TNF and infection: When plasma levels of cytokines from individuals from the Amazon region of Brazil with either a Plasmodium infection or an intestinal parasite (G. intestinalis, A. duodenale and S. stercoralis) infection or concurrent Plasmodium-helminth (G. intestinalis, A. duodenale and S. stercoralis) co-infection were compared to uninfected individuals, the levels of TNF-α, IL-2, IL-10, IL-6 in the Plasmodium and Plasmodium-helminth co-infected group were similar, and both significantly higher than the uninfected group.