In this work, we present the proinflammatory (IL-2, IFN-γ, IL-1β, TNF-α, IL-6, and IL-12) and the anti-inflammatory (IL-15, IL-4, IL-5, IL-13, IL-1Ra, and IL-10) serum cytokine profiles of MDD adolescents. Here, IL15 is linked to major depressive disorder.