A new Australian study reveals why women have higher rates of autoimmune diseases than men.
Researchers have identified genetic and immunological differences that make the immune system in females more active and prone to inflammation, which gives them a greater ability to resist viruses, but at the same time increases the risk of the body attacking its own healthy tissues.
The study, conducted by researchers from the Garvan Institute of Medical Research and the University of New South Wales in Sydney, comes ahead of World Lupus Day on May 10, in an attempt to understand the biological reasons why women are affected by diseases such as lupus at rates up to nine times higher than men.
The researchers relied on modern techniques to analyze immune cells with unprecedented accuracy, studying more than 1.25 million immune cells taken from about a thousand healthy people as part of an Australian project known as "OneK1K," which aims to understand the impact of genetic factors on the functioning of the immune system.
The analysis revealed that women have higher levels of certain immune cells associated with inflammation, such as B cells and regulatory T cells, while men have higher proportions of monocytes responsible for the primary immune response and cellular maintenance functions.
Dr. Sarah Baloos, a researcher involved in the study, said that this "high immune activity" gives women an advantage in fighting viral infections, but it also makes their immune system more susceptible to something like "friendly fire," where it mistakenly attacks healthy body tissues, leading to autoimmune diseases.
To understand the genetic reasons behind these differences, researchers investigated what are known as "genetic control switches"—variables that control gene activity within immune cells. The team was able to identify more than a thousand genetic switches that function differently in women and men.
Surprisingly, according to the study published in the American Journal of Human Genetics, most of these differences were not found on the X and Y sex chromosomes as previously thought, but on the autosomes common to both sexes.
The researchers also discovered genetic variations that affect the activity of two genes associated with systemic lupus erythematosus in women, which may explain the high incidence of the disease among females.
Dr. Sehan Yazar, the lead author of the study, said the findings confirm that autoimmune diseases may not develop in the same way in men and women, and therefore their treatment should not be based on a uniform approach.
He added that many previous medical studies relied heavily on male samples, which led to ignoring the biological differences between the sexes and their impact on understanding diseases and responding to treatment.
The researchers believe that these findings may pave the way for the development of more precise treatments that target each patient's specific immune and genetic pathways, rather than relying on general immunosuppressants that weaken the entire immune system.
