Some maternal IgG antibodies that cross the placenta to provide passive immunity to the fetus can also attack the fetal brain. It is proposed that inflammation within the brain promoted by inflammatory responses to harmful gut microbiome impacts brain development. Pro-inflammatory cytokines IFN-γ, IFN-α, TNF-α, IL-6 and IL-17 have been shown to promote autistic behaviors in animal models. Giving anti-IL-6 and anti-IL-17 along with IL-6 and IL-17, respectively, have been shown to negate this effect in the same animal models. Some gut proteins and microbial products can cross the blood–brain barrier and activate mast cells in the brain. Mast cells release pro-inflammatory factors and histamine which further increase blood–brain barrier permeability and help set up a cycle of chronic inflammation. Mirror neuron system
The mirror neuron system consists of a network of brain areas that have been associated with empathy processes in humans. In humans, the mirror neuron system has been identified in the inferior frontal gyrus and the inferior parietal lobule and is thought to be activated during imitation or observation of behaviors. The connection between mirror neuron dysfunction and autism is tentative, and it remains to be seen how mirror neurons may be related to many of the important characteristics of autism. Social brain interconnectivity
A number of discrete brain regions and networks among regions that are involved in dealing with other people have been discussed together under the rubric of the social brain.
Although ABA therapy has a strong evidence base, particularly in regard to early intensive home-based therapy, ABAs effectiveness may be limited by diagnostic severity and IQ of the person affected by ASD. The Journal of Clinical Child and Adolescent Psychology has deemed two early childhood interventions as "well-established": individual comprehensive ABA, and focused teacher-implemented ABA combined with DSP.Another evidence-based intervention that has demonstrated efficacy is a parent training model, which teaches parents how to implement various ABA and DSP techniques themselves. Various DSP programs have been developed to explicitly deliver intervention systems through at-home parent implementation. In October 2015, the American Academy of Pediatrics (AAP) proposed new evidence-based recommendations for early interventions in ASD for children under 3. These recommendations emphasize early involvement with both developmental and behavioral methods, support by and for parents and caregivers, and a focus on both the core and associated symptoms of ASD. However, a Cochrane review found no evidence that early intensive behavioral intervention (EIBI) is effective in reducing behavioral problems associated with autism in most autistic children but did help improve IQ and language skills. The Cochrane review did acknowledge that this may be due to the low quality of studies currently available on EIBI and therefore providers should recommend EIBI based on their clinical judgement and the familys preferences. No adverse effects of EIBI treatment were found. Studies on pet therapy have shown positive effects.Generally speaking, treatment of ASD focuses on behavioral and educational interventions to target its two core symptoms: social communication deficits and restricted, repetitive behaviors.