Immune changes and predictors of response in patients with depression

Abstract

Worldwide major depression is one of the most important reasons for years of life lost and years lived with disability. In Germany, more than 5 Million people suffer from unipolar or bipolar depression. Nevertheless, the knowledge on the pathophysiology of depression is still limited. In recent years, there is a growing evidence for the involvement of the immune system in the pathophysiology of depressive mood changes. Immune alterations, in the form of both activated inflammatory processes and reduced immunocompetence, have been reported in unipolar depression and bipolar disorder. Despite this data, only little information exists regarding the relevance of immunoregulatory mechanisms for antidepressant responsiveness.In a prospective clinical trial, we included patients with a diagnosis of unipolar (or bipolar) depression. Patients with axis I disorder other than unipolar or bipolar affective disorder according to Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria were excluded, as well as patients with current treatment with cytokines or any immune therapy, chronic infection, autoimmune or severe somatic comorbidity.Following baseline evaluation, patients received antidepressant treatment with citalopram or venlafaxine as clinically needed and/or psychotherapy. Assessments for mood changes were repeated at 2 weeks intervals during the first 8 weeks of treatment. Mood changes were characterized by validated clinical depression (e.g. Montgomery and Asberg Depression Rating Scale [MADRS]). Patients were characterized regarding responders and non-responders as well as early responders (after 2 weeks). Blood samples were taken for the measurement of inflammatory markers (pro- and anti-inflammatory cytokines, hsCRP).The specific aims of this study were to assess the relationship of inflammatory markers with depression severity and response to antidepressant treatment. Especially early immune changes and associations with early response or none response were investigated. Clinical results combined with immune measurements will be presented.