In addition to the well-known issues with communication and behavior, some people with autism show signs of changes to their immune systems. Mouse studies have pointed out a protein that might offer a clue to these changes, as well as suggesting potential routes to diagnostics and treatments.
Children with autism have higher levels than normal of a fragment of a protein produced by the immune cells, known as amyloid precursor protein (APP). To test out the connection, the researchers at the University of South Florida inserted a gene coding for this biomarker, known as sAPP-α, into the genetic material of mice that show symptoms similar to those in people with autism spectrum disorders. These mice developed higher levels of sAPP-α in their blood, and showed abnormal changes to their immune systems, including increases in the cells that normally kill virally-infected cells, and decreases in the cells that the immune system uses as its "memory" of past infections.
"While there are reports of abnormal T-cell numbers and function in some persons affected with autism, no specific cause has been identified. The disorder is diagnosed by behavioral observation and to date no associated biomarkers have been identified," said research team leader Dr. Jun Tan, Ph.D., professor of psychiatry and the Robert A. Silver Chair, Rashid Laboratory for Developmental Neurobiology at USF's Silver Child Development Center.
The rates of autism diagnoses are increasing, and the reasons are unclear. One theory is that this is because of a change in the criteria used in diagnosis, rather than an actual rise in cases. While this research is at a very early stage, an objective biomarker could make this clearer, as well as support early diagnosis, treatment and support for children with autism and their families.
- read the press release
- see the paper in The FASEB Journal