With respects to serotonin or 5-hydroxytriptamine (5-HT), it displays immunomodulatory properties, interfering with T-cell activation, cytokine release from monocytes, and natural killer (NK) cell stimulation (21–25).Multiple pre-clinical studies have unanimously suggested that selective serotonin reuptake inhibitors (SSRIs) promote remission of the clinical signs of experimental autoimmune encephalomyelitis (EAE), the most prevalent animal model of MS, by curbing pro-inflammatory cytokine release (IFN-γ, TNF-a, IL-6, IL-7) and reducing T-cell proliferation (26–29). This evidence concerns the gene TNF and myeloid sarcoma.