Serum and salivary immunoglobulin G4 levels in children with autism spectrum disorder from south India: a case-control study.

Background: Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with wide spectrum of symptoms and few effective therapies. Evidence is suggestive of an association between immune system dysfunction and autism spectrum disorders (ASD) among children with ASD. Immunoglobulins (Ig) are found to be increased in the circulation of individuals with autism.