IL6 and hemophagocytic syndrome: In this study, we found that patients with VL associated HLH exhibited excessive immune responses characterized by the much higher serological levels of immunoglobulin G and Th1 cytokines (TNF-α, IFN-γ, IL-1beta, IL-6, IL-8, IL-12p70), Th2 cytokines (IL-4) and Th17 cytokine (IL-17, IL-23) compared to VL without HLH (Fig 2).