Subjects and methods: Plasma from 49 autistic children (39 males; mean age 11.4 years) (17 with diagnosed gastrointestinal (GI) disease –
chronic diarrhea and/or constipation (10 of these GI patients were taking probiotics) and 26 receiving probiotic therapy) and 36 neurotypical controls
(29 males; mean age 10.2 years; controls were not assessed for GI disease) were tested for MPO plasma concentration using Enzyme Linked Immunosorbent
Assays (ELISAs). Plasma concentration of MPO in autistic individuals was compared to plasma concentration of copper and zinc