Increased IL-8 concentrations in the cerebrospinal fluid of patients with unipolar depression

Introduction: Unipolar depression is a common and debilitating disorder. Immunological explanatory approaches have become increasingly important in recent years and can be studied particularly well in the cerebrospinal fluid (CSF). Previous studies discerned alterations in interleukin (IL)-6 and IL-8 levels; however, findings regarding IL-8 were partly contradictory. The aim of the present study was to investigate the concentrations of different cytokines and chemokines, focusing on IL-8, in the CSF of patients with unipolar depression. Materials and methods: Participants included 40 patients with unipolar depression and 39 mentally healthy controls with idiopathic intraaanial hypertension. CSF cytokine levels were measured using a magnetic bead multiplexing immunoassay. Results: IL-8 levels in the CSF of the patient group with depression were significantly higher than those in the control group (Mean +/- SD: 38.44 +/- 6.26 pg/ml versus 21.40 +/- 7.96 pg/ml; p < .001). Limitations: The significance of the results is limited by the retrospective design and methodological aspects. Discussion: The main findings of this study were significantly higher concentrations of IL-8 in the CSF of patients with unipolar depression than in the control group. The detection of high CSF IL-8 levels in this study supports the idea that inflammatory processes might play a role in the pathophysiology of a subgroup of patients with depression. (C) 2020 The Authors. Published by Elsevier Inc.