The medical community has long held the belief that there's a link between a mother's immune system and the likelihood her child will develop autism but the exact mechanism that triggers the disorder has been elusive. Now, however, a University of California at Davis (UC-Davis) team of researchers led by Judy Van de Water seems to have found the link.

Van de Water, a UC-Davis professor of rheumatology, allergy, and clinical immunology, has identified the targets in the fetus immune system (antigens) that come under attack by the mom's immune system (antibodies). In most cases, the mother's immune system works as one, in lock-and-key fashion, with the developing child's but immune protection becomes impaired when the process is interrupted in the way that leads to autism. This interruption, known as maternal autoantibody-related autism (MAR), affects as many as 23% of all children diagnosed within the spectrum of autism. Male children with MAR outnumber females four to one.

In a collaborative study, Melissa Bauman, a neuroscientist at the UC-Davis MIND Institute (Medical Investigation of Neurodevelopmental Disorders) worked with human maternal autoantibodies injections in an attempt to mimic what happens when a child develops the disorder.

The Bauman phase of the study was conducted on rhesus monkeys, which are genetically similar to humans. Results achieved with the monkeys paralleled clinical observations in human children diagnosed as autistic.

These observations included behaving in ways considered awkward and possibly dangerous, as when a child enthusiastically approaches a stranger or known individual who is not as eager to engage in social interaction with him or her. Another similarity is increased brain size in male autistic children but not in females. These and other developmental deviations were as apparent to rhesus mothers and their communities as they are within a human family of an autistic child.

Findings were published July 9, 2013, in Translational Psychiatry. Further study of both the immune system and neural development is expected.

Source: University of California - Davis: Some Cases of Austim May Be Traced to the Immune System of Mothers During Pregnancy (2008).