Neuroimmunological investigations of cerebrospinal fluid in patients with recent onset depression - a study protocol

BACKGROUND: A proinflammatory response has been suggested to be involved in the pathophysiology of depression in a subgroup of patients. However, comprehensive largescale studies on neuroimmunological investigations of the cerebrospinal fluid (CSF) are lacking and no largescale longitudinal CSF studies comparing patients with depression to healthy controls currently exist. METHODS: A longitudinal case-control study including at least 100 patients with first time depression (ICD-10: F32) within the past year with ongoing symptoms and at least 100 sex and age matched healthy controls with collection of CSF, blood, and fecal samples. All individuals will be evaluated by neurological examination including neurological soft signs, interviewed for psychopathology assessment and have symptomatology evaluated by relevant rating scales. Level of functioning and quality of life will be evaluated by a panel of interview questions and rating scales, and cognitive function assessed by a relevant test battery. In addition, a large number of potential confounders will be registered (BMI, smoking status, current medication etc.). Primary outcomes: CSF white cell count, CSF/serum albumin ratio, CSF total protein levels, IgG index, CSF levels of IL-6 and IL-8, and the prevalence of any CNS-reactive autoantibody in CSF and/or blood. Secondary outcomes: exploratory analyses of a wide range of neuroimmunological markers and specific autoantibodies. Power calculations are computed for all primary outcomes based on previous CSF studies including patients with depression and healthy controls. DISCUSSION: This study will represent the hitherto largest investigation of CSF in patients with recent onset depression compared to healthy controls. We expect to elucidate neuroimmunological alterations in individuals with depression and characterize an immunological profile paving the way for the development of effective treatments based on biomarkers. TRIAL REGISTRATION: The study is approved by The Regional Committee on Health Research Ethics (Capital Region, j.no: H-16030985) and The Danish Data Protection Agency (j.no: RHP-2016-020, I-Suite no.: 04945). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12888-021-03633-0

Immunological investigations of the cerebrospinal fluid in patients with recent onset psychotic disorders:A study protocol

BACKGROUND: Though many previous studies have indicated immunological alterations in psychotic disorders, the role and prevalence of neuroinflammation is still unknown. Studies previously investigating immune related biomarkers in the cerebrospinal fluid (CSF) of these patients are mainly small studies on few markers, and many have not compared patients to healthy controls. METHODS: We will conduct a large case-control study including at least 100 patients with recent onset psychotic disorders and 100 sex- and age matched healthy controls. The cases will include patients diagnosed with a psychotic disorder according to ICD-10 (F20/F22-29) within a year prior to inclusion. We will collect both CSF, blood and fecal samples, to gain insight into possible immunological alterations. The psychopathology of all participants will thoroughly be evaluated using the SCAN interview, and multiple rating scales covering different symptom groups. All participants will partake in a detailed neurological examination, including the Neurological Evaluation Scale assessing neurological soft signs. Additionally, we will assess cognitive functioning, evaluate quality of life and level of functioning, and collect data on a broad array of possible confounders. Our primary outcomes will include CSF leucocytes, CSF/serum albumin ratio, CSF total protein, IgG index, CSF levels of IL-6 and IL-8, and presence of antineuronal autoantibodies in CSF and blood. For our secondary outcomes, exploratory analyses will be performed on a broader panel of neuroimmunological markers. All participants will be invited for a follow-up visit to assess longitudinal changes. The current study is part of a larger CSF biobank build-up for severe mental disorders (PSYCH-FLAME). DISCUSSION: This study will represent the largest investigation of CSF in patients with psychotic disorders compared to healthy controls to date. We expect the study to contribute with new, important knowledge on pathophysiological mechanisms, and to help pave the way for future investigations of individualized treatment options. TRIAL REGISTRATION: The study is approved by The Regional Committee on Health Research Ethics (Capital Region, j.no: H-16030985) and The Danish Data Protection Agency (j.no: RHP-2016-020, I-Suite no.: 04945)

Comparisons of 25 cerebrospinal fluid cytokines in a case–control study of 106 patients with recent-onset depression and 106 individually matched healthy subjects

Abstract Background Neuroinflammation has been suggested as a contributor to the pathophysiology of depression; however, large case–control studies investigating cytokine levels in the cerebrospinal fluid (CSF) from patients with recent-onset depression by multiplex analyses are missing. Methods An individually matched (sex and age) prospective case–control study comparing patients with recent-onset depression to healthy controls. CSF was analyzed with the Mesoscale V-PLEX Neuroinflammation Panel 1. Outcomes: comparisons of analyte levels in the CSF between groups with interleukin (IL)-6 and IL-8 as primary outcomes and 23 other cytokines as secondary outcomes. Results We included 106 patients (84.0% outpatients) with recent-onset depression and 106 healthy controls. There were no significant differences in the primary outcomes IL-6 (relative mean difference (MD): 1.10; 95% confidence interval (CI) 0.93–1.30; p = 0.276) or IL-8 levels (MD: 1.05; 95% CI 0.96–1.16; p = 0.249) relative to healthy controls. IL-4 was 40% higher (MD: 1.40; 95% CI 1.14–1.72; p = 0.001), monocyte chemoattractant protein (MCP)-1 was 25% higher (MD: 1.25; 95% CI 1.06–1.47; p = 0.009) and macrophage inflammatory protein (MIP)-1β was 16% higher (MD: 1.16; 95% CI 1.02–1.33; p = 0.025) in patients with depression relative to healthy controls. However, only IL-4 was significantly elevated after correction for multiple testing of secondary outcomes (p = 0.025). Conclusion We found no significant differences in CSF levels of the co-primary outcomes IL-6 and IL-8, however, the higher CSF levels of IL-4, MCP-1 and MIP-1β among patients with recent-onset depression compared to healthy controls indicate a potential role of these cytokines in the neuroinflammatory response to depression