A quarterly publication of the Autism Research Institute

The Autism Research Review International is quarterly publication of the Autism Research Institute

Fall, 2019 | Number 4, Volume 33

Postmortem study finds new evidence of immune system response targeting specific brain cells in individuals with ASD

A new study reports that the brains of individuals with autism spectrum disorder (ASD) frequently show evidence of an immune system response targeting specialized brain cells. 

In the post-mortem study, Marcello DiStasio and colleagues compared brains from 25 donors with ASD to brains from 30 neurotypical donors matched as closely as possible for age and medical history. In more than two-thirds of the brains of individuals with ASD, the researchers detected an excess of perivascular lymphocyte cuffs, which are accumulations of immune cells surrounding blood vessels in the brain. These cuffs are an indicator of chronic inflammation. The researchers also identified bubbles or blisters called blebs around the cuffed blood vessels, and determined that these contained debris from a type of brain cells called astrocytes. 

While perivascular lymphocyte cuffing is a sign of viral infection or an autoimmune disorder, the pattern the researchers observed did not match any previously documented infection or autoimmune disorder of the brain. 

Senior study author Matthew Anderson comments, “While further research is needed, determining the neuropathology of autism is an important first step to understanding both its causes and potential treatment. Investigators typically aim potential treatments at specific pathologies in brain diseases, such as the tangles and plaques that characterize Alzheimer’s disease and the Lewy bodies seen in Parkinson’s. Until now, we have not had a promising target like that in autism.” 

In separate experiments, the researchers found that the perivascular lymphocyte cuffs in the brains of individuals with ASD were composed of killer T-cells, a subset of immune cells that attack and kill damaged, infected, or cancerous cells. These killer T-cells may also target normal cells, causing autoimmune disease. The researchers speculate that the T-cells are either reacting normally to a pathogen such as a virus or abnormally to normal tissue. 

Anderson says, “With this new research, we haven’t proved causality, but this is one clue in support of the idea that autism might be an autoimmune disorder, just like multiple sclerosis is thought to be.”


Citations

“T-lymphocytes and cytotoxic astrocyte blebs correlate across autism brains,” Marcello M. DiStasio, Ikue Nagakura, Monica J. Nadler, and Matthew P. Anderson, Annals of Neurology, October 8, 2019 (online). Address: Matthew Anderson,  [email protected]

—and—

 “First evidence of immune response targeting brain cells in autism,” Medical Xpress, October 18, 2019.