Scientists discover how vitamin A drives the human lung immune system to control TB

Dr Jim Harris

A collaborative international research team, including Monash researcher Jim Harris, have discovered a new way that vitamin A helps the lung immune system to deal with tuberculosis (TB).

TB is a major threat to global health. TB killed 1.7 million people in 2016; the top cause of death related to infection worldwide. With the increased incidence of drug-resistant TB, additional strategies are required to treat the disease.

Published last week in leading respiratory journal, the American Journal of Respiratory Cell and Molecular Biology, the study adds a potential mechanism to explain why vitamin A deficiency is associated with a 10-fold increase in the risk in developing TB.

Co-author Dr Jim Harris from the Centre for Inflammatory Diseases, Monash University, said the mechanism by which vitamin A protects people's lungs against TB infection had been unexplored.

The research team has shown for the first time how vitamin A effectively supports lung immunity against TB.

“We’ve explained a crucial mechanism that underpins vitamin A, or its metabolite all-trans retinoic acid (atRA) as a therapeutic option for this disease,” Dr Harris said.

“Our study shows that vitamin A supports the recycling and waste disposal functions of immune cells (called autophagy) and this in turn allows for better clearance of the bacteria that cause TB.”

“The discovery has the potential to assist in developing more lung targeted treatment of the disease by boosting the patient's immune response with vitamin A supplementation.”

The scientists also demonstrated that vitamin A supported the immune system in killing the bacteria Bordetella pertusiss, which causes whooping cough. With the incidence of whooping cough increasing, the research also suggests that vitamin A might be useful to treat that respiratory infection.

The study was led by Dr Sharee Basdeo and Professor Joe Keane from Trinity College Dublin.