reported that the serum concentrations of TNF-α, IL-6, IFN-γ, IL-8, IP-10, and RANTES (but not IL-4) were much elevated in HFRS patients (29), compared with controls; and that the highest concentrations were usually found during the febrile, hypotensive, and oliguric phases, particularly in severe and critical-type HFRS cases. Here, IL4 is linked to hemorrhagic fever with renal syndrome.