Dysfunctional regulation of the levels of the cytokines/chemokines IL-6, IL-8, IL-10, IFN-ɣ, KC/GRO, MCP-1, MIP-1a, MIP-2 and TNF-α, after infection of C3H/HeJ mice with virulent Leptospira, were correlated to the severity of leptospirosis observed in this animal model [70–72]. The gene discussed is CCL2; the disease is leptospirosis.