<qa>  What is the etiologies in most patients with autism?Current estimates indicate that 1 in 110 children are affected with autism. Despite this striking statistic, we remain unable to describe the pathophysiology for autism, and we do not have adequate treatments for autism. The etiologies in most patients with autism are unknown, but emerging evidence supports a causal role of immune activation in autism. Multiple studies provide clear evidence of immune activation in peripheral blood of patients with autism, as demonstrated by elevations in immune markers IFN-gamma, IL-1RA, IL-6, and TNF-alpha. Studies also demonstrate immune activation in cerebrospinal fluid CSF of patients with autism, as evidenced by significant elevations in cytokines and TNF-alpha. Finally, three postmortem brain studies report neuroimmune activation in patients with autism ages 4-45. Combined, these three postmortem studies show activation of microglia and astroglia through elevations in cytokines, histology and stereology. 