Immunological Abnormalities in Autism Spectrum Disorders

Abstract

Secondary to clinical features indicating chronic inflammation and immune dysregulation, the immune system has long been suspected to have a role in autism spectrum disorders (ASD). Studies of postmortem autistic brains indicate the presence of immune mediated chronic inflammation in some but not all autistic brains. However, studies of immune abnormalities in ASD children yielded no conclusive results. Instead, immune abnormalities reported appear to affect almost all aspects of the immune system and are often contradictory. This may be associated with the marked heterogeneity of ASD subjects, since ASD is a behaviorally defined syndrome. In addition, variable co-morbid conditions could affect the immune-parameters, making such analysis very difficult. Alternatively, various immune abnormalities reported may be associated with the fact that ASD is a polygenic condition affected by multiple genetic and environmental factors, resulting in similar behavioral symptoms. At present, it is unknown how the immune system contributes to the onset and progress of ASD. Nevertheless, the results of previous studies indicate the presence of chronic inflammation, in at least a portion of ASD children. This review summarizes previous immunological findings and the problems associated with these studies. The direction that future research needs to take will also be discussed.