Furthermore, plasma levels of IL-1β, IL-6, MIP-2, and MIP-1α were obviously down-regulated in C5aR knockout mice when compared with wild type littermates (Rittirsch et al., 2008), suggesting that the harmful effects of C5aR during sepsis might result from C5a-mediated cytokine storm. The gene discussed is C5AR1; the disease is Sepsis.