title: Cytokine aberrations in autism spectrum disorder: a systematic review and meta-analysis.
abstract: The role of non-diagnostic features in the pathophysiology of autism spectrum disorders (ASDs) is unclear. Increasing evidence suggests immune system alterations in ASD may be implicated in the severity of behavioral impairment and other developmental outcomes. The primary objective of this meta-analysis was to investigate if there is a characteristic abnormal cytokine profile in ASD compared with healthy controls (HCs). We identified relevant studies following a search of MEDLINE, EMBASE, PsycINFO, Web of Knowledge and Scopus. A meta-analysis was performed on studies comparing plasma and serum concentrations of cytokines in unmedicated participants with ASD and HCs. Results were reported according to PRISMA statement. Seventeen studies with a total sample size of 743 participants with ASD and 592 HC were included in the analysis. Nineteen cytokines were assessed. Concentrations of interleukin (IL)-1beta (P<0.001), IL-6 (P=0.03), IL-8 (P=0.04), interferon-gamma (P=0.02), eotaxin (P=0.01) and monocyte chemotactic protein-1 (P<0.05) were significantly higher in the participants with ASD compared with the HC group, while concentrations of transforming growth factor-β1 were significantly lower (P<0.001). There were no significant differences between ASD participants and controls for the other 12 cytokines analyzed. The findings of our meta-analysis identified significantly altered concentrations of cytokines in ASD compared to HCs, strengthening evidence of an abnormal cytokine profile in ASD where inflammatory signals dominate.
authors.affiliation: Autism Clinic for Translational Research, Brain and Mind Research Institute, University of Sydney, Camperdown, NSW, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Masi
authors.affiliation: Autism Clinic for Translational Research, Brain and Mind Research Institute, University of Sydney, Camperdown, NSW, Australia.
authors.forename: D S
authors.identifier: 0000000328760004
authors.initials: DS
authors.lastname: Quintana
authors.affiliation: Autism Clinic for Translational Research, Brain and Mind Research Institute, University of Sydney, Camperdown, NSW, Australia.
authors.forename: N
authors.initials: N
authors.lastname: Glozier
authors.affiliation: Inflammation and Infection Research Centre, School of Medical Sciences, University of New South Wales, Kensington, NSW, Australia.
authors.forename: A R
authors.identifier: 0000000162778887
authors.initials: AR
authors.lastname: Lloyd
authors.affiliation: Autism Clinic for Translational Research, Brain and Mind Research Institute, University of Sydney, Camperdown, NSW, Australia.
authors.forename: I B
authors.initials: IB
authors.lastname: Hickie
authors.affiliation: Autism Clinic for Translational Research, Brain and Mind Research Institute, University of Sydney, Camperdown, NSW, Australia.
authors.forename: A J
authors.initials: AJ
authors.lastname: Guastella
mesh_terms: D000067877:Autism Spectrum Disorder / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism*; D016206:Databases, Bibliographic / Q000706:statistics & numerical data; D006801:Humans
chemical_list: D016207:Cytokines