DIFFERENCE BETWEEN PLASMA N-TERMINALLY AND C-TERMINALLY DIRECTED BETA-ENDORPHIN IMMUNOREACTIVITY IN INFANTILE-AUTISM

Objective: The authors investigated whether there is excessive opioid activity in infantile autism by measuring plasma beta-endorphin in pat ients with autism compared with patients who had Rett's syndrome and n ormal comparison subjects. Method: Radioimmunoassays for beta-endorphi n using C-terminally and N-terminally directed antisera were applied t o plasma samples from 67 children who met both DSM-III-R and ICD-10 di agnostic criteria for infantile autism, 22 girls with Rett's syndrome, and 67 normal children matched in age and sex with the children with autism. Results: Median N-terminally directed beta-endorphin immunorea ctivity appeared to be slightly lower in subjects with autism (7 pg/ml ) and clearly higher in the girls with Rett's syndrome (40 pg/ml) than in the comparison subjects (9 pg/ml). Median C-terminally directed be ta-endorphin immunoreactivity was higher in the girls with Rett's synd rome (35 pg/ml) and much higher in patients with autism (70 pg/ml) tha n in comparison subjects (8 pg/ml). Conclusions: These findings demons trate the existence of a wide discrepancy between C- and N-terminally directed beta-endorphin immunoreactivity among children with autism. D espite the fact that the nature of the antigen recognized in the plasm a of autistic children by the C-terminally directed anti-beta-endorphi n serum remains to be characterized the difference between C- and N-te rminally directed beta-endorphin immunoreactivity might suggest an abn ormal processing of the pro-opiomelanocortin gene in infantile autism.