immune dysfunction in the diabetic lung also impacts other respiratory infections, such as influenza, bacterial pneumonia and COVID-19.”
First author of the study Dr Leanie Kleynhans said that people with diabetes are three times more likely to develop TB.
“As diabetes rates rise globally, this dual epidemic is a growing threat,” she said.
Indonesia—where TB incidence is 388 cases per 100,000 people—is Australia’s favourite holiday destination. In 2024, 1.53 million Australians visited Indonesia, mostly Bali.
“Global health problems don’t stay overseas,” Prof Ronacher said.
“With international travel and migration, TB can and does reach our shores. There are approximately 1,500 TB cases in Australia every year.
“Understanding how diabetes changes lung immunity helps us protect vulnerable Australians.”
This research provides critical new insights into the lung environment in diabetes, identifying immune pathways that could become targets for future interventions.
“Our findings open the door to therapies that restore lung immunity in people with diabetes,” Prof Ronacher said.
“This could mean better TB prevention and treatment for millions worldwide.”
