Anti-brain antibodies are associated with more severe cognitive and behavioral profiles in Italian children with Autism Spectrum Disorder

Highlight
• Further evidence of pathomorphic roles for patient- and mother-produced antibrain antibodies in Autism Spectrum Disorder.

Circulating 45 and 62 kDa antibodies targeting the cerebellum were previously associated with Autism Spectrum Disorder (ASD), lower adaptive/cognitive function and aberrant behaviors. Moreover, 37, 39 and 73 kDa maternal antibodies (mAb) targeting the fetal brain were previously correlated with broad autism spectrum, irritability, abnormal brain enlargement and impaired expressive language. The present study aims towards clinically characterizing individuals with brain-targeted IgG and/or exposed to maternal antibrain antibodies in a large sample of Italian autistic children (N = 355), their unaffected siblings (N = 142) and mothers (N = 333). The presence of patient- and mother-produced anti-brain antibodies does not confer increased risk of autism within the same sibship. However, the 45 and 62 kDa antibodies are correlated with autism severity: the 45 kDa Ab is associated with cognitive impairment and lower scores at the Vineland Adaptive Behavior Scales, the 62 kDa Ab with motor stereotypies, while both correlate with larger head circumference (all P < 0.05). On the other hand, maternal 37, 39 and 73 kDa antibrain antibodies, either alone or in combination, are correlated with impaired verbal and non-verbal language development, neurodevelopmental delay and sleep/wake cycle disturbances in their autistic children (P < 0.05). Presence of the 62 kDa autoAb in the child is significantly associated with presence of the 39 and/or 73 kDa antibodies in his/her mother. Our results confirm and extend previous observations in an ethnically distinct sample, providing further evidence of a pathomorphic role for anti-brain antibodies in autism while demonstrating their familial clustering.