Ruxolitinib, a selective (JAK1 and JAK2) inhibitor, reduces GVHD by inhibiting the production of proinflammatory cytokines, including IL-1, IL-6, IL-12, IL-17, TNF-α, and IFN-γ, reducing T-cell proliferation and preserving the beneficial graft-versus-leukaemia effect [9–12]. The gene discussed is TNF; the disease is graft versus host disease.