ISG15 and viral infectious disease: The highest ratio in this set was two-fold and out of the top 10 specificities, 7 were in the Type I interferon signature (IFITM3, MX1, IFI6, IFI44L, ISG15, OAS1, IFIT3) and one encodes a protein that is activated by dsRNA as might be present in a viral infection (EIF2AK2).