Description:  Levels of Macrophage Inhibitory Factor (MIF) a critical regulator of innate immunity, and chemical responsible for expression of toll like receptors was measured in children with autism and normal control children.  Concurrently, genetic analysis was undertaken to evaluate for known promoter polymorphisms known to increase levels of MIF.  Genetic mutations known to increase levels of MIF were found to be associated with a diagnosis of autism.  Likewise, circulating levels of MIF were found to be higher in children with autism than in normal controls, and the amount of MIF was found to correlate with autism severity when measured across several scales.