Elevated levels of serum IL-5 are associated with an increased likelihood of major depressive disorder

• Main Authors: Elomaa Antti-Pekka, Niskanen Leo, Herzig Karl-Heinz, Viinamäki Heimo, Hintikka Jukka, Koivumaa-Honkanen Heli, Honkalampi Kirsi, Valkonen-Korhonen Minna, Harvima Ilkka T, Lehto Soili M
• Format: Article
• Language: English
• Published: BMC 2012-01-01
• Series: BMC Psychiatry
• Online Access: http://www.biomedcentral.com/1471-244X/12/2

<p>Abstract</p> <p>Background</p> <p>Inflammatory mediators in both the peripheral circulation and central nervous system (CNS) are dysregulated in major depressive disorder (MDD). Nevertheless, relatively little is known about the role of the T-helper (Th)-2 effector cytokines interleukin (IL)-5 and IL-13 in MDD.</p> <p>Methods</p> <p>We examined the serum levels of these cytokines and a Th-1 comparison cytokine, interferon (IFN)-γ, in 116 individuals (MDD, n = 58; controls, n = 58).</p> <p>Results</p> <p>In our basic multivariate model controlling for the effects of potential confounders on the associations between MDD and the examined cytokines, each 1-unit increase in the serum IL-5 level increased the likelihood of belonging to the MDD group by 76% (OR 1.76, 95% CI 1.03-2.99, p = 0.04; model covariates: age, gender, marital status, daily smoking and alcohol use). The likelihood further increased in models additionally controlling for the effects of the use of antidepressants and NSAIDS, and a diagnosis of asthma. No such associations were detected with regard to IL-13 (OR 1.08, 95% CI 0.96-1.22, p = 0.22) or IFN-γ (OR 1.02, 95% CI 0.99-1.05, p = 0.23).</p> <p>Conclusions</p> <p>Elevated levels of IL-5, which uses the neural plasticity-related RAS GTPase-extracellular signal-regulated kinase (Ras-ERK) pathway to mediate its actions in the central nervous system (CNS), could be one of the factors underlying the depression-related changes in CNS plasticity.</p>