MMR vaccine may induce autoantibody formation against the gut (secretin or its receptor) and/or the brain, contributing to the pathogenesis of autism-spectrum disorder. - GreenMedInfo Summary

In a subgroup of children with autism-spectrum like conditions symptoms seem to appear as a 'regression' (in normal development). It has been postulated that the onset of such autistic symptoms may involve an autoimmune response against the central nervous system and that the antigenic determinant could possibly be gastrointestinal in origin. It has been suggested that the presence of the measles virus and 'autistic enterocolitis' demonstrates the possibility that the MMR triple vaccine may be mediating the inflammation with possible production of antibodies against the virus containing vaccine. Such an antibody may share antigenic determinant to molecules found in the gut. We propose that this may be secretin or its receptor, found in the gut as well as in the central nervous system. The antibody response to the gut may also conceivably occur in the brain at a critical time in development. The modulation of development by secretin may be a static event possibly occurring at a specific time in early childhood development and if it involves an autoimmune response then a disruption in development may result. These hypothesized events can only occur if the MMR vaccine shares antigenic determinants that resemble secretin or any of its receptor types and remains to be studied.