Clinical data showed that cytokines such as interferon-gamma (IFNγ), interleukin-18 (IL-18), transforming growth factor β (TGF-β), interleukin-6 (IL-6) were highly elevated in the acute phase sera of severe acute respiratory syndrome (SARS) patients and their expression levels are related to the mortality (12). Here, IL6 is linked to severe acute respiratory syndrome.