In order to demonstrate the role of cytokines in the modulation of HAT progression, we assayed six cytokines (IFN-γ, IL1-β, TNF-α, IL-6, TGF-β and IL-10) in plasma of both cases (N = 49, after excluding 6 malaria co-infected patients) and controls (N = 41). This evidence concerns the gene IL6 and malaria.