IFNG and dengue disease: The serum level of IFN-γ was gradually decreased in 3–5 days, 6-7 days, 8–10 days, and 14–17 days since illness onset in both mild and severe dengue patients [24], and it was higher in severe dengue patients in 8–10 days after illness onset compared with the mild dengue patients, but no difference was found in the other times between these two groups [24].