TNF and Lassa fever: Nevertheless, recent studies focusing on early stages of the LF in NHP [205] and immune responses [82] confirmed previous observations and reestablish markers of fatal LF: unchecked viremia, elevated liver enzymes, low or undetectable levels of proinflammatory cytokines (IL-1β, TNF-α, IL-8, and IP-10), and low and/or ineffective T cell activation.