A novel concept of immunological and allergy interactions in autism spectrum disorders: Molecular, anti-inflammatory effect of osthole.

Background: Autism spectrum disorder (ASD) is a neurodevelopmental disorder defined by Diagnosis and Statistic Manual 5 (DSM-5) as persistent social interaction and communication deficient across multiple contexts. Various immunological findings have been reported in children with ASD, and co-existing allergic problems have been recorded in children diagnosed with ASD. Osthole, the effective component of Chinese traditional medicine, is reported to have anti-inflammatory effects. This study assessed the anti-inflammatory effect of osthole on the histamine-induced inflammatory responses in PBMC cells.

Methods: Peripheral blood mononuclear cells (PBMC's) from children with: (1) ASD group with co-existing allergies/asthma (n = 29); (2) ASD group without allergy/asthma (n = 29); (3) Allergy group (n = 30) and from typically developing age-matched control subjects (n = 28) were stimulated with either histamine, FXF, osthole or mixture of this substances. mRNA COX-2 gene expression, COX-2 production and inhibitory effect of tested substances on COX-2 were assessed after stimulation.

Results: Children with ASD may show either an innate proinflammatory response or increased activity of COX-2 which could display more impaired behavioral profile than children with non-inflamed. This study indicated that COX-2 may be involved in pathogenesis of ASD and/or allergy, and osthole could be used to decrease the effects of COX-2 in inflammation and ASD development. High incidence of allergy in ASD patients may indicate immune dysregulation that could be of relevance to the pathophysiology, symptomatology or neuroimmunology of ASD.

Conclusions: This study shows that fexofenadine (FXF - antihistamine drug) and osthole exhibit selective COX-2 enzyme inhibitory activity. The selective COX-2 activity of osthole may explain further the anti-inflammatory properties of osthole in relieving congestion in allergic rhinitis, and as distinctive effects between FXF and osthole were observed, individual antihistamines may have different modes of action via the COX enzyme system.