One can conjecture that systemic treatment with IL-7 may act in undesired places, as illustrated by the following: IL-7 worsens graft-versus-host-induced tissue inflammation [81]; favors inflammation in colitis [82], contributes to arthritis severity [83]; upregulates chemokines, IFNγ, macrophage recruitment, and lung inflammation [84]; and, finally, increases production of inflammatory cytokines by monocytes and T cells [85]. The gene discussed is IL7; the disease is colitis.