In animal models of leptospirosis, the triggering of inflammatory response, particularly through the excessive production of pro-inflammatory cytokines including interleukins (IL)-1β, IL-6, IL-12 and tumor necrosis factors (TNFs) could lead to activating immunomodulatory cytokines such as IL-4, IL-10, IL-13 and TGF-β, which result in a sepsis-like syndrome associated with organ failures [31]. The gene discussed is TNF; the disease is leptospirosis.