Maternal antibodies may contribute to autism

A team of researchers at Johns Hopkins University in Baltimore suggest that autism may also be caused or triggered by maternal antibodies that cross over through the placenta and are directed against the brain tissues of the fetus, adversely affecting brain development.

It was noted that children with autism have antibodies in the blood that react against brain tissue. Antibodies are an important part of the immune system in which proteins are produced and mount a defense in response to the presence of a foreign body, such as an invading virus.

Most studies into the origin of autism have focused on autoantibodies as a possible explanation. Autoantibodies are antibodies the body makes that react against the body's own tissues by mistake; this mechanism is involved in allergic reactions and autoimmune diseases.

However, another possible explanation involves the transfer of reactive antibodies from the mother through the placenta to the fetus.

Mothers of children with autism had a stronger reactivity or more areas of reactivity between antibodies and brain proteins compared with mothers without an autistic child. The presence of maternal antibodies also correlated with having a child with developmental regression, a primary feature of autism.