Bacteria link to early asthma

THE exposure of a child’s lungs to bacteria in the first two months of life could hold the key to preventing asthma and other chronic conditions.

World-first research by Melbourne scientists has found bacteria in a newborn’s airways directly influences the development of the immune system, raising the possibility of preventive treatments.

Every individual has within them bacterial communities, known as the microbiome.

On analysing samples taken from deep inside newborns’ lungs, Monash University’s Professor Ben Marsland was stunned to find the bacteria that developed in the airways in the first two months of life set up the microbiome.

“It seems that the early-life microbial exposures shape which direction your immune system goes,” he said.

“We now know, when they are forming it is happening really quickly, and they are talking to the immune system along the way.

“We refer to it as a window of opportunity … when your immune system is developing and gets signals from different environments … that will send the immune system in one direction or another.

“That can have lifelong consequence for the development of allergies and asthma, for example.”

Results published today in the journal Cell Host and Microbe show the Monash-led study found that an infant’s immune system develops at the same time that the bacteria in their airways is forming a microbiome.

As the two develop in parallel, the immune system switches on genes to combat the bacteria, prompting the microbes to produce their own genes as a defence system.

The arms race between the two forces the immune system to grow stronger, developing an arsenal to thwart conditions depending on which bugs it has been exposed to.

Prof Marsland’s latest work, done in collaboration with his brother Dr Colin Marsland, an anaesthesiologist in New Zealand, and scientists in Switzerland, follows his earlier studies on mice, which identified the particular part of the immune system that dictated whether asthma would develop.

If the scientists can pinpoint the same part of the human immune system, and the bacteria that influences its development, it offers hope of finding a “powerful way of preventing asthma”, Prof Marsland said.

“What we are talking about at the moment is prevention,” he said.

“If we can shape those early-life exposures and microbes, the formation of the microbiome is going to have the best effect for the individual, and society.”