First, no genes encoding for any known type I IFNs were observed to be up-regulated in association with the "anti-viral state" or the down-stream activation of ISGs; although type one IFN expression is not an absolute requirement for ISG activation during cytomegalovirus infection [36], this IFN-independent activation of ISGs remains to be demonstrated in other viral models in which IFN production at mRNA and protein levels are believed to be crucial [30,37]. The gene discussed is IFNA1; the disease is cytomegalovirus infection.