Autism spectrum disorder (ASD) involves a complex interplay of both genetic and environmental risk factors, with immune alterations and synaptic connection deficiency in early life. In the past decade, studies of ASD have substantially increased, in both humans and animal models. Immunological imbalance (including autoimmunity) has been proposed as a major etiological component in ASD, taking into account increased levels of proinflammatory cytokines observed in postmortem brain from patients, as well as autoantibody production. Also, epidemiological studies have established a correlation of ASD with family history of autoimmune diseases; associations with major histocompatibility complex haplotypes and abnormal levels of immunological markers in the blood. Moreover, the use of animal models to study ASD is providing increasing information on the relationship between the immune system and the pathophysiology of ASD. Herein, we will discuss the accumulating literature for ASD, giving special attention to the relevant aspects of factors that may be related to the neuroimmune interface in the development of ASD, including changes in neuroplasticity.

Autism spectrum disorder (ASD) is a highly prevalent developmental disorder characterized by deficits in communication and social interaction and in stereotyped or repetitive behaviors. Besides the classical behavioral dyad, several comorbidities are frequently present in patients with ASD, such as anxiety, epilepsy, sleep disturbances, and gastrointestinal tract dysfunction. Although the etiology of ASD remains unclear, there is supporting evidence for the involvement of both genetic and environmental factors. Valproic acid (VPA) is an anticonvulsant and mood stabilizer that, when used during the gestational period, increases the risk of ASD in the offspring. The animal model of autism induced by prenatal exposure to VPA demonstrates important structural and behavioral features that can be observed in individuals with autism; it is thus an excellent tool for testing new drug targets and developing novel behavioral and drug therapies. In addition, immunological alterations during pregnancy could affect the developing embryo because immune molecules can pass through the placental barrier. In fact, exposure to pathogens during the pregnancy is a known risk factor for ASD, and maternal immune activation can lead to autistic-like features in animals. Interestingly, neuroimmune alterations are common in both autistic individuals and in animal models of ASD. We summarize here the important alterations in inflammatory markers, such as cytokines and chemokines, in patients with ASD and in the VPA animal model.