Abstract

Background: Eosinophil cationic protein (ECP), a cytotoxic protein contained in eosinophils granules, can contribute to various inflammatory and immune responses. Autism may be one of the pediatric autoimmune neuropsychiatric disorders. The exact possible role of eosinophils in autism has not yet been elucidated. The aim of this study was to evaluate serum expression of ECP and its relation to anti-ganglioside M1 brain specific auto-antibodies in autistic children. Methods: Serum ECP and anti-ganglioside M1 auto-antibodies were measured by ELISA test in 45 autistic children aged between 3-11 years and 45 healthy-matched controls. Results: Serum levels of ECP were significantly higher in autistic children [median (IQR) = 30.8 (14.1) ug/L] than healthy control children [median (IQR) = 13.6 (11.9) ug/L], P < 0.001. There was a significant positive correlation between serum levels of ECP and results of CARS (r=0.98, P < 0.001). Autistic children had significantly higher percent positivity of serum anti-ganglioside M1 auto-antibodies (62.2%) than healthy controls (4.4%), P < 0.001. Autistic patients with positive serum antiganglioside M1 auto-antibodies had significantly higher serum levels of ECP [median (IQR) = 33.8 (25) ug/L] than children with negative serum anti-ganglioside M1 auto-antibodies [median (IQR) = 21.8 (5.5) ug/L], P < 0.001. Conclusions: Serum ECP levels were elevated in some autistic children and they were significantly associated with the increased levels of serum anti-ganglioside M1 auto-antibodies. Further research is recommend to determine the pathogenic role of ECP in autism and its relation to brain specific auto-antibodies that have been found in some autistic children.