In the study, led by Karolinska Institutet and Uppsala University, the "regulation and adaptation over time" of the immune system has been analyzed in 23 trans men who have undergone gender-affirming testosterone treatment. According to the press release from KI, the individuals were born as women and have received the male sex hormone testosterone for gender-affirming purposes.
During the study, the researchers could see how the part of the immune system that deals with virus protection was regulated down by testosterone, while the sex hormone regulated up an inflammatory response.
Greater risk
This can explain why women are at greater risk of developing autoimmune diseases such as Sjögren's syndrome and SLE, a rheumatic disease with chronic inflammation where the immune system attacks the body itself. Nine out of ten who develop these diseases are women.
The study's findings can also explain why men are more severely affected by certain infectious diseases such as COVID-19, HIV, and tuberculosis.
Women also tend to respond better to vaccines but more often experience side effects from them.
Developing medications
The new knowledge will help us to better influence people's immune systems without using sex hormones. For example, one can develop new medications to affect these mechanisms and thereby balance the immune system for women with SLE, says Nils Landegren, physician and researcher in autoimmune diseases at Uppsala University in the press release.
The study has been published in the scientific journal Nature.
