TNF and viral infectious disease: Moreover, NK cells also show efficacy against assaults like viral infections and tumor development.[15] It is important to include assays of NK cell markers, peripheral WBCs, TNF-α, IFN-γ, IL-1β, IL-2, IL-6, IL-12 as immunological biomarkers, as well as IgG1, IgG2, and IgM as allergic biomarkers.