Last Updated on May 7, 2026 by Jaspreet Kaur
Researchers from the Garvan Institute of Medical Research and UNSW Sydney found new genetic evidence that might explain why women are more likely to get autoimmune diseases like lupus than men.
This discovery is important because it happens before World Lupus Day on May 10. It also gives us a picture of how women’s and men’s immune systems work differently at the genetic level.
The study, which was published in The American Journal of Human Genetics, found over 1,000 switches that work differently in women’s immune cells compared to men’s immune cells.
These differences seem to increase inflammation in women, which might make them more likely to get disorders like lupus. Scientists say these findings show that medical research and treatments should not be the same for everyone.
Why Lupus Affects Women More
Autoimmune diseases happen when the immune system attacks parts of the body by mistake. Lupus, rheumatoid arthritis and multiple sclerosis are all examples of this. Lupus is particularly interesting because women get it more often than men. In some cases women are diagnosed with lupus up to nine times more often than men.
For a time researchers knew that women’s immune systems are stronger than men’s and this helps women fight off infections and viruses.
However, scientists also thought that this strength might come with a cost, which’s an increased risk of the immune system getting too active.
Until now we did not know why this happened.
Looking at Cells One by One
One reason we did not understand this before is that earlier studies looked at blood samples together. This method measured the immune activity of many different types of cells which hid important details about individual cells. New technology that lets us look at cells has changed this.
The Australian researchers looked at over 1.25 million cells from nearly 1,000 healthy people. These cells, called blood mononuclear cells, are important for immune defense.
By looking at cells one by one researchers could see how women’s and men’s immune systems differ. The results showed differences between the sexes.
Different Immune Profiles
The study found that men have monocytes, which are immune cells that respond quickly to infections. Men’s immune systems also focus more on maintenance and protein production.
Women on the other hand have more B cells and regulatory T cells. These cells are important for signaling and inflammation. Researchers found that women’s immune cells are more associated with inflammation.
In terms, women’s immune systems are more alert and reactive. This might help women fight off viruses. It also increases the risk of the immune system attacking healthy tissues by mistake. Scientists think this might explain why autoimmune diseases like lupus are more common in women.
The Genetic Switches
One important discovery was about genetic control points called expression quantitative trait loci or eQTLs. These genetic switches control how specific genes are turned on or off.
Researchers expected to find these differences on the X and Y chromosomes, which determine sex. Surprisingly, they found that most of these genetic switches are on autosomes, which are chromosomes that both men and women have.
Over 1,000 of these switches were found. Some of them are connected to genes linked to lupus. The findings suggest that women might inherit controls that increase inflammation making lupus more likely. Scientists say this discovery changes our understanding of differences between men and women.
Beyond One-Size-Fits-All Treatments
This study might change how we treat diseases in the future. Now many treatments use broad immunosuppressant drugs that reduce the activity of the entire immune system.
While these treatments can help manage symptoms they might not address the pathways that drive illness in different patients. Researchers think the new findings support the need for medicine, where treatments are tailored to an individual’s genetic and immune profile.
The team argues that men’s and women’s autoimmune diseases might not behave the way and might require different treatments. Scientists also say the findings highlight the importance of including both men and women in medical research.
Historically many studies have focused on men, which might limit our understanding of diseases that affect women differently. By identifying the pathways linked to inflammation in women the researchers hope future therapies can be more targeted, effective and personalized.
The study is a step towards understanding why autoimmune diseases develop differently in men and women and how medicine might adapt to those differences.