title: A meta-analysis of chemokines in major depression.
abstract: Chemokines are increasingly recognised as playing a role in depression. Here we meta-analyse the data on concentrations of all chemokines in patients diagnosed with a major depression versus healthy controls. We included studies which utilised Diagnostic and Statistical Manual (DSM)-IV diagnostic criteria for major depression, participants free from major medical conditions, studies with healthy controls, and unstimulated measurements of chemokines. We only included chemokines which had ≥3 studies performed. Two chemokines and 15 studies in total met criteria for this meta-analysis; 8 for Monocyte Chemotactic Protein (MCP)-1/CCL2 (n=747), and 7 for Interleukin (IL)-8/CXCL8 (n=560). There were significantly higher concentrations of CCL2/MCP-1 in depressed subjects compared with control subjects - overall mean difference of 36.43pg/mL (95% CI: 2.43 to 70.42). There was significant heterogeneity across these studies (I2=98.5%). The estimates of mean difference between the control and depression groups did not remain significant when the trim-and-fill procedure was used to correct for publication bias. There was no significant difference in concentrations of IL-8/CXCL8 in depressed subjects compared with control subjects. Significant heterogeneity was found across these studies (I2=96.7%). The estimates of mean difference between the control and depression groups remained non-significant when the trim-and-fill procedure was used to correct for publication bias. This meta-analysis reports significantly heterogeneity in this field among studies. There are higher concentrations of the chemokine MCP-1/CCL2 in depressed subjects compared with control subjects, and no differences for IL-8/CXCL8. More high quality research and consistent methodologies are needed in this important area of enquiry.
authors.affiliation: Discipline of Psychiatry, School of Medicine, University of Adelaide, Adelaide, Australia; Semel Institute for Neuroscience and Human Behavior, UCLA, Los Angeles, CA, USA; School of Medicine and Dentistry, James Cook University, Townsville, Australia.
authors.forename: Harris A
authors.initials: HA
authors.lastname: Eyre
authors.affiliation: Discipline of Psychiatry, School of Medicine, University of Adelaide, Adelaide, Australia.
authors.forename: Tracy
authors.initials: T
authors.lastname: Air
authors.affiliation: Discipline of Psychiatry, School of Medicine, University of Adelaide, Adelaide, Australia.
authors.forename: Alyssa
authors.initials: A
authors.lastname: Pradhan
authors.affiliation: Discipline of Psychiatry, School of Medicine, University of Adelaide, Adelaide, Australia.
authors.forename: James
authors.initials: J
authors.lastname: Johnston
authors.affiliation: Semel Institute for Neuroscience and Human Behavior, UCLA, Los Angeles, CA, USA.
authors.forename: Helen
authors.initials: H
authors.lastname: Lavretsky
authors.affiliation: Discipline of Psychiatry, School of Medicine, University of Adelaide, Adelaide, Australia; School of Medicine, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Stuart
authors.affiliation: Discipline of Psychiatry, School of Medicine, University of Adelaide, Adelaide, Australia. Electronic address: Bernhard.Baune@Adelaide.edu.au.
authors.forename: Bernhard T
authors.initials: BT
authors.lastname: Baune
mesh_terms: D018925:Chemokines / Q000378:metabolism*; D003865:Major Depressive Disorder / Q000378:metabolism*; D006801:Humans
chemical_list: D018925:Chemokines
keywords: Chemokine; Cytokine; Depression; Diagnosis; Inflammation; Meta-analysis; Mood disorder