Autism and autoimmunity: more evidence

Autism and autoimmunity, mediated by brain-reactive antibodies produced by the mother during pregnancy, is emerging as an important association to bear in mind for prevention and treatment. A study just published in Molecular Psychiatry adds to the evidence that should be known to every practitioner offering support before and during pregnancy:

"It is believed that in utero environmental factors contribute to autism spectrum disorder (ASD). The goal of this study was to demonstrate, using the largest cohort reported so far, that mothers of an ASD child have an elevated frequency of anti-brain antibodies and to assess whether brain reactivity is associated with an autoimmune diathesis of the mother."

The authors examined the plasma (blood) of 2431 mothers of children with autism and plasma of 653 other women of child-bearing age for anti-brain antibodies. Mothers who had an ASD child were also examined for anti-nuclear antibodies which are associated with numerous other autoimmune disorders. There was a very strong correlation:

"Mothers of an ASD child were four times more likely to harbor anti-brain antibodies than unselected women of child-bearing age (10.5 vs 2.6%). A second cohort from The Autism Genetic Resource Exchange with multiplex families displayed an 8.8% prevalence of anti-brain antibodies in the mothers of these families. Fifty-three percent of these mothers with anti-brain antibodies also exhibited anti-nuclear autoantibodies compared with 13.4% of mothers of an ASD child without anti-brain antibodies and 15% of control women of child-bearing age. The analysis of ASD mothers with brain-reactive antibodies also revealed an increased prevalence of autoimmune diseases, especially rheumatoid arthritis and systemic lupus erythematosus."

Lead investigator Betty Diamond, MD, PhD was quoted in Medscape Medical News:

"This study strongly suggests that maternal antibrain antibodies associate with autism spectrum disorder [ASD] in the child, as others have also shown, and suggest that the presence of antibrain antibodies may be associated with other manifestations of autoimmunity in the mom."

Quoting also from Medscape Medical News:

"These data are consistent with a predisposition to more generalized autoimmunity in some mothers with anti-brain antibodies who have a child with ASD," Dr. Diamond and colleagues say. Self-reported autoimmune diseases, especially RA and SLE, were also more common in the mothers of an ASD child with antibrain antibodies...The possibility of autoimmune mechanisms being a contributing factor in ASD has been entertained as early studies suggested that individuals with ASD have a family history of autoimmune disease," the investigators note. A recent study examining autoimmune disorders in women, with data for more than 600,000 births, showed that women with either RA or celiac disease had an increased risk of having a child with ASD (Atladottir et al, Pediatrics 2009;124:687-694)."

The authors conclude:

"This study provides robust evidence that brain-reactive antibodies are increased in mothers of an ASD child and may be associated with autoimmunity. The current study serves as a benchmark and justification for studying the potential pathogenicity of these antibodies on the developing brain. The detailed characterization of the specificity of these antibodies will provide practical benefits for the management and prevention of this disorder [autism]."

Clinical note: considering how common autoimmunity has become, screening antibodies should be considered for all women planning pregnancy.Readers interested in this post should also see the earlier Autism and maternal antibodies that attack the fetal brain.