Regression models including IL-12p40, IFN-γ, IL-10 or IL-10/TNF-α ratio and sTNFRII as independent variables, in addition to age, gender, length of exposure to malaria and parasitemia, revealed that parasitemia (β = −0.332, P = 0.005) and age (β = −0.419, P<0.001), but none of the other variables, were independent predictors of platelet counts in vivax malaria. This evidence concerns the gene IFNG and Plasmodium vivax malaria.