Wednesday, February 13, 2008

Mother's antibodies tied to development of regressive autism: study

VANCOUVER (CBC) - Scientists have identified a potential new cause of autism in children, by examining what happens in the womb before a baby is born.

Researchers at the Sacramento, California-based UC Davis MIND Institute and Center for Children's Environmental Health have found that in mothers of children with autism, antibodies in their blood bind with the brain cells of the fetus, possibly interfering with brain development and resulting in latent autism.

"This is one of the first studies to identify immunological factors in mothers that could be linked to autism in the very earliest stages of life," said Judy Van de Water, senior author of the study and professor of rheumatology, allergy and clinical immunology at UC Davis, in a release. "Our results should lead to more research on the prenatal environment and the onset of autism."

"We are also optimistic that in the future a prenatal test and therapeutic intervention preventing IgG exposure during pregnancy could protect some children from ever getting autism."

Researchers took blood samples from 123 mothers, 61 of whom had children with autism and 62 who had children without the disorder. They zeroed in on specific antibodies - IgG antibodies - and then exposed fetal brain tissue to the antibodies. They wanted to determine whether the antibodies would react with fetal brain proteins.

IgG antibodies are involved in the body's defence system, helping the immune system fight off infections. They have the ability to cross the placenta and provide a key immune system boost to the growing baby. However, they have also been implicated in autoimmune diseases like arthritis, multiple sclerosis and lupus.

Researchers discovered that in seven of the blood samples, there was a high degree of reactivity between two fetal brain proteins and the IgG antibodies, with six of the seven samples from mothers of children with regressive autism. Regressive autism is a form of autism that develops between 12 and 24 months of age.

None of the reactive samples were from women with children who didn't have autism.

"It's possible that early exposure to maternal antibodies sets in motion a biological path to autism, with the behavioural outcomes not apparent until much later. It's also possible that an environmental exposure sometime after birth could be required to set this process in motion," said Van de Water.

Scientists now hope to test the presence of antibodies in women in all stages of their pregnancies to determine how the reactive process occurs.

The study was published online Monday and will be published in a future issue of Brain, Behavior and Immunity.

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