ISG15 and infection: Eleven of the core set of 15 proteins that had consistently elevated levels in serum, and days 3 and 7 after infection in vitro, also had elevated levels in at least one human organ in vivo: NAMPT, ISG15, MX1, STAT1, TYMP, LAP3, ISG20, UBE2L6, the proteasomal proteins PSMB8 and PSMB10, and LGALS3BP.