IL15 and Sepsis: For the proinflammatory cytokines, the levels of IL-1β, IL-2, IL-6, and TNF-α were elevated in the early sepsis phase (2 h), but most other proinflammatory cytokines, including IL-12, IL-15, IL-17, and IFN-γ, showed significant elevation in the late sepsis phase (24–48 h) (Figure 2A).