The invention provides methods and compositions for administration of allogeneic lymphocytes as an exogenous source of CD4+ T cell help for endogenous, tumor-reactive CD8+ T cells. Depletion of CD8+ T cells from the donor lymphocyte infusion reduces the risk of sustained engraftment and graft-versus-host disease. Removal of regulatory T cells from the infused population may augment the ability of non-regulatory T cells to provide help for endogenous effectors of anti-tumor immunity. Allogeneic T cell therapy is typically given in the context of allogeneic stem cell transplantation, in which the patient receives highly immunosuppressive conditioning followed by an infusion of a stem cell graft containing unselected populations of mature T cells. In the treatment described here, the graft is engineered to minimize the possibility of sustained donor cell engraftment, and the anti-tumor effector T cells derive from the host.