Beta-2-Microglobulin in Autism Spectrum Disorders

Autism spectrum disorders (ASD) are heterogeneous neurodevelopmental diseases of unknown etiology. There are no biological markers for ASD and current diagnosis is based on behavioral criteria. Recent data has shown that MHC I, a compound involved in adaptive immune function, is also involved in neurodevelopment, synaptic plasticity and behavior. It has been suggested that altered MHC I expression could play a part in neurodevelopmental diseases like ASD. To address this possibility, we measured plasma levels of beta-2-microglobulin (β2m), a molecule that associates with MHC I and is indicative of MHC I expression, in 36 children with autism, 28 typically developing controls and subjects with developmental disabilities (n=16) but not autism. The age range of our study population was 17-120 months. We found no statistically significant differences in plasma β2m levels between groups. Therefore, plasma levels of β2m measured in early childhood in autism may not reflect changes in MHC class I in autism.