More Evidence of an Autism Immune Component

A recent study shows that specific autoantibodies found in a modest proportion of mothers with an autistic child may provide more evidence of an immune component related to autism. The study is an expansion of an earlier one at the Medical Investigation of Neurodevelopmental Disorders (MIND) Institute at the University of California, Davis, which demonstrated that 12 percent of women with an autistic child had unusual antibodies not present in mothers of typically developing children or those with other intellectual developmental disorders. That finding raised the hypothesis that the antibodies, which are immunoglobulin G that cross the placenta, might be interacting with the fetal brain, leading to disregulation of development (and, ultimately, to autism).

In the recent study, researchers tested the effects of the antibodies in pregnant Rhesus monkeys. The monkeys were injected over a six-week period with either purified autoantibodies to fetal brain proteins from the blood of the mothers of children with autism or with autoantibodies from mothers with typically developing children. They found that the offspring of monkeys injected with the IgG of mothers of children with autism showed distinctive autistic characteristics, including social impairment and stereotypic behaviors across several behavioral testing paradigms. While the social impairment was subtle and did not reach the level of social impairment consistent with autism, the sterotypy was profound. “Given that [stereotypy] is one of the clinical signs of autism, we thought this was intriguing,” said David G. Amaral, PhD, research director at the MIND Institute. “The ability to reproduce this effect in an animal model was strong evidence that these antibodies may have a disease-causing effect.”

Dr. Amaral and his colleagues have replicated these findings in two independent studies and are currently extending their analysis to a magnetic resonance imaging (MRI) study of brain development in the treated monkeys. In other prior research by the MIND Institute investigators, a substantial proportion of boys with autism have been shown to have precocious brain growth during early childhood, and the MRI studies are designed to determine if similar patterns of brain development occur in the treated Rhesus monkeys. If confirmed, the findings could lead to screening tests for pregnant mothers and, perhaps, to preventive measures for certain types of autism