A new Swedish study appears to suggest a link between taking testosterone as part of gender reassignment treatment and changes to the immune systems of transgender men.
As Scientific AmericanAccording to the report, the scientists studied a small group of 23 transgender men between the ages of 18 and 37 for 12 months. Their goal was to see how taking testosterone affected participants’ vulnerability to viral infections and autoimmune diseases, which have been shown to differ between men and women. As the media points out, men are more likely to suffer from viral infections and women are more likely to suffer from autoimmune diseases, but it’s unclear whether the differences are due to genetics, hormones, or other factors.
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As part of the Swedish study, researchers took blood samples from all 23 trans men before they began gender-affirming hormone therapy. A second blood sample was taken after three months of testosterone treatment and found that most participants had testosterone levels similar to cisgender men, but reduced estradiol and progesterone levels.
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A third blood sample taken after taking testosterone for 12 months showed a decrease in immune responses related to type I interferon, a protein used in the body to fight viral infections, and an increase in signaling pathways related to tumor necrosis factor, which fights bacterial infections through inflammation. Scientific American.
The researchers also took blood samples from cisgender female donors and exposed them to either testosterone or estrogen blockers. They found that testosterone was directly responsible for the increased tumor necrosis factor response, similar to that shown in the trans men’s blood samples after 12 months. They also found that testosterone influenced type I interferon response, although they noted that previous studies have suggested that estrogen may also be involved.
Essentially, that’s the result of a study published in the journal Neurology earlier this month. NatureThese findings suggest that taking testosterone may boost the body’s ability to fight bacterial infections, but also make it more vulnerable to viral infections.
But the study authors cautioned: “We cannot say that these people are now more susceptible to infection, but we can say that their immune profiles are [cisgender] “Men have a lot to learn from this study,” said co-author Petter Brodin, professor of paediatric immunology at the Karolinska Institutet in Stockholm. Scientific American.
Dawn Newcomb, an assistant professor of medicine at Vanderbilt University Medical Center who was not involved in the study, noted the study’s small sample size and added that sex hormones are “probably one mechanism at play, but not the only mechanism.”
Study co-author Nils Lundegren, an assistant professor at Uppsala University in Sweden, cautioned against drawing conclusions about the risks of gender-affirming hormone therapy for transgender men without more information about actual disease outcomes. “We’ll need larger numbers and longer follow-up studies,” he said.
“We urge caution to people undergoing hormone therapy for any purpose,” Brodin said, “and to ensure that follow-up is done to make sure there aren’t any unintended health effects.”
