A new study from MIT and Harvard Medical School has discovered a possible explanation for autism symptoms in children being reduced by having a fever. The researchers believe this phenomenon may be connected to an immune molecule called IL-17a, which is released during an infection and suppresses a region of the brain that has been connected to social deficits in mice.
According to a report this month by Scitechdaily.com, the study was led by Gloria Choi, an assistant professor of applied biology and brain and cognitive sciences at MIT. Jun Huh, an assistant professor immunology at Harvard Medical School, co-authored the study, which was published on December 18 in Nature.
Choi believes the study may help guide the development of strategies that could reduce behavioral symptoms of autism or other neurological disorders. Choi and Huh explored the link between inflammation and autism in a 2016 study, which found that mice born to mothers who experienced a severe infection during pregnancy were more likely to display autism-like symptoms, such as repetitive behaviors and impaired sociability.
In their current study, the researchers found that mice that experienced a fever after being injected with the bacterial component LPS lost the autism symptoms they previously had due to being exposed to inflammation in the womb. The researchers also found that during inflammation, the mice produced the IL-17a molecule, which binds to receptors in the same region of the brain that was originally affected by maternal inflammation. IL-17a reduces neural activity in that region, making the mice temporarily more interested in social interaction. If IL-17a was blocked in any way, the symptom reversal did not occur.
For the next phase of their research, Choi and her colleagues are exploring whether any other immune molecules affect the brain and behavior.
“What’s fascinating about this communication is the immune system directly sends its messengers to the brain,” Choi said, “where they work as if they’re brain molecules, to change how the circuits work and how the behaviors are shaped.”