In recent years, a growing body of research has highlighted the gut microbiome’s critical role in human health. It influences everything from our responses to fear and stress, to weight and mental well-being, and even our susceptibility to autoimmune diseases such as lupus and type 1 diabetes.
Now, a new study published in The Journal of Immunology has identified a potential link between the gut microbiome and autism—specifically, the mother’s microbiome during pregnancy. Conducted in animal models, the research suggests that it’s not our own gut microbiome that influences autism risk, but rather the microbiome of our mothers.
“The microbiome can shape the developing brain in multiple ways,” said lead researcher John Lukens, a PhD student at the University of Virginia School of Medicine. “It plays a key role in calibrating how the offspring’s immune system will respond to infection, injury, or stress.”
A central focus of the study is the immune molecule interleukin-17a (IL-17a). Known for its role in conditions like rheumatoid arthritis, multiple sclerosis, and psoriasis, IL-17a also helps prevent infections, particularly fungal ones. Crucially, it appears to influence fetal brain development.
To explore the link between IL-17a and autism, researchers worked with two groups of female mice. One group carried gut microflora that promoted an IL-17a-driven inflammatory response, while the control group did not. When IL-17a was artificially blocked, offspring from both groups exhibited neurotypical behavior. But without intervention, pups from the first group developed autism-like behaviors, including altered social interactions and repetitive actions.
To confirm that gut microflora was the driving factor, the team performed a fecal transplant—introducing gut bacteria from the first group into mice from the second group. The result: offspring from the previously unaffected group also developed autism-like behaviors, reinforcing the idea that maternal microbiota can influence neurodevelopment.
While these findings are preliminary and based on animal models, they open new avenues for autism research. They suggest that maternal gut health could play a significant role in the development of neurodevelopmental conditions.
The next step, Lukens says, is to investigate whether similar correlations can be found in humans—and to identify the specific components of the maternal microbiome that may contribute to autism risk. IL-17a might be just one piece of a much larger puzzle.
