In order to clarify a potential role for macrophage-derived cytokines in the pathogenesis of New world arenavirus infections, we next examined the production of several key cytokines (IFN-α, IFN-β, TNFα, IL-6, IL-10 and IL-12) following infection of primary human monocyte and macrophage cultures with either TCRV or JUNV at an MOI of 0.1. This evidence concerns the gene IL10 and infection.