Markedly elevated levels of interferon (IFN)-gamma, IFN-alpha, interleukin (IL)-2, IL-10, and tumor necrosis factor-alpha associated with fatal Ebola virus infection.

The role of immune mechanisms in the pathogenesis of Ebola hemorrhagic fever (EHF) remains to be elucidated. In this report, the serum cytokine levels of patients who died of EHF were compared with those of patients who recovered and those of control patients. A marked elevation of interferon (IFN)-gamma levels (>100 pg/mL) was observed in sequential serum samples from all fatal EHF cases compared with patients who recovered or controls. Markedly elevated serum levels of interleukin (IL)-2, IL-10, tumor necrosis factor (TNF)-alpha, and IFN-alpha were also noted in fatal EHF cases; however, they had a greater degree of variability. No differences were noted in serum levels of IL-4 and IL-6. mRNA quantitation from blood clots of the same patients showed relatively elevated levels of TNF-alpha and IFN-alpha in samples from EHF patients. Taken together, these results suggest that a high degree of immune activation accompanies and potentially contributes to a fatal outcome in EHF patients.