On the other hand, fatal outcomes in SARS-CoV infection correlated with a cytokine storm involving elevated Th2 serum cytokines (including IL-4, IL-5 and IL-10), suggesting that an increase of Th2 cytokines possibly mediated by virus-specific CD4 T cells might be crucial in the severe forms of infection [110]. This evidence concerns the gene IL10 and severe acute respiratory syndrome.