It is widely understood that those on the Autism spectrum exhibit immune system abnormalities. There are immune nodules in the distal ileum (the area of the small intestine that intersects with the large intestine) that produce inflammatory cytokines. According to a recent Harvard study, these cytokines travel to, and inflame, the white matter of the brain. This swelling of the brain is an immune system issue. Mesenchymal stem cells effectively treat inflammation and immune system irregularities.