While the early immune mediators mainly activate innate immune cells, promote IFN-γ production and induce Th1 type responses [59,60], the “second wave” cytokines consisted of IL-8, MIP-1α, MIP-1β, G-CSF, GM-CSF, IL-13, IL-15 and IL-4, TNF and VEGF, all of which peaked after clearance of bacteremia (around 18 dpi). This evidence concerns the gene IL15 and bacterial infectious disease with sepsis.