CD258, also known as LIGHT, belongs to the tumor necrosis factor (TNF) superfamily. CD258 is a homotrimer composed of type II single-pass chains. The cleavage of this molecule from the cell surface results in a soluble form of LIGHT. CD258 stimulates T cell proliferation, CTL activity, Th1 cytokine production and induces apoptosis in some tumor lines. CD258 is expressed by T cells, NK cells, macrophages and platelets. The receptors of LIGHT are HVEM, LTbetaR and DCR3. CD258 has an important role in the cell-mediated immune response and in graft versus host disease.