The proteins were in the amygdala, the portion of the brain that is associated with fear, and the dorsolateral prefrontal cortex, responsible for cognitive skills, including memory and attention.
The IL-18 protein has already been linked to other inflammatory conditions such as psoriasis, but researchers from Tufts University School of Medicine in Boston believe it also plays a part in ASD.
They inspected the brains of 16 children who had died, eight of whom had ASD. All the ASD children had high levels of Interleukin-18 and, to a slightly lesser extent, of IL-37.
The high number of inflammatory proteins suggests an immune dysfunction, the researchers say.