ISG15 and immune system disorder: Meanwhile, for the Reactome pathways analysis, the five enriched pathways are regulation of complement cascade (count = 8, p = 9.55 × 10−12), ISG15 antiviral mechanism (count = 5, p = 9.44 × 10−6), diseases of the immune system (count = 3, p = 1.15 × 10−4), SARS-CoV infections (count = 4, p = 2.78 × 10−3) and potential therapeutics for SARS (count = 3, p = 4.14 × 10−3).