Although the pathogenesis of depression has not yet been fully clarified, many studies conducted in recent years have shown immunological changes taking place in this disease [11], and many meta-analyses have shown elevated concentrations of cytokines IL-6, IL-1β, and TNF-α in the blood of patients suffering from depression in comparison to healthy controls [12,13,14,15,16]. This evidence concerns the gene IL6 and major depressive disorder.