A Preliminary Study of Cytokines in Suicidal and Nonsuicidal Adolescents with Major Depression

Abstract Background: Increased systemic cytokine levels, modulators of the immune system, have been repeatedly documented in adult and adolescent major depressive disorder (MDD). This preliminary study extends this work to test the role of cytokines in suicidal symptomatology in adolescent MDD. Hypotheses were that acutely suicidal depressed adolescents would have: (1) increased plasma levels of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1β, and (2) a proinflammatory/antiinflammatory cytokine imbalance (indexed by plasma IFN-γ/IL-4), compared to nonsuicidal depressed adolescents and healthy controls. Methods: Twelve suicidal adolescents with MDD (7 females [58%]; 5 medication-free/naive), 18 nonsuicidal adolescents with MDD (12 females [67%]; 8 medication-free/naive), and 15 controls (8 females [53%]) were enrolled. MDD had to be of at least 6 weeks duration, with a minimum severity score of 40 on the Children's Depression Rating Scale–Revised. Plasma cytokines wer...