A post citing a review in the International Journal of Molecular Sciences claims mast cell activation is associated with "nearly 7 times higher risk and severity of autism." That review is real, and it does cite that number. Here is what it actually says.
What mast cells are
Mast cells are immune cells best known for triggering allergic reactions. When activated, they release histamine, cytokines, tryptase and other inflammatory molecules, normally in response to allergens, infections or stress.
The real study behind the number
The claim traces back to a 2024 review by Kovacheva, Gevezova, Maes and Sarafian, published in the International Journal of Molecular Sciences. Inside it, the authors cite an older dataset: a study of 400 patients with mastocytosis, a rare disease where mast cells build up abnormally in the body, in which 15 also had an autism spectrum diagnosis, 3.75%. Compared to the general-population autism rate cited at the time, about 1 in 180, that works out to roughly 6.75 times higher, the "nearly 7x" figure in the post.
Two things the post leaves out
First, mastocytosis is itself rare, affecting roughly 1 in 10,000 people. This comparison describes a small subgroup with a specific mast cell disease, not autistic people in general, most of whom do not have mastocytosis.
Second, "1 in 180" is an outdated autism prevalence estimate. The same 2024 review cites the current CDC figure as 1 in 36, roughly five times higher than the number used in the original 2008 comparison. Recalculated against today's baseline, the apparent gap would look considerably smaller.
The proposed mechanism
The review's broader argument is mechanistic: mast cell mediators may affect the blood-brain barrier and interact with microglia, the brain's resident immune cells, potentially contributing to neuroinflammation in a subset of autistic people. This is a real, actively studied hypothesis, not settled fact.
The authors' own conclusion
The review ends by stating plainly that data on the association between mast cells and autism "are controversial and poorly understood," and calls for further research, almost word for word what the more careful version of this post says.
If you are exploring your own neurotype, our free autism screening is a starting point for self-understanding, not a substitute for this kind of biological research or a medical diagnosis.
Sources: Kovacheva, Gevezova, Maes and Sarafian, "Mast Cells in Autism Spectrum Disorder - The Enigma to Be Solved?," International Journal of Molecular Sciences 25(5):2651 (2024). Original mastocytosis data point: Theoharides, Doyle, Francis, Conti and Kalogeromitros, "Novel therapeutic targets for autism," Trends in Pharmacological Sciences 29:375-382 (2008). Educational summary, not a diagnosis or medical advice.