A Franco-Australian study published this week reports that testosterone protects males against developing asthma, suppressing the production of a type of immune cell that triggers allergic asthma.
An international team of researchers set out to investigate why females are two times more likely to develop asthma than males after puberty.
According to the research, carried out jointly by the Walter and Eliza Hall Institute in Melbourne, Australia, and the Physiopathology Center of Toulouse-Purpan, France, the answer could lie in our hormones.
The scientists found that high levels of testosterone had a protective effect against the development of allergic asthma, inhibiting immune cells called type-two innate lymphoid cells (ILC2), associated with the initiation of asthma.
As highlighted by a French study published in PNAS in 2014, these cells, which are found in lungs, skin and other organs, play a role in triggering allergic reactions like asthma.
These cells produce inflammatory proteins that can cause lung inflammation and damage in response to common triggers for allergic asthma, such as pollen, dust mites, cigarette smoke and pet hair.
“Testosterone directly acts on ILC2s by inhibiting their proliferation,” explains Dr Cyril Seillet from Melbourne’s Walter and Eliza Hall Institute. “So in males, you have less ILC2s in the lungs and this directly correlates with the reduced severity of asthma.”
This major breakthrough in understanding the mechanisms that drive allergic asthma, as well as key differences between males and females, could lead to new treatments for the disease. These could potentially mimic the hormonal regulation of ILC2 to treat or prevent asthma.