Before ruxolitinib treatment, an accurate TB history should be always taken, and the screening for latent TB must be considered if epidemiological risk factors are significant (history, endemic areas, trips in endemic areas) with Tuberculin Skin Test (TST) or (preferably) IFN-γ Release Assay, IGRA (i.e. QuantiFERON test) [204, 208]. Here, IFNG is linked to tuberculosis.