In the ferret model with 27% mortality based on the .20% weight loss following infection with A/California/07/2009 pandemic influenza virus [22] , sequential lung sampling documented decreased gene expression of CCL2, CXCL10, TNFA and IL1B on day 7 when animals show highest weight loss. Comparison of the human data presented in our study (Table S1) shows that in the lungs of the critically ill patients all these and several other chemokines/inflammatory cytokines are overexpressed. Thus, the gene expression profiles at the time of overwhelming symptoms in the lungs of the infected ferrets (decreased expression) do not match the data on severe human cases from the present series (elevated expressions).