Can Neuroinflammation Influence the Development of Autism Spectrum Disorders?

Abstract

Autism is a complex neurodevelopmental disorder of early onset that is highly variable in its clinical presentation. Although the causes of autism in most patients remain unknown, several lines of research support the view that both polygenic and environmental factors influence the development of abnormal cortical circuitry that underlies autistic cognitive processes and behaviors. The role of the immune system in the development of autism is controversial, but it is clear now that immune factors are involved in the modeling of the central nervous system (CNS) during prenatal and postnatal stages, during which neuroimmune responses may disrupt normal neurodevelopment and lead to the neuropathological abnormalities characteristic of autism. Several studies showing peripheral immune abnormalities support immune hypotheses; however, until recently there has been no demonstration of immune abnormalities within the CNS. Recently, our laboratory demonstrated the presence of neuroglial and innate neuroimmune system activation in brain tissue and cerebrospinal fluid of patients with autism, findings that support the view that neuroimmune abnormalities occur in the brain of patients with autism and may contribute to the diversity of the autistic phenotypes. The role of neuroglial activation and neuroinflammation is still uncertain but could be critical in maintaining, if not also initiating, some of the CNS abnormalities present in autism. A better understanding of the role of neuroinflammation in the pathogenesis of autism may have important clinical and therapeutic implications. Future studies should focus on the actions of neuroimmune factors during brain development as important components involved in the pathogenesis of autism.