Decreased serum levels of platelet-endothelial adhesion molecule (PECAM-1) in subjects with high-functioning autism: A negative correlation with head circumference at birth

Background: Accumulating evidence suggests that the immune system plays a role in the pathophysiology of autism, and that the adhesion molecules play an important role in the process of inflammation. This study was undertaken to determine whether serum levels of the adhesion molecules in subjects with high-functioning autism are altered as compared with those of normal controls. Methods: Seventeen male subjects with high-functioning autism and 22 male age-matched unrelated healthy control subjects were enrolled. Serum levels of the soluble forms of platelet-endothelial adhesion molecule (PECAM-1), intracellular adhesion molecule (ICAM-1), and vascular cell adhesion molecule (VCAM-1) were measured. Results: Levels of PECAM-1, but not ICAM-1, in the subjects with autism were significantly lower than those of control subjects. VCAM-I showed a weak trend for a lowered level. There was a negative correlation between serum levels of PECAM-1 and head circumference at birth in the autistic subjects. Conclusions: These results suggest that PECAM-1 plays a role in the pathophysiology of high-functioning autism.