IMMUNOLOGICAL ASPECTS OF DEPRESSIVE DISORDER - THE REVIEW

Abstract

Depression represents a mood disorder and is consideredto be one of the most common mental disorders in general. World Health Organization estimates that depression will be the leading cause of disability-adjusted life years, until 2030. Depression is a complex heterogeneous disorder whereimmune system and its regulation play an important role. Innate and adaptive immunity mechanisms are included, along with processes of immune activation and suppression.The expression of humoral factors of innate immunity, especially pro-inflammatory cytokines, is increased, whereas the intensity of cellular immune mechanisms, primarily Tcells and NKcells, are impaired. The influence of proinflammatory cytokines on depression is reflected in their effect on certain enzymes and ensuing reduction of neurotransmitters serotonin and dopamine. They also affect the neuroendocrine function in central nervous system, resulting in increase of cortisol levels and inactivation of glucocorticoid receptors inthe periphery, which leads to neurodegeneration and decreasein neurotransmitter production. Certain cytokines affect neuroplasticity through the decreasing of concentration of neurotrophic brain factor and induction of brain cell apoptosis. Theresults are often contradictory talking about mechanisms of adaptive immunity. On one hand, an increasedactivity of Tlymphocytes is observed, while on the other, there are evidenceof spontaneous apoptosisandimpaired function ofthese cellsin depression. In addition, neuroprotective role of autoreactive and regulatory T cells in prevention of depression has also been demonstrated. The aim of this paper is to analyze the current knowledge on the role of immune mechanisms inthe pathogenesis of depression. © 2024 Sciendo. All rights reserved.