Interleukin-7 (IL-7) is a pleiotropic cytokine with a variety of activities. IL-7 supports differentiation of cytotoxic T-lymphocytes and promotes the generation of lymphokine-activated killer-cells. IL-7 is further responsible for the upregulation of the production of pro-inflammatory cytokines and the stimulation of the tumoricidal activity of monocytes/macrophages.