The immune system and autism spectrum disorder: Association and therapeutic challenges

Abstract

Autism spectrum disorder (ASD) is a neurodevelopmental disorder, affecting communication and behavior. Historically, ASD had been described as a purely psychiatric disorder with genetic factors playing the most critical role. Recently, a growing body of literature has been emphasizing the importance of environmental and immunological factors in its pathogenesis, with the autoimmune process attracting the most attention. This study provides a review of the autoimmune involvement in the pathogenesis of ASD. The microbiome, the representative of the innate immune system in the central nervous system (CNS), plays a critical role in triggering inflammation. Besides, a bidirectional communicational pathway between the CNS and the intestine called the gut-brain-axis is linked to the development of ASD. Moreover, the higher plasma level of pro-inflammatory cytokines in ASD patients and the higher prevalence of autoimmune disorders in the first-degree family members of affected persons are other clues of the immune system involvement in the pathogenesis of ASD. Furthermore, some anti-inflammatory drugs, including resveratrol and palmitoylethanolamide have shown promising effects by relieving the manifestations of ASD. Although considerable advances have been made in elucidating the role of autoimmunity in the ASD pathogenesis, further studies with stronger methodologies are needed to apply the knowledge to the definitive treatment of ASD.