IL18 and infection: In this study, expression levels of IL-4, IL-10, IL-13 and TNF-α were significantly up-regulated while the expression levels of IL-1β,IL-18,IFN-γ, IL-2, IL-15, IL-17F, IFN-α, IFN-β, IL-3 and CSF-1 were markedly decreased in PBMCs at all stages of infection.