Low serum myeloperoxidase in autistic children with gastrointestinal disease

AIM: To assess serum myeloperoxidase (MPO) levels in autistic children with severe gastrointestinal (GI) disease and to test the hypothesis that there is an association between serum MPO concentration and inflammatory GI disease, including antineutrophil cytoplasmic antibodies (ANCA), previously seen in a subgroup of autistic children. SUBJECTS AND METHODS: Serum from 40 autistic children with chronic digestive disease (most with ileo-colonic lymphoid nodular hyperplasia (LNH) and inflammation of the colorectum, small bowel and/or stomach), and 48 controls (12 age-matched autistic children with no GI disease, 20 age-matched children without autism or GI disease, and 16 nonautistic individuals with no family history of autism) were tested using enzyme-linked immunosorbent assays designed to quantitate serum MPO levels. MPO serum concentration of autistic children with GI disease was compared to GI disease severity (including LNH and erythema) and presence of ANCA. RESULTS: We found that a significant number of autistic children with chronic digestive disease had low serum levels of MPO. However, there was no significant relationship between these levels and severity of GI disease, including the presence of ANCA. DISCUSSION: These results suggest a relationship between low MPO levels and GI disease seen in a subpopulation of autism spectrum disorders individuals. MPO concentration may therefore be a useful biomarker for GI disease in this group of autistic children.