Abstract
There are often sex differences in susceptibility to infectious diseases and in level of mortality after infection. These differences probably stem from sex-related abilities to mount proper or unwanted immune responses against an infectious agent. We report that hantavirus-infected female patients show significantly higher plasma levels of interleukin-9 (IL-9), fibroblast growth factor 2, and granulocyte-macrophage colony-stimulating factor and lower levels of IL-8 and gamma interferon-induced protein 10 than male patients. The results demonstrate that a virus infection can induce sex-dependent differences in acute immune responses in humans. This finding may, at least partly, explain the observed sex differences in susceptibility to infectious diseases and in mortality following infection.