A collaborative study between Johns Hopkins School of Medicine and the University of Alabama concerning an analysis of autopsied autism and control brains was published in the December 2014 journal Nature Communications. The study found that although there are many different combinations of genetic traits that can cause autism, brains that are affected by autism show “genes responsible for inflammation responses seemed to be perpetually turned on.”1
The study involved 104 brain samples from 72 individuals where the researchers analyzed gene expression. They found that a “specific type of support cell known as a microglial cell” appeared to be “perpetually activated in the autism brains.” According to Dan Arking, Ph.D., an associate professor in the McKusick-Nathans Institute for Genetic Medicine at the Johns Hopkins School of Medicine, “inflammation is unlikely to be [autism’s] root cause…rather a downstream consequence of upstream gene mutation…” and that the “next step would be to find out whether treating the inflammation could ameliorate symptoms of autism.” Another researcher involved in the study, Andrew West, Ph.D., an associate professor of neurology at the University of Alabama, noted further that “this type of inflammation is not well understood, but it highlights the lack of current understanding about how innate immunity controls neural circuits.”1
So what is this microglia?
Microglial cells are the primary immune cells of the central nervous system. They respond to pathogens or injury by becoming “activated” where they change form and structure, increase greatly in number and migrate to the site of the injury or pathogen. At the site, they phagocytose and remove pathogens or damaged cells. Their secretions increase and direct the immune response. Though microglia often have a “protective role, they also have been studied for their harmful roles in neurodegenerative diseases and brain injuries, such as Alzheimer’s disease, Parkinson’s disease, ischemic injury, and traumatic brain injuries.”2
Sources: 1 Hopkinsmedicine.org/news/media/releases/