The immune system reactions to acute SCI are broadly cellular and molecular; and are intricately interwoven. In an injured cord, the cumulative effect of the immune cells (cellular), and regulatory proteins (molecular) is inflammation. Inflammation, a key event in the secondary injury cascade, occurs immediately and persists for several weeks or months following SCI (Fehlings and Nguyen 2010). The immune cells secrete proinflammatory cytokines, including interleukin (IL)-1β, interleukin-6, and tumor necrosis factor-α (TNF-α), all of which increase the extent of inflammation.