Childhood Serum Anti-Fetal Brain Antibodies Do Not Predict Autism
Posted Sep 17 2009 10:12pm
One of the big new concepts in autism research in the last two years is the idea that maternal antibodies might be involved in developing autism.
Two groups, one from Johns Hopkins, the other from California showed that in some mothers with autistic children, their blood sera had antibodies against fetal brain tissue.
This raised the question of whether maternal antibodies, transferred during pregnancy, could influence the risk of autism.
One big question raised was the possibility that this could lead to regressive autism. Could something prenatal be linked to regressions in children who were age 1 or 2?
One big question raised (and unanswered) by these studies was the question of antibodies in the autistic children themselves. Do they have antibodies against fetal brain tissue? Could this be a biomarker? And, if so, could this be involved in developing autism in some cases?
Autoimmune hypotheses for autism include in utero transplacental exposure to maternal antibodies and acquired postnatal insults. Previous work demonstrated that some mothers of children with autistic disorder have specific antibodies against human fetal brain that differentiate them from mothers with typical children. In the present study, Western immunoblotting was used to determine whether children with autistic spectrum disorders (n = 29) have serum reactivity against human fetal brain that differs from that of controls (n = 14). There was no significant difference in reactivity, corrected for serum immunoglobulin G content and brain actin content and with special attention to reactive bands at 36, 39, 61, and 73 kDa, between autistic children and normal control subjects. Thus, in contrast to mothers, antibody reactivity against human fetal brain as measured in children ages 3-12 years does not appear to be a useful biomarker for autism.
The paper is fairly brief as they don’t find any evidence that the children’s blood sera reacted with fetal brain tissues. Here is a quote from the discussion section:
The present data indicate that the measurement of serum antibody reactivity against human fetal brain in children with autistic spectrum disorders does not predict an autistic diagnosis, either for idiopathic autistic disorder or for those individuals with identified etiologies. These data differ from previous findings in mothers of autistic children, which indicated that anti-human fetal brain antibodies reactive against proteins at 36, 39, 61, or 73 kDa appear to be a biological marker for the disorder in some individuals
Before anyone jumps on me for denying the possibility of any immunological effects in risk of autism, here is another quote from the paper:
The present study does not rule out the possibility that other anti-brain antibodies in the children may be important for postnatal effects. For example, children with autism have been shown to possess antibodies against various central nervous system self-components such as glial fibrillary acidic protein, myelin basic protein, neurofilament proteins, cerebellar neurons, and brain endothelial cell proteins [6-9,23,24]. We hypothesize that, rather than a direct association, there is a complex relationship between maternal anti-fetal brain antibodies and various intrauterine genetic, metabolic, and environmental factors.
Papers that don’t show a connection, show a “null” or lack of an effect, are somewhat unsatisfying. They are certainly not unimportant. I look forward to more research from Dr. Zimmerman’s group at Johns Hopkins,