Immunoreactivity of sera to a peptide derived from the serotonin 5-HT1A receptor in a group of children with developmental disorders: possible role in non-autistic epilepsy.

The presence of autoantibodies against the serotoninergic 5-HT1A receptor has been reported in serum from an autistic child using radioligand binding studies. It is now well established that, in cardiovascular diseases with an autoimmune component, patients present in their sera autoantibodies directed against the second extracellular loop of some G-protein coupled membrane receptors. We thus investigated by an enzyme-immunoassay method the presence of anti-5-HT1A receptor antibodies in sera of children with developmental disorders using synthetic peptides corresponding to the first and the second extracellular loops of this receptor. The population of children with developmental disorders was divided in autistic children with or without EEG abnormalities, and in non-autistic children with or without EEG abnormalities. We found that 6 out of 10 sera of non-autistic children with an abnormal EEG recognized the second extracellular loop of the 5-HT1A receptor. This is significantly higher than the other groups of children with developmental disorders or a healthy control group. These observations support the existence of an autoimmune component in epilepsy.