American research has found that autism spectrum disorder could be an autoimmune disease.
Physician scientist Matthew P. Anderson and his colleagues from the Beth Israel Deaconess Medical Centre (BIDMC), a teaching hospital of Harvard Medical School, have discovered cellular features - indicating an immune response targeting specific brain cells - in more than two-thirds of autistic brains analysed postmortem.
These cellular features are believed to provide new insight into the causes of autism, potentially paving the way to improved diagnosis and treatment.
- Homeopaths are dosing kids with vitamin C to 'cure' autism
- Kiwi mum writes children's book following her and her 10yo son's autism diagnosis
- The struggles of raising autistic kids in the provinces
- Countdown to roll out low-sensory 'quiet hours' nationwide
"Investigators typically aim potential treatments at specific pathologies in brain diseases... such as the Lewy bodies seen in Parkinson's," Anderson said in a BIDMC press release. "Until now, we have not had a promising target like that in autism."
The research, published in the Annals of Neurology journal, discovered an accumulation of immune cells surrounding blood vessels in the brain known as perivascular lymphocyte cuffs. Anderson noticed the cuffed blood vessels when examining brains donated to Autism BrainNet, a non-profit tissue bank.
Anderson also observed strange bubbles or blisters, known scientifically as 'blebs', accumulating around the blood vessels. He and his colleagues later found the blebs contained debris from a subset of brain cells called astrocytes.
Perivascular lymphocyte cuffing has not been linked to autism before, but is a well-known sign of chronic brain inflammation - often indicating viral infections or autoimmune disorders.
The lymphocyte cuffs Anderson observed were unlike those found in any other documented infection or autoimmune disorder of the brain.
Compared to 30 neurotypical donated brains, cuffed blood vessels were found significantly more often in 25 brains donated from those with autism. Perivascular cuffs were present in more than two-thirds of the 25 brains.
Anderson's team also discovered the perivascular cuffs were comprised of killer T-cells, a subgroup of immune cells which attack and kill damaged, infected, cancerous or normal cells in autoimmune diseases.
Anderson explained the presence of T-cells suggested they were either reacting normally to a pathogen, such as a virus, or were reacting abnormally to normal tissue - otherwise known as an autoimmune disorder.
"We haven't proved causality, but this is one clue in support of the idea that autism might be an autoimmune disorder," said Anderson.
More common that are typically considered autoimmune include celiac disease (an allergy to gluten), Graves' disease, psoriasis, rheumatoid arthritis, inflammatory bowel disease and multiple sclerosis.